i've got a 99 honda accord lx sedan and want to put a dc header on. i've heard that when you do your check engine light will come on because the o2sencors think that the engine is running to rich. is this tru. if so how do i fix it?

 

I have a Megan header and I have no CEL.

 

sometimes you do get this proublem but like total i also have the megan header. i didnt have any trouble untill i upgraded my intake system. then that annoying little light stays on but its not hurting anything so i just let it be

 

u'll have to disconnect ur battery for about a few minutes (not sure how much but i'd say do it for an hour to be on the safe side) this will reset ur ECU. and then drive ur car around for atleast around 80 miles normally.

If ur CEL comes on when u install the header, this is the way to reset it. although it shouldn't come ON until u put a test pipe on.

So if ur' just putting a header and a down pipe, then ur CEL shouldn't come on. but if it does, then try what wrote above.

 

My buddy had that happen after we installed his cold air intake. Its not hurting anything to leave it on. In order to clear it you may need new o2 sensors.

 

On most cars there is a O2 sensor on the header and on the catalytic converter. The Ecu sences both to points emissions. Get header that will plug up with both o2 sensors and/or does not requier you to remove your cat converter. If your car is 96 or older just erase the code do what ever you want to the exhaust.

 

I don't know what you people do to your cars that you're getting CEL's from an intake or header. I don't have a cat and I still don't get a CEL.

 

thanx i'll just put it on and see what happens

 

I installed my header and downpipe, CEL

 

Did it in any way alter the catalytic converter? What brand header do you have? Did you move the rear o2 sensor from the catalytic converter to anywhere else? What did you do with the front o2 sensor??

This thread is kind of old, next time you may want to make a new thread and reference that you've read this one.