Wits end 1992 Dodge D150

[THEFERMANATOR]

Since you say the problem persisted after PCM replacement, about the only thing that comes to mind to me is a bad ground. The early SBEC is pretty basic, but normally reliable. They can be shorted out and do funky things if the crank sensor gets shorted out, but I've never heard of one firing the injectors and coil at the same time. So either you have a bad ground allowing the board to backfeed somewhere, or you got 2 bad PCM's in a row. The only other thing I could think of is a short to power on one of the sensors freaking out the PCM. I can honestly say I have never heard of a single case like this before though. The most common problems on those early trucks was shorted out crank sensors causing a no start.

[smokeonthewater]

step one unplug EVERYTHING... all sensors and fuel injectors except the coil.... see if condition persists.... If yes then you are left with bad ground, damaged harness or bad pcm (my bet it's this one) if not then start plugging things in one at a time till problem returns....

either the pcm it possessed or being fooled by outside forces

[tsubaki]

Thanks guys, I actually took a short video of the coil being possessed.
We have done numerous things in numerous sequences trying to get it to reproduce this problem, at lease we are that much closer.

A search for a bad ground began after the DIP, PCM and CPS were replaced. So far nothing. We even grounded from the battery to the block, to the frame and then to the firewall, still no difference.
We could tell during the first cession of checking wires that someone else had the same thought process.

Replacing the CPS and PCM again is not out of the question. We just replaced the DIP, distributor cap and rotor again. The distributor cap had two burned places that looked like a welding arc hit it.

Getting another book is probably going to be the next purchase as we have found several things not covered in the one we have.
I'll also see if I can get some real readings and write them down in the sequence tested.

[ssiredfish]

Can I say it? I dont wanna say it but I have to.......ITS A DODGE!!!!

Gettin rid of mine before it killed me was the best thing I ever did. I cant tell you what it feels like to have to slam on brakes and have your vehicle shutdown on you and steering lockup, meanwhile you throw it into neutral, restart, put back in gear and barely avoid the wreck.

......and thats why they call it a DODGE

[smokeonthewater]

The bad ground would be somewhere in the engine/PCM wiring.... Personally I think this is unlikely

[THEFERMANATOR]

Originally Posted by smokeonthewater

The bad ground would be somewhere in the engine/PCM wiring.... Personally I think this is unlikely

DODGE didn't have as many ground issues as GM, but they did happen. The early SBEC PCM's did fail alot though, and would do strange things if a pickup shorted out.

[tsubaki]

Well crap, I traced the ground from the negative battery post to the eyelet/body ground to a harness connection to two wires labeled as ground to the PCM.
Also along the way traced another spliced ground from the above wire to another harness connector to a diagnostic connector and to the PCM.
All these tested to be fine.

Another PCM is on order. It's really gonna piss me off if it cranks up and runs fine after replacing it.