Novak Conversions Jeep Wrangler TJ engine mounts

Catalytic converters glowing red

Shawn&Katie

Shawn&Katie

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May 2, 2018
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Location
Grandview, TX, USA
Stupid question? When running up the RPM, headers turn bright red on the center pipes, but no funny restricted sound from exhaust and engine runs great. Jeep is all stock.
Is this normal or could the catalytic converter be clogging up?
 
That’s a symptom of clogged catalytic converters or an engine running way too rich.
 
I doubt it’s running rich in that case. Sounds to me like your cats may be clogged. That’s pretty common on TJs of this age. Happened to my TJ as well.
 
Chris said:
No problem, happy to help!
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Talked to a muffler shop this morning, not the cat. He says it’s dumping unburnt fuel down the headers and wife finely fessed up and said it overheated yesterday so I guess it just started.
Do you have any experience with the throttle bodies on these things? Something that can be fixed or cheaper to replace?
So weird it’s running so good, it must be dumping straight into the exhaust
 
Not sure if this is the problem but I had similar problems on an F-150 many years ago. The truck ran fine and then temps spiked and it stalled. I opened the hood to find the pipe to the cat cherry red. Figured for sure it was the cat. It had a straight 6 in it. Ended up being a bad battery. I couldn't believe it but the mechanic said the engine was working so hard to keep it charged that the spark was really weak, causing the extra fuel to pass through, accumulate in the exhaust and burn off there. Maybe not the same issue, but sounds like it is worth checking.
 
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Shawn&Katie said:
Talked to a muffler shop this morning, not the cat. He says it’s dumping unburnt fuel down the headers and wife finely fessed up and said it overheated yesterday so I guess it just started.
Do you have any experience with the throttle bodies on these things? Something that can be fixed or cheaper to replace?
So weird it’s running so good, it must be dumping straight into the exhaust
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Ahhh, yep, unburnt fuel in the cats will do that. So it's running rich. Is it throwing any check engine lights. I'm shocked it would have passed emissions with this issue.

Why would you think it has something to do with the throttle body?

The first place to start is to use an OBDII scanner and scan it to see if it's throwing any codes. The next thing I would do is let it idle while running and see if it starts to overheat (shut it off it if starts to).
 
Chris said:
Ahhh, yep, unburnt fuel in the cats will do that. So it's running rich. Is it throwing any check engine lights. I'm shocked it would have passed emissions with this issue.

Why would you think it has something to do with the throttle body?

The first place to start is to use an OBDII scanner and scan it to see if it's throwing any codes. The next thing I would do is let it idle while running and see if it starts to overheat (shut it off it if starts to).
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Haven’t looked at it much at all and not educated on the vehicle. Haven’t worked on cars since the late 80’s either and was assuming it was a throttle body injection. Now that I know it has six injectors it’s quite possible it’s got a couple bad ones
 
Shawn&Katie said:
Haven’t looked at it much at all and not educated on the vehicle. Haven’t worked on cars since the late 80’s either and was assuming it was a throttle body injection. Now that I know it has six injectors it’s quite possible it’s got a couple bad ones
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Definitely no throttle body injection on these things.

You'll want to go to your local auto part store and have them scan it for free (they do that) to see if it has any codes it's throwing. That will be the first place to start. I highly doubt it's a bad injector, but if it's throwing any codes, that will definitely help to point us in the right direction, as it could be a plethora of things.
 
Chris said:
Definitely no throttle body injection on these things.

You'll want to go to your local auto part store and have them scan it for free (they do that) to see if it has any codes it's throwing. That will be the first place to start. I highly doubt it's a bad injector, but if it's throwing any codes, that will definitely help to point us in the right direction, as it could be a plethora of things.
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That’s the plan of action for now. No check engine light and running so great is just mind boggling to me. Wouldn’t the check engine light come on if there were any codes?
 
Shawn&Katie said:
Haven’t looked at it much at all and not educated on the vehicle. Haven’t worked on cars since the late 80’s either and was assuming it was a throttle body injection. Now that I know it has six injectors it’s quite possible it’s got a couple bad ones
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Seems odd that that many would go at once.
 
Did some googling and stumbled across another idea. Have you checked your coolant temperature sensor? Given the overheating incident maybe it is pointing to this. When they go, the engine doesn't know it is warmed up and keeps pumping extra fuel in so it runs rich.
 
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Shawn&Katie said:
That’s the plan of action for now. No check engine light and running so great is just mind boggling to me. Wouldn’t the check engine light come on if there were any codes?
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Typically it would come on, yes. However, it's worth checking anyways just to see.

If it's running okay, that seems to suggest nothing is wrong. Are the cats still glowing?
 
tquig01 said:
Did some googling and stumbled across another idea. Have you checked your coolant temperature sensor? Given the overheating incident maybe it is pointing to this. When they go, the engine doesn't know it is warmed up and keeps pumping extra fuel in so it runs rich.
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Checking the cooling system next, it seemed to take too long for the thermostat to open to me. Water didn’t start moving till the pipes were glowing for awhile. Even after coolant was full and circulating well pipes still bright red at a moderate RPM.
 
I don't know man, still sounds just like clogged cats to me. You sure it's not?
 
Chris said:
Typically it would come on, yes. However, it's worth checking anyways just to see.

If it's running okay, that seems to suggest nothing is wrong. Are the cats still glowing?
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Code came back misfire on #4 and several intermittent misfires. All spark plugs looked good but replaced anyway, found a couple of the wires a little loose and found distributer and rotor a little burnt/ deposits. cleaned it up still same problem.
Cats aren’t glowing it’s the manafold at the head down towards the cat that is bright red.
Going through about half a gallon of coolant a data’s of yesterday with no leaks. Noticed more than normal moisture coming out of the exhaust tonight and didn’t smell like fuel.
Going into shop tomorrow
 
Ahhh, so you're going through coolant but it's not leaking? That seems to suggest you are burning the coolant, which could be a cracked head or a bad head gasket.
 
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