# Technical: Why should I unplug the o2 sensor?



## Jefnes3 (Aug 17, 2001)

x


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## [email protected] (Dec 23, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

http://****************.com/smile/emthup.gif


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## TAIVW Boosted-Dubs (Dec 4, 2004)

*Re: Technical: Why should I unplug the o2 sensor? ([email protected])*

This is the same for stock chip+FMU cars as well.....if you unplug the 02 your ECU doesn't "know" you are running rich (what you want) and will not adapt........this is WHY I tell peeps to unplug their 02 with any boosted FMU setup,works so far,the cars don't adapt (except for knock sensor timing)and you have consistent afr........







All the stand alone cars I have done run open loop,and run 15-16's afr under cruise no problem.....14.7:1 is the most chemically correct afr for emissions but not the most ideal under all conditions.


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## BigDaddyCW (Apr 4, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Another http://****************.com/smile/emthup.gif for Jeff!!


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## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

This is very useful information...
Should make ppl feel better about pulling out their o2 sensors.
To me, it's actually much safer to run w/o them then with them.
Now, I've tuned with Jeff and have looked at my a/f ratio at part throttle under boost with his tune and it's damn good/safe.
But I can understand why some ppl may question it, as Jeff says himself...
Your tune better be spot on if you disconnect the o2's, and just to reiterate for those of you that don't have your own wideband sensor (I don't either but I've seen his hooked up on my car) that there isn't anything for you to worry about.
Jeff,
It must be a bit harder to tune in the o2 loop control into the OBD-2 software?
Later,


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## C2Motorsports (Nov 25, 2003)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Hope people find this information useful, as well as comforting in the reasons behind C2Motorsports' tuning.......we do not ask you to unplug the O2 sensors because it is *easier*.....we ask this because it is how we can regulate "correct" under-boost tuning in our software....

Happy New Year 
C2


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## 2kjettaguy (Dec 24, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*

I ran no 02 sensors for over a year. Fuel was tuned with a piggyback. It was perfect, except for the BOV. No problems starting or anything. As long as the tune is right it's Soooooo much better than with 02's. 
Hell, even the neuspeed charger guys could stand some more fuel at part throttle.


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## fastslc (Sep 14, 1999)

*Re: Technical: Why should I unplug the o2 sensor? (2kjettaguy)*

How would this work for the piggyback though and STOCK Chip ?
If you disable the O2 sensor, you've eliminated the feedback
Part Throttle
Stock Chip might not have the A/F that you need to "lock" in place when you remove the O2 sensor.
I guess you can use the piggyback to tune part throttle also emulating a"14.7" A/F like you've retuned a chip a la C2 - essentially locking the A/F 
Full Throttle with boost
Use Piggy back to add required fuel.. 
Would that work ?? 
That's for the OBD1 Corrado Dizzy that I am talking about 
d


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## B4S (Apr 16, 2003)

*Re: Technical: Why should I unplug the o2 sensor? (fastslc)*

On any good standalone setup you will have full closed loop control that is based on MAP and RPM/TPS usually, so I believe that you should mention that as well in your post. Its a very good piece of info for those people running burned chips, and makes 100% sense, but for those of us running standalone, it really does not apply







. The minute my car hits 0 inches of vacuum, it drops out of closed loop http://****************.com/smile/emthup.gif


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## LSinLV (Nov 25, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (B4S)*

Thanks Jeff, this is good info!
http://****************.com/smile/emthup.gif 
Larry


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## CrazyMonkey (Oct 1, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Could you wire a pressure switch into the O2 sensor wiring so when you are under positive manifold pressure it automatically "unplugs" the O2 sensor? Seems simple enough as long as you can find the right swich...


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (CrazyMonkey)*

That's called a hobbs switch. Now, I'm not very acquainted with these computers and how smart they are. So somebody else might need to give you a definite answer. BUT MOST vehicles I've worked on will start ignoring a sensor if it keeps giving interupted data when it's looking for it, in other words, the computer's looking for an input voltage, and it doesn't see it (or it's getting sporadic feedback), so it'll just go into limp mode. 
Either that, or if this computer ISN'T smart enough to do that, low voltage with an O2 sensor means lean, so your computer is going to dump fuel.

There's a slight chance that if this computer is just really dumb, it may think for some reason the O2 is cold or something because it's not cycling and run open loop, but I really think it'll probably kick it into limp mode because it doesn't see the sensor cycling.



_Modified by mechsoldier at 3:36 AM 1-1-2005_


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## vr6swap (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_That's called a hobbs switch. Now, I'm not very acquainted with these computers and how smart they are. So somebody else might need to give you a definite answer. BUT MOST vehicles I've worked on will start ignoring a sensor if it keeps giving interupted data when it's looking for it, in other words, the computer's looking for an input voltage, and it doesn't see it (or it's getting sporadic feedback), so it'll just go into limp mode. 
Either that, or if this computer ISN'T smart enough to do that, low voltage with an O2 sensor means lean, so your computer is going to dump fuel.

There's a slight chance that if this computer is just really dumb, it may think for some reason the O2 is cold or something because it's not cycling and run open loop, but I really think it'll probably kick it into limp mode because it doesn't see the sensor cycling.


IIRC Atwood has previously stated that by taking the 02 sensors out of the loop, the ECU is forced into figuring the mixture off input from the MAF only. Limp mode on the pre-MK4 ECU isn't like limp mode on later cars.
It could be that you could wire the 02 sensors to a switch, and turn them off/on as needed, but the voltage/current generated by an 02 sensor is pretty weak, and the resistance of whatever switch you splice in there might cause problems also.


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## 2kjettaguy (Dec 24, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (vr6swap)*

I believe 02 sensors have a hot lead, so you could switch that. You'd be better off using a device to switch them off around 10" or 5" of vacuum. You'll get better responsiveness with ~14.0 AFR in those areas. It would be cool if you could rig a map sensor to shut them off when you wanted, os "fool" them after a certain MAP value. 
But, if you're going to do all that work you might as well run standalone.


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## Gavster (Jan 8, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (2kjettaguy)*

This is good info for sure....I had a question though....my 02 sensor is hard to reach b/c of my turbo setup...i run mine unplugged, but what if for some reason my ecu gets rest and i can plug the 02 sensor in before i trun it back on...and adapt w/ no 02....what happens? (i wont have this issue when i redo my setup..but for now, just wondering...haha


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## DblYeloRado (Mar 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Just find it strange that a tuner tell people how to bypass emission controls. I know in my state a machanic would be fined if he were to do this. Speed isnt everything to me and most people here dont have race cars . maybe this is for *_OFF ROAD USE ONLY*_


_Modified by NORTAVE2.0 at 9:40 AM 1-1-2005_


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (NORTAVE2.0)*



NORTAVE2.0 said:


> *_OFF ROAD USE ONLY*_
> Yep. Off road 'only'
> 
> 
> ...


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## Gavster (Jan 8, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

What about my question? pweeeeeeeeez? LOL


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## TAIVW Boosted-Dubs (Dec 4, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Gavster)*

You got more emissions coming out of 1 1965 VW Bug,or your 2 stroke weedwhacker than 10 turbo cars with 02's unplugged!


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## 95GLS (Dec 16, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (TAIVW Boosted-Dubs)*

Ok say your state just instituted new emissions laws ( NH )







and your ECU will be scanned and if it shows any codes relating to the engine, you will be failed. So I will have codes from having the O2s unplugged, and a few misfire codes...How would you recommend getting around this for inspection? My idea: Plug the O2s in right before I get there, hook up the laptop and wipe the codes out. Drive in, scan, should come up clear right? What do you think bout that plan?


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## Gavster (Jan 8, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (95GLS)*

Thats what I plan to do ^^^


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## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (95GLS)*


_Quote, originally posted by *95GLS* »_Ok say your state just instituted new emissions laws ( NH )







and your ECU will be scanned and if it shows any codes relating to the engine, you will be failed. So I will have codes from having the O2s unplugged, and a few misfire codes...How would you recommend getting around this for inspection? My idea: Plug the O2s in right before I get there, hook up the laptop and wipe the codes out. Drive in, scan, should come up clear right? What do you think bout that plan? 

On your vag-com you'll see the "readiness status" part which shows "fail" for almost everything right after you clear your codes.
So you have to drive the car for a few days (2 or 3 cold starts) to get the "readiness" to say 'pass'. 
Sure, your codes will be gone, but you'll fail emissions anyway.
Clear your codes 2-3 days prior. Drive with your o2's in and stay out of boost for that period.
Then go and get smogged.
Later,


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## 95GLS (Dec 16, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*


_Quote, originally posted by *nater* »_
On your vag-com you'll see the "readiness status" part which shows "fail" for almost everything right after you clear your codes.
So you have to drive the car for a few days (2 or 3 cold starts) to get the "readiness" to say 'pass'. 
Sure, your codes will be gone, but you'll fail emissions anyway.
Clear your codes 2-3 days prior. Drive with your o2's in and stay out of boost for that period.
Then go and get smogged.
Later,

Wow I had no idea it took that long to really "clear" the codes for good. So I'll have to drive for a few days with the o2s plugged in, and out of boost, and that should do the trick? Is there any way to tell with VAGCOM when the ECU is "passable"?, sorry kinda worded that messed up, but I'm sure you get the picture.


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## TAIVW Boosted-Dubs (Dec 4, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (95GLS)*

If you have the factory manual,you can see what procedures are involved to set readiness,so you can do it faster with the proper outlined procedure,........it will tell you drive for XXmiles,at XX rpm,etc.,etc.,to set the readiness......... but can't you guys just find somebody that will "hook you up" for a 100 bux or something?? Am I the only outlaw here??


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## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (95GLS)*


_Quote, originally posted by *95GLS* »_
Wow I had no idea it took that long to really "clear" the codes for good. So I'll have to drive for a few days with the o2s plugged in, and out of boost, and that should do the trick? Is there any way to tell with VAGCOM when the ECU is "passable"?, sorry kinda worded that messed up, but I'm sure you get the picture.

