First timer needing help please...

[linuxskynyrd]

I've been a member for about a year, browsing around for answers to different questions but I did not know where to post this question so forgive me if this is not the appropriate place....

I have an issue with the voltage gauge on my '78 280.

The voltage gauge needle will show a normal charging position, (between 12 and 16 volts), then suddenly drop to zero and stay there for a while, then jump back to normal. It may stay at zero for an hour or longer. It sometimes drops to zero when I turn the key to the "off" position. Once, when it was at "zero", I pressed the break pedal and it jumped back to its normal position.

The charging light does not come on when this happens but it is a bit unnerving when I'm 20 or 30 miles from home and the gauge starts bouncing.

I don't drive the car much, maybe once or twice every couple of weeks but this did not start until recently.

I tried the following with none of these helped:

1) I replaced the voltage gauge

2) replaced the battery

3) replaced the alternator

4) checked all visible connections

The only way I've found to make the needle jump back to itst normal position is to remove and replace the battery cable. After removing and then re-connecting the battery cable a couple of times, the gauge will "jump" back to its normal position, (between 12 and 16 volts) and stay there...for a while.

If I need to give more detail, please advise.

I was wondering if anyone has had similar issues and what they may have done to resolve. I would appreciate any assistance.

Thanks

linuxskynyrd

[S30Driver]

When you checked all visible connections, did that include the fusible links?

If not, pull them one at a time, clean them of any oxidation & replace.

Also, a vom plugged into the fuse block while you are driving will allow you to monitor the actual voltage when the problem occurs. Might help to narrow down the intermittant problem.

[linuxskynyrd]

Thanks for the reply. I did check the fusible links but I have not used a vom. I have found that the car does not have to be running for the needle to drop to zero. Sometimes, I can simply "bump" the ignition switch with the key as if I was going to start the car and the needle will drop.

[Free280Z]

Bad Ground somewhere.

[Free280Z]

As a newbie to all things "Z" don't listen to me, but, I have had strange things happen too and it was a ground. Very strange things.

[bigoak]

As a newbie to all things "Z" don't listen to me, but, I have had strange things happen too and it was a ground. Very strange things.

K...now I'm intrigued...

[linuxskynyrd]

still investigating voltage gauge issue...i did find that when I turn on my flasher switch, the gauge immediately drops to 0. I disconnected the switch but that does not seem to resolve the problem....I'll keep looking.

[Free280Z]

I also vote for a bad ground.