The Stovebolt Site Forums The Shop Area The Electrical Bay interesting voltmeter

Just recently installed a digital LED voltmeter. I hooked it up to the (anti theft) kill switch wire to my coil, on my 55 2nd pickup. It reads 8.5 volts when the ignition is on and 9.5 when engine is running. I assume it is showing the voltage from the resistor to the coil. My normal voltmeter shows 14+/- volts when engine is running. Could this digital meter be used to indicate any problems or defective ignition points, coil, etc?

Is your 'normal' voltmeter also digital? If not it may have something to do with digital sampling rate and/or the hysteresis of an analog meter. Just a guess. Maybe elevated ground?

No, my voltmeter is analog and shows battery voltage when ignition is on and alternator output when engine is running. I hooked up the new digital gauge to the coil kill switch wire, not thinking of the resistor voltage drop. Kind of cool to see the primary voltage to the coil. Just wondered if it could be used to indicate any electrical problems. The truck is running great!

Are you speaking about the voltmeter mounted in the instrument cluster or an external one you might troubleshoot with. The cluster mounted gauge measures system voltage and unless input is changed doesn't measure coil voltage.
As far as a trouble indicator goes, it might help you see something like ballast resistor failure, condenser failure or something of that order. Truth is, the engine will let you know a problem is occurring around the same time. If the LED display turns your crank, then go for it.