From what I understand it's not that the codes aren't cleared immedietely, b/c they are gone as soon as you delete them. But when you click on "readiness" before and after you clear codes you will see a difference. 
If you have been running your car for a while w/o clearing any codes and go into "readiness" you'll see that most parameters say "passed".
Immedietely following clearing the codes they then say "fail".
They will say "fail" for a while. Whether it's 2 or 3 cold starts is not for me to comment on b/c I'm not sure. But that's my guess.
Be glad you don't have a Volvo. Apparently, lots of Volvo cars are causing a ruckus here in PA (now that inspection is based upon clearing codes). When there are easy-fix codes cleared at the shop the volvo needs to be driven for almost A MONTH (!!!!!)...Yes, almost a month to get it ready again.
That's what I've heard from a couple local guys here in Paoli/Malvern area that have shops....
Later,


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## Vdublin (Nov 18, 2000)

yo you talkin bout the one on the cat right. well mine has been dead for a while now. so thats the reason for sheity gas milage???


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## 95GLS (Dec 16, 2002)

*Re: (Vdublin)*

Damn, this is a pain in the ass. April 1st is when this all goes into effect, 96 and up cars. I got a few places that will do lick and sticks, but I don'tknow if thats going to be possible when this new testing comes out because it is all done on computer in connection with the state.


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## Marty (Jul 14, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (Gavster)*


_Quote, originally posted by *Gavster* »_This is good info for sure....I had a question though....my 02 sensor is hard to reach b/c of my turbo setup...i run mine unplugged, but what if for some reason my ecu gets rest and i can plug the 02 sensor in before i trun it back on...and adapt w/ no 02....what happens? (i wont have this issue when i redo my setup..but for now, just wondering...haha

Then there is no "adaptation". Your fueling will be straight from the maps with no correction factor derived from closed loop operation (such as that for different altitudes, or very different temperatures from wherever Jeff tune'd the chip).


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## EvilVento2.oT (Dec 1, 2003)

*Re: Technical: Why should I unplug the o2 sensor? (Marty)*

so, thats why my car has ben runing like the bomb!!! (the wire melted on the first o2 and ever since then it has been so much stronger , so with the o2 unpluged it reads of the maf imput signal ?? thats freakin cool!!! 
the deal with nh is this there are no tail pipe sniffers , all they are gonna do is plug in a obdII scan tool and look for readyness codes, and emmisons failures of any kind mean a fail .... I give this about 2 years before it goes away


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## Marty (Jul 14, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (EvilVento2.oT)*


_Quote, originally posted by *EvilVento2.oT* »_so, thats why my car has ben runing like the bomb!!! (the wire melted on the first o2 and ever since then it has been so much stronger , so with the o2 unpluged it reads of the maf imput signal ?? thats freakin cool!!! 
the deal with nh is this there are no tail pipe sniffers , all they are gonna do is plug in a obdII scan tool and look for readyness codes, and emmisons failures of any kind mean a fail .... I give this about 2 years before it goes away 

It always reads off of the MAF / TPS sensors. In closed loop, the ECU takes sensor inputs that estimate the engine load and RPM and then lookup in a table the amount of fuel to inject. In closed loop, this fuel injected *should* keep you right around 14.7. If it doesn't (based on O2 feedback), it injects more or less fuel, and keeps a record of how much more or less fuel on average it needs to inject. This is stored as a fuel trim and is used for ALL injections, including open loop. So in open loop, it again reads the sensor inputs and looks up the amount of fuel to inject, trims the appropriate amount from this value based on adaptation, and injects. In the case of resetting the ECU without the O2 sensors plugged in, the trim is simply 0%.


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## vr6swap (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (Marty)*


_Quote, originally posted by *Marty* »_
Then there is no "adaptation". Your fueling will be straight from the maps with no correction factor derived from closed loop operation (such as that for different altitudes, or very different temperatures from wherever Jeff tune'd the chip).
 
Wouldn't the ECU be able to adapt to varying ambient air temps from the inputs from the sensor in the intake manifold? That, and the coolant temp sensors? I can't see how having the 02 sensor unplugged would take the other sensors offline.


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## G-Boi (Aug 29, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (TAIVW Boosted-Dubs)*

how do i know which o2 to unplug? first or secnond o2 sensor??
cuz im planing to boost with a FMU.... 
some info on that?


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (vr6swap)*

x


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## DblYeloRado (Mar 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (TAIVW Boosted-Dubs)*


_Quote, originally posted by *TAIVW Boosted-Dubs* »_You got more emissions coming out of 1 1965 VW Bug,or your 2 stroke weedwhacker than 10 turbo cars with 02's unplugged!
















you missed my point


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_
Unplugging a narrowband sensor only disables the o2
control loop. No limp mode.

What does VW use as a limp mode then, because (like I already said I've mostly worked on modern stuff) every car I've ever seen will kick into limp mode and go by a base map for timing and fuel based only upon a map loaded into the computer that will be super rich and retarded timing in pretty much any circumstances so that you can make it home and not blow it up.....Sounds like you guys are saying these older VW's don't work like that, then when do they REALLY go into limp mode?


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## vr6swap (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (NORTAVE2.0)*


_Quote, originally posted by *NORTAVE2.0* »_
you missed my point








 
Could be that we all did. What was it again?


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## 2kjettaguy (Dec 24, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

I am seeing alot of skepticism in this thread, and there's a few things I want to say about it. 
When I was 19 and gung-ho about turboing my car I will admit I knew nothing about it. I knew little to nothing about engine tuning, I just wanted more power than my supercharger could provide. 
I chose my fueling setup and knew I had to disconnect my 02 sensors. I was a bit bummed because I thought you had to have these sensors in place for the engine to run 'right.' Also, this threw a CEL and I own a mk4 so I don't want that! 
After having tuned my car I plugged my 02 sensors back in to see what would happen. The ECU modified my fuel tuning immediately and removed fuel from crucial areas. Part throttle boost now resulted in detonation and bogging. The car was not 100% driveable. I had to either hit the throttle 100% when I wanted to feel the power, or ease into boost listening and feeling for detonation. What fun is that? There's no part throttle cruising, no passing anyone without completely laying into the throttle. The engine in it's current programming had 2 modes - fuel economy on a very light throttle, or wide open. 
Some people like that. I don't. I like being able to ease into the throttle and pass someone without even getting the revs up. This requires boost at part throttle, and more fuel than 14.7. 
Alot of you are making a fuss over emissions compliance. If you want your vehicle to be emissions compliant every waking moment, you have no business strapping a turbo on a naturally aspirated motor and engine management system. When you disconnect the 02 sensors you get 4 fault codes. One heater failure code for each 02 and one no signal code for each 02. If you access the vag-com's readiness section, you'll see that the 02 sensors and cat fail. 
In my state and many others, vehicles 96+ don't get a sniff test. They get a gas cap test and an OBD port scan. The OBD port scan reads one thing - readiness values. In my car there are 6. I had 3 that passed and 3 that failed when I was turbo. The 3 that failed were all dependent on the 02 sensors - cat, secondary air, and the 02's themsevlves. 
To pass emissions, all you need to do is plug the 02's in and drive around until the readiness values pass themselves. There is a way to force the readiness with the Vag-com which I never got into.
So, what's the argument here? You need to do a few things to pass emissions? Don't go doubling the horsepower and torque of your motor unless you're willing to spend an hour or two getting it ready to pass the code scan every 2 years. If you can't do that, call the emmissions place and tell them your motor exploded and you're broke. 2 year extension.


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## 98VR (Aug 6, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (2kjettaguy)*

"There is a way to force the readiness with the Vag-com which I never got into."
Someone needs to elaborate on this.


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## 2kjettaguy (Dec 24, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (98VR)*

You can find that info in the bentley manual for your car, or post up in the VAG-COM forum on here. It may even have been covered already http://****************.com/smile/emthup.gif 
My car goes in for it's 2 yr checkup this month, but I parted out the turbo setup and am stock. I haven't checked yet to see if the readiness banks have reset.


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## 95GLS (Dec 16, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (2kjettaguy)*


_Quote, originally posted by *2kjettaguy* »_You can find that info in the bentley manual for your car, or post up in the VAG-COM forum on here. It may even have been covered already http://****************.com/smile/emthup.gif 
My car goes in for it's 2 yr checkup this month, but I parted out the turbo setup and am stock. I haven't checked yet to see if the readiness banks have reset. 

Whereabouts in the Bentley would it be? I'm not making a fuss about this nor do I care about my car being emissions compliant everyday of the year, just that one day each year it needs to be inspected. It has been proven over and over again that NH makes almost none of its own pollution, wind currents carry it from the west. I just want my car to pass so I can drive it, once it passes the o2s are getting unplugged and all will be forgotten...till the next year







So yeh a little elaboration on how to force the readiness with the vag-com would be great if anyone would chime in (jeff) http://****************.com/smile/emthup.gif


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## DblYeloRado (Mar 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (vr6swap)*


_Quote, originally posted by *vr6swap* »_ 
Could be that we all did. What was it again?









did you say you can read ??????????
are you the person my post was in response to ?????????

take a hike ****


_Modified by NORTAVE2.0 at 12:14 PM 1-2-2005_


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## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (2kjettaguy)*


_Quote, originally posted by *2kjettaguy* »_ The OBD port scan reads one thing - readiness values. In my car there are 6. I had 3 that passed and 3 that failed when I was turbo. The 3 that failed were all dependent on the 02 sensors - cat, secondary air, and the 02's themsevlves. 
To pass emissions, all you need to do is plug the 02's in and drive around until the readiness values pass themselves. 

Exactly what I was trying to tell ppl a few posts earlier (I think it was in this thread).
It's the readiness values you need to worry about. And just simply clearing codes doesn't do it. YOu gotta wait a few days to get those readiness values to read "pass".
Later,


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## 98VR (Aug 6, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*

And judging by the procedure to remove them via vag-com. You may as well just go out and drive it cause that procedure seems like a real PITA.


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## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (98VR)*


_Quote, originally posted by *98VR* »_And judging by the procedure to remove them via vag-com. You may as well just go out and drive it cause that procedure seems like a real PITA.

Well, what is the procedure?
Is it in the Bentley? 
Curious.
Later,


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## 95GLS (Dec 16, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*


_Quote, originally posted by *nater* »_
Well, what is the procedure?
Is it in the Bentley? 
Curious.
Later,

Same here, or could you give a page number as to where it is in the bentley?


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## Boragirl03 (Nov 23, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (95GLS)*

I have an MKIV as well, wideband sensor, and I have been enlightened on both sides...leave the sensor plugged in, unplug it. Truthfully my car seems to run better with the 02 plugged in. So I have left it that way.


