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I'm not complaining, I got about 12 years (and two vehicles) of service out of this MSD 6A module. I thought I would share this with the group. The only warning sign I got that this module was failing was that my after market tach was acting very erratic. At the time I thought the tach was going out, but in hindsight I think it was reacting to the MSD Module going out.

I was merging on to the freeway and boom, engine died. I pulled off to the side of the freeway and tried to start the engine, it wouldn't start. Once I opened the hood I could smell burnt electronics. Unplugged the MSD module and reinstalled the stock wiring and the truck started right up.

After I replaced the failed module with a new one, I drilled out the rivets and opened it up. About an ounce of water poured out of the casing. I you look in the upper right hand corner, you can see the burn marks on the side of the casing. Looks like one of those power transistors shorted out and went up in a cloud of smoke.

The casing is not sealed against the elements, but the components appear to be covered with epoxy or some sort of sealant. Lesson learned: mount the thing right side up or and an angle so that water can drain out if any get in there.

 

Sounds like that 6al was a good one! I am having the same problem on my 79 f100 w/ the duraspark ign. The tach jumps around 300 or 400 rpm sometimes. The engine speed itself doesnt change though, could it be my module going bad? The one that is on there came out of a friends parts bin because my origional died. any help would be greatly appreciated.

 

It would seem that your ignition module might be failing, if you can get another on the cheap, id swap it out, just for insurance. if it isn't mandatory that you have to have it from a parts store, you can find them everywhere in the junkyards.. good luck and i hope you get your problem fixed

 

Thanks alot for the advise! I will probally try a new one this weekend and see what happens. I think it might be failing lise you said because the plugs look kinda rich, i have reset the mixture several times and still get a rich reading off the plugs. Thanks again!

 

 

I am an electronics engineer. My best guess it that one of your power transistors fried. Check the round looking things on the right. Check all 3 legs on the transistors with a ohm meter. If there is a dead short then it is bad. You can replace a power transistor for about 7 dollars.