# Wideband all over the place - Video attached



## VdubBry (May 9, 2000)

Hey all,

Found the vacuum issue I had before, Just got my brand new C2 chip in today and installed it. My wideband however now is all over the place, I attached a video, as you can see in it, it goes from one end of the spectrum to the other, and then back, rinse and repeat. This is all without touching the gas pedal until the very end of the clip.

Is it with the new software now trying to find the idle point? I even notice a bit of pushback of sorts in the gas pedal at times. This is a C2 setup, 42lb, stage 2, racefile. Vortech V2 charger.

Should I try the Vagcom idle settings etc, or just put some mileage on it?

Feedback is much appreciated. Thanks!


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## TBT-Syncro (Apr 28, 2001)

bad voltage to the wideband, or a bad wideband sensor.

the 02 ratio if swinging that badly, you'd hear it in the idle (it would also start to break up in the 17s).


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## VdubBry (May 9, 2000)

Thanks, when it gets in the 17's range the idle does go a bit wonky. I am not sure what to expect, just rebuilt everything from a cracked piston so I'm leary as hell lol.

But I am not sure if my gauge is reading accurate as well. I also don't know if I have the right FPR. I just took her out and at WOT im in the low 13's, cruising around 2200 RPM its around 14.5-15.1 I thought at WOT I should be at 11's but not sure if it's reading right.


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## pe_turbo (Feb 7, 2009)

Where is the wideband mounted? Ive seen where the wideband won't read accurately at idle based on reversion in the dp/exhaust. Step on the gas to get the car to about 2k rpm and see if it stabilizes. I didn't see the whole video but your idle did change quite a bit as your wideband swept up and down. I wouldnt think based on this single data point that your sensor was bad. I don't exactly know how C2 does it but most systems don't run closed loop on idle which means they ignore the sensor based on the exhaust conditions I talked about earlier. I have C2 software on my golf and it idles the same way with the same AFRs you are seeing. I never really looked into it but i do know idle air control on the factory setup is pretty difficult.

Tommy


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## VdubBry (May 9, 2000)

Thanks fot the info, if I step on the gas and hold it around 2K it does stabilize. It also starts idling funky too and that seems to match the fluctuation at idle as well.

I am thinking since the software is new I may need to plug up the VagCom and do an idle adapation?

I have to go look where the O2/Wideband sensor is mounted, where is the optimum location on our cars?

I just am not sure if this thing reads accurately or how to know, not sure where my AFR's should be and so forth.


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## TBT-Syncro (Apr 28, 2001)

there is no adjustments you need to make
did you allow the ecu to do a TBA before you started the car?

wideband location makes little difference. mine is 6 inches from the turbo on the downpipe, and has always given me accurate readings. Further down the pipe will be fine. It just needs to be in front of the cat (if you have one)

in closed loop (once warmed up), the readings will swing from low 14s to mid 15s. 
cruising will be the same readings. under boost you should be mid 12s or lower.
fuel pressure should be 43psi with no vac line, around 38 psi with vac line on your car.

your readings may be from bad maf readings (common problem on supercharged cars with the maf close to the charger)


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## pe_turbo (Feb 7, 2009)

Location of the 02 will make a difference. Two extreme cases being if the sensor was mounted more than ~45 degree angle, it could collect the condensation during startup/idle and destroy the sensor. The other case being if the sensor was too far back in the exhaust it would take 1500-2000 rpm for it to read properly. I see it on the dyno all the time. Again, extreme cases but I'm trying to eliminate some easy things to provide some info.

Does the ECU use the wideband to make adjustments or is it an add on? Based on the year model of your car there wouldnt have been a factory wideband but I didn't know if C2 had come out with an add on upgrade. My car is a 98 with a kinetic kit that came with the C2 software. At one point in the software development, they weren't using the closed loop feedback at all. I had to pay extra money to get the upgrade for the narrow band. It still idles almost identical to yours. It drives awesome but idles rough. I don't think that setup uses closed loop control at idle regardless of cold/warm, IIRC you can check it with block ~30 on the VAG COM to be sure. I wouldnt be afraid to drive it, especially since you said the AFR stabilizes once you add some throttle. Just watch the AFR under WOT and make sure it doesn't go over about 12.5. I see alot of turbo cars with peak power around 11.8-12.1 but its ~ok to about 12.5-12.9 depending on your timing. When you do your WOT runs, log the knock sensor. If it bumps, back out of it. You can have 11.8 AFR and still have knock which will destroy your engine.


