Help with electrical problem 1967 427 400hp factory air

[Jeff C.]

Tried to start after setting for several weeks batter was dead. Jumped battery to start engine drove car for 20 miles an noticed amp jumping from o to +20 amps. Parked car over night battery dead next morning. Charged battery over over night and it took a normal charge. Started car no problem same amp gage issue. Have not driven car but battery is holding charge I am assuming it is a bad regulator. I will buy a new regulator for a 61 amp alternator but just wanted some advice.
Thanks
Jeff

[Dick W.]

Re: Help with elecrical problem 1967 427 400hp factory air

Tried to start after setting for several weeks batter was dead. Jumped battery to start engine drove car for 20 miles an noticed amp jumping from o to +20 amps. Parked car over night battery dead next morning. Charged battery over over night and it took a normal charge. Started car no problem same amp gage issue. Have not driven car but battery is holding charge I am assuming it is a bad regulator. I will buy a new regulator for a 61 amp alternator but just wanted some advice.
Thanks
Jeff

Could have been the glove box light, courtesy lights, etc staying on.

[Larry M.]

Re: Help with elecrical problem 1967 427 400hp factory air

Jeff:

Before you just start replacing things, you need to do some basic troubleshooting........

It could be as simple as a light left on where it cannot easily be seen. But a check on where these bulbs are in your car and if they are glowing or warm will tell you this. You can also do a current drawdown on the battery using a Fluke multimeter or similar and actually see the battery voltage discharge and a current flow. If you don't own such a meter, you should borrow or buy one. They are good for just about everything electrical on your car.......and your home.

You may have a bad diode in the alternator which is causing battery discharge back thru the alternator. This can be checked by disconnecting the alternator electrical connections and observing battery voltage with time (day or so). Or bring alternator to a shop and have them do a complete function test.

Sticking points in the original type clock will also run down a battery quickly, but the Fluke meter tests I mentioned above will catch this.

Do you have a battery disconnect?? If not, get one. These old cars, just sitting around, need one to prevent dead batteries. Otherwise just about anything can happen while car is sitting.

Your battery can be removed and a load check done to determine battery health.........or drive the car to a shop that has this tool and pay them a few $ to test. Just about all new car dealers with service departments have this battery tester. Same with NAPA, Advance, AutoZone, etc. But some testers are better than others.

Checking the battery voltage and alternator voltage when the car is running, should tell you if the regulator is operating correctly. Or again, an alternator and regulator repair shop should be able to test for you without you having to buy a replacement, which may or may not work for you.

If needed you can call me to talk through the items mentioned above. PM me for contact info if needed.

Larry