Alternator not charging

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partsman1965

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Looking for help! My 74 Dart sat all winter indoors and when started for first time this spring
alt charged for short bit then stopped. I have done the following.
New Alternator since old one was making noise anyway
New regulator
New ballast..4pin
New ground battery cable
Refreshed all grounds to body and engine.
I have the wiring diagram and have found no bad wires yet! I have not yet checked wires as they go through firewall. Anyone know which wires through firewall allow alt to charge?
Main power feed from amp gauge has good connection through firewall.
 
Looking for help! My 74 Dart sat all winter indoors and when started for first time this spring
alt charged for short bit then stopped. I have done the following.
New Alternator since old one was making noise anyway
New regulator
New ballast..4pin
New ground battery cable
Refreshed all grounds to body and engine.
I have the wiring diagram and have found no bad wires yet! I have not yet checked wires as they go through firewall. Anyone know which wires through firewall allow alt to charge?
Main power feed from amp gauge has good connection through firewall.
Do you have a free Harbor Freight voltmeter?
 
And I hope you bought the regulator that was a couple dollars more and not the really cheap one cuz that could be your problem right there. But again we need to start with the cheap Harbor Freight voltmeter. Or any voltmeter for that matter.
 
High School auto shop A1A just because you bought a new part does not mean it works.
(RIP Mr. Kingham)
 
I got a Standard brand regulator. I also have a good Craftsman voltmeter.
So in this situation I put the voltmeter on and check the volts from the battery. I continue right there checking the volts and have the wife crank it over and start it and notice how much it drops while cranking? Then of course what it's doing while it's running? Did it go up did it go down did it stay where it was at?
 
Sometimes you'll see it bouncing up and down and that's the regulator opening and closing.
 
Looking for help! My 74 Dart sat all winter indoors and when started for first time this spring
alt charged for short bit then stopped. I have done the following.
New Alternator since old one was making noise anyway
New regulator
New ballast..4pin
New ground battery cable
Refreshed all grounds to body and engine.
I have the wiring diagram and have found no bad wires yet! I have not yet checked wires as they go through firewall. Anyone know which wires through firewall allow alt to charge?
Main power feed from amp gauge has good connection through firewall.
Read this so you have a good idea how the circuit works.
Understanding Charging Systems with Ammeter

On yours, the blue wire feeds the alternator's field and the green wire controls the connection to ground completing the circuit. So the blue will connect with voltsage regulator and the ignition 'run' side junction on the ballast resistor. This is how the regulator knows the system voltage. It regulates by opening and closing the circuit's connection to ground.
 
Read this so you have a good idea how the circuit works.
Understanding Charging Systems with Ammeter

On yours, the blue wire feeds the alternator's field and the green wire controls the connection to ground completing the circuit. So the blue will connect with voltsage regulator and the ignition 'run' side junction on the ballast resistor. This is how the regulator knows the system voltage. It regulates by opening and closing the circuit's connection to ground.
Field is another name for the electomagnet that spins. The windings create an magnetic field when powered up.

Here's a general diagram of the later charging systems like yours.

Main_charging_wires_plus.png
 
You can prove your alternator CAN work by full-fielding it. You run a jumper from the battery plus to the field terminal, and then ground the second terminal. You will connect the ground, with the engine running, the battery recently charged and a VOLTmeter previously installed across the battery, and all accessories turned off..Alt output must be higher than battery rest voltage by at least 1.25 volts, and increases with rpm. Do not go crazy with rpm, you might blow the ignition module. If it makes the minimum, consider it to be ok.

I connect the ground last while watching the voltmeter, and as soon as I see the voltage, I disconnect the ground. In this way I prevent damage to sensitive components. The charge circuit itself will happily work at 15.5 volts, and mine has withstood 17 volts on occasion. But the headlights didn't.
 
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Post 11!!^^

But in addition, test for an open from battery to alternator output

Hook up as above, and with the jumper connections made, slowly bring up RPM and see if battery voltage rises

If not, move your meter to the alternator "big stud" (output stud) and see if that voltage rises and if so, to a high level. If it does, then you have a bad connection in the circuit from output to battery

If neither meter connection shows a rise, attempt to determine if the field is actually drawing current. With the engine off, and "in the shade" preferably darker, hook/ unhook your connections to the field. You should be able to see a small spark every time you connect the jumper.
 
Black ammeter lead goes to the firewall?? Typically red goes to firewall bulkhead; black goes to main junction. Alternator output is generally Black 12 gage and goes from firewall to main splice.
Each year is a little different so that's why I say generally. You may be right.
 
Found this thread on a search, and thanks for the info!
Solved my charging issue, had a bad connection at the firewall bulkhead connector. Mines a black wire from the alt to the bulkhead, was a cooked/corroded connection.
Will bypass when I find a decent passthrough connector, just cleaned it up for now
 
Depending on your goals, one option is to use no connector. Put a ring terminal on the alternator stud, run a heavy black wire through a grommet in the firewall. If done in parallel to the original wire it can be attached with a ring terminal to the alternator side stud of the ammeter. Otherwise splice into the original alternator feed to the main splice as long as its a very good splice.
 
Some remove the wire from bulkhead connector and drill right thru with drill bit that makes a snug fit. Then as said feed wire through and add your ring terminals.
 
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