Continued from this thread I seem to have derailed: https://dodgeforum.com/m_848862/tm.htm

I have checked the trouble splices, etc. already.

Truck turns over normally, and occasionally will start up normally and run for a few seconds, sometimes a few days. Runs great when it starts. Auto shop diagnosed it as a bad ECU. Not sure of this diagnosis, trying other things first.

What's the process for checking the distributor cap/rotor?

 

Hope you didn't mind starting a new thread, I think it will be easier to get help this way. We want to keep your problem showing up in the new posts with an accurate title.

If you pull off the distributor cap you will see the rotor underneath. Look for carbon buildup and cracks in the plastic. This won't totally eliminate it since there may be cracks that you can't see. Most people will simply replace the cap and rotor, it is a typical tune-up part. Otherwise the sure-fire way to check the cap is if it runs good in dry weather and crappy when it rains.

Grounded plug wires can be an issue too, my truck let me sit in the middle of a busy street after replacing cap/rotor and plugs/wires. After towing it home for $80 my wife tried to start it while I looked under the hood. It was dusk and I could easily see the arcing from the plug wire to the engine, happened in other vehicles as well. If the insulation is burned away, wrap it a couple of times with electrical tape and get it back in the loom.

I really question the ECU being bad, but my understanding is that it will trigger the ASD relay based on input from sensors. Get that cheap meter and check resistance on the crankshaft position sensor, pickup coil, 02 sensor, and temp sensors. Maybe you could get or borrow a junker ECU just to eliminate that.

 

Here is a link to a thread where they discuss the ECU (PCM) being bad.

http://www.dakotausa.com/vBulletin/s...light=shutdown

Might not be a bad idea to pay a dealer for an hour's worth of troubleshooting. They should be able to test the chip and some other things in that time. Call and ask if they'll work with you and just tell you what they found wrong. I hate having to throw parts at a problem.

 

Blue, I'm printing out your post. I'm going to get a multimeter in a few hours and I'll test. I'll also check the cap/rotor and TRY and find all those sensors I wish I could get a SPARE ECU to try out, but it's hard enough to find one to purchase I will call the dealership if all else checks out and see if maybe they could test the computer if I brought it in.. sadly, the dealership is a GOOD drive from me, and the truck is.. well, everything's expired and cops here are ****. I bought this truck from my father, he's an ASE certified mechanic (the one who made the diagnosis I assume). Not on speaking terms with him anymore or I wouldn't have to do this myself

 

Sorry to hear about you and your dad. I've got a son that won't talk to me as well, I feel your pain. Post back if/when you get if fixed. Good luck, I think I've pushed my knowledge to the limit.

 

The truck only had one owner before me according to the carfax I just got.. so it's in pretty good shape. There's a dealership recall on something in the tranny I have to take it in for anyways. Cap/rotor looked fine, I'm going to make a leap of faith and replace the ECU. Some parts of it are damaged looking anyways. (broken bolt areas and stuff)

I do appreciate all the help blue95. My area of expertise as far as vehicles go stops at early 90's mazda/ford cars I'll update whenever I figure out the big problem.