Tracking Down an Intermittent Short in a 1971 Opel GT – Hot Rod Network

In the Hungarian aged country where my family is from, there is an ancient curse, which translates loosely as, “Could you have actually an electrical short, and Could it be intermittent.” It’s an evil curse.

The Opel was filled along with such a fault, and as soon as it happened, the No. 2 fuse would certainly blow, the engine would certainly misfire once, the tach and 3 from 4 gauges would certainly die, and the taillights and transform signals would certainly prevent working.

The easiest program was merely to sustain changing fuses, however as soon as it obtained to a point where the fuse would certainly blow nearly immediately, brand-new fuses came to be impractical, plus I was stressed that I’d burn the auto up. Time when it come to diagnoses!

The initial action was to transform the auto on, then when it come to Tom to wiggle wires in the engine bay while I checked out the gauges when it come to indicators of electrical misbehavior. There was a puff of smoke that we assumed was some oil burning off. (Keep in mind that when it come to later.) The gauges remained steady.

The following relocate was to wiggle wires under the dash. We located that Opels are wired love an amateur Ham radio, however we didn’t locate the create of our short. See that by this point, the Opel owned been operating about and off when it come to much more compared to an hour, and we hadn’t blown any kind of fuses. This is exactly what is so frustrating regarding an intermittent short—you can’t grab it to happen anywhere near to a multimeter.

Finally, I resorted to climbing under the dash and pulling fuses one by one until we discovered one that caused the gauges to go dead. It was connected to wiring in the engine bay, which earned us rethink the oil smoke from earlier. Closer inspection of the wiring revealed a location about the 12V feed to the electric choke that owned rubbed about a sharp corner of the block and exposed bare metal. Electrical tape and spine in business. Curse lifted!