fuel trim ? 98 Z28

[darkness2]

Im trying to figure out why a buddies camaro is running like crap. It had o2 codes galore. They would just flatline at 20-60mV. Replaced them and now they switch properly but during a WOT run they still flatline at 15-40mV. Pulled the plugs and they are the originals( over 100K) and they look very lean. The one thing I noticed is that all the trims are locked at -100% and don't move. Need help figuring this out, input would be appreciated. Basically the car just struggles to get to redline (popping and cutting out) and has no power.

[umrjmac]

If its misbehaving like that, I wouldn't run it hard at all until you figure out what the problem is and get it fixed. If he keeps it up, he is going to break something.

The narrow band O2 sensors wont switch because when you goose it and enter PE, the commanded AFR is no longer stoich (14.7ish). I think that when it does this, the car goes into closed loop, so it uses the last LTFT value as a sort of universal fuel correction until you get back into open loop. The narrow band O2's are only good for taking measurements right at stoich, so hopefully he's tuning using a Wideband O2 sensor.

What has been done to the car? Post a current tune/log/cfg

It sounds like he really needs to tune his VE and MAF...Give this a read and hit us up if you have any questions.

http://ls1tuningguide.com/tuningmanu...ons%20rev3.pdf