# VRT 12v Kinetic stage II - going lean on boost, what are common things to look for?



## CorradoFuhrer (Mar 21, 2002)

Out of no where my car started misfiring, that I thought was my coilpack arcing off my boost tube. I rearranged it a bit, then it would be fine.

Well I go to get on it this one time and it started falling on its face... breaking up - so i backed off throttle. I tried in 4th at low speeds heavy throttle to get a loan on it to see what it was doing, it was going very lean like 13, 14. I dialed the boost down to 5 psi and i'm getting between 12.5 and 13.5. 

I changed the spark plugs, the gap was about .035 -.040 way out of what I read to be .022 or .028 gap. So I put in some new BKR7E's at .023 and hope for the best. 

Same deal... Maybe a tad leaner since the plugs are at the right gap now.

I have no trouble codes. 

Idle is stoich, off boost is stoich. It's only on boost. Chip is a #30 c2 latest race file. 

I have a fuel pressure gauge but the connect on it doesn't correlate to the fuel rail. I'm guessing I need some different fittings. Does anyone recommend a certain brand that might be at a national chain? I guess I need a T into the fuel line to see what the pressure is . 

Fuel gauges aren't cheap, at least a good one. The one I have is the same brand that advance carries for there compression tester. If a VW had a Schrader valve I would be ship shape. If anyone can clue me in on what AN or NPT fittings I have to get to make all this work or what size T adapter and fuel line, that would be awesome. 

Maybe I will get lucky with the Fuel Filter. I've searched about Walbro 255 in tanks as well and got conflicting information about the swap. Some say it is direct and take 20 minutes and than others make it out to be more involved. If anyone could weigh in on that, it would also be appreciated. 

But I didn't know if it being an after market turbo setup on a VR6 if there wasn't something easy that I may be over looking sensor wise, that wouldn't come up at a CEL because the computer isn't recognizing boost OEM. So it assume everything is ok CEL wise.

She still drives ok off boost. :beer: Still mobile!:beer:


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## 'dubber (Jun 15, 2004)

What are your fuel trims telling you? You can use those to decide to track down a misfire or a post-maf vac leak.


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## CorradoFuhrer (Mar 21, 2002)

I don't have an official vag com, but I have a VAG V checker hand held that let's me into most stuff with out the aid of the laptop or software.

All this is happening at wot so I suggest weak fuel pump, filter. Ill have to ask around if someone has one locally to check.

I was hearing a weird noise by my turbo/dv/intake/tb. I adjusted the boost tubes, took off the intake tubes to check turbo shaft for play, its good.

Not sure what the big culprit is typically. Plugs are ruled out, they are new now and still doing the same thing. I can get mafs reading in one of the measuring blocks. Not sure what would be leaking post mafs other than the DV.

Concocting the right T and fuel lines for my fuel gauge is probably in order to see what the fuel pressure is doing. Before I do all that the fuel filter is top on my list.


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## CorradoFuhrer (Mar 21, 2002)

Would a small leak after the turbo make this much of a difference? Everything seems in order it just went being lean out of no where. A boost tube leak wouldn't cause this much to be severe. It would be pre turbo but post mafs right? 

Could be a faulty dv but it holds low boost fine but high Af 12.5-13.5. If I raise it, it would break up high afr 14. Which is why i backed off and turned the boost down.


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## ItsNotaScirocco (Dec 7, 2009)

I had similar symptoms as the result of an intake/boost leak. A bolt on the throttle body backed out completly. This caused break up under boost and occasional backfire.


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## CorradoFuhrer (Mar 21, 2002)

I have an obd-2, i don't think I have any bolts on my throttle body. A boost leak will cause a bad afr? I thought it would only be post mafs pre turbo that would off set the mix there. I'm doing this at WOT too, so its not the 02, the maf and 02 are brand new. Gonna replace the fuel filter tomorrow. Gonna order some stuff off gap. 

Its totally lean. I thought a boost leak I would nice in just a lack of power (psi) rather than being lean. I'm gonna go check my DV, but its a forge job and I don't that's the problem but I gotta start ruling stuff out.

Anyone recommend a certain fuel gauge or what fittings I would need. I guess its 5/16th fuel rail correct?


