HEI Ignition Modules:what's the deal?

[1978LT]

Well after running my last one for well over a year, this morning it crapped out for no reason. Popped in a new one in about 10-15 minutes and on the first hit of the key I was one my was.

Now....my burning question. What are ALL the reasons these suckers pop?? I've even had GM modules go out within unreasonable service life. I know a few obvious reasons, but since I know very little about electronics, I want any and all input possible.

Obvious reasons:
Cheapo brand (Advance, Autozone, etc.)
Lack of insulating lube under the module (definitely not this one)

So what else??

[Loki80RS]

heat and vibration are big factors with those things, and i don't really think the brands have much to do with it i put an advance/autozone one in mine almost 2 years ago never had a problem with it :knock on wood: sometimes sheit happens but like most hei runners i keep a spare module in the glove box just in case good advice imho

[night rider]

Die elec. grease drys out.

Under hood heat, heating up the dist. and module causing module to overheat.

Vibration

Poor ground to engine/intake/dist.

Pick up in dist. going bad

bad plug wires or wide gapped plugs can cause faster wear on coil and module.

[1978LT]

Originally Posted by night rider

Die elec. grease drys out.

Under hood heat, heating up the dist. and module causing module to overheat.

Vibration

Poor ground to engine/intake/dist.

Pick up in dist. going bad

bad plug wires or wide gapped plugs can cause faster wear on coil and module.

The only thing on that list that comes up is is heat. This Summer's heat has been very rough here.

Plug wires are GM Performance 6 months old. No vibration(engine runs so smooth if the exhaust didn't make any noise I'd forget it was running . The 1 year old grease from the last module swap was still on there thick and almost like freshly put on. Engine ground is good and snug ( already checked that). Distributor is only 2 years old, new rebuild (but the module probs basically started stemming from there as it popped a GM module within the month I purchased it). Plug gaps are .045, AC Delco plugs.

Don't know what else to think of. Even if it were only going out once a year or more heck I'd be happy!

[Twisted_Metal]

My original module lasted over 25 years.

I finally replaced my distributor last year and already I have had a module go bad on the remanufactured distributor.

A fluke? I hope so.
I should probably carry a spare in the glove compartment too.

[1978LT]

Originally Posted by Twisted_Metal

My original module lasted over 25 years.

I finally replaced my distributor last year and already I have had a module go bad on the remanufactured distributor.

A fluke? I hope so.
I should probably carry a spare in the glove compartment too.

The old modules were SO much better! Now just about all the electronics is overseas crap, usually China or so.

[GMPARTS 1]

put an MSD unit on it and that becomes your module and you'll get better start-up, idle etc.

[1978LT]

Originally Posted by GMPARTS 1

put an MSD unit on it and that becomes your module and you'll get better start-up, idle etc.

I've seriously thought about that GMPARTS, but I can't sink that kinda cash into an MSD setup right now. I've had the whole setup before (distributor, coil, 6-AL, etc. and it NEVER let me down... but as usual money got tight and there was no way around selling it. When money gets better I'll definitely go the whole way this time!

[1978LT]

Oh, in case I forgot, it ALWAYS happens on the first start in the morning. Ever since my first GM nearly 20 years ago, always in the morning. Had one over the years that idled well, then i believe aroun 1500 RPM started running about like a plug wire was off, and ran that way on up the range. Needless to say that module didn't stay in the dizzy long either .

In around '89 I bought a rebuilt distributor that actually came with a genuine GM module. Crapped out within a week. My latest new rebuilt distributor that is about 2 or 3 years old also came with a GM module...also crapped out VERY quickly.

[Kamikaze]

Couple of things come to mind...

1) Was the car originally equipped with an HEI?
If not, then you could have a resistance wire feeding the HEI with less than 12-volts.

2) The "paste" that comes with a new module is a heat sink compund much like the stuff new PC computer CPU's use. If the paste is dried out or hard and not smeared all over the contact area, then it doesn't help disapate the heat well and can actually reflect it back into the module.

I usually have a tube of high quality heat sink compund which can be purchased at an electronics stor like Radio Shack, Best Buy, Fry, etc. The stuff usually comes in a tiny syringe and flows smoothly. A nice even coat on either the module or the distributor will do the job.

3) MSD module! No better module out there for street use! Period!

Hope this helps!

[Little Naples]

I'm running the original motor, original distributor, original coil and module.....31 years, 203,000 miles....believe it or not.....never had a problem with distributor or module .....testimony to GM, Detroit and Delco, made in the U.S.A.........I'm getting a new Goodwrench crate this summer (made in Mexico)

[camertom]

MSD module and do yourself a favor and get the new one with the built in rev limiter. I have also seen coils cause module problems. An Accel coil smoked a module in a friends truck a few years ago. Didn't seem to be compatible??? I have the MSD coil in cap and module and have never heard the engine miss!

[1978LT]

Naples-If the crate engine doesn't come with a distributor I STRONGLY suggest keeping what you have. I agree with the old stockers...bulletproof and everything in it Made in the good old USA . I shoulda kept the one I traded in way back when (around '89). Never failed me, but it was very worn and the advance mechanism was locked up.

Kamikaze-My car is a '78, so yes it is an original HEI car. There is a Radio Shack down the road that probably has the paste you're talking about. The typical parts store lube that comes with a new module is kinda thin and does dry up quick. I'll get a tube and redo it. Thanks for the tip bro!

An MSD, yes I would buy one no prob, but I wan't to make sure there's nothing else in there killing the modules.

Keep the suggestions coming!