What year is your jeep?

 

1996.

 

Yea but as an American I need a name brand product for it tie quality lolololol. Maybe ill do that. Was the flat stock able to bend at the corners

 

Put it back stock for a day or two and see if it goes back up. What size intake did you use?

 

96. Cruiser said that in order to test it I hook up a vacuum gauge to manifold and rev up to ~2500 for about 20 seconds and then let the throttle snap shut blah blah I'm sure you already know.

 

If you have a press, sure. Mine are flat. No bends in the corner.

 

K thanks

 

You have a check engine light? First year of obd2. If yhe cat was bad it would have a check engine light.

 

From what I've heard it could be clogged without a CEL, but no, I don't have a CEL.. something is giving me this 11mpg and I'm just going down the list. :P
Actually now that you mention it... I guess 96s do have a downstream O2 which would tell me if I had a bad cat.... wouldn't it?

 

Your day going better, Mr Sunshine? LOL.

 

$20 vacuum gauge works wonders. I don't trust CELs for clogged exhaust.

 

It's common for the rare earth element matrix to come loose in XJ factory cat's ...there was even a recall at one point. Just tap the thing with SFH; if you hear the rattle, it's dead ...its a broken matrix. You might NOT get a CEL; just depends. (I got one a couple of times. After a reset, it would go away for awhile. Stupid ECU.)

...and yeah, 11mpg is one possible indicator for a bad cat'.

...and yes, the '96 has a downstream sensor.

DON'T THROW THE OLD CAT' AWAY. A recycler will pay you up to $75 for a full-size cat' (for the rare earth elements). Google it; there's likely one near you.

 

For the sake of argument, it depends: The PCM throws a CEL if the downstream O2's reading is identical or 'too close' to the upstream's. If one or both are screwed then the PCM will think the cat is working normally.

You can also do a quick check with an IR thermometer. A properly functioning catalytic converter's exhaust will be several hundred degrees hotter than the gasses going in. (on phone at a curry house right now so not sure of the actual numbers)

 

Alright alright, I'll get one. I need to get one anyway so I can drive more economically I guess. Thanks Cruiser.

Also, Thanks Salad. An IR thermometer is something I do have!

 

This is what I made.