1967 Mustang charging issues

1970coupe · Oct 23, 2015

I got this car from my father in law before he went to jail, so I'm not positive on the history of the vehicle since he had a tendency to stretch the truth. I do know it has a swapped 260 I6 with c4. There are a lot of wires not connected, especially under the dash. The cluster is connected, but I had to connect the temperature and oil connectors.

When I brought the car home I put a battery in it and all was well. Some jackass (me) left the key in the on position while checking over some things and had to jump it from the truck. I checked the voltage after jumping and it was steady dropping 11.5 was the lowest I saw before I shut it off.

I put an alternator and voltage regulator in the car and the battery is still discharging. It seems to be holding at 11.9 now. I checked the yellow wire under the rad. support, found no issues. The ground on the alternator is grounded to the block. I noticed there is no ground from the block to the body or from the battery to the body. The "field" post on the alternator has a redish orange wire running to it no power at it. "Bat" post has 11.9 at it. I don't think the new voltage regulator is faulty since the one I pulled off looked like it had been replaced recently.

rcodenewf · Oct 24, 2015

Where does your battery negative ground to?

Just take one side of your booster cables...black for clarity and hook it to the negative on your battery then attach the other black cable to a clean spot on your engine block and see how your charging changes.

Your negative on the battery should have gone to a bolt on the passenger forward side of the block.

John

Woodchuck · Oct 24, 2015

Does it have an ALT warning lamp? If so, does it work?

IIRC (but double check me as I can be wrong!), you should have a BLK/YEL to the "BAT" post, a WHI to the "FLD" post, a BLK to the "GND" post and a WHI/BLK to the "STA" post on the ALTERNATOR if you have a warning lamp.

The REGULATOR should have wires to all 4 terminals in the plug, a YEL to the "A+", a WHI to the "F", a GRN/RED to the "I", and a WHI/BLK to the "S", also if you have a warning lamp.

If the warning lamp bulb is not coming on with the key in the "ON" position and the engine NOT running, pull it, check it and replace if burned out, then re-test the charging system.

YeahJohn · Oct 24, 2015

Has it charged properly since you owned it?

Is the 11v battery reading with the car on or off?

Have you checked for a draw using your multi meter?

YeahJohn · Oct 24, 2015

You can trouble shoot and pull off the voltage regulator harness from the voltage regulator and jump the a to f terminal with a wire and take a battery reading while the car is running. This should allow your voltage to spike to 16v +. If your vottage remains low you know it's an alternator issue or if your voltage goes up past 14v you know it's a voltage regulator problem.

1970coupe · Nov 15, 2015

I finally found time to check some things out. I noticed the alternator gauge was not moving, the needle sits dead in the middle at all times. I checked voltage on the back of the gauge cluster the red and yellow wires show the voltage the alternator is putting out. The voltage was 11.5 when checked.

Also the ignition coil was just wedged between the block and the distributor.

1967 Mustang charging issues

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