Ways to bypass resistor wire?

Automotive Stud

Well-known member
I have a '67 Mustang with a 302 I converted to a Pertronix II ignition. The car runs great, but according to Pertronix I should have at least 8 volts at the + terminal on the coil with the key in the run position. I have a 1.5 ohm Mallory 29217 that has been on there since before I went to the pertronix. I only measured 5.5v on the positive terminal, so I bought a Pertonix 45001 0.6 ohm coil thinking that should get the voltage up. I actually only had 3.6v with that coil, which makes even less sense to me?

Anyway, I contacted Pertronix and they said I must bypass my factory resistor wire. I know it's the pink wire going into the ignition switch, which looks pretty much sealed up. I also don't want to hack up my wiring harness. Currently I have a Holley with an electric choke hooked up to the I terminal of the starter solenoid with 12 gauge wire. Could I tap into this off of the electric choke and just run the wire to the positive terminal from there? I don't want it to backfeed through the solenoid or cause any other trouble.
 
The "I" solenoid terminal is a ballast bypass, and is normally off in the run condition. How does your electric choke work?
Just install a new wire from the ignition switch to the coil. :)
 
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You say you don't want to hack up your harness. I think that is a good move. You can pick up switched 12v from your fuse block - just make sure it is not live when in accessory position - turn signals usually good for that - and use that source as a switch wire for a relay. Use a 12v feed from the battery as the power source - battery terminal of the solenoid is good for that - goes to the contacts of the relay and of course the other side to the coil.
Leave the original ignition feed on the coil as it won't start otherwise.
 
The "I" solenoid terminal is a ballast bypass, and is normally off in the run condition. How does your electric choke work?

Exactly my first thought when I read his post. You will only have power to your electric choke when you are cranking the engine. As soon as you let go of the key there is no power to the "I" terminal. :eek::eek:
 
I don't know if the Mustang resistor wire is the same as my 64 Fairlane, but on the fairlane the pink resister wire has a connector near the ignition switch. Since i am running a HEI on a 302 (which needs 12 volts), I disconnected the resister wire and ran a new wire from the wire it was plugged into, leaving the resister wire intact, to the solenoid and the HEI. I would imagine (no expert on wiring) that you would run the wire to the solenoid and the pertronix distributor connection with the plus side of the coil.

This way, returning to stock would mean disconnecting the new wire from the ignition switch wire, plugging in the resister wire and removing the new wire completely.

Of course, you would also take off the stock wire off the solenoid.
 
I'm a little confused here? I have never seen an engine that has a ballast resistor and a high resistance wire all in the same ignition system.
My experience with the elimination of the ballast resistor in a HEI or Petronix system is to just move the wire from the ballast resistor to the coil, putting this wire onto the terminal coming from the ignition switch.
That way for originality, the ballast resistor still appears to be there in the system..
 
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