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Cracked Manifold / Cherry Red Cat

D

Dragline

NAXJA Forum User
Location
Richmond, VA
As soon as the weather cooled off this year, my Jeep started running bad. No power, sounded like it was missing, exhaust sounded different. I started smelling smoke (but not like you would smell if it was coming from the engine) looked around and my floorboards were smoking. Looked under the Jeep and the cat was cherry red. After looking everything over, I noticed the small crack in my exhaust manifold was growing larger. My guess is the crack in the manifold is giving the O2 sensor a false reading making the engine run rich which is making the cat overheat. First of all, does this make any sense?? and secondly is there any way to test this?? What should I expect to see if I disconnected the O2 sensor??? (besides the check engine light coming on)
 
A Cherry Red cat? I have never heard of this but sounds like u are very lucky you didnt ignite the interior of the thing! Un plug the upstream O2 And see if it happens again? If the cat got red hot then the O2 in that must be gone already and I would think that the wires are melted off of it now too.
 
my cat on a ford bronco got cherry red once, it was due to a clogged cat. we noticed a loss of power a few weaks before it started glowing. replaced cat and no more problems.
goodluck
 
1985xjlaredo said:
If the cat got red hot then the O2 in that must be gone already and I would think that the wires are melted off of it now too.
Click to expand...

There is no O2 sensor in the cat. There is only one upstream.

1985xjlaredo said:
Un plug the upstream O2 And see if it happens again?
Click to expand...

Will it run OK with the O2 sensor unplugged

ahm said:
my cat on a ford bronco got cherry red once, it was due to a clogged cat. we noticed a loss of power a few weaks before it started glowing. replaced cat and no more problems.
goodluck
Click to expand...

The shop I took it to won't replace the cat until I get the engine running well. They are scared the engine running rich will destroy the new cat.
 
Dragline said:
I noticed the small crack in my exhaust manifold was growing larger. My guess is the crack in the manifold is giving the O2 sensor a false reading making the engine run rich which is making the cat overheat. First of all, does this make any sense??
Click to expand...
Yes, that does make sense.
I'm replacing my whole exhaust due to too many failures.
Cat was the motivator(plugged when engine heated up, un-plugged when engine was cool), going with pacesetter headers, new O2, new direct fit cat 2.5in high flow Cat, 2.5in Dynomax catback
(still waiting for the header)

Dragline said:
What should I expect to see if I disconnected the O2 sensor??? (besides the check engine light coming on)
Click to expand...
Would the engine run?
 
The shop I took it to won't replace the cat until I get the engine running well. They are scared the engine running rich will destroy the new cat
Click to expand...
Find A New Shop That does what you tell them to do!
It wont run well with the O2 unplugged but it sounds like it might not be working now anyways.
Hell take a sawzall and cut the cat off your self then just put some exhaust pipe in its place (if you dont have to do emissions testing for an inspection). Thats what I did to mine and it made a big difference! Seems to have alot more umph off the line
 
We don't have an emissions test but if the shop that did the yearly safety inspection passed it with no cat, they would be in for a huge fine. Probably little chance of getting caught, but if it were my shop I wouldn't take the chance.
 
i cut my cat out this summer....didnt notice any power gain...and didnt exspect to with the loss of back pressure...but it does sound a little bit nicer. sounds like its just clogged to me...cut it out or replace it with a high flow cat.
 
Dragline said:
What if I just poked a hole in it to see if that was all that was wrong?? Sounds like I need to replace it anyway.
Click to expand...

i dont think you would be able to tell much...if you could see anything at all...and if you did 'poke' a hole in it you would have to trash it anyways...when i cut mine out i looked through the inlet side to see what all was in there...bc i have never seen the inside of a CAT...and i couldnt see anything...and that was looking though the exhaust pipe.
-Willie
 
I was thinking that if it was just clogged and I poked a hole in it, I would get power back and be able to tell if the cat was the only problem.Sounds like the cat is trashed anyway. The more I think about it. it may be better to cut the cat out at least temporarily and put a short section of exhaust pipe in its place (temporarily) and see how it runs.
 
definitely sounds like a clogged cat to me. If you look into a catalytic converter, it is a ceramic honeycomb, and a pretty fine one at that. It doesn't take much to clog it. If that happens, it will overheat, possibly melting, and you will notice a decrease in power. Here's a picture of cat that has started to clog. You can see how fine the matrix is. I've seen pics of one where the ceramic just melted into a big blob, nearly blocking the cat completely.

Jetta_cat_clogged2.jpg
 
Dragline said:
The shop I took it to won't replace the cat until I get the engine running well. They are scared the engine running rich will destroy the new cat.
Click to expand...

Dude.. Find a new shop.. I would not take any of my cars back there..

It's not running well because of the cat..

Tell te shop "STEP AWAY FROM THE JEEP!!"

Elias
 
When they told me they wanted to get the engine to stop missing first, I told them I would pick it up and get the engine right myself and then bring it back. The Jeep is parked in my driveway now, and I have borrowed a friend's beater.
 
just beat the piss out of the inside of the cat out for now, but look into replacing the manifold and the O2.
The shop is trying to do the right thing, thry're just helping you save $$. At the same time they probably would love to do the work for you, they have to make $ too.
I'm not replacing the cat until I have headers, and O2 installed. I don't want to replace the cat again for another 5 or more years or so
 
X2, remove the cat and inspect it. That is what my muffler man would do before replacing. How do you know do fix it it hasn't been removed and inspected inside. See how it runs while you have it off. Your O2 is likely toast and you'll need to test this too.

axiomatik said:
definitely sounds like a clogged cat to me. If you look into a catalytic converter, it is a ceramic honeycomb, and a pretty fine one at that. It doesn't take much to clog it. If that happens, it will overheat, possibly melting, and you will notice a decrease in power. Here's a picture of cat that has started to clog. You can see how fine the matrix is. I've seen pics of one where the ceramic just melted into a big blob, nearly blocking the cat completely.

Jetta_cat_clogged2.jpg
Click to expand...
 
I suspect we already answered the question in this thread...
 
casm said:
I suspect we already answered the question in this thread...
Click to expand...

Looks familiar! Time to poop out a cat or get off the pot.
 
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