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_
What does VW use as a limp mode then, because (like I already said I've mostly worked on modern stuff) every car I've ever seen will kick into limp mode and go by a base map for timing and fuel based only upon a map loaded into the computer that will be super rich and retarded timing in pretty much any circumstances so that you can make it home and not blow it up.....Sounds like you guys are saying these older VW's don't work like that, then when do they REALLY go into limp mode?

You didn't answer my question Jefnes....


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## TAIVW Boosted-Dubs (Dec 4, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

Some VW's have a "limp home " mode if for instance the MAF has gone completely,some will not run at all with no MAF,and the Mk4's will run,but 1.8T's will go to "limp mode" if boost pressure/torque exceeds the checksum values.,all the different models have different "limp home modes"........JUST BECAUSE you unplug the 02's the cars will not drive any different.you may smell exhaust a little ,but with FI that is what you want,a richer mixture.....I have ran unplugged o2 on Digi-1,and Motronic,there are no adverse effects,.......
You do not NEED a 02 sensor.....remember there were already cars and internal combustion engines WAYYY before the 02 sensor was invented....and the only way people know noadays that the 02 has gone south is the "check engine light"...........


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## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_
You didn't answer my question Jefnes....

This thread was just an informative post about unplugging the o2. You could probably read up somewhere else (besides getting info from jeff on everything) about why some cars have a 'real' limp mode and others don't.
Just a thought.
Later,


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_You didn't answer my question Jefnes....


i'm a little busy these days with family stuff.... 
the ecu will only go into limp mode when a primary engine sensor
is missing.... a sensor that is vital to the engine running at all.
cam/crank position....
maf
anthying that will keep the ecu from looking the fuel/ignition
values up properly.
Plus I imagine that the FI ecu's (1.8T, 2.7T) realize that you
can break the engine if the airflow/pressure values are
out of whack...
Where the NA engine is ~safer and won't likely break.
The only limp mode I have ever experienced on the mk3 ecu
is when your missing the cam postion sensor.
Other missing sensors cause 'default' values to be inserted into
the normal calculations. These typically default a little richer.
(IAT, CLT)
The 'default' o2 value is 0.455 volts, which is a lamda of
1, which is also what the ecu will reach for. 
Jeff


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*


_Quote, originally posted by *nater* »_
You could probably read up somewhere else (besides getting info from jeff on everything) about why some cars have a 'real' limp mode and others don't.


I'm ASE certified....I don't really need info on why some cars have a real limp mode and others don't, this isn't a normal thing, that's why I asked him, usually, if ANY sensor is missing from the equation the car goes into limp mode. 


_Quote, originally posted by *"jeffnes"* »_Other missing sensors cause 'default' values to be inserted into
the normal calculations. These typically default a little richer.
(IAT, CLT)

What do YOU consider limp home mode then....I've never even really seen a car that could run without a cam position sensor
Just curious, because what you're describing is typically considered limp mode,



_Modified by mechsoldier at 8:05 AM 1-4-2005_


----------



## BVAMotorsports (Feb 20, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*

Nate (or anyone else for that matter), was curious if in your state you have to run your car on a dyno?
In Oregon all cars from 92 to 99 have to run on a dyno. I agree with the method that Nate mentioned if you just have a CEL inspection and tailpipe sniff, but if they put it on the dyno and run it through the gears, I'm betting they'll hit boost, which concerns me. If they do, will it buck, ping, etc.?
I've seen them run it through the gears 3 or 4 times to see how it performs, and they do it as if you are merging with traffic, so I'm concerned if that would/could cause any harm, and also if the driveability would be so evident that they'd fail it on that.
Just curious if others have similar smog standards?
BTW - Jeff, thanks for the short write-up, and do you guys have an ETA for the 02 loop control in the OBD2 software (I have 1 year until the car needs to be smogged).


----------



## 98VR (Aug 6, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (beetlevdubn)*

Keep in mind you've really gotta give the engine some load to see boost with the kinetic kit. It's not about rpms' it's about load. You could take it all the way through the RPM band almost and not see boost as long as your not giving it too much gas.


----------



## AnotherA2VR6 (Jun 20, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

Specifically on the OBD1 VR6, it is possible to run without the CPS, the ecu will revert to non sequential injection and knock control will be affected so timing will be bumped back to avoid detonation. This is what I consider limp home mode.
If on these cars, the ECT or IAT is disconnected the ECU will insert a default value, (instead of reading the sensor after the fault is registered and is still present, the ECU performs a lookup in code to get a default value). Since a default is used the engine will still run off the standard fuel and timing maps, but could run rough while cold in the case of a missing ECT, IAT has a very minimal impact on these cars.
Without the O2 the ECU will register a fault. The fault will prevent the o2 control loop from performing it's normal operation, of providing active feedback and using the active feedback to affect fuel trims, but the STANDARD map values for fuel and timing will be used. This is NOT limp home mode.


----------



## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_
I'm ASE certified....I don't really need info on why some cars have a real limp mode and others don't, this isn't a normal thing, that's why I asked him, usually, if ANY sensor is missing from the equation the car goes into limp mode. 

Then why would you ask? If you are "ASE certified"...and "don't need info on why some cars have a real limp mode" then don't ask.
Later,


----------



## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (AnotherA2VR6)*

Thx another A2, that's actually pretty cool...I like the way this ECU thinks. Most ECU's are not like this, here's a Dodge thread talking about it. And by the way Nater, it's not that "some cars don't have a real limp mode" its that, VW is the only car I've ever seen that doesn't go into limp mode when you disconnect the O2. And no car ever goes into limp mode from CTS...
http://www.neons.org/forums/vi...+mode
Disconnect the O2, it pulls the rev limiter to 4k RPM, the fans turn on constantly, and it will foul plugs every 2k RPMs....Just something I searched for to show you what I meant, that's how most manufacturers are. This is a bit of an anomaly to be able to do this, that thread, the guy was talking about wanting to do what we do (put it into open loop permanently (all though he said CLOSED)


_Modified by mechsoldier at 8:27 PM 1-4-2005_


----------



## theKid (Nov 26, 2003)

interesting stuff guys!
"Just find it strange that a tuner tell people how to bypass emission controls. I know in my state a machanic would be fined if he were to do this. Speed isnt everything to me and most people here dont have race cars . maybe this is for *OFF ROAD USE ONLY*"
please, just fall off the face of the earth.


----------



## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_ And by the way Nater, it's not that "some cars don't have a real limp mode" its that, VW is the only car I've ever seen that doesn't go into limp mode when you disconnect the O2. And no car ever goes into limp mode from CTS...

I understand that. The reason I used the term "real limp mode" was because of your statement here:

_Quote, originally posted by *mechsoldier* »_Sounds like you guys are saying these older VW's don't work like that, then when do they REALLY go into limp mode?

That's all. 
I totally understand limp mode. I've BEEN in limp mode when my MAF failed along with another sensor...it was when my car had 5 k miles on it - when I was younger and less knowledgeable.
But it wouldn't allow me over 3500-4k rpms - would cut fuel off there so it would buck like mad.
Later,


----------



## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (beetlevdubn)*


_Quote, originally posted by *beetlevdubn* »_Nate (or anyone else for that matter), was curious if in your state you have to run your car on a dyno?

No. My mechanic has to idle the car at the machine where it would sniff the tailpipe. I've watched him do it.
But now, I think IN ADDITION TO that he must hook the machine up to the obd port and scan it.
No dyno.
If it were to come to that...I think I'd just ask my guy to keep out of boost...or give it just enough load (if you can even load it real well on a dyno?) that he didn't get much into boost.
Later,


----------



## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*

In Arizona, it's state run, and it has a tach hookup too. They put it on a dyno, and then the machine tells them what to do and they MUST do it like that. Accelerate to such and such, now slow down, now gun it, let it idle....etc etc.


----------



## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_In Arizona, it's state run, and it has a tach hookup too. They put it on a dyno, and then the machine tells them what to do and they MUST do it like that. Accelerate to such and such, now slow down, now gun it, let it idle....etc etc.

That's crazy. I hope they don't start doing that here in pa.
Later,


----------



## VR6 Mole (Jun 2, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*

Nate in PA, 96 and up cars get hooked up to a diag. computer. and as gas cap check. tthats its.
OBD1 cars 95 and lower ge the gas cap (which i fail due to my sparco gas cap) and get a tail sniffer test at around 2400. Im not sure if its done in neutral or on a set of rollers. 
If u want let me know, i know a guy in philly who will sell u both stickers for 150$


----------



## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (VR6 Mole)*


_Quote, originally posted by *VR6 Mole* »_If u want let me know, i know a guy in philly who will sell u both stickers for 150$

They REAL stickers?
Later,


----------



## 98VR (Aug 6, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (nater)*

I'm not sure what stickers will do for you. If it's state run can't a cop run the plates and pull up all that info?


----------



## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (98VR)*


_Quote, originally posted by *98VR* »_I'm not sure what stickers will do for you. If it's state run can't a cop run the plates and pull up all that info?

It's not state run like nj and de.
That's why we have to have stickers. Because it's not linked like that.
Later,


----------



## BVAMotorsports (Feb 20, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (98VR)*

I think that I will do what you did to break your car in Nate. Put a super low Wastegate spring in the WG, or none, and take it to the smog place and they can run it on the dyno all they want, and it should run fine. Even with the C2 chip in there without boost, it should be ok, shouldn't it?


----------



## nater (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (beetlevdubn)*


_Quote, originally posted by *beetlevdubn* »_Even with the C2 chip in there without boost, it should be ok, shouldn't it?

It'll be perfect. The most important thing is that you have the chip to match the injectors that you have and (if applicable) the oversized maf housing...
I've already discussed it with jeff.
Later,


----------



## nuugen (Jan 2, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (VR6 Mole)*

In OH, 96-up cars get the gas-cap check and a code scan, that's all, no dyno, no tail-pipe sniff...OBD-1 cars get the gas cap check and get put on the dyno, but AWD cars get gas-cap and tail-pipe sniff only(no 4-wheel dynos here)...And the techs have a box that lays on the hood that picks up tach signal voltage and transmits that to the computer...
Funny thing is, when the stations are really busy, they won't even scan it, they look for a CEL, *and if it's not on they fast-pass you *











_Modified by nuugen at 11:51 PM 1-5-2005_


----------



## [email protected] (Dec 23, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (nuugen)*

They let me run the roco on the rollers,the last time. the guy was a little too big to fit in the Momo seats. I wanted to lay into it and seeif they would give me a print of of the run , like at the dyno . But was a little worried, no cat rich as hell, and 30 psi .Not too mention side exhaust. NO muffler in the little building. Just imagine their faces...


