Solved Random engine shut-down (1st post edit)

[mark.s]

My 93 had issue with the random engine stop with no warning sign. After shut-down, it restarts just fine and runs fine.

Changed the fuel pump along with the filter, thinking it is shutting down randomly since it is old. But it didn't solve the problem. :thumbdwn:

ECU was checked visually. Couple of capacitors were leaking and printed board had missing line. I fixed all of that. But, still the problem persists. :thumbdwn:

CEL is coming on, so I pull the code. It was something to do with O2 sensor on one bank. I did not think changing O2 sensor would solve the problem. The truck runs fine when it is running. But I changed both sides anyways. This didn't do squat. CEL still comes on and engine stops at random. :thumbdwn:

Talking to a friend and I decided to change the fuel pump relay. And, this did the trick. There's no more shut-down.

Cut open the old relay to see what was happening. The points were badly eroded.

I think I will be changing relays when I can as a preventive maintenance.

 

[vq5speed]

Could be a Crankshaft Position Sensor going bad.

I just came back today and re-read your post. I see you had already solved the problem..

 

[Wolfie_85]

I had my fuel pump relay cause a no-start issue. Never shut down while running, but no one checks that first.

 

[mark.s]

If it was a bad coil, it would not have started.
If it was an open coil when hot, it would not have restarted immediately after shut down.

I had an external power (12v) apply to the coil and checked for continuity on contact terminals. And, they were good when I checked. This threw me off to other expensive parts of the truck.

The new relay was only $10 from an auto parts store. Should have changed it anyways since it was looking like an original installation from the factory.

 

[Arne13]

I know this is an old post, but wanted to add to it a bit. For all you old folks out there, remember when we used to use the old points and plugs?? Most times when we had problems it would go back to the points, then plugs and wires. Talking about 3,000 to 10,000 miles. That was just a standard maintenance back then. The points had two small electrodes that came together to let electricity thru. After a while they burned and went bad,you pitched them and put in new ones. ( you could adjust them and use them a little longer first.) Anyway, the new relays have the same points in them. When they open and shut, they spark. After a time they burn up and have to be replaced. So, they are just something that gives grief after a while and need to be addressed. I believe most of the electricity is a that runs thru most of the newer stuff is a lower amperage, so we don't have near the problems with it we used to have. Anyway, if you open one up that goes bad, bet you will find the small points inside there have burned and that is where the problem comes from. Arne.