AMP Gauge bouncing WILDLY ! ?

ersatz

Senior Member
My stock ~ 1946 flathead V8 pickup truck suddenly developed a problem with the AMP gauge bouncing wildly between DISCHARGE & CHARGE when driving. At around 35 MPH it might subside and fluctuate mildly back & forth at the center, but then it will continue to bounce from side-to-side. It rarely operates as it should. The system is 6 volts, I have a new voltage regulator. I also have a 40 AMP alternator built by Whitney in California which has been functioning just fine for a year now. WHAT IS MY PROBLEM?
 
Mine does that when I have an intermittent short somewhere or even a permanent short. Tough to find if intermittent. Easier to find if it's permanent and the wire starts heating up and smoking. :)
 
JACK ~ I checked both fan belts for proper tension and all seems fine.

I tend to think OLD HENRY is right. It's probably a short or grounding problem which I've had and can't seem to chase down. It is super annoying! I guess the only way to fix it is to rewire the whole damn thing.

Thanks and Merry Christmas to you ALL!
 
I tend to think OLD HENRY is right. It's probably a short or grounding problem which I've had and can't seem to chase down. It is super annoying! I guess the only way to fix it is to rewire the whole @#!*% thing.

As long as there is no smoke and all the lights are on forget about it until something gets worse.

Put tape over the battery gauge if it's buggin' ya.:rolleyes:
 
Hi, REBEL SYMPATHY!

I wish I could blame it on a cheap Asian voltage regulator, but the one I replaced & the new one (THANK GOD) were both made in the USA.

OLD HENRY........ It seems like you've got the right idea.... Let it go until something obvious surfaces. I hate to do that, but chasing a ghost is getting real old.

Wish you both a Merry Christmas!
 
You could check the output and see if its charging correct voltage reading.
I had a problem with 12 alt,the eletric fuelpump very noisey.
Disconnnected the alt and just battery the fuelpump was quite.
Replaced alt end of problem.
 
Square one: Why did you buy a new voltage reg.?? Was this going on before ?? your going to find this is a grounding problem, your alternator,is it built in an original two brush case? with a ground wire to the base of the voltage reg. ( is it good )??.. When you replaced the reg. did you clean the firewall, maybe painted some?? and interfered with what was a good ground under the new reg?? Now how about the grounds " engine to body" and "body to chassis" dash to body.... instrument cluster to dash ground ?? Now can you run the engine in the driveway a about 35 miles per,hr. and feel the voltage reg. is it steady and quiet, ( put your stethoscope on it ) ... go ahead and run the truck, when the amp. gauge starts to fluctuate, STOP. and feel to wires on the amp gauge, also the wires and contacts on the reg. and at the alternator..... all should be the same as what around there. find a hot one and you got it. chasing a poor ground is liKe trying to rope the wind. been there ... OLD ... BILL
 
Whitney's alternators do not use a voltage regulator (my 12V does not). What are Whitney's instructions? Check your connections, just one at a time. Keep track of what you disconnect and reconnect - write this all down, so you can refer to it as you go along.
 
Most modern alternators are set up for single wire charging to the buss. Only the very early ones used the three pole regulator. Many later models used only two pole since the cut out was eliminated by use of a diode rectifier plate. Near all are now single wire with a built in regulator or they have an external solid state regulator of some sort.
 
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