I just took my car for safety and im a 92 z28 convertible and it passed safety and im but failed at idle. I did recently bump the timing from 4 degrees to about 9 degrees would that cause the idle to be too rich?

Is the oxygen sensor responsible also for a clean idle.


Would some heet help at all or just retard the timing?




Any help appreciated.


Matt

 

Set the timing at 4 degrees and it failed again it was 252 and needs to be 120. Would high co at idle be a oxygen sensor or catalytic convertor?


I thought the oxygen sensor just controlled 2000 rpm plus to reach stiochromatic or does it also control the air fuel ratio at idle too?


Any help or insight is greatly appreciated.


Matt

 

A high CO count indicates a rich mixture. Bumping up your timing would not cause it to run rich. If you haven't changed your O2 sensor in awhile, I recommend doing that. Other items that may cause you to run rich are MAP sensor, or TPS (if tps is reading wrong at idle, it may command more fuel than necessary)