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Glowing red Exhaust .. woah!

boostamante

boostamante

NAXJA Forum User
Location
los angeles california
So Saturday night Cracker, Russ, Beamer and myself finished up and engine swap around 11pm. After finally getting it fired up and Russ holding it to about 3,000 rpm's we noticed the down pipe glowing red.

We immediately cut it off and looked at each other with the "holy shit" look on our faces.

Anyway, I'm just wondering if this is normal or if it's something not usually noticed during the day.

This was the 1st time the engine was fired up and we were attempting the begin the break-in process.

Would a lean fuel mixture cause this? If so, is it related to timing at all? if so, could the timing be off and what can we do to address it?
 
Lean fuel can absolutely cause this. Not sure about the timing. However, maybe off timing can cause lean fuel? Which could cause the red down pipe? Also, is the cat, or cats in good condition? A clogged cat can cause the red exhaust as well.
 
bluejeepkid said:
Lean fuel can absolutely cause this. Not sure about the timing. However, maybe off timing can cause lean fuel? Which could cause the red down pipe? Also, is the cat, or cats in good condition? A clogged cat can cause the red exhaust as well.
Click to expand...

AS far as i know, the cat is in good shape. then again, i didnt look as it ran fine prior to the swap. Minus the WWII tank sound from the engine :p

Digger87xj said:
pretty normal for the conditions. Many if not most 4.0s will do that.
Click to expand...

Hmm... guess we only noticed it cause if was dark out and it stood out??
 
Whats happening that makes you think the fuel is lean?
Also, talked to an old timer friend of mine, he agrees that you should check for a clogged cat. Otherwise, it is probably not a problem
 
bluejeepkid said:
Whats happening that makes you think the fuel is lean?
Also, talked to an old timer friend of mine, he agrees that you should check for a clogged cat. Otherwise, it is probably not a problem
Click to expand...


I guess i'll have to check to see if the cat is clogged. I mean, it did cross my mind. Also thought about timing too.. we'll see
 
Sounds like the dizzy is one to 2 teeth off, late spark, or you have a leaking inject(s), or both and thus raw fuel burning in the exhaust instead of the engine. This is not normal, it is a fire hazard, it will quickly ruin the CAT, and is not visible in day light.

One tooth off is not very noticeable except during heavy acceleration as the ECU/PCM seems compensate. Two teeth off often fires the spark in the wrong cylinder, or fires it too late (thus fuel is still burning in the exhaust). It can be advanced or retarded depending on which way it is off.
 
also might need to go a size bigger on ur exauhst tube u mentioned exauhst swap and small headers on a v8 not making propper flow would do that but i dont know what swap this is.... or a boosted setup, also as anyone else has said the tune/timing etc could be causing it
 
Mike,
At one tooth off advance OR retarded, the HO wont run or runs so poorly you know it's wrong.

I prompt anyone with an HO xj to run it at static idle of 3000 rpm and NOT see a cherry red exhaust.
 
I'll update you guys later today. Finishing up here at work and heading over to work in it in a few hours.

Wish me luck.
 
IMHO.

I'd be concerned if my exhaust was glowing at any point. The "fire proof" header coating/paint says up to 1000 degrees F, but I would not like anything that hot in my engine bay...or anywhere on my truck.

http://en.wikipedia.org/wiki/Red_heat

The first two RED colors might be expected if the motor was good and hot, and it does say "viewed in dull light". With an exhaust restriction (cat, dings, pipe too small, muffler...potato!) higher temps, brighter color bit it being night time, lower temps would be visible.
 
Last edited:
It's not unusual when breaking in a new engine to see the exhaust header glow a bit at night. After all, with you guys "breaking it in" at 3k for a period of 5 to 15 minutes with no air moving over the pipe at all, what would you think a those hot gasses would do to a pipe?
 
WB9YZU said:
It's not unusual when breaking in a new engine to see the exhaust header glow a bit at night. After all, with you guys "breaking it in" at 3k for a period of 5 to 15 minutes with no air moving over the pipe at all, what would you think a those hot gasses would do to a pipe?
Click to expand...
Ed Zachary


Fellas,
Watch a few dyno videos @ http://www.enginelabs.com/videos/ ... you will see many glowing exhausts.
 
Note that those temps listed in the table are C not F. Multiply by 1.8 and add 32 to those numbers to get degrees F :flame:

I have only seen one glowing stock rig manifold and one glowing CAT in my life. And I like to work at night.

ParadiseXJ said:
IMHO.

I'd be concerned if my exhaust was glowing at any point. The "fire proof" header coating/paint says up to 1000 degrees F, but I would not like anything that hot in my engine bay...or anywhere on my truck.

http://en.wikipedia.org/wiki/Red_heat

The first two RED colors might be expected if the motor was good and hot, and it does say "viewed in dull light". With an exhaust restriction (cat, dings, pipe too small, muffler...potato!) higher temps, brighter color bit it being night time, lower temps would be visible.
Click to expand...
 
Digger87xj said:
Mike,
At one tooth off advance OR retarded, the HO wont run or runs so poorly you know it's wrong.
Click to expand...

IIRC the Renix needs to be 2 teeth off to be that obvious.
 
are any of the sensors hooked up? curious what the fuel trims would be? whats the 02s reading? have seen a glowing exhaust due to a cat issue being clogged.....super lean will cause a red exhaust but jeez that lean...let me know if you can get any live data
 
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