84's are plagued with electrical demons. I had such bad issues with mine that I drove it less and less and eventually parked it for over a year. It had an intermittent no start condition that I chased for years. I replaced everything even remotley related. Ignition switch, starter, coil, ecm, battery, clutch switch.... still the problem returned. So my last effort was to attack fusible links and all power side wiring. What I found was the previous owner had hacked the wires on either side of the c500 & removed all fusible links. The issues truly was that the wiring was intermittently failing to make solid contact due to horrible butt connectors. So I soldered everything back, insulating with dielectric grease and covering each with shrink wrap. The fusible links were butt connected properly. The wire to the starter were updated to the new style with a distribution block. The alternator upgraded. And all its wires upgraded. The Sense line for the alternator was made independent of the factory wires and run straight to the dist block for correct sensing. Amazingly this did the trick and the car can sit for months and fire up with no start hesitation or battery drawn! I had a horrible drain before!
I have a write up on pennocks. If u want I can post a link for u