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## VdubBry (May 9, 2000)

Thanks for the wealth of info. This is a 97 obd2 car so no factory sideband etc. 

Do you think I should do an idle adaptation in vag com?

Also when it sits overnight and I fire it up in the morning if I even tap the gas pedal before it's been running for at least 5 minutes it will bog/stall. Then when I go to restart her she struggles almost like it's flooding. The injectors went out to witchhunter and were completely rebuilt and clean bill of health. I pulled them and let them sit thinking they were maybe leaking overnight but all was well. 

Not sure what is causing this, ecu? throttle body?

I also made an appointment at NGP so I'll get them to do a once over on it. Once she is running everything seems great do could just be some quirks that need working out.


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## pe_turbo (Feb 7, 2009)

The adaptation certainly won't hurt but I don't think it's the problem. You can try disconnecting your MAF and see how it idles. Did the problems start occuring as soon as you swapped the software? Are your injectors and MAF matched with the software?


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## VdubBry (May 9, 2000)

I'll try disconnecting the maf. Everything is a fresh build, I had some used C2 software that was supposed to be for my setup but it ran kind of wonky so I called C2 and gave them the full list of my mods and they mapped the software accordingly but it's a pretty standard setup for supercharger setup, 42lb injectors, 95mm/4" maf and compression lowered 1pt from stock. 

Any ideas? What about the weirdness when starting after she's been sitting for a day having to let it run for 5 mins or so before you can touch the gas or she'll stall.


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## TBT-Syncro (Apr 28, 2001)

TBT-Syncro said:


> your readings may be from bad maf readings (common problem on supercharged cars with the maf close to the charger)


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## VdubBry (May 9, 2000)

I was thinking about that and was wondering how the maf readings would affect the wideband since the wideband is standalone and not tied in to the ecu etc.


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## Scrubbs (Mar 14, 2006)

:facepalm:


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## TBT-Syncro (Apr 28, 2001)

VdubBry said:


> I was thinking about that and was wondering how the maf readings would affect the wideband since the wideband is standalone and not tied in to the ecu etc.



the maf sensor is the primary device for fueling. if it is giving false readings as to how much air is going in, then the ecu is sending the incorrect amount of fuel, and your wideband is measuring the outcome.


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## VdubBry (May 9, 2000)

Thanks, after I thought about it, I was like doh, I'm sure the maf could mess things up before it even got to the rest of the car.

How about the not being able to hit the gas pedal when you first start it up til it runs for a few minutes or so? Could all be related maybe?


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## VdubBry (May 9, 2000)

Quick update. Pulled out the maf sensor, it was toast, the actual sensor chip part was starting to flake apart, it was stock to the car (140K miles) Got a new Bosch maf sensor, idle seems to have fixed it self.

Borrowed a buddie's fuel pressure test kit, she is only getting about 38 psi with vac and about 43 without. My bentley shows I should be at 51 / 58. Think the fuel pump is weak, it's stock to the car as well.

Are most of you guys running the stock in tank and a booster, or is there a better in tank that is a drop in solution?

Thanks!


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## TBT-Syncro (Apr 28, 2001)

VdubBry said:


> Borrowed a buddie's fuel pressure test kit, she is only getting about 38 psi with vac and about 43 without.


thats a correct reading. the other values you listed, are obd1 values.


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## VdubBry (May 9, 2000)

So that is the correct readings? Seems low? Should I put my booster pump in (Walboro in-line)?


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## TBT-Syncro (Apr 28, 2001)

VdubBry said:


> So that is the correct readings? Seems low? Should I put my booster pump in (Walboro in-line)?


38/43 is 100% correct for a obd2 VR6

p.s. pump doesnt change fuel pressure


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## VdubBry (May 9, 2000)

Ok thanks, so I am just about right on track then. The new maf fixed the wideband going from one end of the spectrum to the other at idle. It blips up and down now from about 14.6 - 15.2

I think that is ok? I still get a touch of odd idling almost like a little dip/surge. But I am starting to read that these C2 setups where the Cone filter is connected directly to the maf, then piece of pipe then ell and charger have some funkiness to em?

I still think on WOT it's in the low 13's where I should be in the low 12's for AFR correct?


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## VdubBry (May 9, 2000)

Switched to a full DV valve, got the OEM one used in VW/Audi etc. 06A 145 710N. Well it runs way worse, the AFR sits at almost full rich, the idle bounces worse and when I drive the car, it's running lean (per the AEM AFR)


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## pe_turbo (Feb 7, 2009)

What boost? I typically see peak power in the 11.5-12.3 AFR 13 sounds too lean. Are you logging knock?


