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Discussion Starter · #1 ·
The set-up:
’83 with 6M and later model alternator with needed resistor mod in fuse box to keep “check engine” light from constant on, Optima red top battery. Clear day, sunny, warm, 60 degrees.

The event:
I had only driven one mile, traveling about 40-45 and slowing down to make a turn. My radio shuts off, I immediately look at the gauge cluster and see the tack just as it had dipped low and then quickly returned to the natural RPM range (@3k). Radio is nothing special; Pioneer head unit with 4 speakers. I was already letting out of the gas so I didn’t feel anything unusual as far as lost power. The radio came back on. All this was approximately 3 seconds. I looked at the clock and it had reset to 1:00. The electrical power loss was instantaneous, probably less than half a second.

The question:
Anyone else ever experience something of this nature? This happened Saturday afternoon and I’ve since had no issues. I’ve seen nothing unusual poking around under her skirt. What could be a cause of such a quick blip? I’d almost compare it to a power failure at home. Sometimes during a lightening strike the power may skip off and on very quickly. Any thoughts, ideas, things to check or should I just quit drinking?

Oh, we gonna rock down to Electric Avenue.
Scott
 

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Check the usual. How tight are your battery terminals? Any corrosion? Good ground?
 

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Mine has done that too, it turned out to be in my case a ignition switch being bad.
 

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How will you know if you fixed it if it does not happen again? Let it happen a couple more times and see if you can find any common factors, or at least have some idea how often to expect it. The suggestions above are good places to start if you get this far.

Quitting drinking is not an option...

-John
 

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I've had engine not operate on humid day cause ignitor bracket ground was poor. Loosened and tightened bracket mounting bolts extra 1/4 turn and all was ok. Then sprayed bracket with silicon oil to prevent future problem.

Check and retighten your grounds. If problem reoccurs search for loose wire or bad switch or relay.
 

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sounds like you're losing power to the whole system. It'd start at the battery and work my way out. It sounds obvious but is your battery tie-down in place? are they tight? mo orig aftermarket terminals were "tight" but not actually tight on the post...have a look at that if they could be wiggling on you.

it sounds like your deck lost power and your engine died for a second too...indicating that whatever happened, effected the same source. As scott suggested, if you find don't find something at the battery check for looseness and corrosion of your fuse box, relays and maybe try and test your ignition cylinder.

best of luck, this could be a big headache.
 

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Check all of bolt-on grounds too. One at trans x-member, one around bell housing, one to post just forward of the left engine mount, and one at RR cam tower.
-Aaron
 

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Discussion Starter · #8 ·
I checked all the usual suspects: battery, tie-down and OEM terminals are spanky clean and tight. Alternator connections are good. Didn’t think of the ignition switch. I was playing with and swapping the coil, that black, square resistor thing and ground when the 6M went in and wasn’t getting a good spark. (That ended up being the dizzy, it seemed.)

Didn’t check the lower grounds but will recheck all once again. I replaced all those with heavy gauge wire and gold connectors about 4 years ago. Cleaned the connections and tightened snuggly (no, not Snuggy) when the 6M went in 5-6 months ago.

I’d rather check a few things and hope it doesn’t happen again rather than sit back, waiting for it to happen in order to compare commonalities and have it occur without end when I’m somewhere miles from home on the open road. Then I could really use a drink but have no way to get to it.

I don’t know if the engine actually briefly died or not. I didn’t feel any seat-o-the-pants loss of power but I was already out of the gas and decelerating anyway so I can’t be sure. Obviously, though, everything inside lost power for a brief moment. The motion I saw from the tack needle was quick, much quicker motion than would happen either from mechanically increasing rpm or wind-down by depressing the clutch. I saw it when it hit a low point of 1800-2k then quickly jumped back up to 3k, the engines natural range. Certainly a weird sight.

Thanks for all the tips! I hope it doesn’t become a headache.

Checkminster Fuller,
Scott
 

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That sounds like what happened to mine. A good thing is that all the years are the same, I took mine from my 85, swapped it in, and it worked flawlessly. Gl!
 

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Also, Check to see if there is anything grounding out. Something touching the positive post on the battery or Alternator. That can cause the voltage to drop low enough to reset memory and turn the deck off, but the Tach might not drop all the way down to 0.

But after poking around, let it happen a few more times and go from there.
 

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If the basics are good and you feel confident it was a limited power flux then I would look for a simple loose connection since that is the normal problem.

Look for a loose or bad connection with the power circuit from the battery to the junction box no.3, ie loose or corroded connection since the radio and clock share common power only before the box. Black wire from the fusible link next to the battery. Radio and clock split from 2 fuses after the junction box to power those circuits.

Also make sure you check the ground from J/B No.3, radio and clock share ground from that box.
Check all of bolt-on grounds too. One at trans x-member, one around bell housing, one to post just forward of the left engine mount, and one at RR cam tower.
-Aaron
If you don't find any drop voltage in that circuit next should be the separate circuits.
 
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