What alternator do I have?

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TX64DartGT

TX64DartGT

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Trying to identify this thing to replace/upgrade it. It won’t keep my battery charged after roughly 2-3 hours of driving. Noob on electrical systems for mopars, I’ve got a 64 dart with a mild 273, only extra electrical load is a single electric fan.

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That's a 72 and up dual field alternator that someone converted to single field to match your wiring. Grounding one field connection with the red coiled wire was an attempt to do that. Hopefully nothing fried. I would convert the harness to the later regulator when you replace your dead alternator, or go with an original single field alternator. You need a basic voltmeter that reads DC volts. Home Depot has them.
 
Nothing is fried and the car runs fine, it just can’t keep the battery charged. Currently searching the forums, is there a go to place to get a harness and VR to match the 2 field? Or should I just replace it with a single field?
 
some of those were only 35/45 amps does your electric fan run all the time could be using more amps then alt can supply
 
teringer said:
some of those were only 35/45 amps does your electric fan run all the time could be using more amps then alt can supply
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It probably kicks on every 5-10 mins or so when up to temp and runs for probably 2-3 mins. Car stays at 190 degrees no matter what the OAT is.
 
Grab an external regulator and wire it up as per the attachment. If it still won't keep up, you need a bigger output alternator.

Cley
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Only keeps about 11.7-11.9v while running at idle.

Is it a problem if I get a new dual field alternator and ground one field like I have right now? If I get a single field I’ll have to redo some bracketry.
 
IIRC the isolated (2) field alternator, even converted to a single field, running through a mechanical VR is a bad idea. Just hit a bone yard and grab an electronic VR and wire it up as a dual field setup like the diagram says. A square back alternator has better low speed output.
 
Very first thing to do would be to test that green wire for voltage with the engine running or at least with the key on and see that the alternator field is even getting any voltage to it.
If it is, then it's quite possibly a regulator issue, and if it doesn't have any power to it you just found out why it isn't charging.

You can also momentarily jumper from the battery + to that green field wire with the engine running and the alternator should output full charging voltage.
 
TX64DartGT said:
Only keeps about 11.7-11.9v while running at idle.

Is it a problem if I get a new dual field alternator and ground one field like I have right now? If I get a single field I’ll have to redo some bracketry.
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That does seem a bit low. While our alternators do have a problem with low speed output, with no electrical load other than the coil, it should be higher than 11.9vdc. Did you check voltage at a higher rpm, like 1800 to 2000? Going to the later regulator with the alternator is a better plan.
 
I’ll scoop up a regulator from the parts store and take my alternator in with me to get tested at the same time.
 
Will wiring in the later style voltage regulator screw with my electronic ignition? I've got a DUI distributor mounted ignition module...
 
VR installed and running. 12.3-12.5 dcv at the battery when running and 12.0 dcv when off. The ammeter now moves as the revs go up, is this normal?
 
I've lost track of what you have done, but it still isn't right. A fully charged battery should read about 12.5 volts and a working alternator should be putting out around 13.5 volts.
 
skykeith said:
I've lost track of what you have done, but it still isn't right. A fully charged battery should read about 12.5 volts and a working alternator should be putting out around 13.5 volts.
Click to expand...

Swapped to a dual field alternator and electronic voltage regulator.

Been chasing the reason why the battery drains.
 
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