electrical demon

[otter]

I have an all original 1970 Bronco with 57K original miles. At approximately 700 miles, 3 times in a row, I have had to replace my coil. My engine will shut down at high speed on the highway and or at idle. Put in a new coil and she's running like a top, and then shuts down at 700 miles???Can't figure it out...Any ideas or help would be greatly appreciated.Thanks, Otter

 

[El Kabong]

How many volts are feeding your coil? I would think a stock 1970 coil would still use the older style coil that would normally be run off a resistor wire so the voltage is reduced during normal operation. A full 12v is sent to it only during starting. If 12v is there during normal driving it will shorten the life of an older style coil. An easy option if the resistor wire has been replaced is to use a ballast resistor in line to the coil.

Not necessarily the issue, but it's something to check.

 

[Viperwolf1]

How many volts are feeding your coil? I would think a stock 1970 coil would still use the older style coil that would normally be run off a resistor wire so the voltage is reduced during normal operation. A full 12v is sent to it only during starting. If 12v is there during normal driving it will shorten the life of an older style coil. An easy option if the resistor wire has been replaced is to use a ballast resistor in line to the coil.

Not necessarily the issue, but it's something to check.

You cannot determine if there is a resistor in place by checking voltage. You will see 12V with or without it unless there is a load on it. Better way is to measure the resistance from the coil to the red-green wire at the ignition switch. With a resistor you should see 1-2 ohms.