Ok I have been having a Overheating problem for a while now.. At first I had a small leak so at the advice of a friend I added some stop leak to seal It.. Well that did not solve the problem. It stopped the leak but It was still Overheating. So I took It to a shop and had It checked. There was air In the Radiator so they got the air out and checked the themostat to see that It was working. The one thing they did notice was that there was rust In the water and they told me that part of the Radiator might be clogged. Well It ran fine for about a day. Now It Overheats any time I drive It..

My Question Is Would a Flush of the whole system unclog and clean out the Radiator? And can anyone explain how to flush the system or point me to something that would explain how to do It right??

Also should I replace the themostat?? They told be It was working. How can I check It??

 

You have 2 problems that need fixing. I ASSUME the original leak was in the radiator?
What you need is to pull the radiator and take it to a repair shop. They can possibly fix the leak and if so, they can also "rod" out the core to remove any clogged areas. Pouring stop leak into an old radiator is just asking for trouble. It sometimes stops a small leak and pluggs up a questionable radiator at the same time. That stuff should be banned from the market, but I suspect it is marketed by the radiator companies to help drum up additional business.

You cannot flush a clogged radiator and ever hope to clean it out.

If all else fails, get a new radiator and install it yourself. I suspect they are no more than $175 as my daughter had a new one put into my 91 last time she borrowed it and one of the tanks started leaking, for $225 parts and labor.

While you are at it, replace the upper and lower hoses and fill with fresh antifreeze. Now would also be a good time to replace the thermostat too since you are in the vacintity.
Dialtone

 

You are alot of help and I thank you so much.. I will do as you suggested.. Now I have another question..
What would make the Coil Pack get hot enough to melt. I have been around cars all my life and I have never heard of a Coil Pack melting.. I had to replace my Coil pack because It went out.. When I took It off the Engine I noticed that the wires going Into the pack had melted to the Coil. I also noticed that the Coil had melted on the side of the pack as well as on the bottom of the pack there was a large crack. What could have made this happen?? Is It just a bad Coil or Is there something else I need to replace before putting In a New Coil??

 

I cannot guess as to the coil pack problem. I never saw one melted. By itself, it should not generate that much heat unless possibly it was dead shorted internally. If it was, I would think it would have taken out a fuse and possibly even the ignition module that drives it. The large crack in the coil pack is evidence of severe overheating. If memory serves me right the internals are potted into an epoxy compound, so it should be very durable.

I would look around at the exhaust manifold on that side for a crack or leak that might be directing hot gases into the area. If so, it should be visible as heat related damage on adjacent wiring and soft hoses / plastic parts. If the EGR feed tube is in the area, check it out also for a spot that would allow escaping exhaust gas to get to the coil pack.

That is about all I can think of.
Dialtone

 

Ok, Well I checked everything out In that area and nothing else seems to be melted or worn done from heat exposure. As I said before I am having a overheating problem..

It seems as If the Coil for some reason shorted out. Because I checked the fuses and the Coil was the only thing that was affected from what I can tell..
I got my hands on a used Coil today and replaced the plug but once I Installed the Coil and tried to start It I got nothing.. It will crank but not start. From what I can tell It Is not getting any spark.. Is there a way to check the Coil?? How can I check to see If I am getting any spark?
What else would you suggest before I start replacing parts to locate the problem?
One last thing. What would make a tranmission run fine before getting warmed up and then start not wanting to shift gears or slip once the truck has been running for a while?
Again I want to thank you for taking the time to answer all of my Questions.

 

Let's take the starting issue first.
The coil pack wiring harness should have 4 leads whose function is as follows: Note: wire colors given may not be exactly as shown, but should be close.

1. Red/ Light Green This lead supplies power to the coil pack and schematic shows it originates from the ignition switch in the start or run position. It then feeds interior fuse panel fuse #17. Check see if the lead has power at the coil pack connector first with key on. If not, let me know and I will track it backwards.
2. Yellow/ White, Yellow/ Red, and Yellow/Black. These leads come from the EDIS module located on the radiator wall immediately in front of the battery. The module pulses these leads to ground and fires one of the 3 coil pack segments. Corresponding pin on the EDIS module for each listed lead is 11, 12, and 10 respectively. Check the wiring harness for continuity of the leads from the coil pack back to the EDIS module connector.

If all the above tests pass, examine all fuses in both the interior and under hood power distribution box and see if any are blown.

If all these are good, you could be looking at a bad EDIS module or engine computer.

Dialtone

 

Ok, I some what understand what you are saying.. What should I use to check these wires? A volt meter or will a test lamp do the job? And as I said before the New Coil Is used and I would like to verify that It works. Is there a way to do that?

