I had some problems with the TPS and ran the car rich (very rich) while trouble shooting in the garage. After fixing the TPS problem the car idles badly when it goes into closed loop. Question: could the over rich condition screw up my O2 sensor? It's fairly new. :confused:

 

Over rich can foul out sensors. Supposedly you can attempt to "burn them clean" if you run the car at mid-high rpms for a few minutes. I've got my doubts though. If it's the older 1 wire O2 sensors then you are only looking at about $20 each, certainly wouldn't hurt to change them.

A friend of mine had a Z-28 that ran VERY rich because he never had his computer programmed to take advantage of his mods. His was acting stupid whenever it would go into closed loop, ran fine until it got there. He replaced his O2 sensors (4 wire style) and tried again. It ran pretty crappy for a few minutes, we were starting to get mad when suddenly it started running right again. I guess it just took the computer a few minutes to re-learn some things.

His car ran fine until he spun 3 rod bearings and a main bearing a week later :cry So now he's got a 396 in the works :blueangel:

 

Has the car ever ran well with your mods? Since your mods all are for the high end, you lose volumetric efficiency at the low end. If your chip doesn't have fuel enrichment taken OUT of the lower RPMs, then you will never get a good idle or the correct off idle response. I dealt with this for quite awhile on my 85 (computer has slowest response times of TPI engines).

The test: enter diagnostic field mode with the paperclip. This is similar to the code-reading mode, but in 85, you can drive in this mode. CONSULT THE MANUAL FOR REFERENCE since you don't want to drive in this mode for extended periods of time because it plays with your spark advance. When in this mode, the Check Engine light will stay on all or almost all of the time if you are rich, and be off almost all the time if lean. If you see it on all the time at idle and off all the time at high rpm, time for chip changes, because it is the only way to cure a rich on bottom, lean on top condition. Good luck-Matt-


The reason it has to be taken out of the chip is because you will be adjusting the FPR for WOT, and you will be even more rich at idle. I noticed 'Home brewed chip' but I am not aware of how much you have tweaked in the lower MAF vs. VE scalars. -Matt-


[Modified by HighHopes85, 1:37 PM 10/17/2001]

 

Thanks guys. I'll try your ideas. :flag