1974 duster 440 wont start HELP

danho440 said

OK i have a 1974 duster with a 440 it was running fine then just died on me ... after some checking i have no spark at coming from the coil SO i replaced the ballest resister, the module, the coil, still no spark from the coil, now i have a new battery in the mix .. still no spark . working on it today and was having my son trun the key i got one little spark ( i had the coil wire pulled and was grounding it) only one little spark...

ok here is my question i am at a loss . please anyone give me some ideas

i am going mad

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Check to see if you have 12 volts at the positive side of the coil when you are cranking. You should have around 9 volts when you let go of the key. When you're cranking the ignition switch will provide a full 12 volts to make for a hotter spark so that the car starts easier. After letting go of the key the voltage is now coming through the ballast resistor and therefore is at a lower voltage. This is done so that the coil isn't damaged. You can try jumping 12 volts to the positive side of the coil and see if that makes it start. If it does I would suspect the ignition switch. P.S. Do not leave the 12 volts jumped to the coil for a long time as this might damage the coil.

Good Luck!!!