i just put on my headers adn american thunder 3 inch cat back. when i cruise on the highway my check engine light comes on after it starts to warm up but when im in town it doesnt come on. i thought this might be somethin with the Oxygen sensor or something like that.......any ideas thanks....

(also i dont really notice a difference in how it runs when it is on ---if it does it is not very noticable but i would still liek to fix it....

thanks

 

What is the error code being returned?
With the conditions you describe, I would suspect an EGR code.

But come forth with the code # first, we can go from there.

If you don;t know how to determine the code#, do a search- the info on the procedure is covered in numerous posts.
S-D

 

i just got to school today so i will proly check the code tomorrow with a paper clip or somehtin i will let you know from there??

if it is the EGR is it hurting anything...?

 

yep, verify the code. i'm having the same problem with EGR code 32 right now, several weeks after installing headers.

 

The EGR does (mainly) two things:
1) Lowers NOx emissions
2) by returning some exhaust fumes into intake manifold, which has the effect of "cooling" combustion temperatures.

Since your new exhaust system has such low backpressure, the exhaust gas may be more apt to flow out the tail pipe than into the EGR ports (not enough backpressure).

I doubt it is hurting anything, but I imagine that in some cases, it could (could) cause detonation due to increased combustion temps.....

A guy wrote a really good article on EGR operation that can fill in the details- it is a tech article on this site called "The low-down on code 32" or something similar.

You'd need to do a more in-depth search to determine what other people have had this problem and how they got around it.

S-D

 

o great you install a new exhaust on a thirdgen and whats does it do to thank you, it throws out a code!


i guess i cant wait to be fixing the same code then

 

It seems kind of weird- I put a 350 w vortec heads and larger cam into my 91 RS. I followed up with SLP headers and 3" full exhaust (catco and flowmaster).
I have been cruising at highway speeds and have not thrown a code 32. knock on wood.....
S-D