ok I have just put in my new headers, and I have a cat-back
anyway, the car runs fine, no codes.
anyway a friend of mine that drives a 4banger **** thing, asked me about my air/fuel ratio.
he says his car runs like doo doo, after he put his headers and his muffler. says his air/fuel is messed up. (and it was, when he got the car tuned)
anyway, someone else told me that the computer in the IROC will compisate for the new stuff, to an extent.....
so who is right in this aspect?
do I need to start worrying about my air/fuel ratio or not?
like I said the car runs fine, and I did notice lots of difference with the headers on (good).
biker

 

don't worry about it, especially if it's running ok. the ecm controls the fuel and timing, basically. if you have a A/F mixture problem the O2 senser will detect it and the ECM will make adjustments and if it is unable to you'll get a SES light and a code will be set.

 

thanks, thats good stuff
now I get to rub it in his face that my POS 15 year old domestic car don't need to worry about a/f.
he put on a header (4 cl) and a muffler and his a/f was all off...... and its a 01".
thanks
biker
...on probation

 

After I installed headers and exhaust, my A/F ratio was way too low. The car ran strong. The only problem I had was a small amount of detonation in the exhaust in the 2500-4000 RPM range at WOT. I just thought it was one of the effects of going to 3" exhaust and losing some of the backpressure. Turns out the the A/F ratio was 11.2 during that RPM range. It should be in the upper 12's. So I would still have it checked. I have gotten rid of most of the detonation my upgrading my ignition system which made a huge difference in the way the car feels. I haven't taken it to the dyno yet.