Alternator gauge flutters

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OwdKasd

OwdKasd

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My Alt gauge is fluttering back & forth at mild cruise speed. I flutters between 1/4 and 3/4 full charge approximately. It is a 73 Dart Stock Charging system. I did do a search but didn't find anything for "Fluttering". Just hoping for a quick point in the right direction. My ground tests good at VR.
Thanks in advance for any advice. I really appreciate all the help I get here:prayer:
I am still going to do the MAD upgrade. Maybe now is the time to do it?
 
Sounds like it could be a flash/short of some kind.. does it do it with ALL lights off ? I had a light bulb rear running light element that did this in my ramcharger, it was shorting out some way or another.
I am sure you have tested the connections on your V.R and Alternator
What does it do when you start it up and turn the lights on and and keep it in park (not moving) ?
 
tekslk said:
Mine did that once and I changed the brushes and it fixed it.
Click to expand...

Yes!! I bet you just nailed it teksly :cheers: brushes are to short (warn) for the springs to charge correctly, this could harm you V.R. or be hard on it.
 
Does it always show charging? The ammeter shows the current flow into or out of the battery. If fully charged, it shouldn't keep trying to charge it. MeMike's "brushes" sounds good. Might also be that some of the diodes in the alternator are bad, which would make the output less smooth. That would also decrease the output, so more likely you would see it on "discharge" more often.
 
BillGrissom said:
Does it always show charging? The ammeter shows the current flow into or out of the battery. If fully charged, it shouldn't keep trying to charge it. MeMike's "brushes" sounds good. Might also be that some of the diodes in the alternator are bad, which would make the output less smooth. That would also decrease the output, so more likely you would see it on "discharge" more often.
Click to expand...
It's showing charge but fluttering. The Flutter stops by 95% when in Gear and stopped with foot on brakes.
 
As above, first thing I'd suspect is bad/ worn brushes, or dirty, greasy, worn slip rings.

Second thing I'd suspect is a poor connection in the charging line. That is, the path from the alternator, through the bulkhead, through the ammeter, back out the bulkhead (red) through the fuse link, to the starter relay, and the battery.

There is a big factory splice in the black ammeter wire, taped up in the under--dash harness. To find it, you have to remove the cluster, and untape the harness from the black ammeter ring terminal down to find the splice. We had a couple of cases where this splice had failed.

This also you could be right in/ at the ammeter, or breaks in the wire to the molded wire ends at the ammeter.

Your number one suspect is the bulkhead connector.
 
Thanks, I was really wondering if a bad connection would cause a fluttering Ammeter. Are the slip rings what the Brushes "Ride on"??

67Dart273 said:
As above, first thing I'd suspect is bad/ worn brushes, or dirty, greasy, worn slip rings.

Second thing I'd suspect is a poor connection in the charging line. That is, the path from the alternator, through the bulkhead, through the ammeter, back out the bulkhead (red) through the fuse link, to the starter relay, and the battery.

There is a big factory splice in the black ammeter wire, taped up in the under--dash harness. To find it, you have to remove the cluster, and untape the harness from the black ammeter ring terminal down to find the splice. We had a couple of cases where this splice had failed.

This also you could be right in/ at the ammeter, or breaks in the wire to the molded wire ends at the ammeter.

Your number one suspect is the bulkhead connector.
Click to expand...
 
Yes. I'd pull the alternator, easy to do, and just have a look. Pull the brushes and look for length, ease/ freedom of movement, grease, oil, or debri keeping them from making contact, and look for a smooth finish on the slip rings. If there seems to be excessive oil/ grease on e'm clean em with brakeclean, etc.
 
Thanks, I'll report back when I find/fix the problem.
67Dart273 said:
Yes. I'd pull the alternator, easy to do, and just have a look. Pull the brushes and look for length, ease/ freedom of movement, grease, oil, or debri keeping them from making contact, and look for a smooth finish on the slip rings. If there seems to be excessive oil/ grease on e'm clean em with brakeclean, etc.
Click to expand...
 
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