Tired exhaust and very sporadic O2 OBD codes... replace cat? Topic is solved

Post by **theWIFES_S70** » 09 Apr 2018, 01:22

So our exhaust is finally shot.

Pulling out of my cousin's house in Secaucus, the car sounded like the muffler had all of a sudden disappeared! God, it was loud! The entire exhaust is tired and in desperate need of being refreshed.

I'd always wanted to get a new exhaust manifold and bolt on a direct-fit cat, but man this is expensive... and if I'm not getting 02 codes, this means my cat is still (mostly) working, right? I get the P0133 every 500-1000 miles or so.

Rockauto has CARB compliant cats, but why are there two different ones?

https://www.rockauto.com/en/catalog/vol ... erter,5808

How different could these pieces be from one another?

Post by **abscate** » 09 Apr 2018, 08:48

Do you guys have tailpipe sniffing in Queens or just OBD compliance?

WhatAmIDoing · Post by **WhatAmIDoing** » 09 Apr 2018, 09:09

Cheapo cat or no cat at all, and an O2 spacer. No one in America (except maybe california) is going to tailpipe test a 20+ year old car. Or try to find a good one at a pick and pull, but that still is not going to be cheap.

Post by **scot850** » 09 Apr 2018, 09:54

Are used cats not illegal to buy/sell in the US? Where has the muffler failed? It can be the flexi-pipe/down-pipe from the manifold.

Can't advise on the cat part as I am a dog person, nor on the car option either!

Neil.

Post by **theWIFES_S70** » 09 Apr 2018, 22:55

abscate wrote: ↑09 Apr 2018, 08:48 Do you guys have tailpipe sniffing in Queens or just OBD compliance?

Just OBD. I'm going to try to get off work early on Thurs and drive to a muffler shop and see what the diagnosis is. I can't imagine my flex pipe is in good condition either. Last time I was under there, I did notice that my hangers were in poor condition so I just ordered those pieces and will try to replace them before I head to the muffler shop.

Post by **abscate** » 10 Apr 2018, 02:27

I believe current situation in the US is that’s no one is allowed to sell a cat without certifying that it meets EApA standards for the car it is intended to be used. Since most car parts places or junkyards don’t have cat certifying equipment, they can’t sell a cat. I think it’s common practice for most junkyards to pull the cats on new arrivals And sell them to a precious metal recycler for about $100; typically.

I have bought them in a private sale. Down South exhausts last forever so you can get good used stuff.

Post by **Rattnalle** » 10 Apr 2018, 03:41

I'd say there's a good chance the original cat is more or less fine. Find the leaks you're obviously having to begin with. If any of them are before the second sensor you probably have the issue right there.

brunocerous · Post by **brunocerous** » 10 Apr 2018, 18:08

I had a local muffler shop weld shut two holes in my growling exhaust system for less than $70.

I don't know about much about the cat. Like Neil, I am also a dog person.

Post by **theWIFES_S70** » 10 Apr 2018, 20:58

I'm guessing the cat is not as bad as I think it is. (Again, it's only throwing codes every 1k miles or so.) I'm going to see what they can cut, patch, and weld in...

Herb Goltz · Post by **Herb Goltz** » 13 Apr 2018, 08:21

Isn't the PO133 a code for a slow front O2 sensor? That sensor is before the cat, so I don't think you should consider replacing the cat until you sort out the O2 sensor issue, particularly in the absence of cat codes like PO420.

Also, if the exhaust is original, it is well worth finding a good independent exhaust shop to repair the system. I'm in the rust belt, and up here the aftermarket stuff lasts about 3 years. In fact, after the aftermarket cat-back system bit the dust on my 2000 V70, I had an original Volvo cat-back system from a 1995 850 turbo installed. It's been fine for years...