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## VdubBry (May 9, 2000)

It is the stock pulley on the v2. I believe I'm around 8-9lbs boost. 

Since I changed to the full recirc diverter and not the partial bov it is idling at 11's afr and runs like hell. I have to be overlooking something. 

How do I log knock, is that done through the aem uego?


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## pe_turbo (Feb 7, 2009)

Ok. I would expect 12-13 at WOT until about 2-3 lbs of boost then it should fairly rapidly go down to the low 12s high 11s

Vag Com block ~20 for knock. Send some pics of how the diverter is installed maybe we can see the problem. Sounds like some air may be getting released from the circuit prior to combustion after the MAF has done its work.


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## VdubBry (May 9, 2000)

Ok thank you. I will get some pics when i get home from work and then take a look at block 20. I don't know how to setup the logging so I'll have to explore the FAQ a bit.


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## HidRo (Sep 19, 2003)

If that was so, wouldn't it make it richer, instead of leaner? But, I also believe you might have something connected wrong, and loosing boost, maybe staying in the 2-3lbs of boost? What does your pressure gauge tell you?

The car sounds mean, btw:thumbup:


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## VdubBry (May 9, 2000)

Thanks HIDRo, she does have a little mean streak to her lol. That video was when I had a partial recirc valve, now that I switched to a full recirc valve she is rich as hell. ??? :banghead:


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## VdubBry (May 9, 2000)

Here are the pics of the setup. Note I have switched the recirc valve orientation in case it is changeable and noticed no difference.

When I just took it all apart I noticed a touch of oil at the intake side of the charger, would this mean she is starting to leak, it is old, taken off my brothers old car, never been rebuilt.


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## pe_turbo (Feb 7, 2009)

HidRo said:


> If that was so, wouldn't it make it richer, instead of leaner? But, I also believe you might have something connected wrong, and loosing boost, maybe staying in the 2-3lbs of boost? What does your pressure gauge tell you?
> 
> The car sounds mean, btw:thumbup:


Yes it would..he said it was running 11s at idle...too rich


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## VdubBry (May 9, 2000)

What do you think of the pics?


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## pe_turbo (Feb 7, 2009)

IIRC on that valve, the end opposite the vacuum line goes to the supercharger intake side, the other goes to the boost side. Aside from that, do you have any vacuum leaks anywhere? I would certainly check that next.


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## VdubBry (May 9, 2000)

Thanks. Should that recirc valve be Ok for the setup? I really don't think I have any vacuum leaks. I've searched all Over. Is there any good way to check. Could it have anything to do with the secondary air delete?

How about the touch Of oil on the intake side Of the blower?


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## HidRo (Sep 19, 2003)

Have you tested the DV to be in good shape? Simple test, put your finger from the bottom, pushing the "piston" up, and plug the nipple with a finger. remove the bottom finger. It should drop a bit, but stay open enough to pass some air from one side to the other.

Checking for leaks, do a search on leak pressure test. It will show up what you have to do.


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## VdubBry (May 9, 2000)

I checked the DV it seems to be ok. Today I logged in to VCDS and did the throttle body adjustment and also logged in to block 001 and turned the idle rpm's up a bit, they were around 620, kicked it up to 850.

Something still is not right, I just am not sure where to go, setup an appoinment for next week with NGP, maybe they can shed some light on her.

I did manage to pull a fault code finally, it was 16500 Engine Coolant Temp Sensor (G62) - P0116 - 35 - 10 - Implausible Signal - Intermittent.

I know if that is going bad or is bad it could explain some of my issues? What should I log (channels) I went for a 10 minute drive, logged Blocks 20, 26, 31. Would those tell me anything?

Thanks!


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## pe_turbo (Feb 7, 2009)

Yes, the coolant temp sensor will make your car run bad if its not working. If if thinks the car is still cold it will be rich. There are other issues but replace it and it should take care of alot of your issues. There is a way to measure the sensor with a multimeter to confirm its bad prior to you having to buy another one. If you have a bentley manual it will tell you how to do it. The VAG COM website may even have it.


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## VdubBry (May 9, 2000)

Thanks, yes I have the Bentley and saw the test but I figure it's gave the code a couple times I will just go get the sensor and 0 ring at the dealer, I think it's all of $15.

It's the 2 wire blue one correct? Looks like it isn't too bad to change, just hard to get in there etc.

I'll start with that and then see what's next, that may get me good enough running to fix up the rest.