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## Rod Ratio (Jun 6, 2012)

*VRT 12v Kinetic stage II - going lean on boost, what are common things to look*

Pressure test your intake tract using the guide at the top of the 1.8T technical forum. You probably have a leak(s).

After that I'd say fuel pump.

You can't get anywhere with diagnosis without a 100% sealed intake tract however. I mean SEALED; as in no pinhole leaks, nothing.

If you need local help I live in Allentown PA as well:beer:


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## CorradoFuhrer (Mar 21, 2002)

I tested my Forge diverter valve, shes good no leaks. I'll have to do some double checking around. Everything looks to be intact.

My money is on the fuel filter or the fuel pump. It seems to be getting worse. But its only on boost thus far, its all the way down on the MBC, pushing out 5 psi. Seeing AFR's in the 13's more prevalent to the point where there's no point even getting on boost.

I would appreciate meeting up with someone who has a fuel pressure gauge setup to see what shes at at idle and with the FPR vac open to see if the numbers are good or not.

My Fuel Pressure gauge is all in different pieces. I would need the appropriate fittings to make it all work. It would be nice if someone has a built setup that could T in real quick to just let me know where I'm at to rule fuel out one way or another. Plugs are good, Boost tubes were snugged up, intake with DV was checked and snugged up. 

No codes on my V checker. Could the coolant temp sensor be shot and not throw a check engine light, or the throttle position sensor? Two of these things I would suspect would affect idle or off boost. Not gonna dwell on either, just wonder from others experiences.

Problems on boost, leads me to a lake of fuel supply or a leak as previously stated. Trying to narrow stuff down as much as possible. Constructing the boost caps and the bicycle pump will be more involved after the fuel (which I assume to be the culprit) is checked out first.

I'm not sure if this will present itself with out load (being on boost) checking the gauge with the fuel pump. Might be easier said that done there, hoping it shows up right away at idle or with the FPR vac tube taken off.

I know with my nitrous mark viii I would run it up the hill on the high way iwth the gauge taped to the windshield, but I took the line off my wet kit (fuel off schrader) and it was enough to get it barely on the windshield. It was fine with a load and I felt comfortable shooting a 150 shot. (I also had a new fuel filter and Walbro intake 255 high pressure job in the tank, but I wanted to be double shore before letting it go.)

I'm sure i'll be able to construct something at the local A and A if someone doesn't have a custom setup job already that I could slap on real quick. :thumbup:


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## Yareka (Mar 5, 2002)

I would put money on a bad o2 sensor or a leak on the fpr vacuum line.

If you have any doubts about the fuel filter, no reason not to go ahead and change it.

Putting the walbro intank in isnt that difficult and is definitely needed for what you are doing.


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## CorradoFuhrer (Mar 21, 2002)

30 psi at idle, 38 psi with vac off the FPR. Seems low :screwy: All at idle.


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## Yareka (Mar 5, 2002)

Your fuel pressure is definitely low like 2.5 bar if you got the rail fitting worked out. Should be around 44psi with the fpr line off so if you have a 3bar in there its looking like the filter or the pump.


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## CorradoFuhrer (Mar 21, 2002)

It's low but not terribly low. Hoping the filter is just gunked up. But when it started to go I was adjusting boost levels and had recently filled the tank.

This was all at idle, I wonder what it does when it has a load on it. I only got 2 feet of fuel line, I should have got a couple more to stick it up on my windshield and have someone on fuel pressure duty lol

Honestly just glad I was able to rig up this fuel pressure gauge. For the future, all you need to do is get the gauge, a 1/8 to 5/16th adapter... and remove the plug from the male 5/16 nipple on the rail.

I removed the fuel fill line per a write up I read, and got a T fitting. 

Also very glad its not good, so i'm not chasing my tail at less obvious things. :beer:


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## Boost112 (May 8, 2002)

CorradoFuhrer said:


> Honestly just glad I was able to rig up this fuel pressure gauge. For the future, all you need to do is get the gauge, a 1/8 to 5/16th adapter... and remove the plug from the male 5/16 nipple on the rail.
> 
> I removed the fuel fill line per a write up I read, and got a T fitting.
> 
> Also very glad its not good, so i'm not chasing my tail at less obvious things. :beer:


can you post a picture of how you added the fuel pressure gauge to the rail...i was just going to put in an inline gauge on the fuel line going to the rail...tia...


