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1971 Electrical Gremlins

Old 09-14-2018, 03:45 PM
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Default 1971 Electrical Gremlins

I have a 1971 350 That will not start. It is has a crate 350 (Mexico block) with Edelbrock heads, intake, and carb, and an MSD ignition (Digital 6AL). One of the POs installed what seems like a home made anti theft system. There is a kill switch hidden in the carpet next to the driver side seat, and a remote flashing LED light in the vent on the top of the dash. When the kill switch is thrown, everything turns off except the LED. There is a separate switch to turn off the LED on the dash also.

I have driven the car for 1 1/2 years... until a few months ago. Drove it on Sunday. It would not start on Monday. Accessories all worked fine. Engine turned over, but no start. After some investigation using MSD's troubleshooting steps, I determined there was no spark. I replaced the coil with a basic NAPA unit per MSD's suggestion to rule out the coil. Still nothing. So I sent the Digital 6AL back to MSD. They "replaced a resistor" and sent it back. Once re-installed I still had the same situation... for a while. The engine turned over, but would not start. I pulled the coil wire to check for spark and still nothing. Frustrated, I put everything back together and just for kicks, tried to start it 1 more time. When I turned the key, nothing happened, then everything went dark. Even the LED will not light.

Any help would be greatly appreciated.


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Old 09-14-2018, 05:59 PM
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have you checked the battery with a voltmeter?
what kind of distributor?
can you temporarily wire it to run without the MSD box?
are the original wires that ran to the stock ignition coil positive terminal still there?
if the wires are there, what voltage do you get while cranking and what voltage when the key is in the run position?
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Old 09-14-2018, 07:05 PM
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The engine was turning over just fine before I took out the MSD box. It turned over great the first few times I tried once I put the repaired box back in. Then it just would not turn over and all the lights went out.

I don't think the battery is the issue. I had it jumpered to my other car to keep it from running down during all this.

It is an MSD distributor. Not sure what model. Have not checked any voltages, but I don't think there will be anything. The entire car is dead.
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Old 09-15-2018, 12:25 AM
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Take your voltmeter and,
Check directly at the battery terminals.
Check the cables at the battery.
Check from a chassis ground to the positive battery terminal.
Check from the engine block to the positive battery terminal.
Check from the top big solenoid stud to the engine block.
Check from the horn relay to the engine block.

You have found the area with an issue when you find the voltage missing as you go down that list.

If you find all the above is good, then it's likely the wire running from the horn relay into the cockpit.
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