Last fall I had to replace the ignition control module on my 88 TBI 305. It had died on me, and with about 171K miles and it being 33 years old, it was simply time for a new one. Since I had the cap off, I also replaced the cap and rotor, and put a new coil in it, as I wasn't sure at the time what the issue was. Fast forward to yesterday. On my way to work the car died on me. So I got a ride to the auto parts store and got another ignition module. I had only put about 3000 miles since replacing it last fall. I thought it was odd it failed so soon, but was hopeful it was simply a faulty part. Unfortunately, after driving 12 of the 13 miles back to my house, it died yet again. I'm hoping someone here might have an idea of what is causing my issue. The guy at carquest suggested that if the distributor/rotor shaft felt loose, it could be getting to close to the magnet and surging the module, but everything feels fine. Thanks!

 

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I'm more used to large cap HEI distributors, but in those you're supposed to put thermal grease between the module and the mounting surface. Some people say they use dielectric grease and there's arguments one way or the other about how effective that is. But the material needs to have good thermal conductivity.

But unmanaged heat will kill these things in short order.

What kind of spark plug wires are you running?

How's your ground from the engine back to the battery?

 

I would suggest AC/Delco module (unless that's what you're using). I installed a new distributor (with generic ICM) and the ICM lasted about 400 miles before giving me problems. Installed an AC/Delco and still okay after 3,000+ miles. And I don't care if anyone disagrees, dielectric grease is absolutely the wrong thing to use. The distributor acts as a heat sink for the ICM and needs to transfer heat through the base. Thermal grease (white stuff used for computer heat sinks) is a requirement if you want the ICM to last consistently.

 

One thing you may want to look into is a Pertronix ignition module and coil. I used to think these "performance" ignition modules were gimmicks. But I broke down and tried one and was pleasantly surprised at the improvement. I already had their coil so decided to pair their module to it.

Don't get me wrong... I'm not saying I gained 50hp or anything like that. But you definitely notice a snappier throttle, better idle quality and seat-of-the-pants type driveability improvements over a factory one. It's almost like their module takes better advantage of the hotter coil than the stock module.

Pretty reliable too... I've had mine in for about 3 years now too and no issues. Though, again, I used dedicated CPU thermal grease as mentioned in the previous post. Pertronix also told me that you have to run resistor type spark plug wires as opposed to solid core since the solids can burn out the module pretty quickly.