----------



## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? ([email protected])*

you pass?


----------



## Kilmer (Sep 5, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Edit: 
This note primailry applies to Stock ecu on cars made 
BEFORE the mk4's hit the road. 
The ME7.x ecu has a wideband sensor and full
afr control as 'standard' (ever seen a chipped 1.8T afr curve?
its dead flat and goes rich near redline)


while most of t his info is true and is greatly appreciated jeff...one small correction!
the AWD motor in the 1.8T's have a narrow band 02 the 01 AWW motors and AWP motors are the ones that came with the wideband and most newer models including the longi. motors...
I don't know that much about the tt motors or the longi. motors to be 100% but I know for a fact that AWD motors 2000 GOLF BEETLE GTI JETTA 1.8L Turbo are narroband


----------



## UberMike (Dec 9, 2003)

Bump for great information!


----------



## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Rest assured we will fix this in the code.
Jeffrey Atwood

Any updates on the code fix to run with the O2's connected without it leaning out?


----------



## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

Code is in testing now.
Found some bugs this past weekend...

-Jeff


----------



## jimivr6 (Feb 18, 2003)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

bump


----------



## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Code is in testing now.
Found some bugs this past weekend...

-Jeff

Do you think it might be complete in January?


----------



## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

Yes, I am shooting for xmas 2005.

-Jeff


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## BlownGinster (Jun 23, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Will the upgrade be available to the people that bought the software used? ($$$ for the upgrade







)


----------



## EuroTrek (Sep 15, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Yes, I am shooting for xmas 2005.

-Jeff

That's great, since I haven't received mine as of this posting (ordered through my local C2 dealer, S&L), and my car goes into storage today, I'll wait for this new program, assuming this new software includes the OBDII 2.L http://****************.com/smile/emthup.gif


----------



## slappynuts (Feb 27, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (EuroTrek)*

I thought the local C2 dealer was BF?


----------



## Bigfoot. (Nov 21, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (slappynuts)*

jeff you are My hero


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## PBWB (Sep 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (EuroTrek)*


_Quote, originally posted by *EuroTrek* »_I'll wait for this new program, assuming this new software includes the OBDII 2.L http://****************.com/smile/emthup.gif 


Yea, what about obdII? Also, got another question. Car is a 97 2.0T. My motor is obdI, except intake plenum, and TB, everything else to include ECU is obdII. can i expect any problems with runnin obdII c2 software? have plans on gettin your 42lb software, but need to know what boost level the maps are set for. TIA.


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (PBWB)*


_Quote, originally posted by *PBWB* »_

can i expect any problems with runnin obdII c2 software? have plans on gettin your 42lb software, but need to know what boost level the maps are set for. TIA.

If your car runs on ~stock obd2 software/hardware you won't
have issues with my tunes. (no dumping overboard BOV)
re: boost level: ALL boost has been tuned, unpto the inj. max.
you want to run ~10psi go ahead
you want to run ~18psi go ahead
The 42# inj. should max out around ~260ish whp. 
On a vr6 this is equal to ~400whp and we've seen bigger numbers.
2L O2 sensor code: As soon as I get my 2L up and running I will be 
testing the code. Vr6 code will likely be tested 1st.

-Jeff


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## PBWB (Sep 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

ok, that should be cool for me right now, do you guys have a current 50# program? or anything larger than a 42# program for that matter?


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## Jettin2Class (Jun 26, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Yes, I am shooting for xmas 2005.

-Jeff

Ooh! I want that under my tree!







http://****************.com/smile/emgift.gif


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Yes, I am shooting for xmas 2005.

-Jeff

Sweet keep us posted.


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## magics5rip (Mar 17, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

damn, I was considering going with megasquirt for my next build, but c2 is really stepping things up!
Great work Jeff! http://****************.com/smile/emthup.gif


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (magics5rip)*

Thanks.
I can't ~all the credit.
Jacob Harris is the guy writing the actual assembly code.

-Jeff


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## RadoV6 (Oct 9, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Is Kinetic going to include a new chip with their turbo kit when you release the new code ???


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## MaCPiMP1n (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_ (no dumping overboard BOV)
-Jeff

pls. mr. tunah mastah, sir. give me some hints on how I can alleviate my current dilemma regarding this. 
11.8afr
^ in between shifts - air gets unaccounted for
goes 10.1 -- re-spool is slow like a chubby kid till 12.5afr.
another problem is. 4th gear, hit WOT - 12.2afr then millisecond spike to 13.1 and slowly tapers to 12.1 
I would like your help to eliminate the 'dump' points. I want a crispier response going into boost. I have a feeling once I figure and fix one of the 'problems' the other will go away.
I can send you my .bin, but I would like to fix this problem myself (with your help of course







). I have 5 months worth of tuning using a ghetto hex editor into this tune and that's the only obstacle I have.
BTW, obd1 + loop control = on. Decent P/WOT afr and good on gas


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## MaCPiMP1n (Apr 10, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (MaCPiMP1n)*

this is what was happening like indicated above.









a rough tune I whipped out yesterday with much bigger injectors.
- still a lot of bugs to hammer out, richen mid/lean top -- not a prob.
when I get out of the throttle and go back to it again, it shoots rich again.


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## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (MaCPiMP1n)*

i recorded 182 miles to my full tank of gas on mostly highway driving over the week. hurray c2 http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*


_Quote, originally posted by *f0xf0702k1* »_i recorded 182 miles to my full tank of gas on mostly highway driving over the week. hurray c2 http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif 

Are you saying you got 182 miles on a tank of gas? Wow that is like 13-14mpg....OUCH!


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## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

unplugged o2 sensors http://****************.com/smile/emthdown.gif 
no free upgrade to the non ghetto software http://****************.com/smile/emthdown.gif http://****************.com/smile/emthdown.gif 
megasquirt for the same price http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif 


_Modified by f0xf0702k1 at 1:11 AM 12-10-2005_


----------



## BlownGinster (Jun 23, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*

Maybe the software doesn't like your car. I ran 2 tanks through my car before I parked it and I still got 25 mpg with a really slipping clutch. That's about the same I got with the EIP setup.


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## vr6swap (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*


_Quote, originally posted by *f0xf0702k1* »_
megasquirt for the same price http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif 


If you're that unhappy with C2, go ahead and try MegaSquirt. 
You're on here every day crying about how crappy your car runs now, it'll be real entertaining when you start posting about your problems with a homebrew standalone setup. 
Knock yourself out, Skippy.


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*


_Quote, originally posted by *f0xf0702k1* »_unplugged o2 sensors http://****************.com/smile/emthdown.gif 
no free upgrade to the non ghetto software http://****************.com/smile/emthdown.gif http://****************.com/smile/emthdown.gif 
megasquirt for the same price http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif 

_Modified by f0xf0702k1 at 1:11 AM 12-10-2005_

Plug the O2 sensor back in, the car runs reasonably (just try not to get into boost out of WOT) and you can get about 17/24mpg city/highway. That is what I get running closed loop.


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

Get an adjustible boost switch and use it to make your car think you're WOT at like 2 PSI. It's only 10 bucks, IMHO, C2 should supply one with their chip set to the right psi if they can't get a tune with the O2. This will give the best of both worlds....As for those bitching about bad fuel mileage, nobody else seems to be having these problems. You want good fuel mileage buy a civic.


_Modified by mechsoldier at 11:20 AM 12-10-2005_


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## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (vr6swap)*


_Quote, originally posted by *vr6swap* »_
If you're that unhappy with C2, go ahead and try MegaSquirt. 
You're on here every day crying about how crappy your car runs now, it'll be real entertaining when you start posting about your problems with a homebrew standalone setup. 
Knock yourself out, Skippy.

sorry i know how to tune (did megasuirt on a single turbo 5.0 mustang) so i wont have any problems with my "ghetto standalone"
if im keeping the car out of boost cruising on the highway there is no reason why my mpg should be in the toilet, my 95 vr got 29-30mpg highway so no i dont need a daily driver civic.




_Modified by f0xf0702k1 at 5:40 PM 12-10-2005_


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*


_Quote, originally posted by *f0xf0702k1* »_sorry i know how to tune (did megasuirt on a single turbo 5.0 mustang) so i wont have any problems with my "ghetto standalone"
if im keeping the car out of boost cruising on the highway there is no reason why my mpg should be in the toilet, my 95 vr got 29-30mpg highway so no i dont need a daily driver civic.

Not true, I think the C2 chip runs rich even out of boost. Considering keeping a decent cruise with the C2 stage I software, a V1 SC with the 3.87" pulley, and a Bosch DV (plastic 1.8t style), keeps my car at about 15 InHg. I am guessing if the load was less, say 18-20 InHg, the tune might lean up the mixture, but to keep 75mph in 5th, the load is a little higher. *[all the above assumes open loop, with the chip in complete control of the A/F ratio]*
I was told by Jeff that the new "smog" tune, will actually keep the car closed loop (like I run mine) with load ranging from ~10 InHg-no real load(~22 InHg). So basically once you give it enough gas to get the load/vacuum down below 10 InHg and on into boost, it will allow the C2 'richness' to kick in. So you will get the rich/safe power when on it, and the decent fuel economy when 'grandma'ing around town. Well that is the hope at least


----------



## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

yeah thats the thing that sucks, the chip cant really be in too much control without any feedback from the o2 sensors, its just a pig rich setup. its putting out as much fuel at part throttle as it does WOT


_Modified by f0xf0702k1 at 7:22 PM 12-10-2005_


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## BMGFifty (Sep 2, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*

But it gets feedback from the MAF and the TPS.


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## vr6ofpain (Feb 5, 2004)

Gotta admit though, running closed loop has issues. I have to always drive carefully, trying to keep around 5 InHg or more while accelerating. When I absolutely need to get going fast, I floor it to make sure it is WOT (open loop). Though when shifting under hard acceleration, you can feel the momentary fuel cutback as the pedal gets lifted between shifts. Probably a lean spike.


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## mechsoldier (Aug 14, 2004)

*Re: (vr6ofpain)*


_Quote, originally posted by *vr6ofpain* »_Gotta admit though, running closed loop has issues. I have to always drive carefully, trying to keep around 5 InHg or more while accelerating. When I absolutely need to get going fast, I floor it to make sure it is WOT (open loop). Though when shifting under hard acceleration, you can feel the momentary fuel cutback as the pedal gets lifted between shifts. Probably a lean spike.

