Topic: Fluctuating Alternator Gauge

[orlandod]

Electronics is a another one of my hobbies and even I am getting frustrated by whats going on. I started a partial restoration of the dash since I needed to take out the AC/heater box due to cracking. Repainted the lower dash with red oxide on the back and black on the front. The gauge needles were painted, new printed circuit sheet, LED gauge bulbs and lenses, new 5v regulator, new voltage regulator in the engine bay along with a new battery, new ground wire from firewall to block, same alternator but I removed the harness and and cleaned up the connectors and reinstalled. I even went as far to install a secondary ground from the lower dash to the car body and still the Alternator gauge is bouncing around and when it does the foot well lights fluctuate. I stopped into three auto parts stores and they all said the alternator is good..... suggestions would be appreciated.
As I am driving it will settle down but then start up again???
FYI... before starting the project the gauge was rock solid to the point where I thought it was non functional.

[1967 eight barrel]

I had a similar issue with my Shelby with the needle bouncing all over the place. It turned out to be a regulator. I went solid-state. I used the reproduction Concours cover and a Dremel drum sanding bit to shape the resin so the cover would fit.  It's pretty much rock solid again.

                                                                  -Keith 

[orlandod]

I just installed a AMK C8TF-Autolite thinking the old one was bad. Is this new one not solid state electronics???

[cobrajet_carl]

What does it do if the engine is off and you turn on the headlights on hi beam?

[orlandod]

Just went out to the garage and the gauge moves slightly to the discharge side of the dial so that tells me it knows what is going on and reporting properly.

[1967 eight barrel]

No, the AMK units are not solid-state. I had my AMK stater solenoid weld the contacts, as well as the regulator points, burn.  When you have the turn signal in operation, step on the brakes or turn the headlights on it should slightly fluctuate to the discharge side.  Because of the Shelby having six 1157 bulbs burning it was much more apparent until I went to the plasma LED lamps. Much less draw now.
                                                                                                     -Keith

[orlandod]

I have replaces all the bulbs in the car to LED (excluding headlights), front and back turn, interior, gauges, glove, sifter, radio, backup, trunk, side markers. The left side seems to have more difficulty when it comes to turn signals. The left turn rate will actually slow down to the point of stopping when I am at a light. When I reduce the load by putting the car in neutral or if I release the brakes when the is green the indicators start up again.

[1967 eight barrel]

I am running all LED as well but the headlamps and the front running lamp/turn signal bulbs. It's nice to be able to see the instruments at night now.  I have decided to run the plug and play relays for the headlamps from Rocketman. He primarily caters to the cougar community.  The halogen lamps are substantially brighter because they pull power via the battery, not through the harness. They require no modification and for those of us who actually drive our cars, they are night and day difference.
Bob is a great guy and will always take the time to explain anything that is in question.
                                                                                                         -Keith


https://www.rccinnovations.com/index.php?show=menu-mustang-all

[cobrajet_carl]

Just went out to the garage and the gauge moves slightly to the discharge side of the dial so that tells me it knows what is going on and reporting properly.

Really sounds like the regulator.

[midlife]

Really sounds like the regulator.

+1. 
If you're not going true concours, you can get a solid-state version.  Some folks take the concours cover and swap it onto the solid-state with some success. 

[Bob Gaines]

+1. 
If you're not going true concours, you can get a solid-state version.  Some folks take the concours cover and swap it onto the solid-state with some success.

The reproduction assemblyline ones Virginia sells are solid state.

[orlandod]

I honestly thought I was buying a solid state regulator from AMK but as "1967 eight barrel" commented that is not the case. I guess the next thing to do is spend another $25 to eliminate the regulator from the equation. I am looking for an inexpensive one and came across this at Napa...... comments

https://www.napaonline.com/en/p/MPEVR440SB?partTypeName=Voltage+Regulator&keywordInput=voltage+regulator

If this does not solve the problem I guess the alternator will need to be looked at next.

[RoyceP]

This might help:

https://www.428cobrajet.org/forum/index.php?topic=11197.msg66393#msg66393

I honestly thought I was buying a solid state regulator from AMK but as "1967 eight barrel" commented that is not the case. I guess the next thing to do is spend another $25 to eliminate the regulator from the equation. I am looking for an inexpensive one and came across this at Napa...... comments

https://www.napaonline.com/en/p/MPEVR440SB?partTypeName=Voltage+Regulator&keywordInput=voltage+regulator

If this does not solve the problem I guess the alternator will need to be looked at next.

[orlandod]

Solved...... partially. I went out to Napa and picked up voltage regulator VR440SB and that solved the fluctuating alternator gauge and flickering lights.

The next annoying thing is that the turn signals slow down and even stop after sitting at the light for a while. I am wondering if it is cheap electronic flashes I installed to go with all the LED lamps I was putting in the car. Are there better quality units out there?

[carlite65]

"cheap electronic flashes"..............therein lies your answer.