doutrnz

Hi everyone. So, very sad news here. I just had my cat cut out of my Grand Cherokee. I feel devastated and violated. It's one of those things you never think would happen to you, but it did.
I am reaching out here to get information on what to buy to replace it. My Jeep is a 2WD 2003 Jeep Grand Cherokee Laredo, 4.0, stock exhaust. My questions were as follows:
1. Did the cat have a sensor attached to it? (Am I going to have to buy a sensor as well)
2. what size diameter pipe is stock exhaust on Laredos?

It looks like it was cut off at the base of the exhaust manifold and before the muffler.
Any help, suggestions, kind words, anti-theft tips would be greatly appreciated. Thanks for reading this.

doutrnz

Buckwheat65

Dang Methheads!!!

MaskedMallard

Pictures???

If this Jeep we’re to used for “Off Road” use only, you could probably get away with replacing the catalytic converter with a straight pipe, from an exhaust shop.

Jim Malcolm

Apparently the high-flow versions available from the aftermarket aren't worth anything as scrap; sounds like as good a reason as any to upgrade...

Caish

Mine had a cat that broke apart inside.
Oreillys has a piece of 2 1/4" 18" long I think it is, and a couple clamps.
The secondary O2 sensor screws into the cat, and without it will have a Check Engine Light.
Second O2 sensor does nothing to effect running, tuning from from front one.
Of Course I only drive it in Mexico....

oddballracing

I know the feeling all to well. I had the same happen to my '98 last year - within two weeks, my coworker had the same happen to his minivan. This is the route we went.

I don't know what emissions testing is like in your area, but where I am, there is no periodic or sale-time emissions testing (just 'safety' testing).

I'll stick to the technical, and won't bring up legality or morality that seems to hijack so many threads (I'm happy to see it has not yet happened on this one).

On my 1998 Laredo, the pipe is 2.5" outer diameter (needs a 2.5 inner diameter pipe to attach to it.
According to several listed parts for a 2003 Laredo on rock auto, yours appears to be the same size. The pipe you need will have to be 2.5" ID on both ends (or 2.5" ID to OD with a 2.5" ID to ID coupler like i used on mine. You can weld it on, or you can use pipe clamps (2 2.5" clamps if you use a ID-ID pipe, or 3 if you go with a ID-OD pipe with an ID-ID coupler. Unfortunately, I cannot recommend a length, as it all depends on how much was cut out by the thieving vandals. (The length of the stock replacement cat listed is 31.75", but you may need a longer or shorter piece depending on the cut). Verify these measurements on your Jeep, please don't take my word for it.

I cannot confidently say how the absence of the rear O2 sensor will affect the running of the vehicle (I drove mine to my shop from my house when mine got cut and had no abnormal behavior) but it will throw sensor and circuit codes if it is absent and light the CEL.
I went the route of installing the sensor to avoid a constant CEL and honestly to see how easily a catalyst code would be triggered (P0420). For this, you will need a downstream O2 sensor and an O2 bung (rock auto, amazon, etc.). The bung should be welded in approximately where the original one was in the exhaust stream to eliminate any variables (I really don't know if there is in fact any effect on fuel trim from the downstream sensor), this is going to be about 3/4 of the way down the replacement pipe (make sure there is enough wire length so that the harness doesn't touch the driveshaft or exhaust and that the wiring can be tied out of the way without it being taut.

If you have a welder, some basic tools and a space to lift the vehicle, you can do all this yourself for under 100 (that's Canadian dollars), and you wont have to worry about it happening again. The buggers that cut these off know what they're looking for and they won't risk being caught for a $5 steel pipe and not the real thing. Even if they are caught, you've already been affected by it. This gives you a bit of 'victim insurance' so that your vehicle will not become a target of the same crime again, and you wont be stuck with an inoperable vehicle for something someone else did intentionally.

doutrnz

So, luckily, there was no sensor attached to the cat. I did have to buy a California emissions cat, so it was $200 more expensive. The muffler shop told me that I wouldn't worry about this happening again as they go for the original OEM cats, not aftermarket. I guess the aftermarket ones don't use or have very little precious metals they are looking for so it's not worth the value to take it. If anyone is interested, I bought a Flow master aftermarket cat. It was ruffly $600. (Better than $1200 and up, so I kinda lucked out.)

Thanks everyone.