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Hi everyone. I have a 72 Malibu and i converted it over to a HEI system with a MSD-6A ignition box about 4 years ago. The car ran fine, never had a problem with the ignition and starting ever, aside from a bad battery once. I parked the car about a year and half ago so i could do some body work to it. I started it every now and then to get it out of the way and never had a problem. One time I tried to start it and the battery was completely dead, it wouldn't keep a charge from the charger either. So i would jump it, move it, jump it again, move it. I did this several times. Then i was gonna drive it again so I put a new battery in and tried to start it. It wouldn't start. Now the last time i jumped it, it started right up. So i narrowed it down to the MSD and replaced it with a regular ignition module for the time being. Car worked fine or 2 days and blew the module again. Now my question is: can a different size battery mess up a module like that? I did put a different battery in it cause i didn't have the one i had in it originaly available. The original battery was a was Douglas 24-675 battery. I replaced it with a Douglas 58-775. Would that cause the problem? Each time the module went bad was when i went some where, shut off the car, did what i had to do, came out and it would not start, just cranked over and over. Seems like when i shut off the key, it would send a voltage spike maybe to blow it out? I dunno. Any help would be great, thank you. Oh yeah, the charging system is a one wire job that goes directly to the battery from the alternator. That works fine. One time the regulator went bad and it was charging 16.5- 17 volts. I fixed that though. The problems may have started about 3 or 4 months after that. Everything was workin fine when i parked it so that's my problem, thanks. 355 motor, thm 350 p/s p/b
 

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I think your question or problem, if I read things right, is why does the HEI module keep going out. If so, a couple of thoughts.

The HEI input to the BAT terminal needs to be 12 volts (car not running). High voltage from a bad regulator can damage them. They need to be mounted on a even layer of dielectric grease. The distributor needs a good ground. Some aftermaket chrome distributor clamps doen't do a good job.

Had one car in which I had modules going out every 3 months. Changed the module, coil, carbon button, pick-up coil, everything and it wouldn't stop.
Someone in components engineering reminded me the quality of components used in some aftermarket electronics is poor. Said that GM modules exceeded most aftermarket stuff. Bought a GM module from the dealer and stopped the dead module problem.
Only thoughts I have.



[This message has been edited by John_Muha (edited 09-28-2002).]
 

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Discussion Starter #3
Thanks alot, John. I'll try the voltage and ground tests and make sure the grease is evenly spread out. I'll post what I find out and we'll go from there.
 
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