If you cut the wot switch wires and attach them to a pressure switch that's set at 1 PSI you'll never have that problem again.


----------



## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (BMGFifty)*


_Quote, originally posted by *BMGFifty* »_But it gets feedback from the MAF and the TPS.

the MAF and TPS are inputs to the ecu, i wouldnt really call it feedback, it cant make any adjustments to the air/fuel mixture


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## Salsa GTI (Aug 29, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*

Ok all you forced induction people....Ask your parents to buy you a wide band data loger and Vag-Com for christmas, and figure out what your problems are and fix them.
And if your running Forced induction with out these two basic items...you are just a whiny little retard that constantly says my car runs like crap and don't know why....Waaa waaa Waaaa stop all the crying.....Where is my damn beer








Damn I'm so angry for a sunday afternoon


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## vr6ofpain (Feb 5, 2004)

*Re: (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_If you cut the wot switch wires and attach them to a pressure switch that's set at 1 PSI you'll never have that problem again.
 Interesting idea, but with the new software release right around the corner, I'll just wait.


----------



## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Salsa GTI)*

i know what the car is doing and why, its also not running bad its just pissing fuel when it shouldnt have to.


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## vr6swap (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*


_Quote, originally posted by *VWAUDITECH* »_Great #'s for C2 stuff!
"open loop tuning"?? Man fo0x0z2,you really have NO CLUE about what you say do you? HOW can you tune close loop with a NARROW band sensor that will not accurately read below 14:1 afr?
I think your type of "tuning" is "open LIP tuning"........where you don't have a fast car,and haven't tuned a g'dam thing!











_Quote, originally posted by *Salsa GTI* »_
MMmmm great point







fo0x0z2 knows little tunes nothing and drives around in a beat ass high milage jetta vr with a primerd golf front end and rusted coil overs that runs 15"s ...so go easy on him..He knows not what he says


----------



## qschuur1 (May 12, 2004)

*Re: (vr6ofpain)*

1 psi switch the WOT

_Quote, originally posted by *vr6ofpain* »_ Interesting idea, but with the new software release right around the corner, I'll just wait.

I used this trick on my car [OBD2] and it doesn't work, there are problems around the switchpoint. when going into boost you get a lean spike because the switch is always late.
It's even worse going out of boost, at switchoff the ecu sees a very rapid closing TPS from WOT to where it is at that moment. and cuts fuel accordingly.... again lean.
You want a smooth transition, no switching. in stock form there is always a smooth transition from stoich to enrich.


_Modified by qschuur1 at 1:37 PM 12-12-2005_


----------



## mechsoldier (Aug 14, 2004)

*Re: (qschuur1)*


_Quote, originally posted by *qschuur1* »_1 psi switch the WOT
I used this trick on my car [OBD2] and it doesn't work, there are problems around the switchpoint. when going into boost you get a lean spike because the switch is always late.
It's even worse going out of boost, at switchoff the ecu sees a very rapid closing TPS from WOT to where it is at that moment. and cuts fuel accordingly.... again lean.
You want a smooth transition, no switching. in stock form there is always a smooth transition from stoich to enrich.


AHHH One point I forgot to make. Yeah you're right about OBD2, but referring to OBD1, there's no TPS. So the computer can't tell. And you shouldn't have a problem. If you're having a problem with delay, then use a vacuum switch and set it at like 1"


----------



## qschuur1 (May 12, 2004)

*Re: (mechsoldier)*

I was thinking about that, but it brings the following problem, when you start to crank your car [no vacuum] it thinks you are cranking at WOT..... hmmm
I will work something out with my homebrew hybrid_ecu








That is something for a different thread.....


----------



## mechsoldier (Aug 14, 2004)

*Re: (qschuur1)*

Um, you should have vacuum while cranking, that's why a vacuum leak will stop a car from starting sometimes.....also if you didn't you'd be at max fuel pressure while cranking....


----------



## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (vr6swap)*

Great #'s for C2 stuff!
"open loop tuning"?? Man fo0x0z2,you really have NO CLUE about what you say do you? HOW can you tune close loop with a NARROW band sensor that will not accurately read below 14:1 afr?
I think your type of "tuning" is "open LIP tuning"........where you don't have a fast car,and haven't tuned a g'dam thing! 
right.

Quote, originally posted by Salsa GTI » 
MMmmm great point fo0x0z2 knows little tunes nothing and drives around in a beat ass high milage jetta vr with a primerd golf front end and rusted coil overs that runs 15"s ...so go easy on him..He knows not what he says 
all you do is talk ****, we'll see who's quicker this year at the strip, if you ever go



_Modified by f0xf0702k1 at 4:28 PM 12-12-2005_


----------



## aerowerks (Oct 19, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

There is another way to do this, get a LM1 from Innovate Motorsports, put their wideband in place of factory O2 sensor, program one of the outputs so it emulates narowband O2 signal and plug it back into the O2 stock harness. If you do it right, the factory ECU will try to correct to 14.7:1 which is really what you want it to be (12.5:1) by programing the correct curve offset in the LM1 output


----------



## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (aerowerks)*

you don't need a LM1, the LC1 will do fine and it's a lot cheaper.


----------



## maxslug (May 22, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Jeff,
What about using a "faked" narrowband O2 sensor output ? 
If you were to take a wideband O2 controller w/ a simulated narrowband output and move the curve from 14.7 down to 12.5 and send that to the ECU.
Would it run rich at low throttle, but good at boost? Or would you then have to redo all the maps?
-m
PS. What about a closed-loop 42# tune for california gas (91 octane) for XMAS?








EDIT: I just noticed that aeroworks posted the same solution above http://****************.com/smile/emthup.gif 


_Modified by maxslug at 9:32 PM 12-13-2005_


----------



## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (maxslug)*

It would run rich off boost, but you could always use two oxygen sensors (the narrow and wide) and use a boost or vacuum switch (adjustible of course) and a solid state relay to switch over to the wideband with simulated narrowband output when you hit boost.


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## maxslug (May 22, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_It would run rich off boost, but you could always use two oxygen sensors (the narrow and wide) and use a boost or vacuum switch (adjustible of course) and a solid state relay to switch over to the wideband with simulated narrowband output when you hit boost.

Actually, what would be great is if you used a wideband controller that had an option boost input (as many do). Then you could code-up the simulated narrowband output to read rich/lean centered at 14.x off-boost and 12.x on-boost. 
Thinking this one : http://wbo2.com/2b0/default.htm with a little bit more code would be a good candidate. 
I hacked up the graph of that unit's simulated narrowband output to get the idea across : 







. 
It would require the help of the people who make it to turn the output from a 2D (voltage vs lambda) to 3D (voltage vs lambda vs boost). The 3rd-dimension could simply have two data points like you suggest -- on boost and off boost, or you could interpolate points in between and try to get a smoother AFR. 
-m


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (maxslug)*

Your idea sounds feasible but your diagram is innacurate, no matter how you look at it, the ECU interprets any voltage over .750 as being rich, and anything below .250 as lean.








That's better


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

Best news ever, the LC-1 Innovate wideband has 2 analog out signals.....
You can set them up to be whatever you want (such as we were just discussing) a simple circuit would take care of switching it over.













_Modified by mechsoldier at 5:26 AM 12-14-2005_


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## maxslug (May 22, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*


_Quote, originally posted by *mechsoldier* »_Best news ever, the LC-1 Innovate wideband has 2 analog out signals.....
You can set them up to be whatever you want (such as we were just discussing) a simple circuit would take care of switching it over.


Good catch on the diagram. 
Do you think that a sudden jump in the 02 reading to the ECU (negative feedback) would cause any hiccups when you go into boost? I'm not sure how much the ECU relies on this signal to determine fuel mix, but if it were a twitchy system and it relied on it a lot it might do weird momentary things when switching from one map to the other.
-m
PS. the more i look at it the more it resembles the transfer function for a CMOS inverter and we're sizing up the N device ;-) /geek



_Modified by maxslug at 10:06 AM 12-14-2005_


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (maxslug)*

Well, I don't really think it'll be an issue, because the only thing that's going to happen, is the ecu is going to see the voltage drop and stay lean so it'll start adding more fuel. This is why I said a boost/vacuum switch. It's possible you'd need a vac switch to combat the onset of boost. Probably just buy both and test it out. I've got the LC1 already, I'm buying the Auxbox so I'll be able to log A/F, CHT, boost, EGT (external sensor I already have), and acceleration. I'm gonna start REALLY having fun when I can get out of Iraq and back to Germany.
PS I have no idea what you're talking about with the Cmos thing, I'm really good with modifying fuel injection systems, but for the life of me, if it needs too many resistors, or a cap, I'm screwed. I have to stick to relays, boost switches, and pots and I'm straight...haha


_Modified by mechsoldier at 10:37 AM 12-14-2005_


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## AlwaysInBoost (Sep 4, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

There is more info on making the WB act like a NB sensor here:
http://www.innovatemotorsports...t.php


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (AlwaysInBoost)*

yeah that info is in one of the pdf files. You can download their logging program and all the manuals in a file that's like 5 megs. It's some interesting stuff, you can even use their auxbox and a tps to calculate downforce (look at the last page or so of the auxbox manual)


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## qschuur1 (May 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (maxslug)*


_Quote, originally posted by *maxslug* »_
Good catch on the diagram. 
Do you think that a sudden jump in the 02 reading to the ECU (negative feedback) would cause any hiccups when you go into boost? I'm not sure how much the ECU relies on this signal to determine fuel mix, but if it were a twitchy system and it relied on it a lot it might do weird momentary things when switching from one map to the other.
_Modified by maxslug at 10:06 AM 12-14-2005_

A sudden jump in 02 readings would cause a hiccup, it has to adjust 15 % (which is a lot) and it does that in feultrim, the tps for WOT must be disabled because it adds another 15% to the already changed fueltrim (obd2 uses feultrim for WOT map), your A/F is impossible to control..... another problem is your ignition timing, the ecu calculates the ignition for 14.7 and your goal is 12.0, ignition timing isn't the same in these two circumstances.....
Like Jeff posted earlier "it's difficult to implement this in the chip"
How about a system that leaves the stock ecu in control under vacuum, and switches to full standalone in boost....


