Alright, Think of it like this.
your cylinder is doing everything normal but the valves up top are opening late. You wont notice it too much, But when the exhaust valve doesnt open you've got extreme heat. Witch has to go some where to be dissipated aka the coolant which you see as your temp gauge going up up up.

Just how I think of it.

 

A timing light will not work because the engine timing is dynamic. The computer uses what's called a "control map" and will adjust the timing based on input from the various sensors.

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

How to Rebuild Mopar Magnum V8 Engines HP1431 (Paperback)


Great book that was written by one of the engineers who helped design the Magnum engine. He explains that using a timing light is not possible due to the computer control. You need a DRB Scan tool in order to properly analyze it. No matter how often you ask you aren't going to get the answer you want (which is how to use the timing light).

 

i think that i need to focus on the MAP sensor. I can test the TPS and CKP with my DMM, but I won't know what the air pressure is. I think I will test the TPS & CKP, and as long as those test OK, I'll replace the MAP. Remember, if the MAP is reading incorrectly, that is one of the sensors that changes the ignition timing.

 

anywhere from six to thirty degrees, depending on how the computer feels at the time.

 

ok here's an update as to what I did today.

1. Tested TPS. works fine, signal voltage within range.
2. Tested IAC. works fine, plunger moves in and out depending on RPM range.
3. Tested MAP. works fine, signal was just was described in service manual and as stated by other members on this board.
4. Replaced leaky fuel injector o-ring. Now runs smoother.
5. Replaced radiator cap.

Status: Still runs hot. The needle stops increasing once it gets past the entire number "200"

Any other suggestions?

 

After all of this have you changed the thermostat, im not gonna go back an read every post so sorry if you've already been asked this.

Also try flushing the engine, they sell kits at autozone or advanced to do it, you will be extremely suprised at how much crap you can have in your engine from dirty water and sludge which the flush will get 75 - 80% out

Also have you replaced the waterpump ?

 

yes i have a 180* hypertech thermo which is brand new.

No, I haven't flushed the engine, I might try that next.

No, I haven't changed the waterpump. I feel confident that the waterpump works fine since the coolant GUSHES out when that thermo opens.

I think it's either a coolant engine flush thats needed, or maybe the radiator isn't cooling enough. The rad looks to be in great condition too, so I don't suspect that.

 

I would consider doing the water pump man, they'er very inexpensive and real easy to change out.

 

Erm, Ok, you are basing your 'overheating' opinion on the gauge in the dash? They aren't precisely accurate..... Mine, with what I assume is a stock thermo, runs in about the same spot.....

Do the cooling system flush, and see if that doesn't change things.

 

haha you're preaching to the choir my friend. I understand perfectly that the gauge isn't precise, but it is somewhat accurate. My gauge should not be reading almost ALL the way to max, thats a fact.