Voltage Fluctuation

[Super Dave]

I'd like to start off saying I'm new to the site and not well versed in electronics...please be patient. I purchased a 1967 Plymouth Belvedere II last year with a Mopar Performance 360 crate engine with electronic ignition. My mechanic has helped me understand that the original gauge is reading amperage and an after market gauge is reading voltage. The volt reading fluctuates between 13 and 16 volts. The fluctuation varies with RPM's. The gauge reading AMPS fluctuates in an identical fashion. The alternator from Autozone tests normal (alternator matches original 318 engine specification-single field wire). I replaced the voltage regulator with a product from classic industries that replaces the original adjustable voltage regulator (perhaps I need to scrape some paint away from the firewall where the voltage regulator mounts to ensure a proper ground). We have also added a grounding strap to the battery to hopefully eliminate that potential problem. The voltage fluctuation continues. The only place I physically see a problem (beyond the gauges fluctuating) is in the headlights (newer halogen). After replacing the voltage regulator the headlight fluctuation is less noticeable. However, the gauges still have the same readings as before and the headlights still fluctuate. I tried to provide enough background information to see if anyone has experienced a similar problem and has any ideas. I welcome any advice to work toward eliminating this problem.

Thanks,

 

[Super Dave]

This weekend I ground the paint off of the firewall behind the voltage regulator and scuffed up the mounting brackets on the voltage regulator. Now I only have 1/2 volt fluctuation at idle and no visible fluctuation over 1500 RPM's. I've been told some fluctuation was common for a Plymouth of this era.

 

[dryheat]

Well done. Proper grounding solves a lot of electrical issues and it often gets overlooked.

 

[Super Dave]

Well done. Proper grounding solves a lot of electrical issues and it often gets overlooked.

Have you heard that some minor fluctuation would be common?

 

[dryheat]

Fluctuation is perfectly normal.

 

[Super Dave]

Fluctuation is perfectly normal.

Thanks for the feedback. I will stop obsessing (for the most part) since it's now a very minor fluctuation.