Stuck troubleshooting an electrical problem
 

Hi all.

All of a sudden my '84 is acting up :(
Would not start last night. Strangely the battery is only about 2 months old.

- I jumped the battery drove around for about 20 minutes came back, checked the voltage with the car running it showed 13.7.

- Checked the voltage with the car off battery shows 12.10

- Disconnected the ground, checked the amps, only pulling about .8, not enough to drain overnight.

Went to start it today, same story. Went through the same steps got the same result....

Not sure where to turn next....
Any suggestions? :confused:

Starter turns over fine. Just had to jump it today again after the car being parked overnight. After driving around for about 15-20 minutes, the car starts without a jump....

sounds like it may be the battery itself
Rob

Battery shows 12.9 volts which is right within norm....

Take the battery back where you bought it and have them load-test it. You wouldn't be the first to get a bad battery right out of the store. I've had DieHards that did that.

Also, is the battery fastened down? A loose battery will jar the plates and break internal connections, reducing the life of the battery.

You're drawing 0.8A with the key off? that's way too much. Is there a light stuck on somewhere? glovebox? trunk? I don't know what is typical for a 944 but as a rule of thumb I would expect to see only about 15-20 mA from a generic car.

To put this in perspective, a similar size battery used for backup power is rated at about 75AH. That means that a 1 amp draw will *completely* drain your battery in 75 hours. it's entirely possible that even a battery in good condition will drain to the point that the starter won't work properly in a day or so.

nate

Totally agree with toolboy62. 0.8 amp is too much. Like he said, it should be about 20 milliamps which is .02 amp.

Start by pulling fuses one at a time with the ammeter attached. That way you can determine what circuit is not shutting off.