Glowing Headers: Good or Bad???

I researched "overheating", and posted to this thread. Basically, what I orginally thought may have been a gauge error is looking more and more like actual overheating.

The strongest indicator the forum has picked up on is that the headers were glowing red hot after a few minutes of up-idle, but I really haven't seen the overheating issues at idle or even up-idle (to recharge the batterys). If anything idle brings the temp back down after highway speeds.

To me, another strong indicator is that when I shut off the engine after a freeway speed run (such as to get gas), I can readily hear the coolant boiling in the engine. Even the overflow is boiling. Yes, I think it's safe to say the engine is actually overheating.

The general concensus is the exhaust system is clogged with years of crappy gas and being beat to piss on every available opportunity. I am planning on cutting the exhaust tube just in front of the cat and welding a straight pipe (temporary) out the side for some test runs. But if that doesn't fix it:

The question of engine timing comes up. The vehicle lived at sea level it's whole life, but recently has been moved to Colorado, where it serves as a vacation vehicle at my cabin. The altitude is much higher, so the engine computer should lean it out as per the MAP sensor, which I have replaced twice up there, at the engine computers suggestion. Other than the snorkel, the engine is completly stock. Not even a chip.

It is a 1998, so it has the computer (relocated for the snorkel) and IIRC a distributor.

Opinions???


Thanks,

Robert

thats definately a melted-down cat converter, I'd weld in a new one and a new o2 sensor. Running without a cat is driving a mobile carbon monoxide factory.

Ive seen cherry red manifolds before, very bad for everything under the hood,
especially the fuel line quick connects and drivers side motor mount

There are two main things that can cause overheated headers. A plugged CAT and running way too lean. Both are bad.

Right, we've discussed the clogged cat. This thread is specifically if it's NOT a plugged exhaust system. What then???

Like I said in previous posts, I'm in Houston, the Jeep is in Colorado, so I have to plan carefully, taking all the tools I need in order to successfully complete the job the first time.

How would the mixture get that far off on a computer controlled engine?? What can be done to correct it???

92DripCherokee said:

thats definately a melted-down cat converter, I'd weld in a new one and a new o2 sensor. Running without a cat is driving a mobile carbon monoxide factory.

Ive seen cherry red manifolds before, very bad for everything under the hood,
especially the fuel line quick connects and drivers side motor mount

Click to expand...

Thanks, I'll check both those while I'm under the hood.

R

Wow...on a 1998, i'm really surprised the check engine light hasn't come on...especially if it's running THAT lean, and/or the converter is plugged...

It never gets through a global cycle, because I leave the battery disconnected most of the time. When I drive it, it's only for a couple of days at a time, and that's mostly in 4L up and down dirt roads. It never has time to kick a code.

The tranny sensor kicks in after about 20 miles, but that's all I see.

Hopefully your intake/exhaust manifolds have not warped due to the extreme heat. This happened on a 2.5L wrangler I used to have. I'd git 'er checked out pretty soon.

I'm planning on doing a complete exhaust system replacement, from the headers. I'll probably pull the intake manifold during the install anyways, so neither will be an issue. I'm more worried about other stuff melting like brake lines, wiring looms, steering seals, etc....

WildernessJeep said:

I'm planning on doing a complete exhaust system replacement, from the headers. I'll probably pull the intake manifold during the install anyways, so neither will be an issue. I'm more worried about other stuff melting like brake lines, wiring looms, steering seals, etc....

Click to expand...

Good idea!

old_man said:

There are two main things that can cause overheated headers. A plugged CAT and running way too lean. Both are bad.

Click to expand...

Would running too lean actually make the headers glow? What about running rich with a very late timing spark (plus a plugged melted cat!) i.e. one could have led to the other!!!!

I had glowing headers on my 73 (carbed) 351 ford when the distributor's vacuum and centrifugal advance froze up, and it ran fine, good power, but the ignition spark was very late so the fuel was still burning when the exhaust exited into the exhaust manifolds. I am wondering if their is a computer/sensor combo error that could do the same or similar on a 98 XJ?

I had a 76 Dodge Charger lean burn that ran way way too hot:bawl:, but the manifolds never glowed in the dark.

Oh, by the way I went through 2 exhaust gaskets before I popped the hood one night and noticed the glowing manifolds. I replaced the distributor, exhaust gaskets one more time and no more problems, no warpage either. Must have driven it for several thousand miles before I figured out what was going on.

WildernessJeep said:

Right, we've discussed the clogged cat. This thread is specifically if it's NOT a plugged exhaust system. What then???

Like I said in previous posts, I'm in Houston, the Jeep is in Colorado, so I have to plan carefully, taking all the tools I need in order to successfully complete the job the first time.

How would the mixture get that far off on a computer controlled engine?? What can be done to correct it???

Click to expand...

