Smith's Ammeter Jumping Like Crazy

ERA 778 · #1 (**permalink**) 07-07-2011, 07:49 PM

I've just gotten #778 on the road and the ammeter keeps jumping like crazy from zero to +25 amps as I'm driving moderately. Is this normal?
I've got an original type 60 amp alternator and an original type external voltage regulator as well. Since I'm just sorting out the car, I don't know it this is normal behavior or if it indicates some kind of trouble.

Cobra 29 · #2 (**permalink**) 07-07-2011, 08:06 PM

Check the two wires on the back to make sure they are tight. My wires fell off the terminals on a hard stop (because the wiring harness moved forward) and this killed the power to everything. It was tough to find out what happened.

strictlypersonl · #3 (**permalink**) 07-08-2011, 04:38 AM

Not normal at all. Check all the connections, both on the alternator and the voltage regulator, plus the ground on the firewall below the starter solenoid. Also, check the 12-pin plugs 28/53 and the connection at the bottom fuse on the passenger's side fuse box.

gsharapa · #4 (**permalink**) 07-08-2011, 05:24 AM

Make sure you have a good ground but if you have a big electric fuel pump you'll find the AMP gauge will jump when the Alternator starts charging the batteries. Mine does the same thing. It will settle down when the circuit closes and then start again when charging. Many run a 1 wire alternator with a volt meter guage which won't do that.

ERA 778 · #5 (**permalink**) 07-08-2011, 08:20 AM

Thanks for the suggestions. I'll check everything this weekend. By the way, no electric fuel pump.

Also, fuse #6 blew last night when I turned on the panel lights so I've got some other chasing to do as well.

ERA 778 · #6 (**permalink**) 07-08-2011, 09:49 AM

Thanks for the suggestions. I'll check everything this weekend.

Also, the fuse #6 blew last night when I turned on the panel lights so I've got some other chasing to do as well.

ERA 778 · #7 (**permalink**) 07-11-2011, 05:19 PM

I got to work on the car this weekend and found a slightly, I mean, SLIGHTLY, loose connection on the Stator terminal on the alternator. Shaky needle is gone!

Still trying to find reason for Fuse#6 (parking & tail lights & dash lights) blowing - just seems to do it on the road, not in the garage. Isn't that always the way?

Sal Gerace · #8 (**permalink**) 07-11-2011, 05:25 PM

If you are running two batteries disconnect them from the circuit and from each other. Then charge them independantly. Just a thought as my ammeter did this after the winter and my batteries were not fully charged.

ERA 778 · #9 (**permalink**) 07-15-2011, 06:38 PM

Found the cause for Fuse #6 blowing, but only on the road. Left taillight wire contact ( a cheap little sheet metal formed pin from Lucas) had slipped its way through the cheap little sheet metal tube in the taillight and was about 0.002" from the taillight ground. Any little bump in the road and Bang - fuse blown!

Lucas Electric - Home Before Dark! More truth than fiction!

Hal