recently replaced my cat. had loss of power and glowing header....which is why i replaced it.

I opened my hood the other day after highway driving and found my header glowing again????

The heated O2 sensor is less than a year old. The one on the header is original. I only have a narrow band O2 gauge but it reads normal. I would assume if I was running lean it would peg out at lean since it only reads around stoich.

The only thing I can come up with is my header wrap. Could this be holding the heat in and making the header too hot??? I have the RK ceramic header.

Glowing = rich





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Id remove the header wrap as well. That can eat away the header from keeping all the heat in, even if ceramic coated.

Shifted wrote:Glowing = rich

Actually, the opposite. Rich runs cooler. Lean runs much hotter.

Check for a vacuum leak. That's most likely your culprit.
There is probably air getting into the engine somewhere that it's not supposed to be.

Quiklilcav wrote:

Shifted wrote:Glowing = rich

Actually, the opposite. Rich runs cooler. Lean runs much hotter.

You are too generalized. What do you think happens when the exhaust valve opens on an overly-rich motor? This isn't a CAI motor, combustion is not spontaneous. So, the chamber may be cooler, but that doesn't mean everything else is.
Think about what cars you typically see glowing manifolds on...

This can also be caused by excessively-retarded ignition timing.




fortune cookie say: better a delay than a disaster

Quiklilcav wrote:

Shifted wrote:Glowing = rich

Actually, the opposite. Rich runs cooler. Lean runs much hotter.

Check for a vacuum leak. That's most likely your culprit.
There is probably air getting into the engine somewhere that it's not supposed to be.

yeah too lean and to rich can cause that.

learn something new everyday huh?



LE61T PTE6262 Powered

OHV notec wrote:You are too generalized. What do you think happens when the exhaust valve opens on an overly-rich motor? This isn't a CAI motor, combustion is not spontaneous. So, the chamber may be cooler, but that doesn't mean everything else is.
Think about what cars you typically see glowing manifolds on...

This can also be caused by excessively-retarded ignition timing.

I speak from experience. I have seen this problem on an engine of my own before, as well as a few other motors of people I know. Every time it turned out to be a vacuum leak somewhere, whether it was a hose, or a bad gasket (caught a friend reusing a torn runner gasket on a TPI motor because he didn't think it was crucial)

I'll agree that overly retarded timing could possibly be the culprit, but I can't see how it could retard that much on our engines without there being an issue of a timing chain jump, which would mean that the valve would be retarded as well.

An overly rich combustion burns cooler, because it doesn't burn complete. Hence the cooler chamber temperature, as well as exhaust gas temperature. I know what you're saying, but it's an unlikely combination of events. Not impossible, but unlikely.

Quiklilcav wrote:

OHV notec wrote:You are too generalized. What do you think happens when the exhaust valve opens on an overly-rich motor? This isn't a CAI motor, combustion is not spontaneous. So, the chamber may be cooler, but that doesn't mean everything else is.
Think about what cars you typically see glowing manifolds on...

This can also be caused by excessively-retarded ignition timing.

I speak from experience. I have seen this problem on an engine of my own before, as well as a few other motors of people I know. Every time it turned out to be a vacuum leak somewhere, whether it was a hose, or a bad gasket (caught a friend reusing a torn runner gasket on a TPI motor because he didn't think it was crucial)

Any significant amount of air bypassing the TB would also cause it to idle at rediculous RPM, which would be a pretty easy diagnosis.

Quiklilcav wrote:I'll agree that overly retarded timing could possibly be the culprit, but I can't see how it could retard that much on our engines without there being an issue of a timing chain jump, which would mean that the valve would be retarded as well.

Ignition timing is what I was referring to, which could be caused by numerous things, although in this case I'd guess the knock sensor most likely.

To the OP: have you noticed any change in performance?

Quiklilcav wrote:An overly rich combustion burns cooler, because it doesn't burn complete. Hence the cooler chamber temperature, as well as exhaust gas temperature. I know what you're saying, but it's an unlikely combination of events. Not impossible, but unlikely.

When those unburned gases are burning in the exhaust manifold, EGTs go up.
An overly rich combustion burns cooler because there is less relative oxygen content to feed the flame front, not necessarily because it doesn't burn completely. If you have 90% combustion at 100% fuel input, but only 80% at 120% fuel input, you still have a 6% increase in burned fuel (which using your logic would burn cooler, but in reality burning fuel = more heat). Rich engines also have cooler chamber temperatures due to liquid fuel vaporizing on chamber surfaces.




fortune cookie say: better a delay than a disaster

We pulled a bit of fuel at certain spots with HPT and my EGTs went down...so running too rich will infact cause your exhaust to be too hot, such as it would being too lean.




14.330 @ 96.37mph

OHV notec wrote:When those unburned gases are burning in the exhaust manifold, EGTs go up.
An overly rich combustion burns cooler because there is less relative oxygen content to feed the flame front, not necessarily because it doesn't burn completely. If you have 90% combustion at 100% fuel input, but only 80% at 120% fuel input, you still have a 6% increase in burned fuel (which using your logic would burn cooler, but in reality burning fuel = more heat). Rich engines also have cooler chamber temperatures due to liquid fuel vaporizing on chamber surfaces.

I know the reason behind the difference in burn, and why the temperature changes in the combustion with the mixture. The logic I was using behind the cooler combustion is the same as why the chamber is cooler: you still have the vapor present that also keeps the exhaust gas cooler.

Actually, when you consider the possibilities, his problem could also be a combination of incorrect fuel mixture and retard, which would account for the lack of power.

the lack of power was already taken care of by replacing the cat.....it was clogged. the header is definately not glowing like it did with a clogged cat.

I havent done anything with timing. i have a stock ECU. I would still have to go wiht the header wrap being the culprit.
I mainly used the header wrap to keep the coolant hoses in the firewall safe and try to keep temps down in the engine bay...especially w/ a short ram intake.

anyone else think i should get rid of the wrap?? thanks for all the input

The wrap is supposed to help you with performance by holding the heat in the header making the engine bay cooler, that could definitely cause glow. But this also drastically shortens the life of the header making it brittle and prone to cracking and ive heard stories of the runners rusting away from condensation built up in the wrap. That is why most companies say header wrap voids their warranties.

I can't imagine header wrap causing it to glow. Glowing metal is seriously hotter than normal. I have never heard of anyone puting header wrap on and having their header start glowing.

However, Zs Z is correct about the corrosion from moisture getting trapped by the wrap, unless your headers are stainless.

Im gonna have to find someone with a scan tool and take a look. Like I said before...I only have a narrow band and its reading normal, so I dont think it's running rich OR lean. I would probably get a CEL if that happened anyway.