Ammeter

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Nov 28, 2017 | 01:24 PM

#21

Hammerhead Fred

Melting Slicks

Joined: Mar 2005

Posts: 2,093

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From: Midlothian VA

Quote:

Originally Posted by cdj46

OK key off pointer is at -40 so when I turn the key on it stays at -40. Start the car pointer goes to ~ -10 then back to -40. If I move the pointer by hand to 0 it quickly goes to +40 or -40 depending on what side the pointer is from 0..

You're moving the pointer by hand?
Perhaps you've accidentally misaligned the pointer on the shaft.
If you're having no other issues with the car other than the amp meter is displaying @90 degrees to the left of where it should be then it's possible the needle simply needs to be removed and reinstalled on the shaft in the centered position.

Nov 29, 2017 | 01:57 PM

#22

cdj46

Thread Starter

Racer

Joined: Mar 2011

Posts: 359

Likes: 13

From: Elma NY

Amp

Quote:

Originally Posted by ntfday

I missed this earlier. A bad ground at the gauge cluster has ne bearing here since neither side of the ammeter is at ground. Do you get a decent spark when you remove the negative battery cable? If so that is an indication of something at ground that shouldn't be.

UP-date no spark when connecting bat, also gauge goes to -40 and when moved by hand goes to +40 even when bat is disconnected. Volt meter tells me 12 volts to meter when key is on or off.

Nov 29, 2017 | 02:49 PM

#23

cdj46

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Racer

Joined: Mar 2011

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From: Elma NY

Amp

Quote:

Originally Posted by ntfday

No spark when connecting bat. Meter goes to -40 and +40 when moved by hand even when bat is disconnected. Is there a way to bypass the wireing and run the ammeter from bat to alternator?

Nov 29, 2017 | 03:21 PM

#24

ntfday

Burning Brakes

Joined: Mar 2013

Posts: 750

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From: Springfield Missouri

Quote:

Originally Posted by cdj46

No spark when connecting bat. Meter goes to -40 and +40 when moved by hand even when bat is disconnected. Is there a way to bypass the wireing and run the ammeter from bat to alternator?

I wouldn't do that. I'd say the ammeter is toast, that style ammeter is not designed to be in series with the load and that is why there are no 10/12 gauge wires in the passenger compartment. The old style ammeter was mostly discontinued, except for Mopar, in the late 60's or early 70's ans they are very fire prone. Your system is a shunt which doesn't require real heavy gauge wire and is safer. You need to trace the wires and ensure each wire is not open. Use this diagram to check it out.
http://repairs.willcoxcorvette.com/w...ire-added2.jpg

Nov 29, 2017 | 03:22 PM

#25

carriljc

Le Mans Master

Joined: Jan 2001

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Now then, I'm not one to discourage someone from learning, but that ammeter is a relatively sensitive piece of equipment. You really should NOT be moving that needle by hand..... I would stop doing that before you really ruin it.

Not knowing your electrical background makes it a bit difficult on what action guidance to provide....but my suggestion would be to just check the wiring from the alternator, to the horn relay, to the starter area. Also to check the parallel path for the ammeter I recommend checking the continuity from the ammeter leads back to the main lead.

The ammeter is not a "real" ammeter. It reads the voltage drop between 2 points on the lead going from the alternator to the starter....and "mimics" this to a simulated ammeter reading---don't go trying to shove full amps thru that ammeter. It will really fry it.

I hope this makes sense. If it does not, then you probably want to stop and ask more questions.

Quote:

Originally Posted by cdj46

No spark when connecting bat. Meter goes to -40 and +40 when moved by hand even when bat is disconnected. Is there a way to bypass the wireing and run the ammeter from bat to alternator?

Last edited by carriljc; Nov 29, 2017 at 03:23 PM.

Nov 29, 2017 | 04:03 PM

#26

Hammerhead Fred

Melting Slicks

Joined: Mar 2005

Posts: 2,093

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From: Midlothian VA

You didn't by chance replace the starter prior to this issue did you?
How about some background on your car - when did this start happening?
Was the car/gauge operating correctly in the past?

Nov 29, 2017 | 04:37 PM

#27

henrikse

Pro

Joined: Nov 2016

Posts: 729

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From: Kelowna British Columbia

do a search on google for c3 ammeter. you will find a diagram and if you click on it it will take you to this forum for the schematic and explanation

Nov 29, 2017 | 08:09 PM

#28

cdj46

Thread Starter

Racer

Joined: Mar 2011

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From: Elma NY

Amp

Quote:

Originally Posted by henrikse

do a search on google for c3 ammeter. you will find a diagram and if you click on it it will take you to this forum for the schematic and explanation

To all thank you. The car was a basket case and not run for at least 10 years when I purchased it. I did a frame off and have had it running now for about a month. The good news is after checking everything that all the good people on this forum suggested, I found that Fred was correct. The pointer was out of place, perhaps my fault or previous owner not sure (probably me).
Thanks again Chuck