Volt gauge drops to 0, but engine cranks and starts

[TheCrazySwede]

1977 280Z with upgraded alternator and voltage regulator jumped.

 

 

My gauge in the car will read 14.5v and car starts just fine.

 

If I turn on my running lights, all electronics die out in the car and gauge drops to 0.

Turn everything off and wait a while - power comes back on.

 

If I use my turn signals, nothing happens, but if I use my hazards - same thing. All electrics die and voltage reads 0. Same goes for fan.

 

My headlights work, but nothing else does. Even during the "all electrics dead" period, I am able to crank the engine and start the car.

 

Using a voltmeter, my battery gets 13.5v with engine running. With all electronics dead, it reads 12.5v at both battery and alternator, even though gauge in car reads 0.

 

Any ideas why?

 

Thanks!

[Aswad1981]

 

1977 280Z with upgraded alternator and voltage regulator jumped.

 

 

My gauge in the car will read 14.5v and car starts just fine.

 

If I turn on my running lights, all electronics die out in the car and gauge drops to 0.

Turn everything off and wait a while - power comes back on.

 

If I use my turn signals, nothing happens, but if I use my hazards - same thing. All electrics die and voltage reads 0. Same goes for fan.

 

My headlights work, but nothing else does. Even during the "all electrics dead" period, I am able to crank the engine and start the car.

 

Using a voltmeter, my battery gets 13.5v with engine running. With all electronics dead, it reads 12.5v at both battery and alternator, even though gauge in car reads 0.

 

Any ideas why? The volt meter guage is faulty as all accessory voltage passes through it. Bad ground wire is also suspect.