Quote:
Originally Posted by wheela
Quote:
Originally Posted by projectbarnie
STFT is -21 during WOT
At idle in D STFT is near 0 and LTFT is at +14
|
So at idle the DME is adding 14% extra fuel to hit stoich for the amount of air the cylinders are getting. Then at WOT it has to cut fuel, as it's getting too much fuel for the air in the cylinders. The intake tends to be under vacuum at idle, and obviously under pressure at boost. Maybe a boost leak somewhere letting in extra air at idle (sucking extra air in that wasn't counted by the MAF under vacuum), and leaking air out under boost (loosing air that was counted by the MAF)? |
Quote:
Originally Posted by solidsleeper
Quote:
Originally Posted by projectbarnie
STFT is -21 during WOT
At idle in D STFT is near 0 and LTFT is at +14
|
At idle try raising and hold RPM to a steady 2000 RPM for 30 seconds, does LTFT drop or stay at +14?
Assuming your AFRs are good, your WOT fuel trims are ok. +10% LTFT / -21% STFT (-11% total) during WOT is ok.
What makes you think new O2 sensors would be the next fix? Are you getting engine codes? How many miles does your car have? Maybe your injectors are just a little gunky, do you always use top tier fuel? Have you ever tried using one of those fuel system cleaners in a tank of gas like a bottle of Techron/Redline s-1/Liquimoly Jectron? |
Quote:
Originally Posted by wheela
Quote:
Originally Posted by projectbarnie
STFT is -21 during WOT
At idle in D STFT is near 0 and LTFT is at +14
|
So at idle the DME is adding 14% extra fuel to hit stoich for the amount of air the cylinders are getting. Then at WOT it has to cut fuel, as it's getting too much fuel for the air in the cylinders. The intake tends to be under vacuum at idle, and obviously under pressure at boost. Maybe a boost leak somewhere letting in extra air at idle (sucking extra air in that wasn't counted by the MAF under vacuum), and leaking air out under boost (loosing air that was counted by the MAF)? |
Where should I look first? Already had lower intake tract replaced.