Just installed new exhaust - headers back - After my car gets to operating temp. the check engine light comes on. Car is running fine so I took it to a buddy and the code it is throwing says the car is running lean... I noticed that performance had dropped a little and that would certainly explain it. Any one know how long it will take the computer to adjust to the new exhaust system and get the mixture worked out?

 

Im not sure if the ecu in your car adjusts itself --I could be totally wrong

 

well good exhaust will pull heat out , so thats not why it's going lean.

where is your timing at ?

 

I'm not sure about the timing. I would have to check it. All I know is that the car was running fine before that mods and now the light is on. The computer did the codes and said running lean, that was not my guess. If the exhaust went from a 2 inch to a 2/12 it is moving more air so unless the system compensate my adding more fuel it would run lean, right? Surely someone has had this problem before.... two days and two responses maybe not.

 

did you reset the computer after you put the exhaust on?

 

If that is done by disconnecting the battery for a bit then yes, otherwise I am not sure how to do that.

 

i have an 03gt and when i put my headers on i had the same prob right bank was lean....i asked around and found out that the 02 went bad more heat!! for your car runnin weird when a check engine light is on your computer is in like limp mode...or like lucky said try retarding timeing a degree or two!!

 

When my buddy ran the diagnostics it said everything was working as it should. The only code it flashed was running lean. The O2 sensors checked out fine. Today the car started running like crap.... its like it was missing. I could hear the car backfire in the intake, no power spitting and sputtering. It started all of a sudden and after about 5 minutes stopped just as fast as it started. What the hell is wrong with this car. It was running like a top, new exhaust and its a turd.

 

The guy at car fx told me that is I did the full xpipe and did away with the cats I have to reprogram the ecu. Find a good mechanic at a speeed shop and have the reprogram the air/fuel for you.

 

If ur talking about ur 89 then no dyno tune is needed just disconnect batt for a few min and boom ur done!