Need some help please. I installed another ground wire from my engine to the frame--all ground wires are good; still not charging above 12V. I'm not sure that the wiring from the voltage regulator to the altenator is 100% correct. Can anyone tell me how the voltage regulator and altenator is supposed to be wired? It is a standard ford small block (351W) altenator and charging system. Please help--I have to get this truck going today!

 

I have a 1976 to 1986 repair manual and you really need to know what you have they are not all the same wiring. Here are the parts that seem to be common between 1976 - 1983. This entire wiring diagram changes in 1984

1. Alternator B terminal - black / red wire goes to the starter solenoid side that is conencted to the battery. The yellow A+ on alternator regulator is tied to this wire. My guess would be this is the voltage sensing wire the controlles the ouput of the alternator.
2. Alternator S terminal - white / black wire goes to the S on the alternator regulator. My guess is that this is the stator wire.
3. Alternator F terminal - Orange wire goes to the F on the alternator regulator. My guess would be that it is the field wire.
4. Alternator Regulator - I terminal this one is a little harder it shows that the red / green wire goes to alternator indicator, the brown wire in the starter relay and the ignition switch. My guess would be this wire turns on and off with the ignition.

 

Try running a ground from the case of the alternator to the frame.

 

Thanks Chris and Jack... Someone in another post told me to make sure the idiot light is connected--I know I diked it off. I am hoping that is the problem. I changed my ground wires around, and even ran some extra ones--still no change. Thanks for the wiring help. I'm going to trace the wires out this morning.

 

Unless your battery is run down, what's wrong with 12V output into a charged battery?

 

Check out this link.

http://www.americanstreetmasters.com/Wiring_101_4.jpg

Rich

 

The Light will not stop it from charging.
This Diagram should be the same as your 1957.

 

This diagram is for a generator not an alternator.

 

Sorry I missed when he said alternator, I just noticed it was for a 1957 Ford.
Here is one for an alternator from the 70's.
The light has to be there on this one.

 

Thanks for the diagrams... I hooked the indicator light up, and it still drops below 12V when you turn everything on. Plus, I disconnected the negative wire from the battery while the truck was running; the engine died. I should be able to completely disconnect the battery while it is running--correct? I just don't know what else to try short of completely rewiring everything...

 

Try painless wiring's web site they have various wiring diagrams on their site. Go to google and do a painless wire search.
Jaye

 

Sounds like a bad alternator. Should run just the same after started off the Alternator w/o battery. Have the alternator tested and go from there.

 

It should have about 13.5 Volts at the battery while running, 12 Volts is a discharged battery.

A 12 Volts reading at the battery with the engine running means the Alternator is not charging.

However it is normal for the engine to die after about two to three minutes when the battery has been disconnected with a good alternator. The alternator does not have the capability of holding magnetism in it field. An alternator must have a small DC feed to its field to produce power.

 

The light will stop it from charging. On my truck I had the same problem. I hooked up an ammeter and couldn't figure it out. As soon as I spliced the idiot light back on the ammeter jumped to charge. I think I just took the bulb out then. I know it sounds wierd but it worked. John

 

The QUOTE that you referred to was for a 57 Ford generator system and no it will not effect the charging.

Later when I found out that he had converted it to an Alternator then yes it would keep it from charging.

The generator system does not need the key on or any external power source to charge. The Alternator system however does need an external source to charge.

As an example when I was flying aircraft if you had a dead battery and propped (pulled the engine through with the propeller to start it) the engine to start it you would still have to jump it with the engine running to get it to charge. The engine fires off of a magneto.