electrical help needed

[biginch=bigfun]

I am having trouble nailing down an electrical issue : my voltage varies greatly! It bounces between 12v & 16v. If you drive at night the headlights look like stobe lights.

What I have:
1969 RR w/ a 440,

newer style alternator, 2 field
solid state regulator & ballast resister
MSD 6AL ignition
Amp gauge by passed, volt gauge installed
relays on low & high beam heaqdlights

What I have tried:
rewiring

putting my regulator on another car- worked fine

running my Batt. wire off the Alt. to the starter relay with a wire from the positive battery post to the starter relay.

Msd is powered at the positve post of battery.

Any help would be great! Thanks
LJB

 

[67 coronet]

http://www.allpar.com/history/mopar/electrical.html do you have a good eng to chassis ground strap?can cause what you are describing.link provided to huge article on many common electrical issues with our cars.alt ref is about half way down article.

 

[Beekeeper]

Subscribed

 

[biginch=bigfun]

67,

I have a ground from the intake to the firewall & voltage regulator . Another from the negative post to the intake , plus a small gauge from the negative post to the fender. My msd is grounded to a valve cover.

 

[biginch=bigfun]

A couple measurements I just took:

Cold battery is at 12.2v

negative post to regulator mount is 0.1v

with ignition switched on:

battery & Alt are 11.8v

one side of ballast is 10.4v

other side of ballast is ranging from 0 to 6.2v (fluctuating quickly)

does this sound familiar to anyone??!

 

[mr. b]

I had same problem with a msd installed we put fuel pump relay from a mini van wired to voltage regulator fixed the problem

 

[67 coronet]

A couple measurements I just took:

Cold battery is at 12.2v

negative post to regulator mount is 0.1v

with ignition switched on:

battery & Alt are 11.8v

one side of ballast is 10.4v

other side of ballast is ranging from 0 to 6.2v (fluctuating quickly)

does this sound familiar to anyone??!

you should not be getting fluctuation in the voltage readings with the switch on but not running.could indicate bad resistor or something is grounding out.should be constant voltage.charge that battery,should be at a minimum of 12.6 volts to do testing.

 

[biginch=bigfun]

Mr B,

can you expland on what you did? How did you wire the relay in?

- - - Updated - - -

67 coronet,

I should clarify that the readings at the ballast were directly from the wires, unconnected from the resistor.

I will charge the battery & retest.