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## RED1RALLYE (Jul 21, 2012)

*wide band issues*

hi fella. just disconect blue temp sensor and run it in limp mode and if the wideband is still eratic then its not that. its hard to tell from the pics but are you using silicone vac hose to control your wasted boost . have had so many issues with this where byt the vacuum (idle or overrun) actually sucks the hose together thus not releasing valve fully to close causing greater air mass at idle. sbomething to consider. goodluck matt


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## 'dubber (Jun 15, 2004)

Thinwall tubing that collapses is asking for trouble, but would that would give him a cts code? The ecu cts signal does affect fueling. I would test the sensor and wiring, and if the wiring is ok then go ahead and change the sensor since they can fail intermittently and can look fine.


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## VdubBry (May 9, 2000)

Hey all thanks for the info, the sensor was bad and I replaced it. It still is not 100% right though. The tubing I dont think is silicone, feels more like rubber to me? Doesn't seem to be collapsing that I am aware of.

So far here is the weirdness:
1) Cold start (sits overnight etc) start it up, she fires right up, but if you even blip the gas pedal, conks out. Let it run for 2-3 mins without touching gas, no prob.

2) Idles are for the most part ok, it now and then starts to idle funky, I did notice that as long as I am running the A/C it doesn't really seem to do the wonky ilde??

3) Last thing is, now and then say when coasting or slowing down, foot of the gas, the wideband pegs rich, and the car bucks a bit, blipping the gas pedal, downshifting or a quick rev usually fixes it.

Damn gremlin somewhere!


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## 'dubber (Jun 15, 2004)

Did You reset the ecu and let the throttle body align before the first start?


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## VdubBry (May 9, 2000)

Yes, I pulled the positive and neg battery cables and touched together (someone said that is how you reset it) I verified it before starting in VagCom and all stored values were gone. I also did the Throttle body align in VagCom (VCDS) as well.

Seemed like after the reset etc it was good for a few minutes then the gremlin returns.

I just did the O2 sensor test but not sure what to make of the results. Something is telling it to run rich etc, not sure if I'm in to the ECU or the C2 software is off, or a sensor.


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## RED1RALLYE (Jul 21, 2012)

*Wide band issues*

hey fella. whats your manifold pressure at idle . might give you an indication of either diverter valve not returning fully or an air leak. matt


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## VdubBry (May 9, 2000)

Thanks for the info. I have to say I have never checked the manifold pressure and am not sure how that is done?


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## RED1RALLYE (Jul 21, 2012)

*Wideband readings*

Hi fella. basiclly with the throttle vlave closed you should have a neg pressure(vac) of around 250-400 mbar . higher readings than this would indicate an air leak after the throttle or the pressure entering the intake may be greater due to it not being dumped sufficiently(diverter not returning). both these affects will have an affect on your airmass readings causing fueling issues. some boost gauges run neg vac.you may have to convert mbar to hg. if mem serves me right anything under 13hg is ok and anything greater is poss air leak or pressure applied . 1000mb = 1bar=29.52 hg. at sea level 14.7psi=1bar or 1000mbar . hope this may help.


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## TBT-Syncro (Apr 28, 2001)

VdubBry said:


> Thanks for the info. I have to say I have never checked the manifold pressure and am not sure how that is done?


 since your vehicle doesnt have a map sensor, you arent going to be able to, unless you have your boost gauge connected to the manifold.


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## VdubBry (May 9, 2000)

Thanks everyone for the help. I believe I have solved the problem and she seems to be running great. As a last ditch before I threw in the towel I got a new throttle body. It still acted the same but seemed a bit different so I removed the 1.8T diverter. I reinstalled the turbo smart which is mostly recirc but a small portion blows to atmosphere. It is adjustable and I cranked it down as much as possible to barely vent. 

Did another tb adaptation fired her up, instant smooth idle runs right around 14.8-15.2 purs like a kitten. Wot under boost I'm seeing around 12.2-12.7. Cruising is around mid 14 also. 

Couple questions though? 

1) what should my oil psi be around. It seems at wot it's over 100psi my gauge doesn't go past 100 so I need a new one, cruising highway I think around 80. 

2) she still does the cold start issue where when I fire her up after sitting overnight if I rev past 3000rpm before she's ran a few minutes she will stall. ..?? 

3) I dont care about gas mileage but was noticing she does suck down some gas I'm guessing with the big injectors etc, small gas tank I think 11gal. Does around 14mpg seem right for "spirited" driving lol? 

4) lastly it's an old charger never been rebuilt. I did notice a touch of oil at the intake side. Think it's time for a rebuild maybe seals leaking? 

Thanks!


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