O2 sensors and Fuel trims

[Josh0677]

I have recently bought my pocketlogger. I am attempting to tune my low fuel trims. It seems that anything higher then idle is giving me extreme numbers, with the afc set at negative 11 across the board my STFT is reading about -17. I am having to set my SAFC settings to about -30 just to get my STFT to zero out. I have read that a bad O2 sensor will cause abnormal readings extreme one way or the other. I wanted someone elses opionion before i try to drive my car with settings that low. Any help is appreciated, thanks

 

[CanadianTSi]

Just put the settings at whatever they need to be to get your STFT to 0.

Just go out and drive around at 2000 rpms and change your settings until the STFT gets close to 0 and then repeat for 2500,3k,3.5 etc....

 

[el aguila]

Just because your STFT is negative, (ECU is modifying a/f ratio by changing the IPW based on sensor input) does not mean your engine is ridiculously rich. Rather it is just what the ECU is doing to compensate to get the engine to run where it needs to for power/emissions.