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## CorradoFuhrer (Mar 21, 2002)

Boost112 said:


> can you post a picture of how you added the fuel pressure gauge to the rail...i was just going to put in an inline gauge on the fuel line going to the rail...tia...


I made a T per searching on here with a fuel pressure gauge. I had to get a brass fitting to go into my gauge for a 5/16 nipple... turns out it looks like thats whats on the fuel rail. I also bought a 5/16 T and 2 feet of 5/16 fuel line and appropriate fittings (I should have went with fuel injector clamp or whatever but the clamps were what was in front of me)

got it all rigged up T'ing into the top fuel pressure line


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## CorradoFuhrer (Mar 21, 2002)

thanks, I cleaned it up a bit inbox open.




























swapped out a new oem fuel filter. It seems I gained 1-2 psi. Its still 4-5 psi off.


Stock should be 2.5 bar = 36.3 psi
with out vac on FPR 3.0 = 44 psi

I have 150k on the clock with paper work that the fuel pump was replaced sometime before I had it at like 80k or so. The symptoms read that the car wouldn't start in the paper work so the fuel pump was replaced iirc. 

I guess that is just enough not to have the fuel right.


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## Yareka (Mar 5, 2002)

Holy sh
I havent seen a fuel filter that corroded in a while.

Another thing to check is to make sure you are getting proper voltage at the pump :thumbup:s
and then swap in the walbro that you'll need for boost anyways


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## CorradoFuhrer (Mar 21, 2002)

Yareka said:


> Holy sh
> I havent seen a fuel filter that corroded in a while.
> 
> Another thing to check is to make sure you are getting proper voltage at the pump :thumbup:s
> and then swap in the walbro that you'll need for boost anyways


that's a good idea - walbro in tank? or in line. I've still on the fence of what I wanna throw my money at either an upgraded intank which would save me the cost of having to buy 2.

How often is it the voltage? You mean like a bad ground or something?

I've read some posts where fuel pressures were similar and swapping pump did the trick. At least I can rule out everything else at this point.

The stock pump was fine for my setup 12 psi... or maybe I zapped it pushing the boost a bit too far. It coincides when I was adjusting boost around when the thing started showing me higher AFR's and stumbling, then no good with the boost turned down.


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## Boost112 (May 8, 2002)

Yareka said:


> Holy sh
> I havent seen a fuel filter that corroded in a while.
> 
> Another thing to check is to make sure you are getting proper voltage at the pump :thumbup:s
> and then swap in the walbro that you'll need for boost anyways



....Rock Auto has a new pump assembly for like $80 bucks... if you are wanting to replace the intank pump with a stocker... http://www.rockauto.com/catalog/x,carcode,1282610,parttype,6256











and also in case you are worried about voltage you can always relay your stock intank pump...and even better add a switch to it so that you have your own little anti-theft device...a fuel cut switch... check the link...guy had similar issue...

http://forums.vwvortex.com/showthread.php?5415766-Relay-your-fuel-pump!&highlight=relay+fuel+pump


i have been planning on cleaning up my fuel system as well...thought it might help in your situation...


oh and i would do a stock intank with a walbro inline...


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## CorradoFuhrer (Mar 21, 2002)

hey thank you very much! great info


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## Yareka (Mar 5, 2002)

CorradoFuhrer said:


> that's a good idea - walbro in tank? or in line. I've still on the fence of what I wanna throw my money at either an upgraded intank which would save me the cost of having to buy 2.
> 
> How often is it the voltage? You mean like a bad ground or something?


On my slc, and even a mk3 like you have, is getting to the end of the stock pumps life. Why take a chance in boost of it failing, i did the intank walbro originally just to get the old pump out of there and ended up needing it later when I went turbo. If you do inline, you are still still SOL if your original intank dies, just food for thought. I understand your hesitation for doing the intank because of difficulty but its really not that hard. If anything, pick up a used mk3 sender assembly to put the walbro in as practice, if you feel good about it(and you will) swap that in and have your stock backup ready to go just in case it goes wrong.

Voltage drop doesnt just come from a bad ground. Its old wiring and a good distance away from the fusebox. Easy to check and could easily cause the issue you are seeing, worse is that the lower voltage can shorten the pumps life.


