Why wont my alternator charge

[Lee Smith]

I bought a new alternative for my 65 dart gt slant six had them test it before coming home installed the alt and still it doesn't charge over 12 volts I have a 85 pickup dodge it charges when I put it in the truck is it a bad voltage regulator what else could it be It also has a electronic ignition the plate style in the distributor its never charged since I installed that.

 

[Dan the man]

I would get a different distributor since it hasn't charged since you installed it. I would be sure that you have everything properly grounded. What plate are you talking about in the distributor? Is it for limiting advance ignition timing?

 

[Bobzilla]

I bought a new alternative for my 65 dart gt slant six had them test it before coming home installed the alt and still it doesn't charge over 12 volts I have a 85 pickup dodge it charges when I put it in the truck is it a bad voltage regulator what else could it be It also has a electronic ignition the plate style in the distributor its never charged since I installed that.

Isn't a 65 and an 85 going to use two totaly different, opposite regulator and wiring setups?

Does your 65 have only one large output wire attached with a ring terminal and one field wire that slips onto a flat spade terminal? I think the other field wire would be grounded at the alternator itself. This would use a regulator on the input side of the field wire to the alternator.

Does your 85 have one large output wire with a ring terminal and then two different field wires that slip onto flat spade terminals? This would use full battery system voltage in one field wire and then a regulator on the other field wire to control the alternator by adjusting the grounding to the wire.

The newer cannot run properly on the older system without grounding one of the field terminals.

 

[67Dart273]

^^READ CAREFULLY^^ What Bobzilla posted

Up through 69, alternators should have ONLY ONE field terminal, the other brush is factory grounded with no accessible terminal

HOWEVER it is popular nowadays for rebuilders/ sellers to sell you 70 and later alternators which are properly called "isolated field" (not "dual field") and which have TWO insulated brush/ field terminals.

As above, if you have the original type 69/ earlier regulator, you must ground one of the two field terminals. Connect your green field wire as normal

 

[Dartswinger70]

I was going to say external voltage regulator...? didnt they change in 1970 when they went electronic?

 

[RustyRatRod]

It could just be because a 65 alternator is not correct for an 85 model.

 

[Lee Smith]

Isn't a 65 and an 85 going to use two totaly different, opposite regulator and wiring setups?

Does your 65 have only one large output wire attached with a ring terminal and one field wire that slips onto a flat spade terminal? I think the other field wire would be grounded at the alternator itself. This would use a regulator on the input side of the field wire to the alternator.

Does your 85 have one large output wire with a ring terminal and then two different field wires that slip onto flat spade terminals? This would use full battery system voltage in one field wire and then a regulator on the other field wire to control the alternator by adjusting the grounding to the wire.

The newer cannot run properly on the older system without grounding one of the field terminals.

Yes the 85 has one large wire and 2 flat slip on wires I grounded the alternater and at a idle it was charging at 14 volt but when i brought the rpms up it was charging way more volts than it should. I will have to go back and find the brand of electronic ignition I put in the distributor I just started on the car again life happened and it has been sitting for a couple years I will look that up and get back to you thank you for your time much appreciated.

 

[Lee Smith]

Yes they are different the 85 has the main large battery wire and 2 push on wires the 65 has 2 the large Battery wire and the other one is a flat spade coming from the regulator I also put the alternator from the 85 on the 65 of course i didn't hook up the 3rd terminal and it wasn't charging in the 65 but is charging like it should in the 85 the 85 alt should work in the 65 but the alternator from the 65 doesn't work in the 85 with out modification is that correct back to the cause of the 65 not charging at all is it most likely a bad ground or the voltage regulator could there be any other reason

 

[Lee Smith]

It could just be because a 65 alternator is not correct for an 85 model.

Isn't a 65 and an 85 going to use two totaly different, opposite regulator and wiring setups?

Does your 65 have only one large output wire attached with a ring terminal and one field wire that slips onto a flat spade terminal? I think the other field wire would be grounded at the alternator itself. This would use a regulator on the input side of the field wire to the alternator.

Does your 85 have one large output wire with a ring terminal and then two different field wires that slip onto flat spade terminals? This would use full battery system voltage in one field wire and then a regulator on the other field wire to control the alternator by adjusting the grounding to the wire.

The newer cannot run properly on the older system without grounding one of the field terminals.

And yes I grounded the older alt for the 85 pickup

 

[Lee Smith]

It could just be because a 65 alternator is not correct for an 85 model.

