Exhaust manifold overheat !!

I have a 96 voyager 4 cylinders. I start it and run fine for about 1 hour and there the engine stop, it start again but it run with a bad idle and if I keep it running for more than 5 minutes the exhaust manifold gets really hot at the point that it glow like if somebody was welding. I been replacing some of the sensors but I don’t been able to found where the problem come from. I left the car in the dealer for few days but and they didn’t found the problem (I guest they didn’t ran the car for to long). I need help with this is my only car.:banghead:

Parts replaced:
TPS Sensor
Idle sensor
All injectors
Air filter, Spark plug.

The glowing manifolds are usually due to a plugged catalytic converter, or other obstruction in the exhaust system. I don't know if that is the case on your van because of the hour of running before the glow starts.
The other possibility that comes to mind is a timing issue, which could be caused by the computer or sensors. Is it throwing codes? Have you disconnected the battery to reset the computer?

I went to a muffler shop to check the catalyst converter and they say it is fine. I also went to AutoZone to check the computer code but no codes are storage in the computer, the check engine light is working properly they say. I also try disconnecting the battery for ½ hour and do the mopard troubleshooting with the engine running putting it on gear, a/c and all the acc and tern it off and do the on,off,on,off,on and see for the light but no codes. One of the sensor I been thinking is the knock sensor and see if it that one the one playing with the timing. ????

I had a Chevy pickup that after putting the distributor back in the exhaust manifolds glowed red and it turned out we had the timing off quite a bit. My best guess would be it is something affecting the timing.

Let us know what you find out

Good Luck!

Ok...just to eliminate this thought, have you done a tune-up?

If there isn't any exhaust restriction and no codes, it has to be timing related. I guess I would look at anything that might affect timing and replace.
I forget how computer dependant the the 1996 Cly is. This seems to start after an hour warm-up so that suggests some heat issue. I bet this turns out to be some computer control/sensor issue.

Another thing that is cheap to do. Carefully separate all the connectors and treat them to some electronic contact cleaner, before reattaching them. Check grounds also. Sometimes it turns out to be something simple, but most times it doesn't.

You also may have replaced a defective part with a new defective one.

How many miles on engine?
The 4 cylinder engine uses a timing belt, requires being changed at 100,000 miles according to manual, but they can wear out at 59,000 miles.
Sometimes a cog falls off the belt, and that does screw up the timing.
The problem is you usually have to get the water pump changed at the same time.

This van has 125,000 and the timing belt was change last year. I have done few turn-ups. The engine water temperature is always normal and the fans and the gages are working fine.

... One of the sensor I been thinking is the knock sensor and see if it that one the one playing with the timing. ????
Did you change this one out? This has me stumped. Good luck on this, I'm out of ideas.