Need advice on ammeter.

[g49bridges]

Hey guys, my knowledge on electrical is somewhat limited, so I need a little advice here. Working on my 74 small block Duster, which is far from factory. I've switched to an msd pro billet dist and blaster coil. Been running this set up since last fall with no issues at all. This past weekend I decided to add a 6AL-2 ignition box. Double and triple checked that everything in hooked up right, even called MSD tech line and made sure everything was right. The car starts up and runs great, no run-on or anything. But, as soon as I hooked it all up the ammeter goes to 3/4 full charge at anything over idle. lights flicker, etc. I went to the parts store and got a new regulator, changed it out, and now it's even worse...going 100% full charge at anything over idle. Swapped them back and same as before, 3/4 full charge. Checked the battery with the car off and I get 12.3v. With the limited knowledge I have on electrical, this is where I'm lost. No idea where to go or what to check next. Anybody have any idea on this?

 

[pishta]

The electronic voltage regulator varies the ground connection to tell the alternator how hard to work. So yo NEED a solid ground for the box to reference. I suggest you scrape the paint down to metal and use a star washer to mount the reglulator onto sheet metal and then check the alternator for an internal ground at the parts store tester. MSD takes about .7 amp per 1000 RPM...BTW, the battery should show about 14V at idle.

 

[67Dart273]

Without knowing what you changed in the wiring SPECIFICALLY, no way in the world to tell

also, it might be that you have a poor connection say, in the bulkhead connector or even the connector right at the VR that you bumped and worsened the connection.

Also the VR MUST be grounded to same as battery neg

"What to do?"

Start by.........

Turn the key to "run" with engine stopped

Check battery terminal voltage carefully. Check voltage at the alternator blue field wire WITH EVERYTHING connected as normal. That is "back probe" the terminal so it's still connected.

Subtract the difference. You are hoping for a very small difference, a couple of tenths of one volt or less, and the less the better.

Where exactly did you connect the "big red" and "big black" MSD wires?

The "small red" wire?

What exactly did you do with the original ballast resistor terminals?

On a side note, make CERTAIN that ALL as in "the only" connections to the coil are the new wires to the coil from the MSD box.

You do NOT want any other connections to the coil

 

[g49bridges]

Without knowing what you changed in the wiring SPECIFICALLY, no way in the world to tell

also, it might be that you have a poor connection say, in the bulkhead connector or even the connector right at the VR that you bumped and worsened the connection.

Also the VR MUST be grounded to same as battery neg

"What to do?"

Start by.........

Turn the key to "run" with engine stopped

Check battery terminal voltage carefully. Check voltage at the alternator blue field wire WITH EVERYTHING connected as normal. That is "back probe" the terminal so it's still connected.

Subtract the difference. You are hoping for a very small difference, a couple of tenths of one volt or less, and the less the better.

Where exactly did you connect the "big red" and "big black" MSD wires?

The "small red" wire?

What exactly did you do with the original ballast resistor terminals?

On a side note, make CERTAIN that ALL as in "the only" connections to the coil are the new wires to the coil from the MSD box.

You do NOT want any other connections to the coil

Without knowing what you changed in the wiring SPECIFICALLY, no way in the world to tell

also, it might be that you have a poor connection say, in the bulkhead connector or even the connector right at the VR that you bumped and worsened the connection.

Also the VR MUST be grounded to same as battery neg

"What to do?"

Start by.........

Turn the key to "run" with engine stopped

Check battery terminal voltage carefully. Check voltage at the alternator blue field wire WITH EVERYTHING connected as normal. That is "back probe" the terminal so it's still connected.

Subtract the difference. You are hoping for a very small difference, a couple of tenths of one volt or less, and the less the better.

Where exactly did you connect the "big red" and "big black" MSD wires?

The "small red" wire?

What exactly did you do with the original ballast resistor terminals?

On a side note, make CERTAIN that ALL as in "the only" connections to the coil are the new wires to the coil from the MSD box.

You do NOT want any other connections to the coil

Big red and black wires are direct to the battery. Small red is tied into the 12v switched wire that fed the coil before I added the 6al. Only 2 wires I have on the coil are the orange and black from the 6al. Original ballast wires are wired together.