Been building an 89 CRX with a b18a (converted to obd1), nothing special, just a daily. Recently replaced the OBNOXIOUS hacked up fart cannon exhaust that I bought the car with, with a used b18 exhaust mani (old one was hacked at the flange), a cat (old exhaust didnt have), an o2 sensor (also was missing), and a new much quieter catback.

Needless to say it now sounds normal and I can get on it in broad day light without being embarrassed, however during my first test drive with the new system I noticed some smoke; odd smelling, unlike burning oil or anything I have smelled before.

I see two possible causes, one being that with the used the cat and mani, and the brand new catback, it could possibly be burning out some foreign substance. Or, perhaps the o2 sensor may be to blame since this is the first time it has been ran with one in who knows how long, or maybe I mixed up the 2 black wires from the o2 and have them in the wrong places.

Any insight?

 

the smoke and odd smell may be from the new catback or the used cat. it's possible something made a nest in the cat that is now burning off, or that the new exhaust has a coating on it from the bending process (lubricant). I haven't had any such issue with my exhaust, but it's possible. I would give it a few days and see if the smoke goes away. as for the O2, I'm used to seeing a single wire O2 or a 4 wire O2. not familiar with the type you have.

 

Yeah i don't know why it happens but it does. Every time i have gotten a new exhaust it smokes but it usually goes away after a few pulls.

 

Do you have a cel? Have you run it more to see if its still smoking?

 

Thanks for the replies. I have run it a few more times now (mostly at idle, it is not road ready yet), with the o2 connected and disconnected, and the smoke persists, so i'm ruling that out.

I believe it could just be burning off new exhaust residue as bbarbulo said, or maybe the used cat is just clearing out whatever may have been in it (the car I got it off had been sitting with no tires in a puddle in the junkyard).