# vr6 turbo running lean



## booster_ginster98 (May 14, 2010)

1998 GTi VR6 OBD2 

ok here is my dilemma. i just rebuilt my block with all new rings, bearings, and hardware and decided now would be a good time to do a turbo setup, so i lowered the CR, got everything i needed and got it done. 

how it sits now the car is RUNNING. but extremely lean. it will start fine and idle fine, but it sits aruond 15 on the WB and will dance around between that and giong passed 18 on the WB. and when i drive it, i cant tell whether im getting horrible detonation or its misfire, but when i accelerate i can hear a pop every couple seconds or so, and if i get into boost it will sounds like a burst fire rifle. 

heres what im running: 
T04 turbo .70 a/r inlet, .58 a/r out 
9:1 headspacer 
C2 42lb turbo software 
42# green top injectors 
2.5" intercooler piping w/ FMIC 
3" open DP with o2 sensor 
NO CAT 
forge SPLTR DV 
4" maf housing 
262 cams 
Wastegate w/4psi spring 
walbro 255 inline 

now if im very easy on the throttle i can keep the WB in the 14-15 range, but if i try to accelerate like a "normal" person, not a grandma, it shoots to 18+ then will drop to about 15.5-16 when i hit boost. 

the car studders and stumbles and is very hesitant under any type of throttle. ive replaced a lot of stuff and tried everything i can think of, i just DK what would cause it to run lean like it is. does anyone have any ideas? im all ears guys. thanks


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## FaelinGL (Nov 28, 2004)

Is the DV recirculated? If not that may be one of your problems. 

Mike


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## booster_ginster98 (May 14, 2010)

i had it atmospheric for awhile and it ran ok, i just put it back to recirculate and it seems to run worse now. 

anyone thnk that cleaning the TB would help this at all? read somewhere someone had similar problem andd this fixed it. just a thought.


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## arejaygsx (Jul 4, 2003)

any codes? what plugs u running what gap? how old are your wires,maf 02 sensor?


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## booster_ginster98 (May 14, 2010)

spark plugs and wires are both brand new. plugs are one heat range colder plugs, and gapped at .034 

i have a borrowed MAF from a friends car, but he recently cleaned it and im wondering if it got damaged when he cleaned it. i need to find another one to try out. 

and the o2 is the original. car has about 101k on it, but im pretty sure it was fine when i rebuilt motor. however i did have to cut the exhaust off the car, maybe it got some metal shavings on it and fouled out the o2?


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## TBT-Syncro (Apr 28, 2001)

put the maf sensor in backwards perhaps? (check to see which direction the arrow is pointing) 

:beer:


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## booster_ginster98 (May 14, 2010)

arrow is pointing INTO the intake right?


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## slcturbo (Apr 19, 2010)

Any codes? 

For a car to run that badly usually means. 

1) MAF 
2) Throttle 
3) Big vacuum leak 

If it was only fulll throttle I'd include ignition or fuel pump, but to run that bad everywhere would lead me toward those 3. You just did alot of work on the car though. Recheck everything. Wiring, everything plugged in, grounds, vac leaks, etc.


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## slcturbo (Apr 19, 2010)

booster_ginster98 said:


> arrow is pointing INTO the intake right?


 Arrow on the MAF points toward the throttle/direction of airflow.


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## booster_ginster98 (May 14, 2010)

the only codes i have gotten so far were random multiple misfire in cylinder 2 and 4, which i found was from injectors that had been stuck closed, figured that was going to solve all my problems, got it all back in, but didnt fix the problem. 

ive also gotten codes for the TPS. this only happened when i put the injectors back in from having them cleaned. i took the throttle body off tonight and have cleaned it, as it was pretty filthy. would a dirty TB cause the TPS to malfunction or do you think that the TPS might be faulty? 

ive tried about three different MAF sensors. the one im using is a borrow one from my friends passat, and his car was running when we pulled it and is bone stock, but he DID clean it before i got it. it didnt realy seem to make a difference. now before i had the stuck injectors cleaned i tried out another one of my buddies MAF sensors and his made my car run realy funny. im kind of wondering if mine and the one from the passat are faulty and when i tried my other friends it was actually trying to fix what my stuck injectors were causing, hence the running weird. idk 

also the car has about 102k on the original o2 sensor. idk if that would cause this or not. i have a youtube video of the in car shot of my WB at idle. let me find it and i'll post a link. jst a sec.


