Hey all, I have a '66 F100 with a Pertronix distributor and coil. I have come to the understanding that the wire running from my ignition switch to the coil is a resistor wire. So, I read up on some of the fixes and went with using a relay. This is how the relay is set up: 30= 12v power from battery, 85= ground 86 = is connected to the ignition switch wire, 87 = goes to the coil w/ 20amp fuse. The truck starts great revs smooth, before it had a slight stumble, and seems a lot happier. However it won't turn off. If I pull the connection apart on the ignition switch wire it turns the truck off, the truck turned off with the key before this. Do I need to install a diode if so on witch circuit and what size? Would putting a toggle switch in-line on the ignition switch circuit be ok?

 

I wouldn't keep adding stuff. I'd troubleshoot it and get it right.
I'd say most likely culprits are stuck relay or double check your wiring.
Also, can't this be done more simply by replacing the resistor wire with a regular wire.
(Sorry for the edits. Was distracted)

 

66F250 "Also, can't this be done more simply by replacing the resistor wire with a regular wire." yes however I plan to going back to points when I do an engine swap in the fall so I didn't want to hack up the factory wiring any more than I have to.
Thanks for the help.

 

Your resistor wire already has a male connector on the ignition switch end. Just cut it at the cowl plug with enough left to put a female (.186) diameter connector on it. Leave it in and run a solid wire in its place. At some point Ford started putting connectors on both ends of the resistor all the replacement wires have two connectors.
Standard Ignition 2 Terminal Ignition Coil Resistor RW-34 | O'Reilly A (oreillyauto.com)

 

Crop Duster, I will pull back all the electrical tape and see if I can find the connector. If so I will just run a normal wire piggyback with the resistor wire so it will be there when I go back to a points ignition. Thanks

 

You shouldn't have to un-tape anything. The pink resistor wire is connected to the ignition switch pigtail it has a green male plug on it. The other end at the cowl plug may or may not have a female plug. If it doesn't put one on it. This is exactly what the shop manual says to do. You do have one, don't you??

 

Give us more info. What does the ignition switch look like (terminal side). Does it have a one wire alternator. If you have to remove the wire from the ignition switch to kill it, then something is likely back feeding the ignition circuit. Check and see if you have 12v on the ignition wire when you turn the key off and it’s running. Continue to check the voltage at the ignition contact on the ignition switch. When you remove the wire from the ignition terminal (like you said to make it stop) check to see if there is 12v on the ignition contact. If the power goes away when the engine dies, your alternator is back feeding the circuit some where. Hope this helps.

 

I went with Crop Dusters suggestion. The previous owner must have had a product contract with 3M cuz the wiring was taped all the way to the ignition switch. Also, I do not have a terminal block on the firewall, the trucks wiring just runs thru a couple of holes in the firewall, with electrical tape wrapped thick around them. I think the last time this truck had stock wiring was when it left the factory floor. I did find the terminal connector from the ignition switch and ran the new wire from it to the coil, all is good 12V and it shuts off with the key.
Thanks everyone.

 

Who would ever go back to points.

 

If your Pertronix dies when you're out on the road, a set of point and condenser can get you going in just a few minutes. I always keep a set with me.

 

My Pertronics 1 has been going strong since 2015 and I carry a spare in the glovebox. Haven't even looked under the cap in years.

 

My Duraspark II has been going since I pulled it at a bone yard in '96 and dropped in my '65 Something to be said for factory stuff.