1971 914 electrical fire, My '71 914 almost goes up in smoke Options

[jackr67]

My '71 914 sat for almost 15 years, until about two months ago when I was finally able to get it back to life.

Initially, all was well but about two weeks ago I began having starter troubles. Would turn key to accessory and all was normal, again over to start and the fuel pump would click on, lights would dim but no starter action. I was able to use a screwdriver to bridge the contacts on the starter solenoid, and the starter turned
over as normal. I also measured a full 12 volts at the yellow starter solenoid wire when the key was turned to start. Following the harness back I also verified 12 volts at the flat connector on the control board.

After reconnecting the flat connector to the control board, the starter magically began working again. Assumed a loose connection somewhere and was about to take it apart again when the harness went up. The black wire which connects the positive terminal on the coil to the control box seems to have been the source, and melted into the rest of the wires and the sheathing the set is wrapped in.

I had tugged on the harness and hooked my volt-meter back up to the yellow solenoid wire at the starter, hopped back into the car and turned the key to bump the starter and measure voltage when it happened. I assume it's due to something in the start circuit, but can't think of any way the power wire to the coil would itself be directly connected to the starter wire.

The black wire between the coil and control box seems to be the only one to have burnt out - the others all appear to be basically fine. I can only assume that somewhere in the bundle the outer sheath tore and allowed that wire to rub against a piece of metal, trouble is with the wire and sheathing melted I can't tell where that might have been.

Another alternative is that something in the control box has gone bad and created the short. Alternately, something which draws power through that wire via the control box has grounded out and was simply
of a larger gauge wire and didn't burn out as quickly. At this point I really don't know.

I'll pull the harness tonight or tomorrow, pull back the casing and see if I can spot anything. If that doesn't turn up anything I'll wire in a temporary replacement for the black wire and see what happens when I hook that up with the remaining good portion of the harness.

Any suggestions on what to look for?

Thanks,

Cole

[lapuwali]

If the condensor shorted, then that's another path straight to ground, as the condensor will conduct through the distributor body right to ground. Car doesn't run in this condition, as I'm sure you discovered. The coil may also be shorted internally, and that would mean you'd have a fair amount of current flowing from the battery, through the ignition switch, through the coil, through the condensor, to ground. This, however, should have caused the black/red (or black) wire to get pretty hot, too. The 25A fuse on the relay board also should have blown.

I don't know the internal tach circuit well enough to know how the power would flow through it to the coil, where it would again ground if the points are closed. If the tach wire itself shorted to power somewhere, that would cause all kinds of trouble, including possibly burning up your condensor. This short could happen on the relay board, or inside the wiring harness sheath.

What's that black wire with the insulated connector on it lead to? The one also attached to coil -. Is that a remade distributor wire? Those are normally green.