any voltage regulator gurus here? 2.8 1984

[Angie]

on the 84 buggy, i am having charging issues. to eliminate the system I did buy a new alt, even after changing with 3 others i have in the shop. (all 4) have same issues. wanted to eliminate so bought a new one to be sure.

now i get 10 volts to 11 volts with the truck running with the lights on and the heater in full. the battery didn't charge from the maiden run a while back, and i have been just using trickle charges to keep the bat up in charge when it is parked. I have not died yet with the truck how ever, have not driven it more than 10 miles per trip keeping them short in case the bat does die.

i have rewired the alt directly to the regulator with new wires. ground, and field and stator. the wire harness is a bit chopped from PO i also eliminated the (brain box, and electric crap).

I also want to eliminate the AMP meter in the dash. however, can not figure what wires to cut from the wire harness.

can take pics if needed. want to know how to test the regulator properly, or if i have it proper.
cheers thanks

 

[franklin2]

Don't worry about the ammeter, it doesn't work on most of them anyway and causes little harm.

1st thing to check; When you turn the key to run, but do not start the truck, do you have 12v on the lightgreen/red wire? This wire should go to the "S" terminal of the regulator. This wire is what brings the alternator system "online" to charge.

 

[Angie]

hi, key on, at the alt s bolt it says 3.5 Volts, and piercing the same wire at the regulator it says 8 Volts.

my wiring is a bit different from your diagram. i have a ground from alt to the base of the regulator. and two new wires that are "jumped connected" to the existing wires that go to field and S on the regulator. The bat connection goes directly to the battery. nothing to I. hope that helps

 

[franklin2]

If you have a connection from the "S" of the regulator to the "S" of the alternator, take that wire off. It does not belong there. In this configuration, there is no connection to the "S" terminal of the alternator unless you are running a electric choke. Only connection to the regulator "S" is the one from the ignition.

 

[Angie]

ok will delete the s from alt.

 

[Angie]

deleted the wire and shows nothing for volts

 

[franklin2]

Ok. Take your wire off the F terminal on the alternator, make sure to put some tape on it. If it touches ground with the engine running it will blow the regulator.

Put a piece of scrap wire on the F terminal of the alternator, lay it up near the battery. Start the truck. With the truck running, monitor the voltage at the battery and while doing that, touch the scrap piece of wire hooked to the F terminal of the alternator to the battery + terminal. The alternator should go wide open, the voltage on the battery should jump up, and you might hear the engine slow down and the alternator whining some. This will test if the alternator is good.

If it did not pass the alternator check, one thing to check is to turn the engine off, key off, and measure the voltage on the large output lug of the alternator. It should be battery voltage. If it's not, there is usually a fusible link that burns out in that wire. That would keep it from charging if everything else was ok.

So if the alternator passes, make sure the A terminal of the regulator measures 12v with the engine off, key off.

If that passes, the regulator must be bad. If you want to be double dog sure, with the engine running, everything hooked up, 12v on A terminal, 12v on regulator S terminal, check the voltage on the F terminal. You should have something there. This is what controls the alternator output. That is why we put 12v on it during the alternator test to send the alternator wide open. If you have no voltage on the F, then the regulator is definitely bad.

 

[Angie]

ok thanks will try this later or tomorrow cheers. will up date when i get there

 

[Angie]

not sure if i did these tests correct as the results are all over the place.

the F wire test had the volts climbing, stopped at 17.5.

A had 12+ volts engine off key off....

now wasnt sure if the A and F were correct hooked up so did both terminals and switched them. first time both A & F showed 0.0 volts .... switched the two on alt A & F ... got A 0.0 and F hit 3.5 Volts

pics are showing the hook ups. cheers

 

[franklin2]

F wire being at 17.5 volts means the regulator was online, and telling the alternator to put out some power.

You did not do the output wire test on the alternator (I didn't see it if you did). With the engine off, key off, take your meter and read the voltage on the large stud on the alternator. It should be battery voltage. If not, there is usually a fusible link in that wire that burns out.

If the alternator output wire tests good, and you get it running again and you have 17v or whatever voltage on the F wire, then you should have something more than 12v on the battery with the engine running. Some of these older systems will put out about 13.5v-13.8 v. Most of the newer systems put out around 14-14.5v. With voltage on the F terminal, and it's hooked to the F terminal of the alternator, if you do not have the higher voltage on the battery the alternator is bad.

 

[Angie]

the big output terminal is hooked directly to the battery and is a solid 13 Volts key off not running. is that wrong to hook there>? as there seems to be no other place to run a wire to or from ... wasnt any before and was just hooked to the battery