Amp gauge jumping while driving

[68monaco]

Hello follow C body enthusiasts. I own a 1968 Dodge Monaco 2 door hardtop. I have upgraded a few things on it. It originally had a 383 2 barrel, now has a 4 barrel with eldobrock rpm manifold and MSD distributor & ignition, factory up sweep headers and larger exhaust. Now to the dilemma. My amp gauge jumps, more at night. Because of this the headlights blink. I have changed the voltage regulator to electronic and it keeps it steady for about a minute then it's right back to jumping. I have had a place look at it to no avail. Any suggestions?

Terry

 

[68plymouth383]

Welcome to the forum! !

 

[commando1]

Welcome, Terry, to FCBO.

 

[BJS racing]

First thing I would suggest would be to make sure that the alternator case is grounded to the block an make sure that the regulator mount has a good ground. The next place I would go to is to make sure that the bulk head connector isn't starting to melt on you.

 

[rexus31]

Does the needle jump while idling or cruising? Mine wiggles a bit stopped at a light, especially if the turn signal is on. I think that's pretty normal.

 

[Speed_Kills96]

Do you still have the analog voltage regulator? If you haven't changed any wiring for this, I'd put that back in, but first what id do is set the reg to specs.

 

[Speed_Kills96]

Do you still have the analog voltage regulator? If you haven't changed any wiring for this, I'd put that back in, but first what id do is set the reg to specs.

 

[68monaco]

Thanks guys for your quick responses. The alternator I thought was grounded by the bracket it is mounted on. Second the voltage reg is electronic. It jumps all the time, idle, driving, doesn't matter. It tends to jump more when more things are on such as radio, lights, or fan blower. The problem with the analog volt reg is they would not allow the correct voltage, what I mean is it would not regulate properly, it would always charge the system with no reg. Rexcus31 that is normal it's actually doing it's job by showing you the discharge caused by the light blinking

 

[68monaco]

My brother had a 68 Roadrunner back in the day and his did this as well but I have forgotten what it was to fix it and so has he.

 

[BJS racing]

Don't trust the bracket to ground the alternator. It is painted as is the block. I would add a ground wire from the alt to the block to make sure. It's cheap and can save quite a bit of headache.

 

[68monaco]

Don't trust the bracket to ground the alternator. It is painted as is the block. I would add a ground wire from the alt to the block to make sure. It's cheap and can save quite a bit of headache.

I'll try it and see what happens

 

[rexus31]

I'll try it and see what happens

You could have a draw (short) somewhere which is causing it to jump.