Alternator Scamp /6

Hello
Was wondering if this is normal operation for an alternator. I recently cleaned all the ground out connections to the car (battery/wire bolt/ground cable engine block), I never notice before but it appears my alternator in always on the needle in the middle (Pic attached) even when engine off. Also now when engine starts the needle is at the +40 now. I never paid to much attention to this just wondering is this normal operation before I blow something in vehicle.
Thank you for your time
Van Leer

I don't think that's normal.

"It depends."

If you have a larger output alternator that has been installed on the car, and who knows after that many years?

So let's say that the battery is down a little........................

been sitting a week, or maybe the battery is a few years old, and isn't "what it should be," or maybe you have a stereo/ other device with "keep alive" memory, or some other minor draw. OR maybe you just cranked the starter quite a bit to start the car................

so the battery is down....................

Now the thing will charge at a high rate until the battery starts to come up, and then the ammeter should gradually drop to "average" around center

HERE IS how an ammeter should work:

Everything off, centered. This means ZERO current being charged into or drawn out of the battery.

Get in the car, turn on key or lights, or any other load. Ammeter should deflect by some amount, depending on the amount of current.

Start the car-----------depending on how long you cranked the starter, and how large the alternator is, it should charge by some amount. In winter, turning on lights, heater, will REDUCE this amount of charge.

At some point, as the battery "comes back up," the charge rate should drop off and the ammeter should run down the road at just about any speed near zero.

Stopped in traffic, slow idle, in gear, heater, lights on, ammeter MAY discharge some amount, showing alternator will not put out at that slow RPM. "A little throttle" (RPM) should result in a little charge to "PLUS"

As you move again, ammeter should charge some, then drop back to center.

If the battery is in good shape, and charged, and if engine starts quickly, ammeter should charge "hard" for a short time, a minute or two. If it does not drop back, get a voltmeter and check the battery "running" voltage at a "high idle" or in other words an RPM to simulate "low to medium" cruise.

kind of seems like a screwy voltage regulator...so it only spikes like that right after you start it? That doesn't sound too off norm but how quickly does it come back down? Also, how long does the car sit before starting it each time it spikes like that?

Thanks 67Dart273 for the information Ill check into it more and see if it’s an old battery or alternator.
To answer the question and provide more info I do have an aftermarket stereo installed, and yes after I start the engine and the choke kicks on it stays at that 40+. It only drops after I take off choke and idles, but when driving again (reverse and drive) it spikes again to 40+. It stays like that while throttling. Now today while driving I simply tapped on the gauge itself with my finger and it sparked and the needle fell off. So I am wondering if I have some wires touching behind the dash that could have made this occur. I’ am going to do some more investigation in morning.
Sorry if I do not respond right away I work nights.
Thanks
Van Leer

I suspect when you remove that gauge you will find lots of tiny rust particles that shorted it out. I dont know this was the only problem you had but I do know thats what burns the needle out of them.
I have a good used gauge here if you want.

vanleer mopars said:

but when driving again (reverse and drive) it spikes again to 40+. It stays like that while throttling. Now today while driving I simply tapped on the gauge itself with my finger and it sparked and the needle fell off.

Click to expand...

You likely have a couple of problems. Damage to the harness through the bulkhead connector is usual, and damage at the ammeter

Read this article by MAD

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

Then dig in. I would not fool around. Drop the column, pull the cluster, and inspect, repair, or bypass the ammeter.

Pull the bulkhead connector apart and inspect and repair or bypass it. Again, refer to the MAD article.

Inspect the connector at your ignition switch for heating/ damage.

What year/ model we workin' on? You can download a few years of the factory shop manuals

We are working with a 1974 Plymouth Scamp /6, 3.7 liter. And the needle is now back onto the alternator, I place my hand behind the dash and moved some wires away from some metal piece that was extremely hot. But Ill check it out more tomorrow. What I was wondering if I remove the screws in front of the dash would I be able to take off the face plate and gain access to the gauges? Also don’t need any parts yet, but I will post and PM you if I break something or something blows up.
Thanks
Van Leer

Alright the needle no longer shoots toward the 40+ mark now, but it stays on the mid point even after engine is off ( I assume that is not normal). So I still need to dig around a little Im goning to read into the manuel that 67Dart273 provided and maybe this will sovle my issue.
Thanks
Van Leer

Hey Andrew,
To get access to gauges you must remove the entire cluster from the car and then unscrew the 10 or so screws from the back of it. I took one of mine apart and cleaned it all up to paint it and had to remove it to get the face plate off.

vanleer mopars said:

Alright the needle no longer shoots toward the 40+ mark now, but it stays on the mid point even after engine is off ( I assume that is not normal). So I still need to dig around a little Im goning to read into the manuel that 67Dart273 provided and maybe this will sovle my issue.
Thanks
Van Leer

Click to expand...

centered with engine off is normal unless you have engine off and headlights or something with a load turned on

If you see no deflection from zero "ever" the ammeter is likely damaged. Being heated is no good, probably damaged

Read that MAD article I posted, if you have not

Alright guys sorry haven't forgot about you just been trying to fix my throttle cable on my Scamp, it broke and now vehicle is park in driveway waiting for a new one so as soon as I fix this problem I can move back to this one thanks
Van Leer

Alright got my throttle cable fixed, now and I am back on the road.
Here is a break down on what's occurred since being sidelined for over a month.
Ok got Scamp back onto road, in doing this my battery soon was drained, after charging all night I took it into Autozone and was determined through the test I had a bad Voltage Regulator, replaced test done again, came back bad again. an old timer at autozone suggested to unplug VR while engine running, said would fix the problem, I did so and haven't had any problem yet in regards to starting or battery life.
Now as it goes with my alternator reading I read the article that 67Dart273 gave:
http://apicdn.viglink.com/api/click?format=go&key=508e022f256315a50e8e5af8c001704f&loc=http%3A%2F%2Fwww.forabodiesonly.com%2Fmopar%2Fshowthread.php%3Ft%3D231899&out=http%3A%2F%2Fwww.madelectrical.com%2Felectricaltech%2Famp-gauges.shtml&ref=http%3A%2F%2Fwww.forabodiesonly.com%2Fmopar%2Fsubscription.php%3Fdo%3Dviewsubscription
I checked my connections and damage to the harness through the bulkhead connector did not find any burned out wires or spliced wires from the past. So should I still bypass the ammeter? the only splice I found is one recently done for my electric choke for my weber carb
So I am experience another problem that I have had for awhile.
While driving my Scamp in the evening My lights dim and dash light dim while not accelerating.
are all these connected?
I am completely stumped, electric problems are new to me!
I going to do a tune up here shortly for a car show this upcoming July 12, is there any parts or suggestions on what I should do for my electric problems I have been having? I have already replaced my starter and starter relay because they went out 2 weeks ago.
Other than the problems I have listed my Scamp drives fine.
Thanks for your help
Van Leer

vanleer mopars said:

an old timer at autozone suggested to unplug VR while engine running, said would fix the problem, I did so and haven't had any problem yet in regards to starting or battery life.

Thanks for your help
Van Leer

Click to expand...

Did you leave your voltage regulator unhooked? If so of course your lights are going to be dim since you will be running entirely off the battery.

It sounds like it is time for a complete charging system overhaul. Bypass the ammeter, clean every connection and ground point in your charging system including the terminal in the bulkhead connector, and measure the voltage drops in your charging system.

I think we really need a charging system (and guage) overhaul and diag sticky in this forum.