My factory rally pac oil gauge will flutter when I turn the lights on, (this seems to be the correlation, but it does not occur all of the time, not a constant flutter when the lights are on…seems to be that initial current draw from the lamps that sets it off)
I also get a slight needle drop from when the car off, when I turn the lights on (key off). Anyone know why this happening, how to fix it...thanks

 

It's happening because turning the lights on causes a voltage drop, which affects the electric oil pressure gauge. The problem could be the regulator going bad, or it could be any one of a multitude of connections in the wire harness or grounds. Do you have all the ground straps in place between the engine and body?

 

It is always a good idea to run a separate ground wire from the metal housing of the rally pac to a good ground behind the dash. If you know where the ground plane is in the flex circuit, run the ground from that point.

 

In my '79 Olds 88, the voltmeter needle swings back and forth in time with the turn signals. The voltmeter is an aftermarket item , and is part of a trio of mini-gauges. I didn't install the gauges, so I'm not sure where the voltmeter is hooked into the electricals , but it's apparently not the best place to hook up a voltmeter !

 

You have a bad ground. I had a similar problem with my Fuel gauge.
Headlights Off, gauge was correct. Headlights On, needed drifted down towards empty.
One or more of the Metal grounding tabs on your panel is not connected or rusted.
If you cant find/clean the contact you will need to run a new ground wire to the meters effected.

Test:
With a known good and charged car battery, start the car and note the position of all gauge needles (with headlights / AC off). Then turn on the headlights and look for needle movement. If the need changes, you have a ground and or low voltage problem.


https://classicoldsmobile.com/forums...s-issuses.html

 

Thanks. I suspect I have a voltage regulator that is intermittent/not stepping up to the ~ 14 volts rang. Will pick up a new one this weekend. It may or may not help but needs to be replaced. And I need to replace my negative battery cable. .It is the original factory cable. (has the correct factory part number stamped into the cable covering not printed onto the covering as I have seen on repo cables). Been trying to find a quality replacement and I think have found one..So between the two hopfully the issue will get corrected....

 

It shouldn't matter where the voltmeter is hooked. Voltage is voltage. As long as one side of the meter is hooked to something that has a direct line to the battery's positive terminal and the other side is well-grounded, it should work fine. More likely, though, is that the meter is hooked to a line that is switched with the ignition so that the voltmeter isn't reading the voltage 24/7/365. Voltmeters do take a slight draw on the battery and would run it down if left connected permanently.

I think the slight movement of the voltmeter in time with the turn signals is perfectly normal. Each time they turn on, there's a small, sudden draw on the system that it takes a moment for the voltage regulator to react to.

 

It has been awhile since I have had the bezel off.. but I don’t recall the tab missing. But I will look this spring. I think I have a ground issue. Still have the flutter and once I had it on the temp gauge for a few seconds last time I started the car up in late fall, after the car was not ran for a few weeks. I have ran grounds from the case to the battery, grounded the sending unit to the battery and it did not help. I still think one theory is that it’s the sending unit..If I had a factory sending unit to try maybe it would help…just a theory

 

I know this a different question, but I'm new at this and don't know where else to look. I am looking for a wiring diagram for a 67 442 with gauges, all of my books only show diagrams without gauges. I would appreciate any help you guys might have.
Tom.