i just installed my new header and cat. everything went smooth. took it for a test drive everything still fine, get ready to leave my friends house and it comes on. any input why this is happening? BTW i was careful with both sensors.

 

check the o2 sensor see if its unplugged. also is it a 16a in a crx

 

What code(s) did you get? Make sure you reset ECU, and let the ECU learn.

 

I got a CEL after my header/cat/exhaust install. It was a code 67. You might still get a code anyways because your ecu doesn't like the new flow. Quick fix for this....get an obd 1 ecu . People have told me that this won't affect your performance. So i don' think you should worry. The light however bothers me when its on so i just reset it everytime. Reset it and maybe you won't get it again. I've gone 200+ miles so far and i haven't gotten it again.

 

i'm not sure on the code, but i did reset the ecu before ran it. then reset after it came on again. then like a day later it came back on again.