Ammeter dance (1 Viewer)

[Romer]

Since I cleaned up my frame ground my lights don't dim, but the ammeter acts differently.
It use to sit around the middle mark and dip when I turned on the heater (momentaraly) or dip when I came to a stop and the lights dimmed.

Now, when I am idling it dances between the middle mark and 3/4 mark. When I am accelerating it will stay closer to the 3/4 mark and when I am running at a constant speed it runs above the center line. It always dances a little now where before it didn't.

I do have a 60Amp alternator.

I believe the ammeter measures the charge going into the battery, not necessarily the charge being output. I think this means, now that I have fixed my ground the higher Amp alternator is providing more current to the battery and the rest of the system.

The only thing that has me a little confused is the dancing of the dial.

Anyone else see the same thing.

Ken

 

[logic2]

possible problems

My 56 ford pickup had the same problem -
VERY DIM lights and erratic Ammeter.
I removed and cleaned the ground to the lights (no help)
I removed and cleaned the Negative terminal of the battery to truck chassis. (helped a little 20%)
I removed and cleaned the engine ground to truck chassis (no help).
I changed the dimmer switch. (no help)
I measure the battery voltage at the headlight terminals *output of the dimmer switch*
----------
There was a significant voltage drop between the output of the dimmer switch and the end
of the wire going to the headlight.

I ran new wire from the headlights to the output of the dimmer switch and waaa-lah !

BRIGHT Halogens !

Summary: The wires were almost 50 years old and were corroded which meant that their conductivity was severly degraded anc was causing high resistance (high current).

You probably fixed a bad ground on your Cruiser, but if you are still having strange issues with fluxuating ammeter readings, you may still have more problems in your wiring system (bad connections somewhere else causing fluxuations, old corroded wire, etc)

http://www.yankeetoys.org/documents/Wiring_diagram_78_fj40.pdf

Regards,

 

[folsom50]

Romer, my '78 does the exact same thing . I don't really know if it's something to worry about or not, but I just got used too it. After 8k miles I figured that if something was wrong, it would have caused a problem by now.

 

[Romer]

Thanks! I mean I obviously improved it because the lights don't seem to dim at night when I am stopped, but I have only had it back a day

 

[IDave]

Ken,

If things are correct, then current is flowing to the battery (charging) when the needle is above the middle mark, and current is flowing away (discharging) when the needle is pointing below. If, as you describe, the needle is nearly always at the 3/4 mark when you are moving, then your battery is needing charge a lot. It makes me wonder about your battery's condition, or whether you have a situation that is causing a discharge when you are parked.

As for the bouncing, I found that it was much more marked when my brushes were new, and hadn't worn down to the shape of the stator slip ring. If your alternator is new or rebuilt, you may just be seeing that situation. It took a couple of thousand miles for mine to settle down after new brushes.

 

[Romer]

Thanks Dave, the needle was never above the mark before I fixed the ground. Also, the battery got pretty worn down during my engine fun. I would have thought that it would have recharged in the 30 minutes I drove it home Sat night. I didn't pay much attention to the amm, I was focused on the oil gauge.

It's probably nothing, especially since things are working better. Just thought the needle movement was unusual.

Thanks Guys, I'll just put it down as part of my cruisers personality for now. I still am going through the rig wiring mods made by the PO. Everything works, its just a rats nest and thats probably a contributing factor.

Ken

 

[Bob D]

My 77 FJ40 was doing the same thing when I got it last fall. Replacing the voltage regulator helped a lot. I eventually changed out the alternator from a generic that the PO had put in to the correct one for the vehicle. It still jumps around some (like you say, it's part of the personality) but it is much more stable now.

Bob Davis

 

[Romer]

OK, I have had time to observe more. First off I don't have a Volt Reg, I have a Solid State Reg.

Dances the most on startup, tends to smooth out and get closer to the center line after driving for a while.

At night with the lights on, the needle is smack in the center with very little movement. Lights no longer dim, radio doesn't cut out anymore at stop signs. In fact, all the electrical problems appear to have been solved that I have been chasing.

I think that what this means is that the alt is producing more current than needed during the day and now at least enough at night. Producing more current is not a problem.

I replaced the alternator several months ago with a higher (55 amp vs 40) alternator and at the time had no difference. Cleaning that ground up seems to have done the trick. Don't know how it would behave with a standard 40Amp alt.

I recommend that anyone having electrical issues firts disconnect the ground from the frame and clean up the connection until there is good metal to metal contact.

Ken

 

[burnt03]

Going to have to revive this thread.....

My ammeter is dancing around as well. Newer volt regulator, new alternator (50A), still dances but w/ a change.

Now w/ the new alt, it will only dance right off the start and when I turn on some sort of accessory (wipers, heater, etc - radio and headlights don't affect it). When the ammeter bounces, the headlights strobe in time to the bounce. Otherwise while I'm driving it stays pegged near the middle.

I still need to put in a fusible link as the PO seemed to have removed it AND I'll try another battery as well.

Any other suggestions?
Thanks

 

[Degnol]

Mine stays pretty steady until I turn on A-N-Y-T-H-I-N-G, then the ammeter dance begins.
Now my '40 is a '66(more like a '64) with a '74 motor. It is an annoyance, but that's it.
I think cruisers are famous for it.
I'll go back to sleep now...
.02
Ed

 

[srafj40]

Another item to clean is the fuse block. Toyota (as I have been told) used silver in the fuse block and it tends to corrode.

I used toothpaste and solvent to clean mine up. This helped a ton.

 

[CruisinGA]

Often higher amperage alternators lose lower RPM output to gain top-end ratings. Do not know if this is the case in your situation.

There is something to be said for putting a quality battery charger on the battery every once in awhile and letting it really top off and see what sort of condition the battery is in.