# Another lean vrt



## masterqaz (Oct 5, 2007)

obd2 c2 42lb file (brand new chip and greentops) 
New 4'' a/f, 4'' maf (correct direction) 3'' inlet to turbo. 3bar fpr 
oe intake pump, New inline 255 walbro 
oe block fresh chains/gaskets and fresh rebuilt head(valves guides springs lifters) 
8.5-1 comp stainless headspacer, copper sprayed hg 
t04 60 trim on center turbo, atp style exh mani. 
Upper intake short runner, drivers side. 
Msd coil packs 8224? 
brk7e copper plugs gapped at .024? around their 
38mm tial wg sm green spring .5bar 
tba has been done several times 
ive checked for loose couplers/tightened everything 2x over 

Thats basic info, the problem- 
running lean into boost, dies at start up in the morning. 

Cars running 14.7 at idle, idle speed is fine, pedaling into boost it'll drop to 12.5 then 4 pounds in she'll start to lean out to 13.1, then too low 14's and occasional high 14's around 6-7 pounds (maxing out wg spring). 

Ive read about weak pumps and clogged filters, ive got a new fuel filter(shoulda seen inside the old one) and a new inline walbro (seen about 40km) 

Ive read about fpr's (have yet to test this) another concern is the rusty pitted state of the fuel rail at the fpr (sanded it done and blew out before install, but now im wondering if shes blowing pressure back to the tank cause of pitting) 

Ive heard about weak mafs, finding it troubling that the maf has issues as the car drives pretty well partial load and out of boost, even into boost before it hits max (pretty ****ty efficiency at 7psi) 

Ive tryed 2 different cleaned mafs, both drive the same. Ive logged maf and found the numbers to be fairly low, although ive seen it before on someones thread compairing their 1.8t to their vrt. Im seeing high maf readings around 90g/s? does that seem correct. 

Also read about honeycombs for laminar flow- worth a shot? 
Also read c2 likes to run leaner on the 42 file on lower boost. 

Thats all for now, ive busted my head open thinking and i know theres more to say. 

Lets see what the common consensus is


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## 95GOLFIIIJOSH (Aug 13, 2007)

*lean problem*

hmm is it breaking up at alll my buddy had a problem with his vrt and the problem was in the c2 out dated ****.... get united motorsports soft wear its only about 150 bucks and alot better than the c2 thats my 2 cents


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## SVTDanny (Aug 8, 2005)

Check your fuel pressure..


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## masterqaz (Oct 5, 2007)

obviously but no one finds low maf readings curious? i was looking at the laptop today on a second gear pull to around 5 grand and i was seeing 40g/s thats mind blowing low. 

havent tested fuel pressure cause i might as well by a regulator first because its about the same price as a tester. 

talked to the guy at work here and ill be using his to test so ill know soon.


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## viw28 (Oct 8, 2008)

You have exact same symtoms as me buddy, low maf readings, lean in boost, your afr figures are very similar also. 

Here's a maf log I did a while back. Notice my timing pull also  Are you getting that? Have you logged that too? 

What fpr are you using? 3 bar or 4 bar? Mine improved with a 4 bar but still not great. I am also running 1 bar/15 psi boost pressure where you're running half that. 

I did all the fuel pressure and flow tests, new maf, new fuel pumps, new bkr7e's gapped to .22, new leads, new coil pack, tried several different air filters... 

Also tried some mesh in front of the maf but all it did was cause afr spikes, caused it to be all over the place.


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## Boost112 (May 8, 2002)

Hey gethin hope all is well....

...i have the same issue as you...im running 10 psi on um 440 tune...with the 3bar I was seeing the lean conditions... I put the 4bar in and it richened up the mixture..not the best but much safer than before with 3bar...

...i have a adj. Fpr that I want to throw in so I can fine tune full boost afr... I also just got the fuel pressure guage in the mail so I can tackle that hopefully soon...

... I also put in a air flow straightner in front of the maf... Its alot smoother now...nothing crazy but it helped...also replaced some worn couplings with new ones and tightened all clamps...

So far the car behaves like stock off and on boost... No hiccups... I just couldnt figure out why it was lean with the 3bar...


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## viw28 (Oct 8, 2008)

Hey Danny, glad to hear you're getting somewhere with yours  

You haven't tried your adjustable fpr yet then? What kind of afr's are you seeing now?


