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Discussion Starter #1
I Need some help. I have a 1964 GTO tri power. It ran great yesterday. This morning I started it and as soon as I released the key it shut down. I know its electrical but where do I start? I was thinking maybe the ignition switch. Any Idea's? How and where should I begin the trouble shoot?

Thanks Ken
 

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Check the wiring going to the points. 1964 only has one, but later years added a resistor to the circuit to keep the points alive longer. It starts on full 12, but runs on something less. A common 'solution' to reducing voltage is installing a Mopar style ballast resistor, and those go bad. If you have one, jump the wires together and see if the problem goes away.
 

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Resistor Wire ?

If the car still has original ignition ( points ) and original wiring, the wire that goes from the ign switch to the + side of the coil is a resistance wire . It drops the voltage to the ign so the points will last longer and the coil will run cooler .
Your symptoms sound like this wire or the ign switch has failed . The reason it runs while cranking is that there is a separate wire that is energized by the starter solenoid to apply full battery power to the ignition while cranking .
Turn the key on and measure the voltage @ the + side of the coil . It should be around 7 volts .
Hope this helps . Bill
 

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Ok, Finally got a chance to check and I am getting 12 volts to the coil at start. however it drops to .5 at run. I checked the wire at the plug and I get 12V to the switch. any Ideas? The wire at the switch seems to get pretty warm. The same wire appears to have gotten very hot a on time at the firewall connection.
 

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Ok, Finally got a chance to check and I am getting 12 volts to the coil at start. however it drops to .5 at run. I checked the wire at the plug and I get 12V to the switch. any Ideas? The wire at the switch seems to get pretty warm. The same wire appears to have gotten very hot a on time at the firewall connection.
Sounds like something shorting out. You want 12 volts at the coil on start, then it should drop to about 8 volts when the key is in the "run/on" position after starting. There is a resistor wire coming off the key that drops the volts to 8 so it does not burn the points or overheat the coil.

So, ignition switches do go bad as the contacts inside wear out. Replaced my '68 because it was slap worn out. It could also be a burned up resistor wire, especially if you noticed some heat/melting at the firewall. Nothing should be getting hot, which in my opinion is that something is grounding/shorting out.

You can test the wires with an Ohm meter to make sure they are in good working order.

That said, I would be pulling my battery cable to make sure there is no power going through the wire harness which could melt down the wiring or set your car on fire - until you were sure nothing was shorting/grounding out.

If you just wanted to test the car to see if it will run, you can run a jumper wire from the battery (positive side) to the coil to give it 12 volts once you crank it over and it fires up. This will keep 12 volts to the coil and the engine will remain running. This will also confirm that you are not getting the needed voltage at the coil to keep the engine running. Disconnect the wire so you can shut the engine down, otherwise it will continue to run after you turn it off at the key. I would not do this for long because you don't want any back voltage to find the short/ground and burn some wiring up. Just a test to see if it is a voltage/power problem going to the coil.
 

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Discussion Starter #10
Pontiacjim

As you suggested I ran a wire to the coil. It runs great. I checked the wire to and from the ignition switch. 12V goes in but I cant seem to get but .02 out. I checked at the switch, the harness and at the coil. I ordered a new ignition switch to at least to rule that out. Let me know if you or anyone can think of anything else to try. I'll let you know how it works out. Thanks again Ken
 
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