So I guess maybe my original post was too long. I have a '96 4.0 I6 that randomly dies. Years ago I discovered that if I wiggle the connectors to the PCM, it'll work for a while. After researching, I found that if I "clamp" the connectors using three snake clamps going around the entire housing, one for each connector, it eliminated the problem for about 3 years. It recently started doing it again.

It'll drive fine, then suddenly die. Then it won't crank. It turns over fine. Then, after some random amount of time, it'll crank again.

The old PCM that worked for about 3 years after clamping was extremely hot to the touch and had heat damage to the voltage regulator inside. Replaced the PCM, but it's still doing the same thing. Wiggling and clamping no longer works, at least not in any consistent or reliable way.

I'm just looking for a place to start.

Thanks in advance.

Bryan

 

It's a PCM, not an ECM.

 

fixed

 

I would suspect the crank sensor. They usually start to fail by randomly shutting down because of loss of signal when they get hot. You should also check the sockets of the PCM plugs for pin fitment, that is, being stretched out so they don't make a good connection. Use a drill shank the size of the pins to check if they are loose, then carefully pinch the connectors so they are the right size. A tiny pick or mini screwdriver works good to squish the connectors closed, but be careful because the brass is thin and you don't want to break them. Clean everything well. Some of those circuits only carry 5 volts and need good connections.

Loose connections cause resistance. Resistance causes heat. Heat melts connector bodies.

ECM= Engine Control Module
PCM= Powertrain Control Module, because it controls a lot more than just the engine.

 

A new crankshaft sensor is already on the way. I local guy suggested the same thing.

I cleaned the connectors and the pins really well, but never thought to use a bit to check fit, that's pretty good. I'll do that this evening.

 

I have the same issues need help

 

Sorry, Pwall, but I never really resolved this issue before dropping a lifter rod through one of my cylinders. I ended up scraping the truck not very long after i made the original post. It is still my favorite vehicle, may it rest in peace.

Bryan.