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## Rod Ratio (Jun 6, 2012)

*VRT 12v Kinetic stage II - going lean on boost, what are common things to look*

I vote walbro intank, relayed:thumbup:


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## catalina2.o (Oct 27, 2008)

which model intank walbro do we use?
and good write ups on it?


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## Boost112 (May 8, 2002)

...just for simplicity... i would...(and i am)... run a new stock in tank with a walbro in line or a Bosch 044...if your looking for a really nice fueling setup i would do the stock in tank with a 044/surge tank combo...fueling for up to like ~500hp... all in tank walbro are universal and will require you to modify the stock strainer and such to get it to fit...and that doesn't include the uncertainty of what will happen when you don't have enough fuel in the tank with the walbro...

...but if your looking for a solution this is the best link i could find of how would do it...

http://forums.subdriven.com/showthread.php?3478244-High-output-fuel-pump-in-stock-Mk3-housing


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## CorradoFuhrer (Mar 21, 2002)

Yareka said:


> On my slc, and even a mk3 like you have, is getting to the end of the stock pumps life. Why take a chance in boost of it failing, i did the intank walbro originally just to get the old pump out of there and ended up needing it later when I went turbo. If you do inline, you are still still SOL if your original intank dies, just food for thought. I understand your hesitation for doing the intank because of difficulty but its really not that hard. If anything, pick up a used mk3 sender assembly to put the walbro in as practice, if you feel good about it(and you will) swap that in and have your stock backup ready to go just in case it goes wrong.
> 
> Voltage drop doesnt just come from a bad ground. Its old wiring and a good distance away from the fusebox. Easy to check and could easily cause the issue you are seeing, worse is that the lower voltage can shorten the pumps life.


So you currently have a walbro intank? What happens when you get down below a quarter tank? Is that just bad info? What type of custom stuff has to be done.

I replaced my nitrous lincoln mark viii fuel pump with a walbro, and it was very straight forward, it involved cutting bit of the holder but it was pretty obvious how to get it to fit. I had to drop the tank to get it all in which was a pita. But I got it done.

Do you know which walbro you used? The 255 for a mustang? I remember I used some edelbrock part number that was like a high flow pump for a suburban or something, same deal 255 lph high flow high pressure.


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## CorradoFuhrer (Mar 21, 2002)

Boost112 said:


> ...just for simplicity... i would...(and i am)... run a new stock in tank with a walbro in line or a Bosch 044...if your looking for a really nice fueling setup i would do the stock in tank with a 044/surge tank combo...fueling for up to like ~500hp... all in tank walbro are universal and will require you to modify the stock strainer and such to get it to fit...and that doesn't include the uncertainty of what will happen when you don't have enough fuel in the tank with the walbro...
> 
> ...but if your looking for a solution this is the best link i could find of how would do it...
> 
> http://forums.subdriven.com/showthread.php?3478244-High-output-fuel-pump-in-stock-Mk3-housing


that's a great link. I have been searching a lot and didn't come across that.


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## Boost112 (May 8, 2002)

CorradoFuhrer said:


> that's a great link. I have been searching a lot and didn't come across that.


...I have been using vortex for ever...but sometimes I cant find what im looking for using the search function...I just go to google and it will usually give me a lot more links...especially from other sites...just get the key words in...and it usually gets me close enough...


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## 2NICE4RICE (Jun 29, 2003)

*Fuel pump*

I did the IE surge tank with bosch pump submerged and a new oem intank and seems to work good this far, haven't turboed the vr yet. I think your best bet is something similar to mine or go for the walbro intank and be done with it!

From what I hear is if you go with just a walbro inline it basically pulls fuel through the (stock) intank which eventually kills


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## CorradoFuhrer (Mar 21, 2002)

Yareka said:


> On my slc, and even a mk3 like you have, is getting to the end of the stock pumps life. Why take a chance in boost of it failing, i did the intank walbro originally just to get the old pump out of there and ended up needing it later when I went turbo. If you do inline, you are still still SOL if your original intank dies, just food for thought. I understand your hesitation for doing the intank because of difficulty but its really not that hard. If anything, pick up a used mk3 sender assembly to put the walbro in as practice, if you feel good about it(and you will) swap that in and have your stock backup ready to go just in case it goes wrong.
> 
> Voltage drop doesnt just come from a bad ground. Its old wiring and a good distance away from the fusebox. Easy to check and could easily cause the issue you are seeing, worse is that the lower voltage can shorten the pumps life.


