Not Charging!!! What have I missed?

[Dragon]

My 71 and the 72 I am working on for a friend are 4 wire systems.

[fordman]

thats wierd both of the 71 i have here only use three of the four regulator pins. i thougth it shopuld have had all four pins with wires to them but they don't. i even checked the 72 diagrams and they only show three pins being used. unless you are talking about the extra wire that goes over to the resistor on the regulator. then it is a four wire deal. but only three pins are on the two trucks i have here.

[Thunderfoot]

Both my 69's are 3 wire systems at the Voltage Regulator, so is my 68 Mustang... they all have the AMP gauge as well... It seems to depend some on the configuration of the truck, if it has AMP gauge or not, or something else that I haven't figured out yet.

I am having the same problem as the original poster, in my '69 I have replaced everything, Battery, starter solonoid, regulator, rebuilt the alt and had it tested, even replaced the old 4 amp inline glass fuses with 4 amp blade fuses, cleaned all connections, checked my grounds, double, triple checked my wires and connections to make sure it was all wired up right.
The only thing I noticed was that the diagram for the truck shows a fourth hookup on the alt, the stator, and there being a fourth wire on the regulator harness, I only have three, , and after cutting the tape back on the wires, I cant see any sign of there ever being a wire there.
My dash gauge does not work, and I am not getting a charge to the battery. I put a voltmeter on the battery, starter solonoid, and alt battery connector, not running I got a 12.5, running I got a 12.3 at all the spots.
I am out of ideas, please help!

If you look at the Voltage Regulator wire connector you can jumper the Field wire with 12V and then check to see if the Alternator is working. If after jumping this, the voltage goes up then the Voltage Regulator is not working (more then one member here has gotten a bad NEW regulator), if the voltage doesn't go up then there is a problem with the Alternator or a wire.

Couple of other checks.
1)Be sure you have power on the B (battery) wire on the back of the Alternator (engine off). This will tell you that the fusible link to the battery from the alternator is not blown.
2)Check that you have 12V on the Green-red striped wire at the Voltage Regulator with the key on. This is the exciter wire to tell the alternator to start charging.

[majlz40]

I have a 1971 Sport Custom. I was told the 'hot start'/'charging' issue I'm having may be because there should be an ground connected from the engine to the firewall/chasis. Is there any truth to this? My current set up as far as 'grounds' are concerned are: Battery to engine block (behind the alternator bracket), Alternator to engine block (behind the water pump) Voltage Regulator (#26 black and red) to the alternator. It just seems odd to me that I have always been advised to ground all the aboved mentioned parts to the motor and not the firewall, but the largest moving part under the hood (the engine) is to be grounded to the.....firewall. Please confirm.

[Thunderfoot]

Actually the main battery cable ground is to be connected the engine (as you have already), then the engine makes a ground connection to the rest of the truck via the firewall (this is the ground for everything in the cab and all the lights). the motor mounts are rubber so there is no transfer of ground through them, so this is why there needs to be a connection from the motor to the sheet metal... right now as you have it that ground wire from the alternator to the voltage regulator mount is acting as this connection. As the alternator is grounded to the case itself and the alternator is mounted to the engine it is getting its ground connection from the engine to the battery that way (plus you say you have an extra wire mounted to the water pump).
The main battery cable needs to grounded to the engine as the starter draws the most current and needs the BIG cable connection to handle all that current, everything else on the truck is minimal current draw in comparison so doesn't need as big of cable to handle it.

[majlz40]

I guess everything is cool, I adjusted the starter cable just a little bit (it was loose..well at least it moved when I touched it). Took one of those $8.99 testers/voltmeters from Advance Auto and checked both batt/alt while running and not running then started her up took off and drove to the store got gas....she started right up... another 4 miles stopped....and she started right up...im so shocked at the consistency !! Think I'll drive it to work tomorrow (31 miles) and see what happens. Thanks for your advice!

I still have issues though: hesitation between 60 and 70mph which maybe due to gas tank trash.. Ill install one of those clear filters so i can monitor.

Not changing gears... well at least into third gear (C6 tranny with low end or standard shift rear end). I drove from work yesterday (31 miles) and my tach stayed at 4k the entire drive! I dont think it shifted from 2nd gear into third. Ill post this in another forum. Please assist. Both motor and tranny have been rebuilt. The tranny guy says it just takes time for the gears to adjust to the load one places on the engine.