Yeah I replaced both the upstream O2 sensors, but this 3rd one is downstream of the cat on the old exhaust, and upstream of the cat on the new one... Doesn't make sense to me regardless if the cat is in or not... But the old sensor won't reach the new port. Actually, I don't think the port on the y-pipe is for my year. I am just wondering what to do with that 3rd sensor...

Won't that resonator take care of the rasp...? If not, I will keep the cat.

 

dont know anyone thats used one. the headers usually have the cats before the y pipe, im thinking maybe thats what happened

 

should be able to get a extended 02 sensor harness

 

Not sure what that means... because i'm pretty sure that's impossible for my setup... unless you meant "O2 sensors" in place of "cats".

Here's what I think I am going to do: when I take it in to get the final connections welded, I will have them drill a hole and weld on a nut for the sensor to screw into where it's supposed to be. Maybe I will try to find a suitable nut ahead of time to bring in (so I can make sure it isn't too thick or something). Seems like it would be an easy fix... I'm gonna crawl under there tonight and get a better look at the situation... Thanks

 

What you are looking for is a O2 bung. I think these are a pipe threads so a normal nut is going to be a problem. Just google O2 bung, I think most parts stores and exhaust shops will have them.


Normally the Magnaflow system does not include the S-pipe. The S-pipe makes the sharp turn right after the Cat and then another sharp turn to the intermediate pipe. Stock the O2 sensor bung should be in the S pipe. The S pipe is considered part of the CAT.

I could not find a great picture but this give you an idea
1995 Chevy Camaro - Y-Pipe / Mid Pipe with CAT Catalytic Converter - Hermes Auto Parts

As a mechanic I can not advise that if you to make the bung thicker so the O2 sensor is backed out of the exhaust stream the second O2 sensor will detect less O2 then the first and the computer will assume the Cat is doing its job even if it is not there. Also moving a dead O2 sensor to the second position will do the same thing.

 

Unfortunately, the magnaflow system DOES come with that s-pipe, but there is no port in it... Thanks for bung info. That is my solution - at least I was on the right track, lol. I'm gonna head in to the parts store today with my sensor and order the bung. Thanks again!

EDIT: ...O-Reilly's said they couldn't get the right one. Napa was closed. Went to a hardware store to see if there was a nut that would fit on the sensor just so I could at least know the size, but of course normal size nuts do not work... 5/8 too small 3/4 too big (all I could find was grades 5 and 8). So no luck at all... I'm tellin' ya, EVERYTHING about this project has been an f-ing problem... BUT, totally brought it upon myself, lol... And I'm not quittin' til its done!! Anyway, anyone know what size the bung is...?

 

the early model 3.8's 95-97 had a pre cat and post cat o2, thats what that whole is for. most use it for a wide band o2 gauge, for tuning. If you got pacsetter headers it should have came with a bung for that hole, your post cat senor plugs in right after the cat and before the s pipe. if you had a gotton a magnaflow cat back for a 93-95 lt1 it would have came with the s pipe and you would have gotten a 3" system giving the 3.8 a deeper less raspy sound.

 

i believe its a 18x1.5

 

O2 Oxygen Sensor Nut Bung 02 M18 x 1 5 Thread | eBay

 

Well, it's at the muffler shop. Dropped it off just before closing so will hear from them tomorrow about the price before they start. They said they have the bung so problem solved It's a big step that I got it back together and to the shop - there were sure times I was worried I had bitten off more than I could chew this time! BUT, I'm not celebrating til the car is back home and the bill is paid...

I am thinking of making a youtube vid of the car once its all done If anyone's interested - I have sunk quite a bit of cash into it and I think it's paying off. Watching such vids was helpful in my deciding what to do/get.

Sad thing is, it's getting finished just in time to go into storage... We already have snow and ice here... Wanted to finish it earlier, but there just aren't enough hours in a day...

Thanks all