_Modified by qschuur1 at 5:55 PM 12-16-2005_


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## f0xf0702k1 (Mar 30, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (qschuur1)*


_Quote, originally posted by *qschuur1* »_another problem is your ignition timing, the ecu calculates the ignition for 14.7 and your goal is 12.0, ignition timing isn't the same in these two circumstances.....

WOT a/f on a stock car is not 14.7


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (qschuur1)*


_Quote, originally posted by *qschuur1* »_A sudden jump in 02 readings would cause a hiccup, it has to adjust 15 % (which is a lot) and it does that in feultrim,

It wouldn't jump, the new reading would register as lean, then the computer would start adding more, and we aren't even talking about WOT anymore because the ecu doesn't pay attention to the oxygen sensor under WOT. Like another guy already said, the ECU doesn't calculate for 14.7 at wot


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## qschuur1 (May 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (f0xf0702k1)*


_Quote, originally posted by *f0xf0702k1* »_
WOT a/f on a stock car is not 14.7

Yes i know that, but the trick is to tell the ECU that it is, while at 12.0


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (qschuur1)*

you're missing the point of what we're saying, the ECU doesn't use the O2 at WOT, because 14.7 is the ratio at which the cat works best and gives best emissions, it isn't what a stock ecu is tuned for at WOT


_Modified by mechsoldier at 12:29 PM 12-16-2005_


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## qschuur1 (May 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

Maybe i'm missing the point here.
I see it this way, get a wideband with the ability to shift the simulated output from 14.7 to 12.0 MAP based (like maxslug is suggesting), off boost you want 14.7 and on boost you want a smooth transition to 12.0. i think this can work. but O2 control needs to stay on.
This is what you want right ?, you dont need switches or anything, your done.


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (qschuur1)*

Yeah you're right about that one, but I don't know of a wideband that can do that. All you would need is a pressure switch set at 1 psi (or atmospheric possibly) and it'll kick it over. $15 for a boost switch , $150 for the LC1 (you can find that kind of deal on ebay) and you're done. You don't need a smooth O2 transition, the O2 fluctuates anyways, so when you open the throttle the ecu is used to seeing the voltage on the O2 drop anyways.


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## qschuur1 (May 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

Yes, i did get the point.
But why not leave the ECU in closed loop control, it will follow the wideband table and you get every A/F you want


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (qschuur1)*

I plan on doing that when I get back to Germany.....We'll see if it works, maybe you can ride in it if you're lucky I gotta swing by Amsterdam to visit the Heineken factory and visit some coffee shops for some....uh.....coffee


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## EuroTrek (Sep 15, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Yes, I am shooting for xmas 2005.

-Jeff

Jeff, how's this coming along, any updates would be great


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## shmaptoe (Aug 6, 2003)

*Re: Technical: Why should I unplug the o2 sensor? (EuroTrek)*

good thread. my car was impossible to tune with the o2 hooked up. no narrowband and my life was much easier.

i believe plx m-300 uses the lsu-4 and is also able to tap into the ecu for narrowband. i like that over the lm-1 because the display interface is much smaller( coming from a kid who owns an lm-1)


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## PBWB (Sep 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (PBWB)*


_Quote, originally posted by *PBWB* »_ok, that should be cool for me right now, do you guys have a current 50# program? or anything larger than a 42# program for that matter?

^^^^^


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (EuroTrek)*


_Quote, originally posted by *EuroTrek* »_Jeff, how's this coming along, any updates would be great








 http://****************.com/smile/emgift.gif http://****************.com/smile/emgift.gif http://****************.com/smile/emgift.gif http://****************.com/smile/emgift.gif


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

code is done....
I don't have any runnning cars to test it on, at the moment.








-Jeff


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## garef001 (Dec 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

just send me a chip


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## 95GLS (Dec 16, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_code is done....
I don't have any runnning cars to test it on, at the moment.








-Jeff

If I brought my car down the week after chirstmas, would you fine tune it with that chip in, seeing as I need a fine tune anyways?


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## AlwaysInBoost (Sep 4, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_code is done....
I don't have any runnning cars to test it on, at the moment.








-Jeff

I can come up the first weekend in January for a little R&D...


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## vr6ofpain (Feb 5, 2004)

and here I am living on the west coast...


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## BlueMk3VR6 (Aug 7, 2001)

*Re: (vr6ofpain)*

bump


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (AlwaysInBoost)*


_Quote, originally posted by *AlwaysInBoost* »_I can come up the first weekend in January for a little R&D...

So will you be the tester?


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## Marty (Jul 14, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

Didn't you guys crack the open / closed loop switch stuff in the OBD-2 Mk3 ECU yet?


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (Marty)*


_Quote, originally posted by *Marty* »_Didn't you guys crack the open / closed loop switch stuff in the OBD-2 Mk3 ECU yet?


Yep. the code has been added. Not fully tested.
Now the o2 control loop is rpm/load dependent.

-Jeff


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## Salsa GTI (Aug 29, 2000)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Nice http://****************.com/smile/emthup.gif


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_Yep. the code has been added. Not fully tested.
Now the o2 control loop is rpm/load dependent.

-Jeff

You'll let us know when it is ready to be shipped right? You can be sure money will be coming your way as soon as it is ready. I love the power the car has running open loop, but my gas mileage was uncool. Now I enjoy decent mileage, but odd power...plus I have to drive it "safely" staying out of boost at part throttle (hard sometimes). http://****************.com/smile/emthup.gif


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## 97TURBVR6 (Jun 12, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Hey Jeff, 
I've had your 42# injector kit since April 2004.......
I think its time for an upgrade.....








Tony


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## EuroTrek (Sep 15, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

Is this chip ready and available yet (it is past x-mas), I need to get one on order through my local C2 dealer!


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (EuroTrek)*

~anyone send me an IM if you have a vag-com tool and can/will test the software. 2L and Vr6.

-Jeff


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_~anyone send me an IM if you have a vag-com tool and can/will test the software. 2L and Vr6.

-Jeff

PM's sent.


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## BlueMk3VR6 (Aug 7, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

bump


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## vr6ofpain (Feb 5, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (BlueMk3VR6)*

Ya I am not sure if Jeff sent me the chip to test it. I am willing and have a VAG-com. We'll see if it shows up. It would be nice to have the power back in. I also picked up some Seafoam and setup a valve on one of the vacuum lines that came from the carbon canister fuel vent stuff. When it is oil change time, I am gonna run some Sea Foam through the intake, hopefully cleaning up the tops of the pistons. These fuel system cleaners don't seem to be doing enough...or my ping lies elsewhere.


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## vr6ofpain (Feb 5, 2004)

^


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## 97TURBVR6 (Jun 12, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (vr6ofpain)*

Jeff
Any updates, is the chip ready to ship?? http://****************.com/smile/emthup.gif


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## Jefnes3 (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (97TURBVR6)*

Test stuff is out in the mail...
once I get the data back (if its ~good), i'll be ready to roll.

-Jeff


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## Jettin2Class (Jun 26, 2002)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

IM sent. I could probably help you with this too.


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## vr6ofpain (Feb 5, 2004)

I'm going to find out of this car still passes SMOG in CA! Going in on the 11th. Obviously running closed loop. All my readiness spots are showing PASSED, so I think I'll be good to go.


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## maxslug (May 22, 2005)

*Re: (vr6ofpain)*

I am *very* interested, please keep us posted how the smog check goes.
http://****************.com/smile/emthup.gif 
EDIT: You know you can pass smog w/ two of the readiness codes not set in California. Not sure how you're going to pass the visual










_Modified by maxslug at 9:52 PM 1-30-2006_


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## Jettin2Class (Jun 26, 2002)

*Re: (vr6ofpain)*

Unless you have a "friendly" shop that doesn't do the visual, you won't pass. All the intake bits and everything need to have a CARB E/O on them. The only FI setup I'm aware of with that is the AMS S/C kit. Good luck to you with that none the less. I like it out here in AZ...so long as all the other required emissions stuff is hooked up, any "extra" stuff is OK. But even still, they didn't plug mine in this last time around, put me on rollers and the sniffer and I passed. (Kinetic stage II)


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## Maverik869 (Jan 3, 2003)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

im sent about testing!


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## PBWB (Sep 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (Maverik869)*


_Quote, originally posted by *maxslug* »_I am *very* interested, please keep us posted how the smog check goes.
http://****************.com/smile/emthup.gif 
EDIT: You know you can pass smog w/ two of the readiness codes not set in California. Not sure how you're going to pass the visual









every state ive known of lets you have 2 readiness codes not set from '96-'01, and '01+ can only have 1 not set.

_Quote, originally posted by *Maverik869* »_im sent about testing!

yea, me too.


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## magics5rip (Mar 17, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (PBWB)*

I can't beleive the open/closed loop problem might be fixed. Hell yes to C2! if this test data comes back OK, i'm definatly buying a chip for #42 injectors from you guys.
Great work so far! http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## vr6ofpain (Feb 5, 2004)

I have the CARB EO# plaque from the AMS kit. It seems to work for the visual (it did 2 years ago)!


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## pgoutsos (Dec 1, 2001)

*Re: (vr6ofpain)*

Bumpity.


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## Maverik869 (Jan 3, 2003)

*Re: (PBWB)*

my car is almost done....
after this my 2.0 c2 software is going in
will let u know how it is!


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## EuroTrek (Sep 15, 2002)

*Re: (Maverik869)*

Jeff, any updates, I hope this is ready before the snow melts


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## Jefnes3 (Aug 17, 2001)

*Re: (EuroTrek)*

the first version of code ~failed.
testing is continuing. 

-Jeff


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## EuroTrek (Sep 15, 2002)

*Re: (Jefnes3)*

If we buy the current software, while waiting for this to be completed, would there be an exchange or upgrade program. 
I had one on order in December through S&L Imports, but when you said you'd have this ready by the new year, we cancelled the old chip order.
Would you say you are weeks or months away from having it done?
Let me know, thanks Jeff


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## Maverik869 (Jan 3, 2003)

*Re: (EuroTrek)*

i think it will cost u like 50$ for a reflash of the chip....


