Ammeter not at zero
Thread Starter
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 331
From: Indy Indiana
Ammeter not at zero
My amp meter needle on my '70 constantly reads to he right of zero, about halfway between center ( zero) and +40, I would guess it is at about +22.. This is with the engine off, and also with the battery disconnected, when I start the car it does jump to the right all the way past 40.. it pegs past 40 and hits the stop to the right. when running it does register when you put a load on the engine, heater blower and wipers and lights etc.. it seem to be working ok but is not zeroed out...
is there a way to adjust to zero these things or do I have to replace it with a new one??... I tested the alternator and it puts out 14+ volts and 30-50 amps at load so it is OK..
is there a way to adjust to zero these things or do I have to replace it with a new one??... I tested the alternator and it puts out 14+ volts and 30-50 amps at load so it is OK..
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Joewill,
The needle is a pressure needle. I use a pair of front cut wire cutters to pull them off. I cut a notch in the top and bottom large enough to keep from ever cutting the bottom of the needle. It allows me to put tension on the needle from all points too! Works great.
While you have the gauge out, test across the poles for continuity, if you have continuity the gauge is more than likely good. If you have no continuity then the gauge is defective.
Once you have the needle set where it belongs then test the gauge with a pair of double A batteries soldered in a series. You just want to bump the positive against one of the poles and this should reflect a tiny movement in the gauge. There have been several people post here on how to make one recently, so far I’ve not seen anyone with a bad idea on doing this.
It seems strange the needle would be off that far too! I think you may have a problem going on inside the gauge. Before you remove the needle and this will not hurt anything, rotate the needle back and forth between the stops a bunch of times. You may have an oil problem inside the gauge and sometimes this will free it up. (Doubtful but worth a try).
Willcox.
The needle is a pressure needle. I use a pair of front cut wire cutters to pull them off. I cut a notch in the top and bottom large enough to keep from ever cutting the bottom of the needle. It allows me to put tension on the needle from all points too! Works great.
While you have the gauge out, test across the poles for continuity, if you have continuity the gauge is more than likely good. If you have no continuity then the gauge is defective.
Once you have the needle set where it belongs then test the gauge with a pair of double A batteries soldered in a series. You just want to bump the positive against one of the poles and this should reflect a tiny movement in the gauge. There have been several people post here on how to make one recently, so far I’ve not seen anyone with a bad idea on doing this.
It seems strange the needle would be off that far too! I think you may have a problem going on inside the gauge. Before you remove the needle and this will not hurt anything, rotate the needle back and forth between the stops a bunch of times. You may have an oil problem inside the gauge and sometimes this will free it up. (Doubtful but worth a try).
Willcox.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You need a needle 'puller' so that you don't damage the mechanism when you pull on the shaft. The puller has a fork that fits below the needle and a threaded pin which pushes in on the shaft while the fork pulls the needle off. You could take it in to any watch shop and ask them to pull the needle. It's a 30 second job...
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
It should not be that hard to get off but if it is, I guess you could use a needle puller.
The design of the gauge is such that the bottom of the pindle will bottom out against the inner plastic housing that holds the oil, it shouldn't cause any damage.
But, 7t1 is correct there is a tool for this if you are worried I would follow his instructions.
I still think you have something going on in the gauge for the needle to be acting the way it is.
Willcox
The design of the gauge is such that the bottom of the pindle will bottom out against the inner plastic housing that holds the oil, it shouldn't cause any damage.
But, 7t1 is correct there is a tool for this if you are worried I would follow his instructions.
I still think you have something going on in the gauge for the needle to be acting the way it is.
Willcox
Thread Starter
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 331
From: Indy Indiana
Thanks guys, it worked!!.. I do get continuity thru my ohmeter on the guage, I expect the previous owner was fooling with it.. he actually had the wrong plug set into the guage when I was working on it last year, he had plugged in the wiper relay or something like that into the ammeter... so I plugged in the correct one and it started working, but was off zero like I described...
I had to give it some 'friendly persuasion' , but the needle did come off, so I centered it at zero an pressed it on, took it out to the garage , plugged it in, started the car, and it works great...
you guys saved me 60 bucks! thanks!
I had to give it some 'friendly persuasion' , but the needle did come off, so I centered it at zero an pressed it on, took it out to the garage , plugged it in, started the car, and it works great...
you guys saved me 60 bucks! thanks!
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