Quote:
Originally Posted by lutronjim
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When looking at wiring diagram, I see wire going to solenoid and then to coil. To keep solenoid from firing when switch is run position, I see another of the wires on the solenoid goes back to the switch and, I think, grounds when switch is in crank position. Thus enabling two power sources without a diode.
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I don't think there is a ground when switch is in crank position, and I don't think a diode would be needed.
The purple wire has 12 V in start position and this causes the solenoid on the starter to engage.
The yellow wire on the outboard terminal of solenoid on the starter sends 12V to the coil only in the crank position.
The pink wire under the dash in the cab also gets 12V in both crank and run positions, and it goes to the coil through the white resistor wire that joins up with the yellow wire. Or for those with HEI, they have probably replaced that resistor wire with a plain wire that comes from the same position on the firewall connector where the resistor wire was attached, or from a terminal in the cab that gets its voltage from the pink wire such as the IGN UNFUSED terminal.
I have found that every now and then, I get no voltage or reduced voltage to my HEI during crank, because I get no spark. I crank it for a long time, and I get spark immediately upon releasing from crank position to run position and the engine then runs. So, this is giving me the idea of putting the yellow wire back in place to also power the HEI, so I'm sure to have good power from at least one source during crank. It has not bothered me often enough to made me do that yet. I think I would blame this problem on my ignition switch but it is pretty hard to diagnose when it only rarely happens.