6AL msd and charging issues

[dan juhasz]

Recently installed an Msd 6AL ignition with an msd distributor in the 66 Hemi coronet. It previously used a Mopar orange box electronic ignition. Did the install as per instructions, main leads direct to battery, switched ignition dark blue wire to msd switched red, plugged in the pre wired distributor. Started up set timing . Thought nothing of it. Went out for a drive a few days later, noticed my amp meter would go all the way over positive at 2000 rpm and over. Checked it out a couple days later it fried the alt battery lead at the connector over the valve cover. Fixed that , still overcharges, voltage across the battery struggles to reach 13v. Swapped alternator, voltage regulator, checked bulkhead connections, tried bypassing amp meter, ran separate ground to regulator, ran test lead from bat positive to alt positive. Nothing made a difference. Hit the internet, seems this is not unique, could be a voltage drop issue in the only switched lead that comes into the engine bay that feeds the regulator, ballast and now the msd red on lead. Has anyone had this problem? What’s the best way to resolve?

 

[tonysrt]

What do you mean that it overcharges but voltage is less than 13 volts? If volts were higher that would be overcharging. I just had a problem with this but output was 17 volts and I found blue wire from alt. had pulled out of connector. After I repaired wire all was good again at almost 14 volts.

 

[dan juhasz]

Alternator is being signaled most likely by lower voltage to regulator, amp meter spikes high above 2 k rpm and black wire from alternator positive gets hot enough to damage connector over valve cover

 

[383man]

You need to check the alt amps and voltage. I have had bad batteries that would keep taking in amps but not bring the voltage up. You can easily tell if the alt is showing an output of something like 30 or more amps (depends on alt) with all acc turned off and the battery volts still wont come up to about 14.2 with eng running it may be the battery is bad. I have had this a few times over the 40 plus years I have been a tech. You have to check the alt amps output at the alt output wire while also looking at battery volts and then you can diagnose the problem. Check it and let us know. Ron

 

[dan juhasz]

I had a wiring issue with the way the mopar electronic was wired and the way the msd needed to be wired. I may indeed have a battery issue, it passed load and conductive tests but the charging system voltage came into a normal range with a new battery. I don't have an explanation I hope it holds up. I need to install a volt gauge now as I disconnected the amp meter and I'm not going to remove the cluster to hook it back up.