Hey everyone,
Been awhile, good to see that SRS is still growing strong.
Awhile back I noticed the voltage increasing in my truck and when I verified with handheld voltmeter it was almost 20 volts. I pulled the alt. off and carried to repair shop, their response was, we couldn't get it to do anything. They changed the internal voltage regulator and a diode. I put the unit back on truck and it is still going high and now other problems popping up. When I turn headlight switch or a/c blower on my temp, oil, and gas gauge increase on scale, the voltmeter drops off to about 14 volts.This is with engine running. With the engine off I can turn headlights on and the temp gauge goes way high, so I guess I am getting stray voltage feeding the sensor wire or maybe the high voltage has burnt some wiring. Also when turn signals are on the voltmeter pulses pretty bad. I wired the truck using a donor fuse box and made my own harness, I was smart enough though to make a pretty good wiring diagram, so I guess I will take one step at a time and try to eliminate the problems. Any suggestions will be appreciated.
Bobby
--
BOBBY

You need to install some ground wires. Engine to body, engine to frame, at least two on each. Those nasty elecrtons are looking for a ground where ever they can find it.
--
Anyone can restore an old car, it takes a man to cut one up.

Sounds a bit like the battery terminal or terminals could also be corroded or glazed over. The battery is the usual load for the alternator and disconnecting it from the circuit, especially with the engine running can allow the voltage to run high. It could also be a poor ground connection between the battery and either or both the frame or engine grounds. I learnerd the hard way over the years that poor connections can present a wide variety of problems. When I built my '27, I ran seperate cables straight from the battery to the engine near the starter and also to the frame. Another step to try is making sure the ground lead of the voltmeter has a direct path to the battery ground. I've had bad meter conmnections in the past and had problems just like you described. Good luck! Electronic gremlins are hard to track sometimes and eliminate. FredP
--
Fred P.

The other posters here have some great suggestions and you want to make sure the grounds and terminals are up to par as they have expertly suggested.

The voltmeter and the rest of the gauges uses the supply voltage from the fuseblock as a reference for the meter to use as it senses the respective application. If you are getting variations in these readings as you increase loads then the main wire from the battery, or battery post or whatever feeds the fusebox which in turn feeds the reference voltage is not big enough or is a very poor connection(s). The increase in load from the headlights or electric motors is dropping the voltage somewhere between the battery and the fusebox which makes the used reference voltage drop, making the gauges inconsistent (go up or down...depending on application) in their performance. You can easily test for this by runnning a #10 or larger from the battery and plug it into one of the "hot" circuits on the fuseblock and then add load such as the headlights. The result should be that the gauges are alot more stable if they move at all. My guess is that the main feed from the battery is too small of wire. Try it and let us know what's up!

Here is a link on wire size, length of run and current... http://www.amplepower.com/primer/gauge/
--
Steve Jack
Marketing Technologies Limited,LLC
ConceptOne Brackets and Pulleys

Good news, the grounds have it!!!! Yeap it was bad grounding all along. I had run all my inside stuff to a grounded terminal strip. The wire I used to ground the strip had worked a bit loose from the cowl. Also the frame to engine block ground was not cleaned properly. I added several more connections, engine to frame, body to frame and cleaned thoroughly the existing places.The main feed wire to my fuse panel was #8 which was of sufficient size.
What added even more to my confusion was my multimeter was reading extra high. The in dash voltmeter is about 3-5 volts high so I've ordered a new one to replace. also suspect that my temp. gauge has been damaged.
Thanks a lot fellows for all the advice, I will pay particular attention to the grounding circuit on my next project. I'm just glad I got it fixed and didn't have a fire.
Thanks again--Bobby
--
BOBBY