Coil isn't getting power

[BIGEVIL]

Hello all,
On my 64 my coil only gets power while the starter is cranking.

I know the coil only sees a full 12 volts while the starter is turning over the car. Once the car is running, the voltage is reduced. But how much?

According to the repair manual the power wire itself provides the resistance. That wire must be damaged somewhere as it has no voltage to it anymore.

I'll probably just run a fresh wire instead of trying to chase the original one through the back of the dash, but I'm sure I'll need some sort of resistor. Any ideas?

Thx

[northgahearse]

i think it goes like this

Wire from a 12v with the key on, to the resistor then to the + side of the coil. Then run a wire from the R terminal of the starter to the + side of the coil.

The 12V from the starter will "bypass" the resistor while you're trying to start the car

[SarahtheSweet]

HEI or points?

[BIGEVIL]

She has prehistoric points.

Just a side note, when I take a jumper wire straight from the battery to the + of the coil, she runs just fine.
But I know that it will ruin the cap/rotor or coil if I leave it that way.

I have found a few ballast resistors on Summit racing, but there are a few different resistance values. Not sure what to go with. Most of the are for high performance racing ignition systems, not stock.

[Highbars]

Ok.. The wire from the starter or the one that only has power when cranking delivers a full 12 volts to the coil for a hotter spark for quicker starts.. the other wire from the Ignition switch is a resistor wire that reduces battery voltage (12 volts) down to 6-7 volts to the coil after the engine starts. Running a jump wire will work for a short time but will damage the points in time and they will require filing and regapping or replacement. If you can find an older Chrysler product from the 70's you should find a ceramic rectangular block with 4 terminals on it. put it in line with the new wire you run connect your wire from one end to the other. and test voltage with the key on, it should be 6-7 volts that you need to keep the points from frying....

[BIGEVIL]

6-7 volts! Thats the number I was looking for.
Thx

[pyro]

try a new ignition switch

[BIGEVIL]

try a new ignition switch

Since everything in the car was getting power except the coil, I really didn't think it would be the switch.

I ran a fresh wire with 12v and a ballast from Carquest. The car runs great now. With the ballast, the coil sees 7 volts.
Perfect.

[Morella]

The saddest part of all of this is that when car companies switched to 12v from 6v systems, they had a whole shitload of 6v ignition parts which should have gone into the dumpster ($175,000,000 in reparations for NCOBRA), but they put them into cars instead, using a resistor to bring them down to original 6-7 volts that they ran on in the older cars. An aftermarket ignition system (some are better than others) might be an option if you would rather drive it than work on it.

BTW, while you're cranking, the starter is huffing your battery, so a cranking voltage of 9V or better is usually acceptable.

-denise