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Catalitic converter problems?

S

Steelerfan

NAXJA Forum User
Location
Las Vegas Nevada
What are the symptoms of a catalitic converter being clogged? I am having some problems with my XJ, when I try to accelerate faster than normal my engine doesn't seem to want to rev. It was suggested to me that it might be the cat. Does this sound right to you guy's? Any one have any other ideas?
It's a 1989 4.0 automatic.
 
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Have you looked at the cat at night after running it for awhile? I had an old ford and when the cat clogged, it glowed red after running it for a 1/2 hour or so, I could see the glow without getting under it. I replaced the one in my 84 CJ7 with a walker cat. In most states, you can replace the cat after 50k miles.
 
My dad had an Olds that the muffler actually stopped up and did this. My Regal recently did the same thing and it was a stopped up cat. It also glowed red after some driving. Better check that cat and get it replaced before it catches something on fire.
 
Visual inspection (glowing), vacuum testing, and of course "disconnecting" it are some ways to determine if you have a clogged cat.

Your symptoms however, could be a lot of different things. Verifying fuel pressure and comparing to factory spec. if you get stuck is never a bad idea.
 
I'm about to put a Magnaflow High-Flow Cat on mine. Got it for $60 shipped brand new on Ebay (it's a store that sells them), and it even has the bung for the 02 sensor since I have a 98. You can get one w/o the bung for $50 shipped.

If you cat looks like it's falling apart, might not be a bad idea.

Also, try taking a hammer and banging on cat a bit to loosen stuff up. If things are just plugged, that might help you out.
 
Steelerfan said:
What are the symptoms of a catalitic converter being clogged? I am having some problems with my XJ, when I try to accelerate faster than normal my engine doesn't seem to want to rev. It was suggested to me that it might be the cat. Does this sound right to you guy's? Any one have any other ideas?
It's a 1989 4.0 automatic.
Click to expand...
You can remove the O2 senser,it will be loud, but if the cat is plugged, it will free up the exhaust, if it runs better, it can confirm a clogged cat. Or just drop the pipe behind the cat so you can see up in there.
 
Symptoms on mine were overheating and a very hot passenger floor as well as trouble getting up grades.
 
The first sign for me was overheating while going down the highway. It seemed to get better after a while but finally plugged while in the Panamint Valley in July. It would rev up pretty high but not go over 5mph and when I put the pedal to the metal to get out of the backcountry and to a highway so it could be towed, it boiled over like a son of a bitch. I could actually hear the coolant boiling and bubbling in the engine block.
 
If the engine would rev high it doesn't sound like a plugged cat.

When the cat is becoming plugged, the back pressure to the engine builds up. The exhaust flow at idle/low RPM can still pass through the cat (or exhaust system, for that matter), but at higher RPM = higher exhaust flow the restriction in the exhaust system causes too much back pressure against the engine--like a cork in a bottle.

Sadly, maybe you should have the engine tested for a blown headgasket.
 
joe_peters said:
If the engine would rev high it doesn't sound like a plugged cat.

When the cat is becoming plugged, the back pressure to the engine builds up. The exhaust flow at idle/low RPM can still pass through the cat (or exhaust system, for that matter), but at higher RPM = higher exhaust flow the restriction in the exhaust system causes too much back pressure against the engine--like a cork in a bottle.

Sadly, maybe you should have the engine tested for a blown headgasket.
Click to expand...

I need to learn how to read. Regrets!
 
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