Beavis
Well-Known Member
why does my alt gauge go crazy when my car is running?
ALT gauge
- Thread starter Beavis
- Start date
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67Dart273
Well-Known Member
Could be several reasons. You mean it bounces some, or does it wildly peg, or exactly what?
69? What you running for charging system, IE orginal type Mopar, or converted to something else?
I tend to divide the charging system into sections.......
Is it field wiring?
Is it output (charging line) wiring?
Is it bad alternator?
Is it bad regulator?
This problem can be tricky. "Let's say" it's a bad connection in the charging line, most likely at the bulkhead connector, but could be at the ammeter itself, or (rare) the "welded splice"
Review this article:
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
and the diagram on that page, which gives you a simplified view of main power.
"What I'd do."
Might be intermittent / worn brushes, loose connections in the output line, or loose / bad stator / diode connections in the alternator.
First thing I'd try is DISconnect the regulator. You can just pull the green wire off at the alternator. Connect an alligator clip lead at that alternator terminal, and jumper it over to the starter relay "big stud." (battery)
Now run the engine, slowly bring up RPM, and see if the problem is still there.
If so, it's now either the alternator itself, or the output wiring.
To eliminate output wiring is a "bit" tricky.
Start by running the engine and monitoring battery voltage with the clip lead in place, bring voltage up to "about" 15---15.5 and try to maintain that.
Next, move your voltmeter hot lead over to the alternator output stud. See if the voltage seems "way more unstable" at that point.
If so, you likely have a loose connection in that line.
If the voltage is fairly stable, it is more likely a problem in the alternator.
FRANKLY I just HATE to recommend "throwing money" at a problem, but this is one of those times when it makes sense.
Consider investing in a new alternator. If you buy a 70/ later "square back" you can ground either field terminal and hook the thing up just like your old one.
69? What you running for charging system, IE orginal type Mopar, or converted to something else?
I tend to divide the charging system into sections.......
Is it field wiring?
Is it output (charging line) wiring?
Is it bad alternator?
Is it bad regulator?
This problem can be tricky. "Let's say" it's a bad connection in the charging line, most likely at the bulkhead connector, but could be at the ammeter itself, or (rare) the "welded splice"
Review this article:
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
and the diagram on that page, which gives you a simplified view of main power.
"What I'd do."
Might be intermittent / worn brushes, loose connections in the output line, or loose / bad stator / diode connections in the alternator.
First thing I'd try is DISconnect the regulator. You can just pull the green wire off at the alternator. Connect an alligator clip lead at that alternator terminal, and jumper it over to the starter relay "big stud." (battery)
Now run the engine, slowly bring up RPM, and see if the problem is still there.
If so, it's now either the alternator itself, or the output wiring.
To eliminate output wiring is a "bit" tricky.
Start by running the engine and monitoring battery voltage with the clip lead in place, bring voltage up to "about" 15---15.5 and try to maintain that.
Next, move your voltmeter hot lead over to the alternator output stud. See if the voltage seems "way more unstable" at that point.
If so, you likely have a loose connection in that line.
If the voltage is fairly stable, it is more likely a problem in the alternator.
FRANKLY I just HATE to recommend "throwing money" at a problem, but this is one of those times when it makes sense.
Consider investing in a new alternator. If you buy a 70/ later "square back" you can ground either field terminal and hook the thing up just like your old one.
Beavis
Well-Known Member
It's all stock. It goes crazy non stop, back and forth
67Dart273
Well-Known Member
"Something I forgot." Another thing to try, this will eliminate the charge line as a problem
Go to Lowes or other outfit that will cut wire and buy some large gauge wire, at least no10 and preferably no8. Get some eyelets on it even if you have to use the "house wiring" ones that clamp on. Hook it to the alternator stud and jumper over to the starter relay stud. If the VOLTAGE settles down, it's probably a bad bulkhead connector problem, or ammeter as mentioned.
When you do this, your ammeter will no longer be functional. You should, however be able to tell with a change in the voltmeter readings
Go to Lowes or other outfit that will cut wire and buy some large gauge wire, at least no10 and preferably no8. Get some eyelets on it even if you have to use the "house wiring" ones that clamp on. Hook it to the alternator stud and jumper over to the starter relay stud. If the VOLTAGE settles down, it's probably a bad bulkhead connector problem, or ammeter as mentioned.
When you do this, your ammeter will no longer be functional. You should, however be able to tell with a change in the voltmeter readings
ir3333
Well-Known Member
bump ...fixed?
moparmat2000
Well-Known Member
First schematic is the stock wiring.
Second schematic is dewiring the amp gage.
After that install a volt gage. Your better off.
Second schematic is dewiring the amp gage.
After that install a volt gage. Your better off.
moparmat2000
Well-Known Member
Heres pix.
BillGrissom
Well-Known Member
Often the thick ALT and BAT wire connectors on the back of the dash to the ammeter are loose or corroded. They often then melt. Feel them for heat. Disconnect the battery, then remove and sand the ring terminals. Insure the studs on the cluster side are secure. Coat with dielectric grease when re-installing. Also check the bulkhead connector, where they often corrode and melt.
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