hello first post ,

i have a 01 Monte SS we recently went on a road trip out west

and i started to notice the muffler was getting little louder as we were on the way back ,
once back I'm looking at it and i find the noise / muffler sound is coming from the catalytic ,
from laying on the ground at the drivers door i can see a nipple ( best i could describe it ) coming out the side that is like a open port nothing in it , stuck a pencil in it( handy ) to block off some of it and the sound reduced , so what is that hole for ,

this catalytic is the 2ND one first one was replaced after i first got the car , so there is now about 15,000 miles since the replacement ,

so it looks like a spot for something but what,,,, i have no clue

any one knowing what this is i would appreciate it

thanx

 

are you talking about the hole for the rear oxygen sensor?

If you have your stock downpipe it would be in the U-Bend

 

thats what I was thinking...


did any lights come on for the service engine soon? I would imagine it would throw a code if the sensor just flat out got up and left....

 

well kind of but no , the port is directly out of the side of the catalytic ,

its raining now i will get a pic of it so easier to tell , rather than relying on my description

 

so now there's a pic of the port , what is it and whats missing out of it ,

i don't see any wires hanging any ware , i cant get under it very far , but from what i can see

 

That looks like its for the tube that goes to the air pump. you might want to see if there is anything pipe hanging in that area.

EDIT:

You wouldn't happen to be from California?

DId some more searching and the only ones that have that tube are the 4th Gens. Is it possible that someone swapped that one in?

 

most companies build cat part number 12345 and it fits cars x, y and z this is the result of the cat being built for a few diff cars but your car is missing it and like mentioned i would guess it fits a grand prix and thats for its shtty air pump they put on for california types, they were notorious for breaking due to ground clearance

 

live in Wisconsin ,

and that's the one that the repair shop replaced the original with ,

was there a plug in it that some how fell out ,

 

no if your car was not bought in california it will not have the pump to fit in the connection or the wires to connect it to the computer

 

YOu can probably just have it plugged up until you can get an upgrade.