Gets hot, bucks, shuts off

[Adhawk]

Hi,

New guy here with a problem on my 2.9 that I can't put my finger on and hoping somebody has some input. I acquired my 86 from my cousin about six years ago, and right off the bat the emission light was on - as well as every light I came to the truck died. I replaced the O2 sensor, the light stayed on but it never died again, it would just seem to miss every so often under acceleration.

Well, about a month ago I was cruising home from work and stopped at a stop sign. While sitting there, I noticed the temp gauge was around the 3/4 mark. When I went to drive again, it started violently bucking, no matter what gear I was in or how hard I put the pedal to the floor so I pulled over and it died. It turned over, tried to start, but quickly died again. I called AAA, checked everything out under the hood where the antifreeze was a little low with some gunk on the radiator cap and by the time they showed up an hour later - it started and I drove home fine. I spent the next couple days flushing and reflushing the radiator.


A few weeks ago it did it again on my way up a hill, I pulled to the shoulder with temps around the 3/4 to 7/8 mark, bucking, died wouldn't restart. I hung out with the heater on, waited about 20 minutes, it restarted and drove fine from there home.


I've looked around on here and google with my symptoms and the only thing that really matches my symptoms is a plugged\bad catalytic converter. Anyone have any other thoughts, or should I start there - it does look to be the originals?

Thanks,
Bret

 

[Earl43P]

Sounds like the ICM (Ignition Control Module) to me.

You should see if it has spark and fuel pressure when it dies, then go from there.

Could be a bad fuel pump relay if it isn't getting fuel. There is a tire stem - like port on the fuel rail that you can connect a gage to or simply depress and see how much fuel pressure there is. Try it while it is still running good, then again when it dies for comparison. Use a rag, it's gonna spray!

Keep a spark plug with you and connect it to any spark plug wire and lay it on the engine and see if it sparks. No spark, probably ICM.


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[Adhawk]

Thanks for the reply,

I'll look into that. Most everything in the fuel system minus the injectors is new due to a wiring gremlin a year and half ago. I ended up replacing the fuel pumps, filter, pressure regulator, relay and harness to later find out it was a bad wire in the loom crossing over the top of the engine. Kicked myself after I discovered the problem for throwing parts at it, but it was pretty intermittent.

 

[jhammel85]

My 1st thought is also the tfi module.