 

Test lamp will do fine (but a voltmeter is handy to have also) . Clip it to ground and check for battery on the red lead at the coil pack connector with switch in run position. Then plug the connector into the coil pack.
Next check each of the other wires at the connector on the EDIS module. The lamp should light on all of them indicating battery is being fed thu each of the 3 the coil pack segments. As you touch these leads with the lamp probe, there may be enough current draw thru the test lamp to generate a small spark from the coil segments to the spark plug, but I cannot be sure about that. If so, it will fire both sides of the coil segment at the same time (left and right plug wires fire together)
Dialtone

 

So If all of this checks out does that mean that the Coil Is bad?? I have tested the leds and the Coil Is getting power but I just can not tell If the Coil Itself Is sending out a spark when I try to start the truck and thats what I want to know... I got the Coil from the guy that worked on my truck In the first place so I am not even sure If It works..

 

OK. I did some research on the EDIS system and found that it is capable of generating the basic spark signals without any other input from the EEC module.
All the EDIS needs is a signal from the crank sensor and basic battery and ground supplies.
If you tested the coil pack leads as I previously stated, then check the EDIS connector for battery on pin 8 (Red wire) and ground on pin 9 (black/ white wire) with key on. Note: This battery supply also feeds the injectors, IAC valve, and transmission shift solenoids as well as other many other major engine controls.
Next, check the leads from the EDIS to the Crank Sensor. On the EDIS connector they are pin 5 (Dark Blue) and pin 6 (Green/ Yellow). Crank sensor pick-up is located near the crankshaft main pulley. Check these leads for continuity all the way from the EDIS plug to the point where they plug into the sensor connector. To test the sensor will require a meter. The sensor should show a fairly low resistance (but not a dead short) between it's 2 leads. If it is OPEN or dead shorted, then the sensor is bad.

If all that is good then the coil pack should be throwing a spark when the engine is cranked. If not then the EDIS module is most likely bad. I would suggest getting a basic timing light to verify this is happening, if so the coil pack and EDIS is functioning.

Again, wire colors may vary slightly from those given, but the pin position will not.
Side note on the coil pack. There are no really high tech electronics inside it, so it should be pretty rugged. If it looks physically OK then it probably is. If you read continuity from the battery supply pin to each of the 3 trigger inputs, the coil windings are not open. Next,using a meter, you should NOT see any continuity between coil pair output segments (1-2, 2-3, 3-1) but you will see a high resistance between mated segments outputs( 1/4, 2/6, 3/5)
Dialtone

 

Thank you so much.. I will give this a try and I will get back to you and Let you know what I find.. Again thank you for all your time and any trouble I might have caused..

 

Ok I got It running. One of my friends suggested I unhook the battery so the computer would reset. I did that and It started up and ran fine for about 20 minutes. Then the problem I had In the first place came back. It started missing first off not so bad but as I let It run It got worse missing more and then to the point that I had to shut It down because the Coil was heating up again as If It was Shorting out like before..
What could be causing It to run fine and then start missing and almost short out the Coil?
I now know there was a reason the Coil had a melt down because the new one almost did the same thing.. I am not sure If this Is true or not but my friend was telling me that If I unhook the battery again and the truck starts up after resetting the computer for the second time that the computer Is bad.. Can you please help me figure out what has went out or Is shorting out to cause this problem?

 

OK. Now you know it runs, so take the problems 1 at a time.
Overheating issue: While running the engine for the 20 minutes, did the temp gague indicate the engine itself was overheating? If so, fix that issue first. You really need to pin down the root cause of the problem before jumping off to other conclusions.

If the engine did NOT overheat, then I suspect the EDIS module is holding the coil trigger signal longer than normal resulting in excessive current flow in the coil pack that is overheating it. As I stated earlier, the EDIS does not need any input from the computer to derive basic timing and spark controls. It does have some inputs and outputs to the computer, but they are diagnostic, tachometer, and timing advance related signals.

Link to EDIS operation.
http://www.dainst.com/info/edis/edis.html

Dialtone

 

Ok well I just reconnected the battery and try to start It and It started, missed real bad and died.. As for It overheating. It only overheats when It has been running for at least an hour and no It did not have time to overheat before It started missing. The Coil Is still working but now something else Is wrong and what ever It Is, It Is causing the truck to miss real bad and not want to stay running and also causes the Coil to heat up..

 

This may be a shot in the dark, but given the overheating and running problems, have you thought about a bad ignition wire or plug? Can you identify the problem to a specific clyinder(s)?