One thought. If it went into open loop mode due a sensor failure (like an O2 sensor or MAP) it runs rich which has been reported to be able to damage, melt, clog up cats on the inside guts, which might make the rich burn pile up and burn off in the manifold, thus the glow, I THINK! But I am not sure.

Clogged cat and maybe a bad O2. The computer should be throwing a code for the o2 but may just be getting bad readings due to the bad cat. IF the fuel mixture was to lean it would throw a code. Wouldn't take long to throw it once it was past the warm up stage. Timing is not an issue being that the computer is controlling it. If the Jeep sets with the battery disconnected alot this would have reset the computer to run at the higher elev. Next time you pull the cables cycle the headlights on and off a few times to bleed off any excess juice stored in the computer.

WildernessJeep said:

I researched "overheating", and posted to this thread. Basically, what I orginally thought may have been a gauge error is looking more and more like actual overheating.

The strongest indicator the forum has picked up on is that the headers were glowing red hot after a few minutes of up-idle, but I really haven't seen the overheating issues at idle or even up-idle (to recharge the batterys). If anything idle brings the temp back down after highway speeds.

To me, another strong indicator is that when I shut off the engine after a freeway speed run (such as to get gas), I can readily hear the coolant boiling in the engine. Even the overflow is boiling. Yes, I think it's safe to say the engine is actually overheating.

The general concensus is the exhaust system is clogged with years of crappy gas and being beat to piss on every available opportunity. I am planning on cutting the exhaust tube just in front of the cat and welding a straight pipe (temporary) out the side for some test runs. But if that doesn't fix it:

The question of engine timing comes up. The vehicle lived at sea level it's whole life, but recently has been moved to Colorado, where it serves as a vacation vehicle at my cabin. The altitude is much higher, so the engine computer should lean it out as per the MAP sensor, which I have replaced twice up there, at the engine computers suggestion. Other than the snorkel, the engine is completly stock. Not even a chip.

It is a 1998, so it has the computer (relocated for the snorkel) and IIRC a distributor.

Opinions???


Thanks,

Robert

Click to expand...

just change your plugs (igniterz) and all will be well.

I would go Borla or Banks for the header. Good Luck!
P.S. I am so Jealous you get to wheel Colorado so frequently., I have an aunt in Parker Co. I want to go but I'm afraid soething will break on a trail and I'll have to go for broke to get her back home in Ohio.

I disagree that timing can not be the problem. Just because the computer controls timing does not mean it is working properly.

Had another thought on the timing. Been thinking the distributor might be off a tooth or two but you have not confirmed that it was ever pulled or changed, but what about the timing chain? Could it have jumped time a tooth or two... and be causing the intake valves to open too early?:doh:

Not a pleasant thought of course.

Onkover said:

Clogged cat and maybe a bad O2. The computer should be throwing a code for the o2 but may just be getting bad readings due to the bad cat. IF the fuel mixture was to lean it would throw a code. Wouldn't take long to throw it once it was past the warm up stage. Timing is not an issue being that the computer is controlling it. If the Jeep sets with the battery disconnected alot this would have reset the computer to run at the higher elev. Next time you pull the cables cycle the headlights on and off a few times to bleed off any excess juice stored in the computer.

Click to expand...

straight pipe it first, for diagnosis.

jeepman121 said:

I would go Borla or Banks for the header. Good Luck!
P.S. I am so Jealous you get to wheel Colorado so frequently., I have an aunt in Parker Co. I want to go but I'm afraid soething will break on a trail and I'll have to go for broke to get her back home in Ohio.

Click to expand...

I just drive the Nissan Titan up there, then drive the Jeep around town. This also helps keep performance awards to a minimum, because for some reason the Colorado LEO's target Texas license plates.

If you have another daily driver, you are more than welcome to leave your Jeep at my property. Then its just a $59 (Southwest roundtrip) flight away. Three day weekends leave two days of Colorado wheeling available.

I'm planning on a Borla header (once I confirm that it is in fact a clogged exhaust system), and stainless everywhere else. I wanted to look into low profile stuff, so I can finally get around to fabbing up the 1/4" plate steel belly pan I've always wanted. The Jeep hasn't been cheap thus far, I'm not going to start now. I have ARB's in both axles, and Bulletproof bumpers on both ends, so you can see the caliber of exhaust I'm looking for. Any other opinions???

Onkover said:

Next time you pull the cables cycle the headlights on and off a few times to bleed off any excess juice stored in the computer.

Click to expand...

Good idea. Thanks.

WildernessJeep said:

I just drive the Nissan Titan up there, then drive the Jeep around town. This also helps keep performance awards to a minimum, because for some reason the Colorado LEO's target Texas license plates.

Click to expand...

Man, it's so funny that you say that. It's true! I've lived in Colorado for 13 years now, married a Texas girl whose family routinely makes the trip up to see us and it's never failed that they get pulled over on every trip. I'm not sure where Weston is...gimme a clue! I've seen the Uhaul pics in your other posts, and it looks like killer wheelin up there!