Couple alt/reg questions

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frozennorth

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Sorry for the dumb questions fellas. New to me car and trying to iron
out the po's stuff.

I have a 1 wire alt that is not charging.
12.5 V on both the battery and lug on the back of the alt.
Same 12.5 V to the bottom of the regulator (I think).
The pic of the firewall is where i got the V reading. I read the V
off the bottom of the box (blue wire) as the top was 0 (green wire).

IMG_1135.jpg


The second pic is of the alt. I don't think the po finished the 1 wire install
as there are 2 more wires laying off to the side. None of the spare wires has any voltage to them but I will have to confirm that.

IMG_1140.jpg

IMG_1137.jpg


Any ideas or hints?

Thanks
 
run a 12v jumper wire and touch it to the field [green] wire meanwhile having a volt meter reading the output at the batt post, if it jumps up to 16 or so, the alternator is good and you need to either find the break in the wire or replace the regulator.
 
you can convert to electronic regulator easy if the alternator has 3 wires.

Is there another wire on the bottom like the green wire, except blue maybe?
 
There is a "spare" brown Female spade wire near the alt that is not hooked to anything. The regulator has a blue wire on the bottom of it.
 
Just buy a new style '3 wire' alternator or make sure you have a working one, then do this....

you keep the green and just run it the the regulators lower right hand plug wire as well as the blue which is piggy backed onto the new/3rd field terminal and then ran to the upper middle wire in the plug.
 

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If there is another connection on the alt it should be grounded. Most rebuilt alt are wired for the newer style regulator. I have just grounded the other conection and it works with the black old style regulator.
 
1wild&crazyguy said:
run a grounded jumper wire and touch it to the field [green] wire meanwhile having a volt meter reading the output, if it jumps up to 16 or so, the alternator is good and you need to either find the break in the wire or replace the regulator.
Click to expand...

Incorrect, from what I see here. The picture he posted APPEARS to be a 69/ earlier vehicle, is that correct?

"Quicky" checks:

Sounds like you are OK on the output stud, but the deal is, in the end, there STILL could be an "intermittent" or other poor connection, that when measured with a meter and NOT UNDER LOAD, will show "good."

Look carefully as someone else mentioned, at the alternator. Make sure there is NOT another field terminal (the small push on connector(s) that is UN connected. If so, ground it.

You seem to have an early alternator.

Check at your regulator, key on, in "run" one lead should be blue and marked "ign" and the other should be green, marked "FLD". BOTH terminals should have close to battery voltage on them with the key in run.

If not, you have a wiring problem

If you do not have 12V on the green, you probably have a regulator problem.

To check this alternator for at least "some output" and HERE AGAIN I'm thinkin you have a 69/ earlier?? What you want to do, is pull the green wire off the alternator, and then.......

put a clip lead from the exposed alternator terminal (push on) to the battery stud.

Start the engine and gently rev it a little. As you increase RPM, it should put out more and more, at "low cruise" should pretty much peg the meter.

If this is OK, and if you had battery (in run) back at the regulator IGN terminal, looks like you need a new regulator


EDIT. Just looked at the very top of your alternator in the picture. It APPEARS that I can see the grounded brush mount---the empty hole--with nothing in there. IF THIS is true, it either means that

the grounding brush is missing, or......

you have a typical rebuilt whereby a rebuilder modified the original to turn it into an "isolated field", that is, TWO small field push on connections. IF THIS is the case, as someone above said, just ground this second connection---it matters not which one you ground
 
retractable said:
If there is another connection on the alt it should be grounded. Most rebuilt alt are wired for the newer style regulator. I have just grounded the other conection and it works with the black old style regulator.
Click to expand...

yeah it's easier for rebuilders to just ground the 3rd wire for use with mechanical regulators.


Thats the 1st thing I do to a car with old style charging system..is change it over, and all of the sudden the head lights get brighter.
 
Just had a quick look. There is a small bolt in the lower hole on the back of the alt. Is that the one that I should ground?

And yes, sorry, its a '66 Valiant that I just picked up.
 
67Dart273 said:
Incorrect, from what I see here. The picture he posted APPEARS to be a 69/ earlier vehicle, is that correct?

"Quicky" checks:

Sounds like you are OK on the output stud, but the deal is, in the end, there STILL could be an "intermittent" or other poor connection, that when measured with a meter and NOT UNDER LOAD, will show "good."

Look carefully as someone else mentioned, at the alternator. Make sure there is NOT another field terminal (the small push on connector(s) that is UN connected. If so, ground it.

You seem to have an early alternator.

Check at your regulator, key on, in "run" one lead should be blue and marked "ign" and the other should be green, marked "FLD". BOTH terminals should have close to battery voltage on them with the key in run.

If not, you have a wiring problem

If you do not have 12V on the green, you probably have a regulator problem.

To check this alternator for at least "some output" and HERE AGAIN I'm thinkin you have a 69/ earlier?? What you want to do, is pull the green wire off the alternator, and then.......

put a clip lead from the exposed alternator terminal (push on) to the battery stud.

Start the engine and gently rev it a little. As you increase RPM, it should put out more and more, at "low cruise" should pretty much peg the meter.

If this is OK, and if you had battery (in run) back at the regulator IGN terminal, looks like you need a new regulator


EDIT. Just looked at the very top of your alternator in the picture. It APPEARS that I can see the grounded brush mount---the empty hole--with nothing in there. IF THIS is true, it either means that

the grounding brush is missing, or......

you have a typical rebuilt whereby a rebuilder modified the original to turn it into an "isolated field", that is, TWO small field push on connections. IF THIS is the case, as someone above said, just ground this second connection---it matters not which one you ground
Click to expand...



Have a read, the mechanical setup does control alt output by means of lower/raising currant to the single 'green' field terminal, so yea hooking full voltage from the batt post will cause full output @2000rpm+

but on the dual field style you just ground the 2nd field 'blue' and the alternator will full output, because the new style regulator controls the ground to the alternator.

http://www.davesmopar.com/techreg.htm
 
1wild&crazyguy said:
Have a read, the mechanical setup does control alt output by means of lower/raising currant to the single 'green' field terminal, so yea hooking full voltage from the batt post will cause full output @2000rpm+

but on the dual field style you just ground the 2nd field 'blue' and the alternator will full output, because the new style regulator controls the ground to the alternator.

http://www.davesmopar.com/techreg.htm
Click to expand...

I understand that, and have understood that since the early '70's. What is in conflict with this and what I wrote?

It looks to me like you changed your original post??

Originally Posted by 1wild&crazyguy
run a grounded jumper wire and touch it to the field [green] wire meanwhile having a volt meter reading the output, if it jumps up to 16 or so, the alternator is good and you need to either find the break in the wire or replace the regulator.


If so, then what I wrote referred to that, and not what is currently on the board.


While I agree that the newer alternator and regulator is a "better deal" I resist the urge to "just go out" and buy the new stuff, and engage in a bunch of rewiring, which may make finding the original problem more difficult.

TROUBLESHOOT the problem first, THEN decide if you want to upgrade as part of the fix. Hell, with all the talk about "Denzo's" 'n stuff, I'd be tempted to not even run a Mopar alternator. I ran Delco's back in the 70's after I rattled a couple of Mopar units to death.
 
Hey everybody. Turned out to be the voltage regulator. I do have some part numbers for everybody tho.

I will put them in a new thread so you don't have to scroll through all this.

Thanks to everyone for the help.
 
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