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## masterqaz (Oct 5, 2007)

i tried a log on the drive to work but it didnt save so i didnt see if it was pulling timing but holy hell batman thats pulling a lot of timing, those maf numbers are pretty much the same ball park. 

ive been having troubles finding anyones maf numbers on vrts, its all 1.8 maf logs around these days. 

ive tryed the 4 bar but was not satisfied with its results, its all wacky across the board and screws with the afr's at idle from time to time, partial throttle load sucked too.


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## Boost112 (May 8, 2002)

viw28 said:


> Hey Danny, glad to hear you're getting somewhere with yours
> 
> You haven't tried your adjustable fpr yet then? What kind of afr's are you seeing now?


 ..yeah im trying to work on it when I can...but no garage and the miami heat makes working on the car brutal...i damn near burnt my hand when I put it on the fender this last weekend...lol...

...im seeing about the same afr on full boost...12.5-11.8 towards redline...but much more stable ever since the air flow straightner...and when I say stable I mean the transition from positive pressure to 10 psi looks much better...

... I wanna see what the fuel pressure is at idle with 4bar and crank it up a bit and stay in the 11.0-11.8 afr at full boost... Im thinking it will be in the 4.5 bar range... And once that is set I want increade boost...i want to see what happens to the afr with more pressure going to fpr... I just need to put the 3" exhaust on already...


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## Boost112 (May 8, 2002)

masterqaz said:


> i tried a log on the drive to work but it didnt save so i didnt see if it was pulling timing but holy hell batman thats pulling a lot of timing, those maf numbers are pretty much the same ball park.
> 
> ive been having troubles finding anyones maf numbers on vrts, its all 1.8 maf logs around these days.
> 
> ive tryed the 4 bar but was not satisfied with its results, its all wacky across the board and screws with the afr's at idle from time to time, partial throttle load sucked too.


 ..thats the one thing I didnt notice with the 4bar... It drove just as good if not better with it in...across the board...idle is stable...part throttle is good too... And wide open is much improved...its just wierd....


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## SVTDanny (Aug 8, 2005)

masterqaz said:


> ive tryed the 4 bar but was not satisfied with its results, its all wacky across the board and screws with the afr's at idle from time to time, partial throttle load sucked too.


 
An ECU reset wouldn't be a bad idea when switching between FPR's.:thumbup:


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## masterqaz (Oct 5, 2007)

djsheijkdfj said:


> An ECU reset wouldn't be a bad idea when switching between FPR's.:thumbup:


 smart guy right here  yeah i figured it makes sense. we'll see.


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## masterqaz (Oct 5, 2007)

logged 05? 045 and 046 at lunch on a trip to a buddies shop, didnt pull a single degree of timing ?!?! i find that hard to believe, maf didnt get up passed 60ish, this is some wack shiit


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## viw28 (Oct 8, 2008)

:screwy::screwy: Confusing.... 

Is your maximium 60g/s at 7000 ish rpm? I know limiter is 7200 but it rarely logs it 

Danny, sounds like yours is running great now  Im still only seeing those afr's occasionally  

Had mine on a good 650 mile round trip there a few weeks ago and it ran ok, not perfect but still quite good. Funny thing is it seemed to be a bit sporadic the way it ran, just on observation of afr's alone. Sometimes it was going good with afr's in the low 12's, other times it was back up into the 14's :screwy: and that was 300 miles each way only stopping the car once or twice for fuel stops. 

Weird happenings lol


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## masterqaz (Oct 5, 2007)

60g/s at around 5500 6000 didn't bother pulling to 7000


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## CorradoFuhrer (Mar 21, 2002)

masterqaz said:


> obd2 c2 42lb file (brand new chip and greentops)
> 
> Also read c2 likes to run leaner on the 42 file on lower boost.
> 
> ...


anyone else have experience with the 42 file running leaner on lower boost? I'm going try and get my walbro in and raise the boost but seeing 13's at 9-10 psi, i think that could do some damage at 17 if I just get up and lay on it after the walbro install.

but this could be the source of my problem, because its leaner before than the 30# tune I had and this is setup for lower compression.

C2 has not made a mention of this and still aiming at my fueling. I have to check the fuel pressure under boost to see what it says.


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## dubbin95 (Mar 18, 2007)

I am having the same type of issue you are. Running same c2 file but the older version. And 4 bar FPR and still wants to lean out to high 13's low 14 a/f when at around 10psi. any fixes yet for your car?


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## MRosier (Sep 17, 2006)

I also have c2 42# at 10psi and it at WOT its in the 12-13 afr range. I ran higher boost with the 30# tune and it was in the 10.5-11 range. Car runs great


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