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## booster_ginster98 (May 14, 2010)

ok found it. now this was BEFORE i had the injectors cleaned. i had just taken the car to the gas station and had the codes cleared, the CEL is for the random multiple misfire, cylinder 2 and 4 misfire. 

http://www.youtube.com/watch?v=rCBYbsGI6U8


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## booster_ginster98 (May 14, 2010)

i also have one other question to throw in there. 

would a leaky intake manifold gasket cause the lean fuel mixture along with the studder and hesitation?


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## booster_ginster98 (May 14, 2010)

one question i do have on top of all this. well...actually a few questions. 

first, i had a buddy hook up his vag-com to read some blocks and get a better idea of whats going on and causing misfire. except i didnt know what blocks to read. anyone know which ones to check for any of this? 

one thing we DID read with it was that the timing was a little bit ritarded, about 9si degrees, and that sparked two questions. 

A. is my timing off? 

B. i do have the autotech 262 cams installed, and i have heard of some people having trouble with cars that are not normally turbod after they turbo them and have cams in them with a chip that is not setup for cams. not sure if thats the case or not. im starting to lean towards the timing, which i hate, but if thats what it is, then a somewhat "easy" fix lol 

thanks


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## GinsterMan98 (May 19, 2008)

It is real easy to slip a tooth while putting cams in. Pull the top cover and check your timming. Yes, a leak in the intake manifold could cause running issues. How much vaccum are you pulling at idle? Also, go into vag com and select obd2 tab. select the read data tab and a screen should come up with several blocks to monitor outputs. You want to look at long term and short term fuel trims. If either is around -20 that would cause a lean condition. What fuel pressure are you running with the 42's? How far away from the end of the exhaust is your O2 located?


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## GinsterMan98 (May 19, 2008)

To answer question B, cams should not effect how the C2 chip functions. It fuels based off mass air flow, so if cams were to blame you would run more rich, not lean due to the increased flow from the cams. I have DSR 256's and they had no effect on afr reading, just the powerband and overall power output.
What do you have your plugs gapped to and what kind are they? The reason you may be showing lean is from the misfire. when fuel is not burnt due to a nonfire on a cylinder the o2 sensor will read the unburt oxygen and show lean. I think your issue is spark related or timing related. Check your timing and report what type of plugs and the gap distance you have them set at. The most widely accepted plug for VRT's is NGK BKR7E gapped at .024 to.028 deppending on who you talk to. I run these plugs gapped at .024 with no issues.


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## booster_ginster98 (May 14, 2010)

thanks for the answer.

today i checked the timing, i set cylinder one to TDC, and had the valve cover pulled to check the cams, they all lined up properly, could slide my cam lock tool into place with no problem. 

the o2 sensor is located in the DP that was prefabbed into, so about 1/3 of the way down the downpipe, close to stock location, and the WB o2 is about 6-8 inches below that in the DP. i am CURRENTLY running no exhaust other than DP, just due to piping size. so NO cat, and no secondary 
o2 sensor. and the main o2 is what i BELIEVE to be the original from the factory, so im curious if that is whats causing my problem.

i am running bkr6e plugs, all gapped to .034. i have tried both these and bkr7e plugs gapped at .024. have also replaced the plug wires, only thing i have NOT replaced is the coilpack, but it was replaced about 25k ago. 

im not as much having LEAN problems anymore, but more on the misfire side. i need to data log some stuff on vag com, but the best i can describe the current symptoms are thus:
idles good, but throttle is hesitant, luggy, feels like its not running on all cylinders, i.e. no power, and pops thru what i believe is the exhaust. i can also feel the car shudder on start up, but its not constant, like one little shake every 3-5 seconds.


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## dubbinmk2 (Jan 15, 2008)

u need a new coil pack my man !!!!!!!!!!!


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## GinsterMan98 (May 19, 2008)

Its worth a shot if you got a spare or could borrow one from a buddy for troubleshooting purposes. Just remember when you clear codes you reset your fuel trims. It can take several days of varying driving conditions and throttle load to set these in the ECU. This just means the car might run funky at times until it learns how much fuel it needs to run corectly. If its "trimming out" or the values in the obd2 tab are going really far from 0 you have problems.


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