1979 Chevy Corvette Burnt alternator while jumping dead bat

AMYE73

MEMBER
1979 CHEVROLET CORVETTE
V8
2WD
AUTOMATIC
82,000 MILES

I have a 79 vette that must have some electrical problem. It will start fine if I start it about every other day. If it sits longer, the batter goes completely DEAD. I have stored it in the garage over the last 3 months for winter. Got it out today and tried to jump it with my 02 Chevy Impala (always worked great before!). We hooked up the cables correctly. My impala was running. It charged for a few seconds. I revved the impala and when the rpms went back down, my battery light on the impala was red and my warning chime was going off and my husband was yelling the the corvette was smoking. The vette was not running. Battery still dead. We popped the hood on the vette and it had burnt metal/rubber smell coming from the alternator. Did I fry it? Did I fry my whole electrical system?

Saturday, February 20th, 2010 AT 5:55 PM

3 Replies

ERNEST CLARK

MECHANIC
1,730 POSTS

Though it's rare, it is possible to fry an alternators diod/rectifier bridge when jumping that car from another.

If you had the key in the "On", or "Acc" position on the car being jumped, then the car that is running is forcing electricity into the jumped car's starting/charging system.

The alternator on the jumped car is designed to allow electricity to flow only one way, but you forced electricity to flow in the opposite direction.

But you wouldn't have fried your entire electrical system because the fuses in the fuse box wouldn't allow that.

In the future, make sure your ignition key for the car being jumped is in the off position. And once you've allowed the battery to charge for awhile, disconnect the bat cables and then try starting that car.

The best way to do this is to remove the dead bat from the vehicle, and then connect the jumper cables. But it can be done safely the other way.

Was this

answer

helpful?

Yes

No

Monday, February 22nd, 2010 AT 8:36 AM

AMYE73

MEMBER
2 POSTS

Thanks for the input. Since this all happened, I hooked up the dead Vette battery to a trickle charger. It took 8 hours to charge the battery. But when I try to start the car, I get nothing. Not even a dome light.
None of this makes sense to me and I really don't even know where to start!

Was this

answer

helpful?

Yes

No

Monday, February 22nd, 2010 AT 8:43 AM

ERNEST CLARK

MECHANIC
1,730 POSTS

Check to make sure you have a good ground. Hook a DVOM to the negative bat cable and the the engine block. The from the neg. Bat cable to the frame, and finally from the frame to the engine block.

If all of your grounds are good, then check the power circuit. Also, check the ignition switch and the contacts/wiring.

Was this

answer

helpful?

Yes

No

Monday, February 22nd, 2010 AT 9:16 AM