Hi everyone,
I have been installing anew sound system (will post pics shortly) and it's up and running fine. About 2 montsh ago my battery started to drain while the car was off. I have been getting a healthy spark when i attach the cables to the terminals. I initially thought that I knocked a wire loose because over the winter i lost my dsah lights. However, today I fired up the car to go for a ride (nice in chicago today) and it started idling very rough and dropped down to 500 RPM from about 900. I experienced these very same symptoms about a year ago and it was my MSD 6AL box causing the problem. I sent it back to MSD and they repaired it for me. Another thing I noticed is that my Ammeter has a constant 12V to it even though the ignition is turned to the off position.

Does this sound like the same thing again (MSD)? It does to me, but last time I wasn't pulling current off the battery while the car was shut down. Could be responsible for my battery drain also?

Thanks,
Dan

Welcome!!!

Personally, I am not a fan of MSD boxes. I don't feel they do much more than break and cost money.

considering your history with the MSD, it sounds reasonable to think its the same problem. I would remove and test without.

I agree completely. If I can figure out how to bypass the box and the car runs well I might just leave the whole thing out. My distributor and coil seem to be working fine.

It's easy to bypass... the unit, IIRC, runs inline to the coil.

MSD, for those unaware, means "Multiple Spark Discharge." It abuses coils for fun and profit. The idea is to make the coil fire a number of sparks, versus, the one conventional spark. The only time MSD really helps is at constant high-RPM operation, where misfires are more common. NASCAR uses them a lot - you can see them on the dashboard!

If it was my money, I would convert to a distributorless ignition system, vs anything with a distributor.

Now there's an interesting idea. I've just been considering going back to an HEI - every HEI i've had has been bullet proof and this MSD system is nothing but a pain. I don't run higher than 7,000 RPM so I think I should be fine.

Can you make a recommendation for a distributorless system?

My friend yanked his 6AL for similar reasons... it was killing the battery and failing intermittently during startup.

I vote HEI. You can get stock HEI parts to run perfectly in even aggressive engines. There are after market HEI parts available for extreme builds.

I too have never been a fan of MSD. Fast their reputation, getting sour, it is. (Yoda.)

Heck, my 405 is getting the replacement HEI distributor I bought a few years ago to replace the 30 year old stock one.

Everyone seems to agree it's the MSD based on your statements, but just to play devil's advocate, have you tried to narrow down the battery voltage drain by using a voltmeter and pulling fuses one at a time?

Matthew

I'll go through the fuses and test today.

In the meantime I'm going to wire up an extra Mallory Hyfire box i borrowed from a friend and see what happens. I noticed yesterday that the manual recommends that the boxes never be wired directly to the alternator- 1 guess where mine was pulling power from...

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Yeah that's one thing that I have heard as well, and pulling power from the starter lug seems best for most electronic accessories.

This car is full of surprises...

I think the starter lug might be easier (and the manual says it is acceptable but not preferred) than running all the way back to the battery but I think I'm going to suck it up and run the heavy red and black wires all the way back there.

For a street car I think you are much better using a "stock" type ignition. If you do have a problem you can go to any autoparts store to repair it.

For racing I would use an aftermarket ignition system. As hard as racing is on a car most people do not put as many miles on thier race cars as a street car.

From a electrical point of view you are always better pulling power from your starter stund than your alternator. Alternators generate a lot of "noise" which can interfear with the operation or damage electrical components.

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Halleluyah! I've replaced so many pointless aftermarket parts on my truck.

When I'm stranded I don't want to be waiting 4 days for some "performance" alternator to show up in the mail. I want something that fits and is readily available.

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I agree 100%. In fact, the easiest way to upgrade is to put a new coil in your stock distributor, and if the bushings are worn, have it rebuilt. The stock HEI system was no slouch, I think almost 40K volts. I would take a stock HEI over an MSD or other after market system ANY day for a street car.