Hi guys. I have a Lean Boost problem the last couple of days.It common I know , but I can`t figure this out.
I have attached some loggs (only with VCDS I am afraid I can`t log with ME7logger right now due to hardware issues) .
Requested λ is where I want it to be , actual some times is so lean that I couldn`t do correct loggs.
The car is boosting @1.6 bar requested λ is about 0.8x ,actual some times is more than 1 .When boosting less actual λ can follow to a degree.
Seems like fuel pump/FPR or injectors I thought...well.. no .Fuel pump is great,injectors too ,fuel lines ok , FPR ok too.
Checked for leaks, vacuum lines ,boost lines. Nothing. EVAP (N80) does some weird clickings last few days,thats it.
Fuel trims are on the spot ,both (-0.5 and -1.5) .MAF reads fine ( I did some loggings without it just in case) .I thought about Lambda sensor failure , but at low boosts it follows better ,at Idle it is ok. EGT`S (welll calculated no sensor in this GOLF IV) , seems ok for such a lean condition but I don`t push the car ofcourse.
The weird thing is that Injector Duty Cyce (at low boosts can be seen better) is not at 100% ,injector`s may be working at 70% and still my actual is far from requested..
The owner recently changed DP and moved the CAT way back added a 4 bar FPR and I updated (little more boost and 4bar fuel correction ofcourse), Lambda sensor is in the right place.Car was fine when I left it (before DP and 4bar FPR) .
At the "weird Lambda" log I can see massive Bank 1 Lambda contril correction (but it is Mafless) and some weird requested Lambda at low Rpms ..It is Mafless
any , ANY thoughts would be useful wish I had better loggs .thank you