Potential boost leak? Negative fuel trims

Ms3orDie

Ms3orDie

Greenie N00B Member
Greenie Member
Im trying to chase a potential boost leak and I think ive exhausted all my options here. Boost leak tested and found nothing. Tuned for 25 psi but im only getting 14-16 at wot. Rarely i get 19-20 but only during certain conditions. My ltft is at -9.52 and stft is at -3.28 at idle. At wot, they both go to -0.16. Only cel i have is for my deleted egr and tpms.

Recent work done:
Valve cleaning
Injectors flow tested
Injector CS seals
EGR Full Delete
PCV plate and valve
VTA Oil Catch Can
New Intake Manifold gasket
New Throttle Body gasket

But even prior to this i had a potential leak and fuel trims were worse on the negative side. About -15 for long and short term was sporadic anywhere from 4 to -14. Recent work definitely helped the fuel trims. Through the ap, i see that my evap system is not ready. Unsure if this has anything to do with it. Any ideas? Tia.
 
Easter Bunny said:
Fix the eval system it's throwing off the trims
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Wouldnt a bad evap system throw a code?

Edit: i get what you mean now. Ill need to do a drive cycle to get systems ready. But damn i put at least over 100 miles on it since the recent work
 
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Is the code for the eval turned off in your tune?
 
It should only be throwing off your trims if it isn't working correctly if it's just not ready them it should be fine
 
Is your air filter really dirty?
 
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Ms3orDie said:
Stupid question but, i tried doing a boost leak test on the intake side and air is escaping from my vta cc. Could this be causing the leak? I have a brand new pcv valve and the check valve that damond supplied.
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That's a fairly large boost leak, so yes. Is there a chance that the check valve between the IM port and the OCC is backwards? Or did it happen randomly after having it installed for a while.
 
broda said:
That's a fairly large boost leak, so yes. Is there a chance that the check valve between the IM port and the OCC is backwards? Or did it happen randomly after having it installed for a while.
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So when i purchased the occ from damond, the hose already had the check valve pre-installed. I didnt bother to check it.
 
Ms3orDie said:
So when i purchased the occ from damond, the hose already had the check valve pre-installed. I didnt bother to check it.
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That'd be the best thing to double check. You're naturally going to leak a small amount of pressure into the crankcase because of putting air into the cylinders so that'll go through the PCV into the OCC. You could just be seeing that but if it's a significant amount of air then it's likely to be that check valve.
 
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