Just put on my new pace setter long tubes and y-pipe and know my service engine light is on. Had it scanned and it said was running to rich. I bought the O2 ext. and I have no exhaust leaks. Service engine light only comes on when the engine gets warm and when just crusing it loads up badly and runs rough. Let it set and start it and it runs fine to the light comes back on. Thanks for any help

Josh

 

possibly false knock from the longtubes? Im not sure but that would be my guess. Somebody please chime in here.

 

"False knock" isn't going to cause it to run rich.

What is the exact code? And while you're at it, what year is your car and what are the other mods? Gets hard to answer the questions sometimes with no basic info. A "signature" with that info is a good idea.

Do you think its really running rich? Can you smell excessive amounts of fuel in the exhaust? Are you getting black smoke? Need to determine if its really running rich or if the PCM is getting bad data from the O2 sensors, causing a "false rich" condition.

 

sorry about that my car is a 94 Z28 A4 and mods are LT4 KM, pcmforless tune, 1.6 rr SA, LT4 valve springs, pacesetter longtube, and a TCI converter. I dont remember the code but I can call the guy that done it and check. No black smoke and do not smell and excessive fuel either. Car has 130K miles on it and I have not replaced the o2 yet.

thanks again
Josh

 

Do the headers have the AIR and EGR fittings? If not, I am assuming you got those two device blocked off properly and tuned out of your PCM. If you did install emission compliant headers, you could still get an EGR code, I did. After researching these boards, I found that the EGR valves like to see a little exhaust backpressure to operate properly. But without pulling the codes, you wont know for sure.