What would cause exhaust manifolds to get orangish red hot on 1993 4Runner especially when run with high RPMs??

I took it to a muffler shop and I was told that there is no obstruction in the exhaust system, and there is plenty of exhaust air coming out. They could not diagnose the problem and sent me to a different shop which I have not taken the car to.

I only noticed this problem after having changed the water pump, fan clutch, thermostat and the timing belt. Not sure if the problem was there before this work was done.

Anyone experienced this problem? Can the improper installation of the timing belt give me this problem? Even though the engine seems to idle and drive fine.

 

maybe heat.... theres movies of people on dynos all the time with this... a certain degree of this may be normal...

are they hot to the touch or just orange colored?.... jk, DONT touch them

 

My guess is a runing lean situation. Check your TPS, AFM, coolant temp sensor and especially your O2 sensor -- all for proper operation and adjustment within specs.

Mike in AR

 

I don't know if mine got re or not but I could smell the metal. This sort of melted smell. Mostly after I was driving fast then stopped. The exhaust manifold was cracked when I bought the truck. I set my TPS and timing and the smell went away. I bet this is the same problem. It will get a bit red at night, that is normal.

 

I had the same problem on my 4Runner and it was a clogged catalytic converter.

RBMC

 

I would say catalytic converter as well, I had the same problem on a chevy s-10 and the cat looked lke someone had taken a cutting torch to it on the inside. Cut off the bolts with a grinder and if you can't see throught the cells, it is clogged. Get a new one if so.

If it running that hot, your gonna toast your motor.
Graham

 

Update: No one can find what's wrong with it, so had to take it to the dealer, the work order says that they set the timing which was off and they fix the EGR hose. No new parts were needed, just one hour and a half worth of labor. Car runs fine. I thought I would share in case someone encounters the same problem.

 

Glad to hear its fixed, but to a cetain degree there gonna get hot, EGT on gas engines can hit 1600 deg F or higer...thats warm.