Digital HEI Module?

[Old Ironsides]

Has any members here had problems with their HEI modules constantly failing?

Well I have, and after 5 modules in 8000 miles (it seems that the last 3 were in the last 200 miles) and a changed coil the problem still persists.

As a last ditch effort before swapping the whole system out, I saw this:

http://documents.msdperformance.com/83647.pdf

Is anyone using this module?

Any type of feedback would be appreciated.

[Old Ironsides]

I am running the DUI setup now and don't know if it would even work on mine with that plug.

[tgreese]

Which brand HEI modules are failing? Generally I would pick Delco or Standard.

Why not try the Street Fire module? https://www.summitracing.com/parts/msd-5596/overview/

[babywag]

it?s a sad state really for ANY aftermarket stuff these days.
Even big name stuff like AC Delco, Delphi, etc. are manufactured offshore or across border.
I know a few folks who have had multiple failures.
My BIL replaced a 200k+ OEM ICM only to have the new AC Delco from dealer fail almost immediately. He replaced it, and it failed again.
He?s running the original again w/o issue.

I have also had brand new big name parts that were crap right out of box.

Frustrating doesn?t even begin to express issue.

[Old Ironsides]

I had 2 DUI module failures (who knows where they were from), and 3 that I got from O'reilly. The box says "Select" on it.

I'll check the Street Fire module and see. I am beginning to wonder if it is some other issue causing this.

So far I have checked the resistance on the leads (all OK), have plenty of voltage to the coil, used a liberal amount of silicone between the module and the Dizzy each time, replaced the coil (just in case it was drawing too much and overloading the module). I cant think of what else to do.

One thing we did was put in a larger wire to the Distributor. That increased the overall voltage but I wouldn't think it would have a negative effect. The original lead worked fine too.

Perhaps I have a faulty relay? I added a fuse box that was switched by a relay for the ignition. That is the only other thing I can think of. I guess I need to wait for it to fail again and then check it with a light.

[fulsizjeep]

Been running HEI here for a while. It was the best solution in my mind for the Prestolite fails. The first Mallory ran from 2010 to 2013 when it just started eating modules like candy. We were stranded in AZ. I bought all the standard replacement parts by AC Delco, cap, rotor, modules, coil and kept eating modules. It turned out to be a fault in the pick up coil but I had a spare Mallory and threw that in after borrowing a Skip White unit from JSINJEEP to get us home. It can be a crap shoot with any parts nowadays. I decided to go with Skip White units and bought two to swap out the other Wag with Prestolite and have a spare. They are much cheaper than Mallory and if we burn out out, it is a quick swap to be back on the road. My 88 GW has a Skip White in it and I have probably put about 8000 miles on it so far and no complaints.

[tgreese]

...
So far I have checked the resistance on the leads (all OK), have plenty of voltage to the coil, used a liberal amount of silicone between the module and the Dizzy each time, replaced the coil (just in case it was drawing too much and overloading the module). I cant think of what else to do.

...

I would not use silicone - instead I would use heat sink compound, like they use under CPUs. I use this stuff https://www.amazon.com/Dow-Corning-1...+sink+compound - Long ago I bought a tube at a hamfest for a few bucks - a 5oz tube is a lifetime supply. It's silicone grease filled with metal oxides to make it heat conductive, so it's white like toothpaste.

I would also worry about voltage spikes and rf noise. Besides heat, junk on the power feed can kill electronics. IIRC there is a condensor inside the HEI distributor that offers some protection. Are you using solid core plug wires?

[Old Ironsides]

No I am not using solid core plug leads. Just changed the feed direct to the ignition switch with an online fuse. We'll see what happens!

[DarkMonohue]

I have...used a liberal amount of silicone between the module and the Dizzy each time...

I'm going to second what tgreese said. HEI modules generate a lot of heat, and they need to be able to dissipate that heat via a heatsink. There are thousands of types of silicone products, and if the stuff you are using doesn't transfer heat effectively, the HEI module will fail.

There are also thousands of goofball suggestions on the internet, but since the object is to allow heat transfer from the HEI module to the heat sink, it makes sense to use heat sink compound (thermal paste). Any electronics store or computer parts/repair shop will have it.

[Old Ironsides]

Thanks

I'll remember the heat sink paste.

My ignition problems ended up being simple and not module related. I changed the feed from the fuse panel, and ran it directly to the ignition switch. I think what was happening was that when things heated up the resistance also went up enough to starve the dizzy of power.

Drove it about 200 miles and no more quitting!

[fsj454]

8365

I ran a 8365 and it ran like crap!!! Did this did that still crap . I went DUI and all problems solved .DUI tests all there ignitions before they ship to you .8365 are not tested 50 50 chance .and mine lost .Oversimplifyed!!!!!

[Old Ironsides]

Update: Still not fixed

Well it started quitting again. This time I ran a direct lead from the battery to a toggle switch in the dash that I knew was solid. It still backfired a bunch of times on my 80 mile commute. Once the engine quit, I pulled over, cranked (smelled gas), and it started on the 2nd try.

Just ordered that Dow Corning heat sink paste (Thanks Tgreese), and my last ditch effort will be to install a new module and try that.

[babywag]

I ran a 8365 and it ran like crap!!! Did this did that still crap . I went DUI and all problems solved .DUI tests all there ignitions before they ship to you .8365 are not tested 50 50 chance .and mine lost .Oversimplifyed!!!!!

Didya even read the thread? He started with DUI.

[fsj454]

cant reed