Got MSD? Who among you runs with a diode?

So I've been running an MSD 6A for a couple of years now. Recently I also upgraded my stereo amp. I've also been experiencing some intermittant battery drain-downs. I checked the amp to make sure it was turning off - yep. I've noticed some wierd stuff including voltage in the chassis (about 2.5 volts or less) even with the battery TOTALLY disconnected. When I drive, I can hear what I believe is the regulator on the firewall switching on and off. At about the same frequency all the lights in/on the car pulsate. Sometimes when I disconnect the positive lead from the battery and inadvertently touch it to the chassis I get a significant spark - WOW - where the hell did that come from - I thought.

My old man (who really isn't that old, and who used to repair TVs for fun and supplemental profit) and I have been speculating that the capaciters in the MSD are pushing juice back through the chassis when the rest of the car is not on. We also think that the MSD is affecting the regulator.

The MSD instructions indicate that to stop run-on after turning off the car a diode should be placed between pole four of the voltage regulator and the charge/idiot light. My car never has experienced run-on so I never installed the diode. How many of you are running this diode? Did you have to to prevent run-on?

Any theories before I put this diode in place?

Thanks for your time guys.

 

I had some intermittent battery drain down issues one time. I also experienced the chassis shock when I was worrking on my stereo amp. I touched my leg to the rocker panel and I felt this tingling sensationuzzled: :shock:

So, what I did on a whim, was chance the voltage regualtor, and whaddya know, it fixedthe draining problems and my shock syndrome.

I also had problems with the clicking from the regulator, and my radio would turn itself on and off whenever it wanted to.


The new regulator fixed everything.

I dont know why either.


Maybe because the regulator developed a short in itself and grounded the power to the chassis sometimeso No:

 

I have a Mallory Hy-Fire and it took about 3 months to finally notice run-on. the one thing i noticed is that the instructions didn't seem too clear, but after reading them a few times I thought that if you had any vehicle that may have run-on you should use the diode. I don't think that the diode will harm anything though (am I right here anyone) so if it won't what can it hurt to stick it in.

 

I have a MSD 6AL and am experiencing run-on. I will be installing the doide this week in my wire going to the voltage regulator. I think it's the brown wire, but don't quote me on that.

 

Don't forget that many stereo installations also have a power filter, so you don't get a buzzing through the amp. Frequently this "filter" is just a capacitor, and can cause a bzzzt because of the stored juice.

-Bob C.

 

I used to have the run-on problem but after i switched to an internal regulated alternator and got rid of the voltage regulator it stoped doin it.