Catalytic Converter

Just wondering what cat to use for my 99XJ, federal emissions.

Here's the story. Took my 99 to the muffler shop to re-work part of the exhaust system. Part of it was hitting on of my LCA's, and another was hitting the rear leaf. Muffler looked like original with over 200,000 on it.

Decided to do a cat back exhaust, same set up as I have had done before at this shop. Shop didn't have the right cat in stock, (Kommiefornia is particular about cats) and was having trouble sourcing one. Kept coming up as needing pre-cats like for 2000-2001. Not sure what the issue was. Ended up keeping the existing cat and changing out the muffler and some pipe. Job went fine. Went home to do some research on cats.

My question is: what would be a suitable replacement for my cat? Can you provide a part number?

My options are:
1. Sourcing a Cali legal cat. Brand? Part number? Having trouble finding the right one. Not sure why.

2. Buying a federal cat and having it shipped to an out of state address and picking it up myself. (I would never have it shipped to my daughter in Oklahoma and bring it back next time we visit this summer :laugh
Looking at this one: https://www.summitracing.com/parts/wlk-15820
Would that one be the right one? It's much cheaper than Cali cats.

Any info would be appreciated. Looking for input from people who have bought cats that would fit my year, and can provide a brand and number.

A word to the wise, in California, the emissions tech is supposed to check the cat and if it is a replacement, find the stamped number and check it against the State's database to verify it certification, I know, been there twice.
Make sure the replacement is California certified.

Rock Auto shows the WALKER 82789 as being C.A.R.B. Compliant.
https://www.amazon.com/Walker-CalCa...utomotive&vehicleId=22&vehicleType=automotive

lazyxj said:

A word to the wise, in California, the emissions tech is supposed to check the cat and if it is a replacement, find the stamped number and check it against the State's database to verify it certification, I know, been there twice.
Make sure the replacement is California certified.

Rock Auto shows the WALKER 82789 as being C.A.R.B. Compliant.
https://www.amazon.com/Walker-CalCa...utomotive&vehicleId=22&vehicleType=automotive

Click to expand...

That's what he was trying to do, but for some reason he was having trouble. He's a Magnaflow dealer, and for some reason a proper replacement wasn't showing up.

JonnyCat63 said:

That's what he was trying to do, but for some reason, he was having trouble. He's a Magnaflow dealer, and for some reason, a proper replacement wasn't showing up.

Click to expand...

I have a Magnaflow CARB-approved converter on my 97 XJ.
You can find the part number at Magnaflow's website.

Been there done that as well. CARB Cats are ridiculously expensive, and direct fits for my '88 are getting harder to find.

Once you find a CARB compliant Cat, double check the Executive Order number embossed on the cat. When you find the EO, make sure the part number, also embossed is listed.

One time there was a glitch of some kind and it reported I had a non compliant Cat. I had a copy of the EO, so they looked it up online and verified.

You can search for compliant models here:

https://arb.parts/

That's a cool website, thank you.

However, when you put in a 99xj with a 4.0L, it shows listings for pre-cats, too. I wasn't aware 99's ever had them. Am I missing something. I did a 97 and 98 search and got different results.

Planet Magnaflow is the place I got mine, a Calif type1990 XJ.

https://www.partshopper.com/item/magnaflow-339229-direct-fitcatalytic-converter/

use the coupon they offer, it was something like 50 bucks off, you need to click on it and fill it out

My exhaust smog measured near zero with this baby.


Mine is a direct fit bolt on. for a 1999 XJ you can get the universal fit type for less money...

https://www.partshopper.com/?s=4471...eep+Cherokee&type=ca&model=Cherokee&make=Jeep


Note they list it as a rear cat, so evidently the 1999 has the three cats? however you said your 1999 is a FEDERAL spec XJ. Now I am assuming, but maybe the FEDERAL 1999 XJ had one cat, and the Calif 1999 had the three cats?

At anyrate, in california, even if your XJ is a FEDERAL built XJ, you need to have the more pricey Calif approved cat for replacement, but you only need one if indeed that is what your FEDERAL vehicle was built with, but it MUST be a california approved cat, even on a FEDERAL car.
To further this theory, if you search for a 1999 federal spec cat, they dont list it as a front or rear cat, rather it is just the cat.

You need to put a calif. cat on a FEDERAL car. no problem.

The magna flow is highly rated, and a few months ago when I bought mine, had the best price at Planet Magnaflow when the online coupon is used. I also bought a Magnaflow calif cat for my van late last year, again super clean emission test, also stainless steel.

unless your O2 sensor is brand new, replace it with the cat. busted or even a weak O2 sender i.e. lazy sensor signal, can ruin a new cat really quick. the O2 sensor is dirt cheap, and a new one can save a multi 100 buck cat from ruin. plus your jeep might run surprisingly better.

so change your O2 sender also.

And yes, the smog techs do read the cat label to assure it is Calif compliant, did on both my cars, and even a friends car. Now if you still have an old working standard cat, you can get away with it, but that old cat better not be all new and pretty lookimg, else they will be looking for that calif approval number on it.
Besure the cat is installed for the number can be read. My friend had his new cat in a subaru mounted with the number up against the floor board, he had to remove it and install the other way so as to pass the smog test cause the number had to be visible.

anyway, you are look for a california approved cat to fit a 1999 FEDERAL Jeep. The universal fit Calif one for the rear should be fine. These are weld in, not bolted flange types.

good luck

PS...

if you dont want to have the new cat welded in place, get something like this...
https://www.amazon.com/dp/B07YDGFPR3?tag=duckduckgo-d-20&linkCode=osi&th=1&psc=1

they make these in different diameters. they seem to work well, however the nuts and bolts provided are low grade and strip when fully tightened, so buy some grade 5 or 8 bolts at the hardware store to replace the ones in the clamp kit. I run these with better hardware

Thank you all for the info! Very helpful.