Did you have to dremel all sorts of stuff and buy rubber fittings like that write up below mentios. Or did you just pull out the pump housings, slap the pump in there... and off you go? So dremelling is reuired to remove plastic to get it to sit in right?


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## Yareka (Mar 5, 2002)

CorradoFuhrer said:


> So you currently have a walbro intank? What happens when you get down below a quarter tank? Is that just bad info? What type of custom stuff has to be done.
> 
> I replaced my nitrous lincoln mark viii fuel pump with a walbro, and it was very straight forward, it involved cutting bit of the holder but it was pretty obvious how to get it to fit. I had to drop the tank to get it all in which was a pita. But I got it done.
> 
> Do you know which walbro you used? The 255 for a mustang? I remember I used some edelbrock part number that was like a high flow pump for a suburban or something, same deal 255 lph high flow high pressure.


That was the original setup I had years ago. Now I have a 10gal fuel cell gravity feeding an IE surge/044 Combo but I had the walbro intank for years with no issues. I didnt have any issues with it sitting different than my stock pump but I never let my drop-in fuel pumps get below 1/4 tank especially under boost.

I dont remember exactly what I had to do to modify the cage but like you said with your lincoln, it was very straightforward once you pull the stock pump out, and you definitely dont need to drop the tank for this one :wave:

Its very close to the same dimensions and the stock bottom cap fit over the filter sock for the walbro. And it was the mustang walbro that I used, its the same walbro intank that all the vw vendors sell. You might also want to look into the aeromotive drop in and I believe there is a new walbro out now that flows more.


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## CorradoFuhrer (Mar 21, 2002)

Yareka said:


> That was the original setup I had years ago. Now I have a 10gal fuel cell gravity feeding an IE surge/044 Combo but I had the walbro intank for years with no issues. I didnt have any issues with it sitting different than my stock pump but I never let my drop-in fuel pumps get below 1/4 tank especially under boost.
> 
> I dont remember exactly what I had to do to modify the cage but like you said with your lincoln, it was very straightforward once you pull the stock pump out, and you definitely dont need to drop the tank for this one :wave:
> 
> Its very close to the same dimensions and the stock bottom cap fit over the filter sock for the walbro. And it was the mustang walbro that I used, its the same walbro intank that all the vw vendors sell. You might also want to look into the aeromotive drop in and I believe there is a new walbro out now that flows more.


does anyone market a modified drop in tank for that Aeromotive to fit the mk3? Or is it just like the walbro, where you have to do a bit of custom work to get it in there correct?

Did you have to dremel anything? I just remember having to break a small plastic piece with my Lincoln which I did with a snips or something. and other than that it wasn't too far off like the stock one like your saying.

for 90 bucks you can't beat it, a better fueling pump with out having to replace the stock one. Later down the line if I max out the walbro I'll have no quams really going for a 500 dollar unit rather than a 90. Walbro 255 holds up a lot of power. I won't be able to get to this until the end of summer as i'm leaving for leaving for europe for study abroad. 

but i'm still curious and want to have a good game plan when I get back. Must say that IE 044 inline sump is reallly nice.


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## CorradoFuhrer (Mar 21, 2002)

This video show's way higher stock numbers than I read online here or on the internet somewhere? 

This says for a 3 bar. I know they made a 4 bar for the older VR's OBD1 or so right? I'm just trying to figure out what the numbers exactly should be for next time. 

Not sure why his numbers are higher, but I verified that its supposed to be 43.5 with the vac line removed.


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## Rod Ratio (Jun 6, 2012)

*VRT 12v Kinetic stage II - going lean on boost, what are common things to look*

(1) bar for the atmosphere
+
(3-4) bar for your fpr
+
(Whatever psi boost you're running)

The fuel pressure must overcome the boost pressure, and atmospheric pressure to achieve the setting of the fpr.

Example. A car running 14.7 psi @ 3 bar; will actually be running 5 bar of fuel pressure.


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## 'dubber (Jun 15, 2004)

Check voltage at the pump plug and battery. 
You might be able to stop there. If not, then 
dead-head test the pump briefly. 
If that checks out too, then 
check fuel volume at the rail feed line.


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## dub_slug (May 12, 2008)

Good info in here :beer: I'm leaning out slightly in boost, gonna check the fuel pressure tomorrow and swap out the fuel filter.


