Ok. I have had 3" tbe exhaust on my car for a while, (tanabe downpipe, test pipe, DC Sports catback) and never had a problem with a check engine light. But recently, I got pulled over and cited for having "modified exhaust," so i had to put my stock cat and catback exhaust on for about a month to prove my case and get it dismissed. Well I put my cat back exhaust only back on a few days ago. I left the stock cat on, being that I'm ordering a highflow cat. Well, now that I did that my check engine light has come on. i tried disconnecting my battery to see if it goes away, but it doesn't. I have heard from a few people that a CEL delete will fix it. Does anyone know of anything or can suggest how I get the light to go away? thanks for your help in advance.

 

either a mechanical O2 elim or perrin O2 similator. Either work just fine

 

I went threw the same thing..but when I reset the comp. it never came back on...I dunno

 

The evos have 2 O2 sensor. One before the cat to take an initial reading of stuff coming out of the engine and then another "secondary" O2 sensor after the cat to make sure the stuff coming out of the cat is being cleaned up by the cat. So having a test pipe will obviously make the engine think somethings wrong because there are still plenty of hydrocarbons and NOx's coming out. What weird is that you werent throwing a light with the TBE and no fix and now that you have a cat its throwing the light. You can go to autozone and get them to check the light for free. It might be something non sensor related. If it is the secondary sensor then the mechanical O2 fix should work. There are plenty of write ups on here about how to do it. It really simple. Good luck and i hope it helps.

 

go to your auto parts store, purchase 2 spark plug anti-foulers (long ones or short ones... short ones worked for me).

drill one out, put the O2 sensor in there and put it back in your exhaust. That should fix it (it did for me)

 

The CEL shouldnt have come on from putting the stock cat on and just a cat back exhaust. If this happened, you might have twisted the wires on the 02 sensor to much and caused a break. Might want to check it out. Best thing to do is check the codes with a scanner.

 

Why dont people check codes when they get CEL's. I mean come on. Its probible that its a cat efficiency code but it could be somthing else. Get CEL codes scanned. Simple mechanics.