1985 Firebird -

Where is the o2 sensor on this damn thing?? I'ved been searching for an hour trying to find it. I know its before the cat and in the manifold somewhere, but i just cannot find it. Help?

Thanks

I've got a 86 V6, so thats what I'm going from...


Find where the two pipes from the manifolds meet (your Y-pipe) and go towards the cat like a foot-ish from the weld. Mine is on the left side of the pipe if you're looking from the cat.

Yeah I found it. (or should I say I didn't) No wonder I'm getting a check engine light for 02 sensor. There isn't one. There is a big weld spot right where the o2 sensor should be, and the connector piece for the o2 sensor is right above it. Looks like I'm going to need a new exhaust. Oh well, I needed one anyways.

Thanks for the reply,
Jake

Hah. Yeah...that would make it hard to find.

WOH WOH WOH! You don't think you need a new exhaust because there isn't an O2 sensor there, do you? You can pick up a basic one for like $30. It screws in, doesn't need to be welded. The weld you see is just a bung to screw it in to.

Someone may have welded shut the O2 bung, that's what it sounds like. Then he will need a new exhaust.

Yeah, someone welded it shut. Plus, the current muffler and cat and in fact the entire exhaust piping is hung by pieces of chicken wire. Plus has hundreds of holes and is almost rusting through in some spots.I got a good deal on the car though, so alls good. Yep, that exhaust needs to be changed. How much better gas mileage do you think I'll be able to pull off with straight pipes and that o2 sensor? I pull off 21 right now, and I have cat on it (Which I'm sure is blocking airflow, it rattles when I move it)

Thanks

#1, a muffler will not hurt the power output of the wimpy V6
#2, no one wants to hear a blasting loud 2.8 trying to make it up a hill, use a muffler!!!!!

hehehe...

LOL it is true, my 83 now-V8 trans am originally had a 2.8 in it, back when my friend owned the car. With a cherry bomb on it, it sounded like a dying cow as it struggled to go up hills, as handicap vans passed on the left.

Heh. But how much better gas mileage would it get if I had an oxygen sensor?

Depends on how rich the open loop tune on that engine is at operating temp, vs. the closed loop tune. You will probably get at least a few mpg better w/ the O2. No guarantees though.