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## CorradoFuhrer (Mar 21, 2002)

Boost112 said:


> ....Rock Auto has a new pump assembly for like $80 bucks... if you are wanting to replace the intank pump with a stocker... http://www.rockauto.com/catalog/x,carcode,1282610,parttype,6256
> 
> 
> 
> ...


 This fuel pump is considerably cheaper than the rest of the pumps listed on rock auto. Has anyone had direct experiences with this? If its good i'm going to buy it, if its not reliable (most stock fuel pumps i've seen are around 200 ish bucks plus shipping) i'm more inclined to go with a Walrbo in tank and just have at it.


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## CorradoFuhrer (Mar 21, 2002)

Rod Ratio said:


> (1) bar for the atmosphere
> +
> (3-4) bar for your fpr
> +
> ...


 I thought the numbers were supposed to be 2.5 bar at idle and 3.0 bar with out vac reference (no fpr vac) at idle. 

3 bar with out vac reference would be 43.5 - this guys numbers at idle are way higher, either he doesn't have a 3 bar as stated in the video or i'm missing information. Is it 3 bar at idle with the vac reference or with out? Make sense that at 0 vac, it would put out the most fuel. So at 3 bar it should be 43.5 not extremely higher like it is in the video above. 

mine are significantly lower than the video but not so far bad from 3 bar. Just trying to figure out how off my fuel pressure actually is. 

You can see my pics of my pressures in the first page. 

I wound up just ordering that 80 dollar rock auto pump. Hopefully that fixes the problem. I was going to do a Walbro but just hate the idea of sputtering along when under a quarter tank .


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## VEE-DUBBER (Nov 22, 2000)

The cheap pumps level sending unit is so fragile, and the tubing likes to kink when you put the pump in. That's my experience with the cheap one a customer wanted. The plastic is super brittle


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## CorradoFuhrer (Mar 21, 2002)

Are we talking about the same pump? Damn that sucks, Oh well already ordered it. I hope it isn't too cheap or i'll be buying twice.


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## Gerg (Sep 15, 2006)

My #42 OBD2 vr was running lean due to bad ecu and or coolant temp sensor 
Mine you I changed nearly everything


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## KubotaPowered (Jan 27, 2005)

I've had C2 42lb software that would stay in the mid 13's afr and then dive down to 11.8 with a little more RPM. No knocking or other driveability issues.


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## CorradoFuhrer (Mar 21, 2002)

What turbo and psi were you running on the 42 software. I've been pretty happy with the C2 stuff so far. I get some random CEL's here and there for evap, even though its the race chip and I thought it was deleted...


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## CorradoFuhrer (Mar 21, 2002)

VEE-DUBBER said:


> The cheap pumps level sending unit is so fragile, and the tubing likes to kink when you put the pump in. That's my experience with the cheap one a customer wanted. The plastic is super brittle


apparently the fuel pump went in fine, i didn't hear any complaints from my buddy... Its gotta be better than a used one. I'll have to talk to him about it to see what he thinks.


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## CorradoFuhrer (Mar 21, 2002)

Gerg said:


> My #42 OBD2 vr was running lean due to bad ecu and or coolant temp sensor
> Mine you I changed nearly everything


wouldn't a bad coolant temp sensor be running rich as its usually the case? Doesn't it also throw a CEL when its faulty?


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## dub_slug (May 12, 2008)

I recently changed injectors to 630's, pro Maf, low temp coolant sensor/thermo, new OEM fuel filter, and a walbro. She's running beautifully now. AFRs are kinda rich under boost sometimes @ ~11.3 so I raised the boost and they're looking good. 24psi is really nasty 

I would do the fuel filter for sure then work your way to the coolant temp
Sensor


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## CorradoFuhrer (Mar 21, 2002)

dub_slug said:


> I recently changed injectors to 630's, pro Maf, low temp coolant sensor/thermo, new OEM fuel filter, and a walbro. She's running beautifully now. AFRs are kinda rich under boost sometimes @ ~11.3 so I raised the boost and they're looking good. 24psi is really nasty
> 
> I would do the fuel filter for sure then work your way to the coolant temp
> Sensor


 Fuel filter was done, fuel pump - turns out the alternator kept dying according to my buddy who had the car and did the pump while i'm away in Germany... I stuck a new battery in there as well, and it all seemed fine and the alternator readings showed 14xx, after he got it he said it was dying out, even after he did the pump. He said it was the alternator. I kinda protested but told him to go swap it out, and he said its all good now. 

