I have a 1987 that goes thru ignition modules. It is a project car and I have very little run time on the motor. I have replaced the Ignition module 4 times with in the past couple of years with only tuning time on the motor (and a couple trips around the neighborhood without a muffler just to aggravate the H.O.A. President). I replaced the distributor with a D.U.I.-Davis Unified Ignition. The Ignition module has failed with only a few hours of run time. Could a loose ground or other wiring issue cause this? I an looking for a starting point to get to the root cause of this issue. Please Help.

 

I wonder if it's possible that the DUI coil is pulling more current and that current is causing the Ignition module to overheat...

 

Something is frying it, only explanation. I would suspect its the coil doing something as well.

 

It was frying them before I installed the D.U.I. Two before and two after.

 

The big flaw of the GM HEI is heat buildup under the cap. A lot of this comes from having the coil mounted on top of the distributor.
The best way to deal with this IMHO is the MSD Super HEI kit
https://www.holley.com/products/igni...ts/parts/85001
Moves the coil off the cap, and integrates a 6A ignition box, which replaces the module all-together.

You can also do this a little more budget using their coil relocator setup and skip the 6A box. A the 8401 Dust cover and a 8207 Remote Coil. You'll also need a coil wire.

 

Are you using heat sink compound under the module?

 

No on first two yes on second two

 

The fact that once supplies of us made gm modules ran out it all got sourced from China, let's see the 7 pin hei module was used for roughly 8 years on 2-3 cars, so the demand for a replacement with good quality control just isn't there. Best advice, swap it out for an external coil small cap hei, or scour a junkyard for 84-91 c4, some early Cadillac 4.3 V8 (you won't find either) or ditch the module all together and go msd 6a box and keep your large cap hei. , Or go crank trigger and msd box, use stock gutted distributor for spark routing and be done with the headache.

 

Same coil with both distributors, or two different coils?

Edit: Any previous CalProm changes to the ECM?

 

New coil with DUI

 

I had the same problem on my 87. What I found was oil in the there making its way up in there. I replace mine with the DUI small cap and remote coil.

 

I just put in a Pertronix 7 pin and I am happy with it. I got it for $80 on Amazon (but FREE with my points!) Pertronix is a good brand they do have their own site I just chose to search it on Amazon to see if I could buy it that way. It wasn't a necessary replacement, I was chasing down some issues and this was on the list in the process of replacing all ignition components. If you're killing modules I would make sure everything (such as the coil) is grounded. It has a ground strap (solid metal shaped piece) under it in the cap, I forgot to switch this over once before....
That being said, if you want a free OEM module, the one I removed worked just fine and I wouldn't mind shipping it to you if you need another one to burn through for testing! I don't want any money for it. It just sits in my stock pile.

In regards to the AC Delco ones no longer being made here- Supposedly the one I got from RockAuto was Made in USA ( I know the box at least said so) it was DOA and I was very displeased. I'm sure it was old stock and that's why it made it's way to RockAuto, I don't doubt new 7 pins are uncommon to source. Just really sucked to have a supposed USA part be DOA and that's why I started going for expensive quality aftermarket parts for my '84. After putting in 8 Chinese AcD plugs and 4 Mexi-Merican 'OEM' shocks, I have given up on AC Delco. Nothing American about it apparently.

 

I had the same with one from Summit. Dead. No spark. It's getting absurd the new junk failure which wastes hours of our time and takes all the fun out of owning these older cars.

 

Just put a "GM Genuine" on mine from Rockauto and it has been good so far. Hopefully it stays that way!

 

seriously guys, 50 bucks at a junkyard, any 88-95 truck take the coil, wiring from dis to coil, and clip the wiring going to the distributor from the ecu, and distributor four wires to splice into your existing harness . its basically a direct swap the 8 pin modules do not fail, and if they do (usually high mileage or other short circuit causes them to fail) quality replacement parts are available.

 

You are correct! I went to a carb set up on my 84 C4 and even run a 1965 Chevelle points distributor with U S made SMP Blue Streak points and igntion coil. Once had a factory module go out on my brand new 76 Trans Am on a very cold -10 degree morning in Milwaukee!

 

I do use the Petronox Electronic conversion to replace the point and condenser in my stock dizzy. They do have built in adjustable rev limiter option.

No need for an ignition box.