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## PBWB (Sep 12, 2004)

*Re: (Maverik869)*


_Quote, originally posted by *EuroTrek* »_If we buy the current software, while waiting for this to be completed, would there be an exchange or upgrade program. 
I had one on order in December through S&L Imports, but when you said you'd have this ready by the new year, we cancelled the old chip order.
Would you say you are weeks or months away from having it done?
Let me know, thanks Jeff









ive been talking to chris @ C2, who has been talkin to jeff, and they understandably cant put a date or timeframe on when they will have the code working. If they did, and didnt have it in time, theyre awesome ego would lessen, so as a business, they really cant provide an answer to something like that.

_Quote, originally posted by *Maverik869* »_i think it will cost u like 50$ for a reflash of the chip....

Yes, there is an upgrade program which you can take part in when the code works out. Chris said it will be a nominal fee, probably no more than $50. You can either show face at Waterfest, or mail in your current chip, and another chip with the upgraded program will mailed or given back. It will be a one-for-one exchange, because its unrealistic for C2 to 'reflash' 1000 different people's chips in a resonable amount of time after the new chip is released.
*DISCLAIMER NOTICE:* This post does not reflect official statements by C2 Motorsports or any employee therein, Im just giving you guys what i got by talking to chris on the phone. I got this info, and thought everyone else could use it.
Oh, and i already ordered my chip, and have had the injectors since last week.










_Modified by PBWB at 10:58 AM 2-11-2006_


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## EuroTrek (Sep 15, 2002)

*Re: (PBWB)*

Chris, can you confirm this exchange program, and I will have Josh contact you to get one coming, again http://****************.com/smile/emthup.gif


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## maxslug (May 22, 2005)

^


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## 95GLS (Dec 16, 2002)

*Re: (maxslug)*

Jeff you real busy?? I'm hoping to get my car down to you at the end of March for a fine tune on my 42# chip.


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## elRey (May 15, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

I didn't read the whole post. So if anyone before me brought this up, sorry.

edit: http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif 


_Modified by elRey at 9:23 AM 2-15-2006_


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (elRey)*

Yeah I brought that up http://****************.com/smile/emthup.gif 
It would work well if you used the pressure switch as the WOT switch on cars so equipped


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## vr6ofpain (Feb 5, 2004)

Car passed smog. Apparently the AMS EO# is good to go. The tech said that it states "that this is ok with this"...or something along those lines. As expected the exhaust was clean too (running closed loop).


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## vr6ofpain (Feb 5, 2004)

Does anyone know if the GIAC tuning in the old VF kits (specifically the stage II kit) addresses this? Did GIAC figure out the "O2 code" a while back, or do they just run closed loop (having the same leaning out at part throttle boost as the C2 stage I kit does) or does it simply always ignore the O2 (like unplugging the O2)?


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## VWn00b (Mar 4, 2005)

Any word back on the testing so far?


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## GTTechnics (Apr 2, 2003)

*Re: (vr6ofpain)*


_Quote, originally posted by *vr6ofpain* »_Does anyone know if the GIAC tuning in the old VF kits (specifically the stage II kit) addresses this? Did GIAC figure out the "O2 code" a while back, or do they just run closed loop (having the same leaning out at part throttle boost as the C2 stage I kit does) or does it simply always ignore the O2 (like unplugging the O2)?

centrifugal chargers don't have the part throttle problem because they are not as responsive as turbos are (in other words you will never get 7+psi at less than 70% throttle)


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## vr6ofpain (Feb 5, 2004)

*Re: (GTTechnics)*


_Quote, originally posted by *GTTechnics* »_centrifugal chargers don't have the part throttle problem because they are not as responsive as turbos are (in other words you will never get 7+psi at less than 70% throttle)

This is not a valid statement. Even with a centri charger you can get boost at part throttle, with any boost and a ECU leaning the car back to 14.7 A/F you'll not be in a great spot!
Oh and I got my answer from a reputable tuner who has looked at GIAC's code. Apparently the VF/GIAC software allows the car to lean back to 14.7 at part throttle just the car does from the factory...not the best design IMO. I wonder if all their kits are like this...I was just reading about VF's kit for the 540i...though I guess with a max pressure of 6psi, it isn't _likely_ going to cause a problem, but it still isn't the _best_ design.


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## Scooter98144 (Jul 15, 2002)

*Re: (vr6ofpain)*

I second that in a HUGE way. I am always hitting 2-7 psi at part throttle. But how much boost depends on the load at the time.

_Quote, originally posted by *vr6ofpain* »_
This is not a valid statement. Even with a centri charger you can get boost at part throttle, with any boost and a ECU leaning the car back to 14.7 A/F you'll not be in a great spot!
Oh and I got my answer from a reputable tuner who has looked at GIAC's code. Apparently the VF/GIAC software allows the car to lean back to 14.7 at part throttle just the car does from the factory...not the best design IMO. I wonder if all their kits are like this...I was just reading about VF's kit for the 540i...though I guess with a max pressure of 6psi, it isn't _likely_ going to cause a problem, but it still isn't the _best_ design.


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## GTTechnics (Apr 2, 2003)

*Re: (Scooter98144)*


_Quote, originally posted by *Scooter98144* »_I second that in a HUGE way. I am always hitting 2-7 psi at part throttle. But how much boost depends on the load at the time.

really?
I sure as hell don't see 7psi at 60% throttle....and that's with a 10psi pulley, 2psi more than stage 2 (the kit in question) and the same as stage3


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## Scooter98144 (Jul 15, 2002)

*Re: (GTTechnics)*

Well I am used to seeing 14-15 psi and maybe 7 psi at 60% is a tad high. Just hard to say as I am busy looking at the road and not the boost guage. I do know that boost at part throttle is VERY common.


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## vr6ofpain (Feb 5, 2004)

*Re: (Scooter98144)*


_Quote, originally posted by *Scooter98144* »_I do know that boost at part throttle is VERY common.

Especially on the highway, any _reasonable_ amount of throttle at all will jump you to 1-2psi very quickly..


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## GTTechnics (Apr 2, 2003)

*Re: (vr6ofpain)*


_Quote, originally posted by *vr6ofpain* »_
Especially on the highway, any _reasonable_ amount of throttle at all will jump you to 1-2psi very quickly..

but this is my hangup- Since boost builds in such a strange manner (the square root of max boost is achieved a half max rpm, not half boost), reaching a small amount of boost is relativley easy, but higher boost becomes progressively higher to reach. I don't think that a pound of boost is cause for concern in closed loop, especially on a MAF based system, but I could be wrong


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## vr6ofpain (Feb 5, 2004)

*Re: (GTTechnics)*


_Quote, originally posted by *GTTechnics* »_I don't think that a pound of boost is cause for concern in closed loop, especially on a MAF based system, but I could be wrong

That is a good question.


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## EuroTrek (Sep 15, 2002)

*Re: (vr6ofpain)*

Jeff, is the new code complete, cause Chris told my local C2 dealer S&L Imports on Friday, that it was.








If not can you confirm the upgrade/exchange program that has been discussed here, so I can get the old version coming again!


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## Maverik869 (Jan 3, 2003)

*Re: (EuroTrek)*


_Quote, originally posted by *EuroTrek* »_Jeff, is the new code complete, cause Chris told my local C2 dealer S&L Imports on Friday, that it was.









If not can you confirm the upgrade/exchange program that has been discussed here, so I can get the old version coming again! 

last i heard is that he tested the code... but still no o2 control


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## magics5rip (Mar 17, 2004)

*Re: (Maverik869)*


_Quote, originally posted by *Maverik869* »_
last i heard is that he tested the code... but still no o2 control

I believe a post on day 5 of this thread from jeff states that he tested the first code, and the test failed.


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## EuroTrek (Sep 15, 2002)

*Re: (magics5rip)*

Yeah I can read thanks








now back to my question, which is really for Jeff http://****************.com/smile/emthup.gif


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## EuroTrek (Sep 15, 2002)

*Re: (EuroTrek)*


_Quote, originally posted by *EuroTrek* »_Yeah I can read thanks








now back to my question, which is really for Jeff http://****************.com/smile/emthup.gif


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## Doolie (Jun 7, 2003)

So if im reading what i've read up until here right, in reality if you have vag-com and are able to clear codes you can unplug the o2 at the track so the car runs better overall with lesser milage - and then plug the o2 back in for cruising and get the better mileage - Are you able to run an O2 while keeping the C2 chip in?
Would there be a power decrease with the O2 plugged in even at WOT? - i know this conflicts with my question but im just wondering.


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## BLSport (Dec 24, 2005)

*Re: (Doolie)*


_Quote, originally posted by *Doolie* »_So if im reading what i've read up until here right, in reality if you have vag-com and are able to clear codes you can unplug the o2 at the track so the car runs better overall with lesser milage - and then plug the o2 back in for cruising and get the better mileage - Are you able to run an O2 while keeping the C2 chip in?


*Yes, just be careful to avoid partial throttle boost as the O2 sensor will work against C2's fuel map, trying to pull your A/F ratio back to 14.7/1.*


_Quote, originally posted by *Doolie* »_Would there be a power decrease with the O2 plugged in even at WOT? - i know this conflicts with my question but im just wondering.


*No, at WOT the O2 sensor is ignored and fueling is based on C2's fuel map.*


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## BlueMk3VR6 (Aug 7, 2001)

*Re:*

what's the status?


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## maxslug (May 22, 2005)

^^^


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## EuroTrek (Sep 15, 2002)

*Re: (maxslug)*

kinda quiet around here








I want to give C2 my money and am not being given the oppertunity


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## vr6swap (Aug 17, 2001)

*Re: (EuroTrek)*


_Quote, originally posted by *EuroTrek* »_kinda quiet around here








I want to give C2 my money and am not being given the oppertunity









Chris has been out of town the last week or so.


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## EuroKid83 (Jan 26, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

How about instead of unpluging your O2 sensor, leave it plugged in and run a hobbs switch. All you need to do is wire it into your O2 thermo switch and under boost it will switch to open-loop. (CIS only)


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## vr6swap (Aug 17, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (EuroKid83)*


_Quote, originally posted by *EuroKid83* »_How about instead of unpluging your O2 sensor, leave it plugged in and run a hobbs switch. All you need to do is wire it into your O2 thermo switch and under boost it will switch to open-loop. (CIS only) 

Not many vr6 cars are running on CIS.


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## EuroKid83 (Jan 26, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (vr6swap)*


_Quote, originally posted by *vr6swap* »_Not many vr6 cars are running on CIS. 

True that...


