A friend of mine got an exhaust put on for his b-day today. He got a bomb muffler and straight pipe (Both aquired from me). Problem is, his CEL is on all the time now...and I am not sure why. The guy at the muffler place was an idiot, and didn't think he needed the o2 or the tube coming off the cat. I told him NOT to let him take off the o2, and he didn't. He cut off the other hose though, and I am not sure what it is. It's coming off the cat, and looked like a vacuum hose.

The guy at the muffler shop told him that b/c there is no backpressure (relative to when he had a stock cat) on there, that the o2 can't read the air going past it b/c it's going so fast. He said he would need to get an AEM o2 w/ bigger fins, and get his ECU reprogrammed.... Both of which I have never heard of in my life...but it might be true.

I can't get to his ECU right now....freaking covered with 3 layers of black sound/head deadening crap and his carpet...so I am not sure which code it's throwing.

Anyone have any suggestions?

jB

 

Its probably most definatly from that missing o2 sensor. There is nothing else it could really possibly be since thats the only thing that would communicate with the ECU to make it read that. I would bring it back to him and see if he could reattach it. He may have just been lazy and not wanted to deal with it. I really don't think there are any vacuum hoses on the entire exhaust system. I installed my dc exhaust not too long ago and all I recall seeing was 2 o2 sensors on the cat and 1 on the header. Theres my 2 cents, dunno if it helped any.

 

I'm sorry, I forgot...

He DID put the o2 sensor back in, after I told him NOT to let the guy take it out. On his engine though (D16y8), he only has 1 (4 wire) o2 sensor, and that hose coming off the cat. I don't know what that hose is, so I don't know whether it would be throwing the code or not. The 1 o2 is on there though, and we reset the ECU and it came back on seconds later...

jB

 

That vacuum hose is for emissions, it runs to the intake manifold