What does a properly function amp gauge look like?

[TheMopars]

Since I've owned the truck most of my gauges haven't worked. Finally got them all working but not
sure the Amp gauge is correct. My old gauge pretty much did the same thing so maybe this correct.

Here goes...

When I first bought the truck the battery wasn't charging and kept going dead. Confirmed alternator
was bad and had it rebuilt.

Replaced the original VR. New VR would go just left of center at start up and almost peg to 50 when
revved. When I drove it would get to about 35 and then rapidly kick back to zero over and over. Not
really knowing but assuming this wasn't correct I bought a new electronic regulator. Same at start up
and also goes to almost 50 if I rev the motor. Haven't gotten to take it for a ride yet as my truck is
blocked in right now by a couple of cars.

So is this what it's supposed to look like when functioning properly or is there something else wrong?

1964 D100 w/ 318 and AT

[712edf]

A properly working ammeter of that era does move visibly, but shouldn't be pegging out in either direction. They do show the most charge just after start-up then swing back to almost center in a matter of seconds. Turn signals & brake lights also cause instant movement.

Sometimes under certain conditions it may show a slight discharge at idle. This may not be a problem with the ammeter itself but an indiction the the charging system isn't putting out enough juice to meet the electrical load at idle.

Mine doesn't swing very much at all when the engine is revved.

What amperage is your alternator? I don't think a 64 would have much originally.

On the ramcharger site there a post about how to upgrade your ammeter to make it more safe (less of a fire hazard), plus there are numerous descriptions on how to do a bypass or switch to voltmeter.

Bucky

[stumblinhorse]

The gauge is pretty straight forward. It is designed to show the flow of charge in 1 direction or another. Meaning charge to the battery or charge out of the battery is a simple way to describe it. Your alternator should be putting charge to the battery when running and therefore show a small up tick, a stock 35 amp alternator isn't going to give a whole lot, but not much is needed. if you were to run all your electronics you should see a amp draw on the gauge. if there are wild swings I would say your VR is not working or your gauge is not working. There was a good post on here on how to diagnose. Do a search. Jumping your FLD straight to the battery should spike your gauge since the you are overriding the VR to tell your alternator to do a full charge.

[TheMopars]

Thanks Guys. I'd say it reacts how you describe for the most part except it doesn't go back to
zero until the truck goes back to idle.

I just took a ride and the new electronic regulator is doing the same but less violently, it's
smoothed it out some but it's still bouncing between zero and 25-35.

My last cluster the gauge acted the exact same way so I'm now wondering if it's the alternator.

[TheMopars]

Going to clean some ground connections first. In my service manual it list check/clean
all connections/grounds for both an over charging scenario and excessive ammeter fluctuation.
Retesting the alternator too while I'm at it.

[712edf]

Drive it around with your headlights on. Then lights & blower motor. See if it changes how jumpy the needle is.

Bucky

[PwrWgnDrvr]

If your battery is not fully charged, ie it has been sitting undriven for a few days or more, it will charge at a high rate after starting, especially if u crank the starter for more than a few seconds. It will come back to center once the battery is fully charged. Older batteries never come back to center once they are unable to reach full charge. Pulsing is normal.

[TheMopars]

Cleaned the connections at Alt and VR... no change.

Battery is new and measures 12.8v on my meter.

I took if for a drive and ran everything I have on, lights w/ high beams,
blower on high. Meter dives to -25 at idle instead of just to the left of
center. While driving about 35-40 meter goes up to about 25 and rather
than jumping down to zero quickly it does more of a wiggle between 15-25.

Also, with everything on it has a little stumble coming off idle like it
did when my points were going bad. I replaced with Electronic Ign set up.

[712edf]

Sounds about normal. At idle you're probably not quite getting enough current but it seems to be charging at speed.

Cleaning the connections through the firewall & at the back of the ammeter. Plus there are other things you can do to upgrade the overall electrical system, like installing headlight relays & additional grounds.

Bucky

[PwrWgnDrvr]

At idle the alt puts out very little amperage. With everything on it will definitely show a significant discharge from the battery. That part sounds normal.
Pulsing between 15-25 while driving is not normal.

[TheMopars]

Pulsing between 15-25 while driving is not normal.

I figured it wasn't normal from reading other threads about the amp gauge. I've never
had a vehicle with an amp gauge before. I thought for sure it was the regulator but now
that two mechanical and one electronic ( less so with the electronic but still does it) have
all done the same things I'm stumped. When I rev at idle it's almost like a tach lol.

[stumblinhorse]

Put a multimeter on your battery and see what it does when you rev it up. I went through 3 different VRs and the 4th was a good one. Your battery shouldn’t see more than 14 or so volts.

[TheMopars]

Put a multimeter on your battery and see what it does when you rev it up. I went through 3 different VRs and the 4th was a good one. Your battery shouldn’t see more than 14 or so volts.

I'll give that a try. This is the one I installed today.... Airtex 1V1067

https://www.ebay.com/p/Voltage-Regulato ... 7/75359383

[stumblinhorse]

Put a multimeter on your battery and see what it does when you rev it up. I went through 3 different VRs and the 4th was a good one. Your battery shouldn’t see more than 14 or so volts.

I'll give that a try. This is the one I installed today.... Airtex 1V1067

https://www.ebay.com/p/Voltage-Regulato ... 7/75359383

That is what I used... The only one that worked for me.

https://www.autozone.com/batteries-star ... -regulator

[TheMopars]

Put a multimeter on your battery and see what it does when you rev it up. I went through 3 different VRs and the 4th was a good one. Your battery shouldn’t see more than 14 or so volts.

Tried this and got the result you mention, goes between 13.5-14.3 when rev'd or held at 2500-3000 rpm.

[stumblinhorse]

And your gauge is still wagging? if so, there is something wrong with the wiring to the gauge or the gauge itself.

[TheMopars]

And your gauge is still wagging? if so, there is something wrong with the wiring to the gauge or the gauge itself.

yeah, still. it's not swinging as much as before now, more like a 3-5 difference. I'm going to clean all the contacts
from the fire wall in next.

[wally426ci]

Firewall is what I was goint to mention...

[Kaegi]

do you still have the old VR? maybe re install and see if it smooths out. the new solid state ones are junky. I always buy NOS or echlin.