Truck stalled at highway speeds, wouldn't start again

[geezer101]

Awesome Are you going to install a coil with a ballast resistor? It would suck having to go through this ordeal again... not saying that the lack of a ballast resistor was the cause of the ICM failure but I think having one in the ignition circuit should be considered.

[haruman]

Yes I will. I'll get that one from eBay.

As of today, new coil, new distributor cap & rotor, new plugs and wires, got thermal paste on the new ICM, everything is as smooth as butter again.

[geezer101]

Nice OOC are you using the factory tune? If you dial it in you'll gain some performance out of it.

[Giovanni89]

Awesome! At least on my 89, the ICM was wired to the key switch side of the ballast, meaning it see's 12 volts. Hooking it to the 6-9 volt side of the ballast will up the current through the ICM, and I think that's what cooks them. Earlier trucks very well may be different, couldn't hurt to check the wiring diagram.

[haruman]

Anyone have a picture or diagram how that eBay coil is supposed to get wired up? I'm a visual kind of guy...

[SubGothius]

Here's a pic of mine, note I disassembled the mounting bracket and reassembled it with the resistor block on the other side of the coil, as that made for easier wire routing:

[haruman]

Thanks for the pic, that's super helpful!!!!