Ignition problems part 3

[ANTON]

Miles check the fire wall connector as it sound like you are loosing power to the coil in the start position for the key. If it start when shorting the solinoid you are bypassing the starter power wire to the coil.

Mopars have to two power wire to the coil one in the run position and one in the starter position. Both these wire go to the ballast resistor. Starter wire bypasses ballast to give 12 volt direct to coil to help starting and run wire goes to the other side of ballast to drop voltage to the coil.

[MilesnMiles]

Thanks for clarifying Anton. I've also been pm'd with some tests to check that process too which I wil follow up.
Mostly only able to get to car at weekends but will report back when I've done those tests

[Dave999]

has it been fitted with a mini starter?

on the earlier cars
the starter motor had a 3rd pin that provided a feed to the coil in the cranking position of the key. that feed came direct off the same switch that kicks the starter motor pinion forward inside the cap of the solenoid.

on a 2 wire starter you can achive the same thing by connecting a wire to the big stud and wiring it into the coil end of the ballast resistor

however you have to put a fat diode in it to stop the coil dumping back emf into your starter and arching the contact for the solenoid

details on the powermaster website Fitting instructions.


here we go

What do I do with the wire that went to the "R" terminal on the original starter?

In early original wiring harnesses, the "R" circuit was a ballast resistor bypass. This terminal is no connection when the starter is at rest, and is +12VDC while cranking.This circuit provided +12VDC to the ignition coil during cranking for easier engine starting. Cars that do not have a ballast resistor (i.e. HEI, MSD, or other aftermarket ignition systems) should not need this connection. In most cases, this wire can be eliminated. If the engine has no ignition during cranking, then the wiring of the coil is going to require an "R" terminal signal. To accomplish this, connect a 3A/400PIV diode (or Powermaster part # 600 ) in line with the MOTOR SIDE of the solenoid. (Note: This is the terminal on the solenoid which has the cable from inside the starter motor connected to it. It is opposite the BATTERY terminal on the solenoid. The cathode or banded end of the diode goes away from the starter. This allows current to go from the starter to the coil and yet not from the coil to the start

[MilesnMiles]

Thanks Dave. I do have a mini starter.
I'm waiting for a new switch (the loom part) to arrive before I delve further. I figure if the key and barrel parts were knackered after 40 years, so might the switch contacts.