Starting Problems Petronix???

[Guest]

Anyone know how I can diagnose problems with my Petronix installation? It has been in the car for over 10 years now and seemed pretty reliable. But I can not get my car to start now. It cranks OK but does not seem to be firing. The coil resistance is ~ 4 ohms. There is 12 volts at the coil. The weird thing is that the car seems to want to fire sometimes when I turn the ignition completely off (or maybe from start position to run position). I want to eliminate the Petronix as a source of the problem if I can. Any ideas.

By the way this is a 1974 car which had the seat belt interlocks on it originally. I have jumpered out the circuits for that though.

[Marty]

Check to see if you have 12v at the coil while cranking, it sounds like your resistor starting bypass circut is at fault

[Guest]

I have ~9 volts at the coil while the starter is cranking. Is this too low.

Also, the car is definately trying to fire when I cut the ignition off. It is like the Pertronix is not causing the coil to fire. Do you know any way to test this?

[ingraham]

It should be about the same as the voltage at the starter. Measure the voltage at the big bolt on the starter motor during cranking and compare.