Probably over spent for a battery and a pump - oh well they can't hurt on a non turbo, turbo car. 

Is your Walbro in tank, he was gonna go for that, but I searched till my eyes bleed and figured to do a sump or external. :beer:


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## CorradoFuhrer (Mar 21, 2002)

Boost112 said:


> ....Rock Auto has a new pump assembly for like $80 bucks... if you are wanting to replace the intank pump with a stocker... http://www.rockauto.com/catalog/x,carcode,1282610,parttype,6256
> 
> 
> 
> ...


 I went with this pump, i'm getting the exact same fuel pressure as the replaced oem pump.... The voltage was at 17.xx at the pump. I'm not sure why it was so high, maybe my voltmeter is shot, but it was 13-14.xx at the battery. 

C2 mentioned that the fuel pressure being slightly off at idle would have little to no impact on my air to fuel ratio's being drastically off. So they pointed me in the direction of the mafs. I cleaned it off and things seem to be doing much better. 

I guess you really need a catch can because my mafs had gotten a little oily but nothing terrible because the crankcase stuff comes up and goes through the mafs intake housing. 

the last thing that would need to be replaced is the FPR, but i'm not sure if that would cause this issue or not.


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## CorradoFuhrer (Mar 21, 2002)

dub_slug said:


> I recently changed injectors to 630's, pro Maf, low temp coolant sensor/thermo, new OEM fuel filter, and a walbro. She's running beautifully now. AFRs are kinda rich under boost sometimes @ ~11.3 so I raised the boost and they're looking good. 24psi is really nasty
> 
> I would do the fuel filter for sure then work your way to the coolant temp
> Sensor


 wouldn't a coolant temp sensor run rich, throw codes?


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## CorradoFuhrer (Mar 21, 2002)

thanks to c2 turns out to be a dirty MAFS, go with a catchcan or vented mafs to atmosphere. Cleaning it brought it back. Not sure why i got funky readings on my fuel pressure.


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## CorradoFuhrer (Mar 21, 2002)

swapped in another 3.0 bar FPR, same deal on the fuel pressure. So maybe its my gauge. Cleaned my mafs again, and the problem came back, leans out hard under full boost low 13 AFR, i hop right off the throttle when I see it. 


Swapping in known working mafs is the next step.

I have another coolant temp sensor, so before I get covered in coolant, don't these things throw codes at all after the chip? 

and doesn't the coolant temp usually produce a rich condition when its bad?

The car drives great though just shows bad AFR under full boost, outside of boost its fine. i'm lost. I gotta find someone with a vag com in the Lehigh Valley and or a working mafs to double check.


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## dubbin95 (Mar 18, 2007)

What ended up being the solution to this issue?


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## Dimmu (May 25, 2014)

dubbin95 said:


> What ended up being the solution to this issue?


im having the same issue, 14.5 while cruising and 14.5-13 afr in boost. im pretty sure i have a boost leak. i randomly get throttle body codes and the car wont idle at lights, it goes full lean and hardly runs. other times it runs fine. when i did the obd2 swap in my rado i replaced all sensors. also have a new fuel pump, relay and a external bosch 044 (??) relayed off the trigger from the pump. fuel pressure is 45psi at idle and with the vac line off the FPR its 65psi


when i go off throttle it runs super rich (9.1-11.5) 


any suggestions? i know i need to pressure test the system, but if i had a leak it would read read lean at idle correct?


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## Dimmu (May 25, 2014)

Up


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## CorradoFuhrer (Mar 21, 2002)

I had a lean thing with c2 but it went away when I turned up the boost. It's like it stays in the 13 while boost builds/curves up then goes into the 11s. I changed everything in my fuel assembly and it turned out just needed to turn the boost up more for the tune


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## CorradoFuhrer (Mar 21, 2002)

I get rich off throttle as well but not that rich


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## Dimmu (May 25, 2014)

Do they calculate fuel trims by maf grams or is it solely tps or a mixture of both?


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## Dimmu (May 25, 2014)

It only did 9 one time. All other times it dips into the 11s.


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