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## PBWB (Sep 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (EuroKid83)*


_Quote, originally posted by *EuroKid83* »_How about instead of unpluging your O2 sensor, leave it plugged in and run a hobbs switch. All you need to do is wire it into your O2 thermo switch and under boost it will switch to open-loop. (CIS only) 

the hobbs switch was discussed already by mechsoldier and company in this thread. i think its on pg 1.


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## EuroKid83 (Jan 26, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (PBWB)*


_Quote, originally posted by *PBWB* »_the hobbs switch was discussed already by mechsoldier and company in this thread. i think its on pg 1.

Oh, has anyone tried it?


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## mechsoldier (Aug 14, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (EuroKid83)*

I have seen one setup where somebody used it on a digi 1 turbo converted car....I never asked about it, it was in the for sale forums


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## BlueMk3VR6 (Aug 7, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

^


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## VWn00b (Mar 4, 2005)

Bump. Any news?


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## maxslug (May 22, 2005)

Bump. Stage 2 kit installed. Could use the control when out of boost for fuel economy :-D


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## vr6ofpain (Feb 5, 2004)

*Re: (maxslug)*


_Quote, originally posted by *maxslug* »_Bump. Stage 2 kit installed. Could use the control when out of boost for fuel economy :-D

What is your fuel economy now?
I think I am one of the worst case scenerios, but when I used to run my Stage 1 SCVR6 open loop I was getting about 15mpg city (driving like a blue hair) and 22-23mpg highway.
For the most part I have been running my car closed loop now (since I can sortof get away with it using a blower), and I get a consistent 16+mpg in town driving normal to agressive and a solid 25mpg on the highway.


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## BlueMk3VR6 (Aug 7, 2001)

*Re: (VWn00b)*


_Quote, originally posted by *VWn00b* »_Bump. Any news?

http://****************.com/smile/emthup.gif


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## stealthmk1 (Aug 17, 2001)

*Re: (BlueMk3VR6)*

If anyone needs info on manually setting readiness codes IM me with your engine code. http://****************.com/smile/emthup.gif h


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## AnotherA2VR6 (Jun 20, 2002)

*Re: (BlueMk3VR6)*

It's still in test but looks to be near completion.


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## EuroTrek (Sep 15, 2002)

*Re: (AnotherA2VR6)*

Chip went in last night, thanks C2 & S&L http://****************.com/smile/emthup.gif , car idles good, afr around 12.3 (LM-1), too much wisky to take it for a drive, tonight it's f*kcn raining, so tomorrow hopefully take it for a test drive
















And Jeff, I have a VAG-COM, an LM-1 and would love to help test the new code when you need it, let me know http://****************.com/smile/emthup.gif 


_Modified by EuroTrek at 7:59 PM 4-7-2006_


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## jodee2003 (Dec 3, 2003)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*

i've got the car idling around 500-600rpm...is this about right...and when cruisin in low rpm car spitters....
Any input would be a great help.


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## C2Motorsports (Nov 25, 2003)

Our O2 Compliant software is now available









Now you can leave your O2 sensors plugged in.....
Chris
C2


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## skaterhernandez4 (Feb 24, 2005)

*Re: Technical: Why should I unplug the o2 sensor? (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_
This applies to all cars that have 'narrowband' o2 sensors
and were naturally aspirated from the factory.




So what about g60's?


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## jwatts (Mar 11, 2001)

*Re: Technical: Why should I unplug the o2 sensor? (skaterhernandez4)*


_Quote, originally posted by *skaterhernandez4* »_ So what about g60's? 

we at SNS have that one covered








Anxious to see the O2 compliant VR6 software. I know you guys have been working pretty hard on it for a long time. http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## vr6swap (Aug 17, 2001)

*Re: (C2Motorsports)*


_Quote, originally posted by *C2Motorsports* »_Our O2 Compliant software is now available








Now you can leave your O2 sensors plugged in.....


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## AggvGtivr6 (Aug 4, 2002)

*Re: (vr6swap)*

So no cel with the new software??


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## BlueMk3VR6 (Aug 7, 2001)

*Re: (AggvGtivr6)*

bump...has it been tested and everything? 



_Modified by BlueMk3VR6 at 9:26 PM 6-5-2006_


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## PBWB (Sep 12, 2004)

*Re: Technical: Why should I unplug the o2 sensor? (mechsoldier)*

Is the o2 compliant software ready for the 2.0 as well? If so, consider my $50 and old chip on its way.


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## yokomomma (Aug 3, 2000)

*Re: (C2Motorsports)*


_Quote, originally posted by *C2Motorsports* »_Our O2 Compliant software is now available








Now you can leave your O2 sensors plugged in.....
Chris
C2

So is this a free upgrade? When some of us bought the software 2.5+ years ago it was advertised as ''plug and play'' software, not ''plug in the chip and unplug some other stuff and then play''.


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## TBT-Syncro (Apr 28, 2001)

*Re: (yokomomma)*


_Quote, originally posted by *yokomomma* »_So is this a free upgrade? When some of us bought the software 2.5+ years ago it was advertised as ''plug and play'' software, not ''plug in the chip and unplug some other stuff and then play''. 

It must be ladies night around here, seems like a lot of whining going on.


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## BlueMk3VR6 (Aug 7, 2001)

*Re: (yokomomma)*


_Quote, originally posted by *yokomomma* »_
So is this a free upgrade? When some of us bought the software 2.5+ years ago it was advertised as ''plug and play'' software, not ''plug in the chip and unplug some other stuff and then play''. 

It is not a free upgrade. Everybody will need to send in the software that they have now and then receive a new chip with the O2 sensor upgraded. I think the charge is like $50 or something like that, if I'm not mistaken (contact [email protected])
About the "plug and play"....we all knew about the unplugging stuff before we purchased the kits, including myself. 
Still big http://****************.com/smile/emthup.gif for Chris and Jeff....everything I needed questions, problems, testings....I was helped.


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## Doolie (Jun 7, 2003)

I received my chip and head spacer this morning, i will be installing the chip this week and it is the chip WITH o2 sensors so i will let you all know how it runs, im damn excited!


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## AggvGtivr6 (Aug 4, 2002)

*Re: (AggvGtivr6)*


_Quote, originally posted by *AggvGtivr6* »_So no cel with the new software?? 


Anyone?? Im debating buying this new software and the only reason i would is to get rid of the cel, and be able to pass emmisons


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## PBWB (Sep 12, 2004)

*Re: (TBT-PassatG60)*


_Quote, originally posted by *TBT-PassatG60* »_It must be ladies night around here, seems like a lot of whining going on.

true dat. plus that was 2.5 yrs ago. they probably werent even testing codes for o2 compliance back then.


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## big bentley (Jun 6, 2001)

*Re: (C2Motorsports)*


_Quote, originally posted by *C2Motorsports* »_Our O2 Compliant software is now available








Now you can leave your O2 sensors plugged in.....
Chris
C2

But I dont wanna!


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## BlueMk3VR6 (Aug 7, 2001)

*Re: (big bentley)*

mailed mine to Chris last saturday....can't wait to get the new one







.


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## lilnick (Feb 15, 2005)

*Re: (C2Motorsports)*

does the new chip eliminate the random miss fire codes?


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## BlownGinster (Jun 23, 2002)

*Re: (lilnick)*

Is the upgrade available to people that bought the software used? Will any adjustments made with VAG COM need to be re-done with the change?


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## PBWB (Sep 12, 2004)

*Re: (lilnick)*


_Quote, originally posted by *lilnick* »_does the new chip eliminate the random miss fire codes?

if the VRT's are like the c2 2.0T software, you gotta run NGK 7E's. Youre probably runnin Bosch's right now, and their software doesnt like em. Change em out like I did and your golden.


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## BlueMk3VR6 (Aug 7, 2001)

*Re: (PBWB)*

received the new chip today...


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## Ddubb9965 (May 5, 2005)

*Re: (BlueMk3VR6)*

what's the status on the 2.0l 42lb software


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## BlueMk3VR6 (Aug 7, 2001)

*Re:*

Here is my statement....I'm a very satisfied C2 customer.
Finally installed my chip yesterday afternoon, except the 2.75" pulley that I'm upgrading. o2 sensor is fine, connected it, scanned the ecu and cleared the code, throttle adaptation done, idle adaptation set as Jeff's instruction state....value=127 (800rpm). CEL is finally off....







...took it for a ride (very nice, no issues...rpm's usual 2500-3000), gauges reading just fine (idle vac is in 20). Then I took a freeway ride...beautiful, acting like a porn star, no signs of any problems. Didn't wanted to force it, but I had to see some boost...took it to approx. 5K rpm, gauge was reading 6-7 psi...









I'll drive driving it for couple of days (since it's not my daily) to see how everything works...hopefully I won't have any issues. After I get the smaller pulley installed, I'll take it to dyno again. 
Just wanted to thank Chris & Jeff for all the help and time doing this....you guys rock... http://****************.com/smile/emthup.gif . Will update you guys....to be continued.



_Modified by BlueMk3VR6 at 7:46 AM 6-7-2006_


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## PBWB (Sep 12, 2004)

*Re: (Ddubb9965)*


_Quote, originally posted by *Ddubb9965* »_what's the status on the 2.0l 42lb software

x2...............as a few like myself have been stating............


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## lilnick (Feb 15, 2005)

*Re: Re: (BlueMk3VR6)*

bump


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## Jefnes3 (Aug 17, 2001)

*Re: Re: (lilnick)*

2L was completed when the vr6 stuff was done.

-Jeff


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## lilnick (Feb 15, 2005)

*Re: Re: (BlueMk3VR6)*

bump any new info?


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## BlueMk3VR6 (Aug 7, 2001)

*Re: Re: (lilnick)*


_Quote, originally posted by *lilnick* »_bump any new info?

I was thinking that a lot of people will upgrade this. Well, I just know that I'm very happy with it and my beast is running amazing, plus I'm getting better gas mileage....19-20mpg city (around 15mpg before). Good luck


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## YuenglingMike67 (Aug 7, 2002)

*Re: (yokomomma)*


_Quote, originally posted by *yokomomma* »_
So is this a free upgrade? When some of us bought the software 2.5+ years ago it was advertised as ''plug and play'' software, not ''plug in the chip and unplug some other stuff and then play''. 

I like having everything unplugged..
the more I can cut out, the better. http://****************.com/smile/emthup.gif 
(just got my new chip.. gotta pick up some 02 sensors since i no longer have any)


----------

