Fuel Trims are 0

[Rhino79]

I was tuning a 99 Firehawk with LT's, ORY, Sweet Thunder Mufflers, SLP lid, and a 4000 Converter. I upgraded the OS to the 2002 system and when I started logging, the LTFT's and STFT's were on 0 and they stayed there. So I looked at the O2 mv's, one stayed at ~.800 and the other ~.440. Niether switched at all. As far as I know they are the originals, and the car has 75,000 miles. Do you guys think that the O2's are shot and causing the fuel trims to be inactive?

Thanks Ryan

[Tordne]

Are you in open loop? If so trimming doesn't happen

[TAQuickness]

if you are getting DTC's for the O2's, you in open loop and you're trims would likely be 0.

[NewV]

My O2 mv's are constantly changing as they show to the 3rd decimel point. This is in OL or CL provided they are plugged in.

[Rhino79]

if you are getting DTC's for the O2's, you in open loop and you're trims would likely be 0.

O.k so with a bad o2(s), it puts the pcm in OL then? That would explain my problem then cause it had a insufficent activity code for the passenger side O2. Awesome, I've looked through the tune about 4 times last night and today comparing tables to other tunes of the same OS, and I couldn't find anythhing putting me in OL. All the CL enablers were right on with the factory tune. Must be the bad O2 then...thanks!