Pertronix Ingition Question

[scurley]

I have the one wire hookup Pertronix distributor, with integrated coil and GM cap in my 67 fastback.

I am not getting any spark when cranking the motor. I have verified that 12V is going to the positive side of the coil, and with the ignition in the run position, I can measure 12V accross the coil.

I then measured the return end of the coil to ground, and could not see it switching from 12V to 5-6V or 0V while cranking the motor. It stayed at a steady 12V. My question is: Is this the proper way to diagnose this ignition setup, and if so, it appears as if the modulator in the distributor is not switching correctly? Does anyone know where I get a replacement part, and if it is common with other distributors, or is it some proprietary Pertronix part?

 

[ForceFed70]

I think your on the right track.

Have you verified that the rotor is spinning?

 

[scurley]

Yes, i just verified that the rotor is spinning. This should narrow it down to the modulator in the distributor. How often do these things go bad?

 

[ForceFed70]

Hmmm...

Just re-reading your initial post....
You shouldn't see 12V across the coil.

You should see the + terminal of the coil is always at approx 12 volts. The - terminal should measure the exact same..... except when cranking you should see the - side of the coil switching between 0V and 12V.

WARNING! The ground(0V) spike happens rather quickly. Alot of meters don't react quick enough to show the momentary ground pulse. Especially cheaper digital meters.

 

[yeloxr7]

A test light is better than a meter when checking for module switching on the (-) side of the coil.