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Scout19 06-10-2013 11:19 AM

Red exhaust manifold!
Hey guys need some insight. My TJ's exhaust manifold was glowing red last night after the drive from work. Wht causes this? I checked the plugs they are white but also were gaped wrong so fixed that I haven't looked into the o2 sensor but can it make it run lean. I heard white plugs ment it was running lean. And if it is how do I get the mixture back to normal it dose have a 4.0 throttle body with spacer . Oh yeah mine is a 2.5 98 TJ. Thanks guys!

jeepstertj 06-10-2013 11:24 AM

Any Check engine light? Codes? Check gauges?

With that i think you have a intake problem the engine is getting to much air and not enough fuel or vice versa.
Have you tried to remove the throttle body spacer maybe a little air is being sucked because of a bad seal.
Thats my opinion.

jeepwayoflife 06-10-2013 11:27 AM

I would check the O2 sensors. They detect the amount of gas being burned, and if they break or get covered in crud they can tell the engine to introduce more or less fuel than it needs. It looks like in your case the engine is getting less than it needs. I would start there and see. Maybe you can remove the sensors and clean them off? Second I would remove the throttle body spacer. It wont do anything for performance and like mentioned above, air could be leaking past, air that is not regulated by the intake sensor. How many miles on the jeep?

Dubs99sahara 06-10-2013 11:35 AM

Could possibly be your catalytic converter starting to plug up on you too.

Scout19 06-10-2013 12:19 PM

I have 128300 on the jeep. I unplugged the o2 sensor to make sure I would get a check engine like and I did.

Scout19 06-10-2013 12:21 PM

Oh and the cat is welded to the muffler so how do I check it.

Tomdata 06-10-2013 12:59 PM

Probably a plugged exhaust if the check engine light is not on and there are no obd2 codes set.. If it was lean enough to make the exhaust glow red then it would be setting lean codes (unless its an o2sensor slightly out of calibration-very rare problem).

Easiest way to check for plugged exhaust is to hook up a vacuum gauge to manifold vacuum and check it at idle. Should be at least 18-20 inches. Also if he exhaust is plugged you should have a lack of power under medium to full throttle while accelerating.

Scout19 06-10-2013 01:31 PM

Well I do have crappy acceleration but at idle in park it revs right up. I have no check guages or check engine lights on. Where's the manifold vacuum.

Scout19 06-10-2013 01:38 PM

Also there is no emission testing in Indiana so would it hurt to just get rid of the cat

Tomdata 06-10-2013 02:13 PM

Follow the vacuum line from the brake booster to the intake manifold. There should be a port somewhere on the manifold.

Scout19 06-10-2013 03:34 PM

Thanks Tom!

Zdrisko 06-10-2013 03:45 PM

Clogged cat or exhaust valve not seating correctly. Does it run rough?

TJ4Jim 06-10-2013 04:12 PM

Had a similar problem a few years ago and it absolutely was the CAT. The header overheated and lit the adjacent plastic on fire. Car stalled right in front of my local FD just as the Chief was arriving at 6 AM. He was putting out the fire as I was emptying the vehicle of belongings.

Tomdata 06-10-2013 06:52 PM


Originally Posted by JimsJeep (Post 3845869)
Had a similar problem a few years ago and it absolutely was the CAT. The header overheated and lit the adjacent plastic on fire. Car stalled right in front of my local FD just as the Chief was arriving at 6 AM. He was putting out the fire as I was emptying the vehicle of belongings.

Pics!!! We need pics!!!

outofmoney 06-10-2013 06:57 PM

I had the same problem with some cheapie eBay stainless steel manifold. Took it to stealership and they couldn't find anything wrong. Gave it to a cousin with a jeep & he has had no problems with it for the last 3 years. Bought a ceramic coated one & had no problems with it!

TJ4Jim 06-10-2013 07:19 PM


Originally Posted by Tomdata (Post 3846427)
Pics!!! We need pics!!!

Sorry, no pics on that one

Scout19 06-10-2013 09:20 PM

Well runs good little bogged down when acceleration off the line. But going to vacuum test it tomorrow if that comes out ok . Then I'm getting a new cat.

Scout19 06-11-2013 09:52 PM

Well took out my o2 sensor and it looks horrible so guess I'm getting a new one and going to see how that works the vacuum test was good.

Tomdata 06-12-2013 12:39 AM

99% sure the o2 sensor won't fix it.

I still think its a restricted exhaust. Probably the catalytic converter..

What kind of vacuum did you get at idle?

Scout19 06-12-2013 09:26 AM

I'm getting rid of the cat too just needed a new o2 sensor. Indiana has no emission laws so I'm hacking it off and welding pipe to the muffler. Thanks again guys I have learned so dang much from guys like y'all on this forum!

ChaddG 06-12-2013 04:19 PM

knock on your cat with a mallot, see if anything shoots out the exhaust

LiquidDragon 06-12-2013 04:26 PM

why not just unbolt the exhaust from behind the cat and punch the guts out and then bolt it all back up? I have seen this done lots of times on various types of cars and seems to be very easy to do especially on cats that are older and the internals are burnt up. just my $.02

ebilek231 06-12-2013 06:29 PM

I had the same problem I had the firing order of the wires mixed up lol

Scout19 06-13-2013 11:01 PM

And I forgot to mention I checked the plugs they seem like they have a white dust on them I just had it in the shop for an oil leak I couldn't find turned out it was where the rotor goes into the engine so the mechanic replaced it now would it needed retimed if he took it out ?

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