Well if the grounding could not have happened BEFORE the gauge then I am left with the conclusion that the gauge somehow failed. I carefully examined the underdash area where the panel and gauge are and do not see anything that would have caused the grounding.
Remember, I drove the truck, came home and parked it for a couple hours before the smoke deployment. If current is present even when the key is off, I wonder if the wire was slowly getting hotter and hotter due to?? and at some point we know the gauge failed enough to meltdown on the starter wire side. It just does not make sense that it took so long if it was a direct grounding........that should have happened within a short time I would think.
I do not know how these ammeter gauges work internally but the INSIDE of the gauge was cooked as well. The hard black plastic surrounding the metal aspect of the unit on the D side really cooked.....almost as though it could have been from the inside out. If Stuart's description of the grounding was on the back side of the gauge it would have had to be heat transfer or failure of the internal guts of the piece to be melted INSIDEof the unit.
Beyond that theory or the continuing heating of the starter wire long after the truck was off I want to make certain somehow I am not "heating up" or creating resistance somewhere it should not be. The wires on the downstream side of that D terminal were cool to the touch as I checked right away, the voltage regulator and ignition switch as well as generator wires were all cool.
I intend to fuse the line as that was too close for comfort, but I hate not understanding what caused this as it makes no sense to rewire and not have a clue. If the gauge failed or it grounded out when it was parked and not running with the key off for some time, it makes me believe I have done something wrong in the wiring installation. All the terminal connections look good, the wiring is a reproduction harness of good quality. I took the resistor out of the equation as the Langdon HEI instructions say to eliminate it. The harness wires and terminal ends for the resistor were not hooked up.
The other wire that is cooked is the temperature sending unit but I believe it was from being in touch with the starter wire near the back of the gauge in the harness behind the panel. I wondered if that wire could transfer enough heat that it melted after the truck stopped (HOT), then melted the starter wire insulation slowly until it grounded out....... Seems like a stretch but I am grasping at cause and effect. I know the temp gauge did not show hot as I was driving it was in the normal to slightly warm range. Thanks Ralph
