ch45x7

I just changed out the exhaust on my new XJ. New downtube back.
I bought a Thunderbolt Spin Cat with o2 port because it was recommended here and said it meets the requirements.
I'm now getting a CEL. I will double check this tomorrow, but I believe it's for the 2nd o2 sensor.
After some intensive searching I've found that this cat can be a problem for some Jeeps. What can I do about this? If it meets OBDii requirements why is it throwing a code? Is there anything I can do to get it to stop throwing the code other than replacing the cat again?

Please help, I need to get this up and running so it will pass inspection here in NY.

PumpinIron

Hmm I am curious to know the answer as well. I have the same cat I am about to install on my 2000 XJ and I definitely don't want to install it if it's going to throw a CEL.

Also, where did you get your downtube? Is it custom or what? Seems like no one makes aftermarket downtubes for these XJs.

ch45x7

Down tube I bought at pep boys. Advance auto and auto zone had it too but pep boys had a better discount code running the other week.

Tom95YJ

I use a thunderbolt spun cat also. Part number 410250. Mine did not have a O2 bung. I added one 6" after the cat I have no CeL

PumpinIron

Oh my bad! Didn't realize it was a stock downtube!

ch45x7

So did you put it into a piece of straight pipe after the cat then? I don't understand why that would work vs the location that it's at now. Does that little bit of distance matter that much? Isn't it still the same exhaust content?
I'm new to exhaust work so I genuinely don't know.

ch45x7

No worries. Stock down tube is 2.5 at the end so why not use it. It goes in so easy.

perpetual

I can't track down the down tube on Advance or Autozone, at least for my 96. Maybe they have something for different years.

ch45x7

Part number 55277
Walker exhaust pipe
Don't forget the round gasket for where it meets the manifold.

perpetual

Thank you! Take the rest of the day off.

Tom95YJ

Yep I added a 8" long strait between the cat and muffle the heat from a cat will destroy a muffler if it's too close.

rctrav

I'm running the same cat with the o2 bung in it and have not thrown any code's. I've had it on mine for almost two years.

ch45x7

So the code says downstream o2 is not working at all. Going to clean the connectors and apply some dialectic grease see if that clears it up. Hoping it's just a bad connection and not a faulty sensor.

ch45x7

o2 sensor was bad. It has a dent in the end.
Side note, don't go to pep boys! They won't do anything about it even though I have the receipt.

mr white

You bought a new o2 that was faulty out of the box and they wont let you return it?