No but the newer alt should work on the older car and if I ground the the 65 alt it should work in the 85 Is that correct but back to my question I wasn't asking if I could use one alternator in the other vehicle and vises versa I was asking if it could be something else other than a voltage regulator that would cause the 65 dart TN not charge thanks for you time.

 

[Phreakish]

No but the newer alt should work on the older car and if I ground the the 65 alt it should work in the 85 Is that correct but back to my question I wasn't asking if I could use one alternator in the other vehicle and vises versa I was asking if it could be something else other than a voltage regulator that would cause the 65 dart TN not charge thanks for you time.

Yes, it could be a wiring problem. The voltage regulator could be fine and give your symptoms.

An 85 system has two field wires. The 65 does not. If it works in an 85 and not in a 65, you have the wrong alt.

A later model alt can be modified to work in a 65 though, or you can upgrade to the later model regulator and wiring which is what I would personally recommend since many alternators sold for the single wire field aren't compatible with your current setup and even new regulators can be difficult to source for the same reason.

An over charge condition can be caused by many things, not the least of which is poor wiring between the battery and your regulator or a bad ground.

You need to test to see how much field voltage/current is being sent through your regulator and whether the wiring from the battery to the regulator is any good. Also make sure all grounds are clean and show good continuity. That information can be used to determine the fault.

Or you can try a new regulator and hope when you rev it, your car doesn't catch fire before you shut it off. Your choice.

 

[67Dart273]

Yes they are different the 85 has the main large battery wire and 2 push on wires the 65 has 2 the large Battery wire and the other one is a flat spade coming from the regulator I also put the alternator from the 85 on the 65 of course i didn't hook up the 3rd terminal and it wasn't charging in the 65 but is charging like it should in the 85 the 85 alt should work in the 65 but the alternator from the 65 doesn't work in the 85 with out modification is that correct back to the cause of the 65 not charging at all is it most likely a bad ground or the voltage regulator could there be any other reason

This makes NO SENSE AT ALL LISTEN UP

The 70 and later alternators normally use the flat electronic regulator. One field wire receives switched 12V from the ignition "run" circuit, and the green regulator wire controls the "ground" to control charge.

THOSE LATE ALTERNATORS WORK FINE or 69 and earlier vehicles if you GROUND on field terminal of the alternator and then hook them up

YOU CAN NOT USE a 65 alternator on a 70 or later vehicle.

 

[Lee Smith]

Yes, it could be a wiring problem. The voltage regulator could be fine and give your symptoms.

An 85 system has two field wires. The 65 does not. If it works in an 85 and not in a 65, you have the wrong alt.

A later model alt can be modified to work in a 65 though, or you can upgrade to the later model regulator and wiring which is what I would personally recommend since many alternators sold for the single wire field aren't compatible with your current setup and even new regulators can be difficult to source for the same reason.

An over charge condition can be caused by many things, not the least of which is poor wiring between the battery and your regulator or a bad ground.

You need to test to see how much field voltage/current is being sent through your regulator and whether the wiring from the battery to the regulator is any good. Also make sure all grounds are clean and show good continuity. That information can be used to determine the fault.

Or you can try a new regulator and hope when you rev it, your car doesn't catch fire before you shut it off. Your choice.

Thank you that is very helpful I do appreciate your time I have a 85 dodge ram and 65 dart I found out they were different when I thought well heck I will put the alt out of the 85 in the 65 and it had three wires so I just hooked up the 2 wires the same as the older alt and the same issue no charge goes up to 12 volts and also I installed a aftermarket wire harness so your reply helps alot

Yes, it could be a wiring problem. The voltage regulator could be fine and give your symptoms.

An 85 system has two field wires. The 65 does not. If it works in an 85 and not in a 65, you have the wrong alt.

A later model alt can be modified to work in a 65 though, or you can upgrade to the later model regulator and wiring which is what I would personally recommend since many alternators sold for the single wire field aren't compatible with your current setup and even new regulators can be difficult to source for the same reason.

An over charge condition can be caused by many things, not the least of which is poor wiring between the battery and your regulator or a bad ground.

You need to test to see how much field voltage/current is being sent through your regulator and whether the wiring from the battery to the regulator is any good. Also make sure all grounds are clean and show good continuity. That information can be used to determine the fault.

Or you can try a new regulator and hope when you rev it, your car doesn't catch fire before you shut it off. Your choice.