Time for a new CAT - any recommendations?

[MoJoRisin']

After delaying the inevitible it is time to have the left side CAT replaced. Have had a code here for the driver side CAT for some time (probably due to a missfire on one cylinder which has since been taken care of with new plugs and O2 sensor) and wonder if there are any specific universal single CATs you recommend. I'm going to have an exhaust shop weld one on and not get the full Y with 2 CATs to keep cost down.

Any input on the CAT and whether having one welded on is a good decision?

Thanks in advance!!

 

[jrSS]

Run no cats.

 

[Playsinsnow]

Wouldn't you burn through the new single cat faster with just one? Seen a few dual muffler 5.3s...


Just like an escort, get two or go without!

 

[Sparky]

Wouldn't you burn through the new single cat faster with just one? Seen a few dual muffler 5.3s...


Just like an escort, get two or go without!

I thnk he's talking about cutting the bad cat out and welding in a replacement, leaving the other good cat on the other side as it is.

I'm not sure what the stock cat size is, but take a look at the Magnaflow high flow cats.

 

[Jtyler77]

take a look at the Magnaflow high flow cats.[/QUOTE]

Absolutely, I put that sh!t on everything Well, two Chevy trucks and a Mustang gt. Always sounded and let-em breath real good.

 

[willn513]

How about a nice Tabby?

http://en.m.wikipedia.org/wiki/Tabby_cat


sorry I couldn't resist.

 

[tblazerdude]

if you're on a budget just get one from rock auto.

 

[Envoy_04]

if you're on a budget just get one from rock auto.

This will work.

If you're on an even tighter budget, gut 'em both, put spark plug non-foulers in on the post-cat 02 sensors (The 4.2s have them, not so sure about the 5.3 setup) so the sensors only see a portion of the now enhanced flow, and call it a day.

This will only work, obviously, if you live in a state with no emissions inspections.

 

[MoJoRisin']

Here's the scoop from today with a bit of background first.

Last yr had codes loaded in and saw a cat code so took it in.

The exhaust shop checked it all out and said that there was several codes including o2 code indicating a misfire, a cat code and an o2 sensor fail code.

So they recommeded a tune up first which I did have them do as it was in the shop already. Was a bit shocked due to the high price tag (irridium plugs = $$$) but had it done as the TB was approaching 100k miles. Shop recommended to clear the codes and then see what happens.

Codes showed up again, this time the cat code and o2 sensor fail.

So I had the 02 sensor replaced which required the same guys to abandon the old sensor location because it was rusted in and drilled and welded new threaded collar and installed the new sensor (driver side). Had the codes cleared and then got the cat code back.

I was under the impression that the cat problem was related to having the bad cyl missfire and that the bad exhaust gasses fouled the cat. Because it has not resulted in any significant difference in how the car runs I chose to wait to address the cat.

Took it in today and the guys said it was passenger side cat code. Hmmmm.....well I asked them to do pressure check on each cat fore and aft and they called back and said both cats are........OK - plenty of flow!!!

They reset the codes (I have the dreaded cooling fan low efficiency code now) and see what happens.

So after all of this time I'm wondering if lots of driving possibly has removed any buildup on the cat's screen surface and the cats are now working? What do you think??

As far as the cooling fan clutch - yes I hear the tell tale ticking at startup. When is it time to take care of that before complete fail?? I probably will work on that one myself if possible.

Thanks for the feedback and as always you guys are great!

 

[Sparky]

Cats can fail in one of two ways.

1) Plug up. Performance suffers.
2) Stops catalyzing.

Or a a mix of the two can happen also.

Most of the failures on these trucks is #1, but doesn't throw a code because what exhaust does get through is still getting cleaned up. But you definitely could have failure #2 without #1, so while the exhaust is flowing just fine it isn't cleaning it up to spec anymore.