[kelmcmillan]

Hi to all. My 64 has a gas gauge problem, It is a new gauge and new gauge volt regulator. I have a good ground. Gauge move up and down from full to about quarter when driving, the tank is full. Any Ideas?

Thanks

[stlwagon]

Welcome... We'll have better success finding you an answer in here.

[.boB]

How old is the sender?

[andrewmp6]

Sending unit or float is messed up i bet.

[Bob A]

What was the original problem, before you changed the voltage regulator & guage?

[kelmcmillan]

I have never changed it.

[Veronica]

Hello. If the water temp gauge isn't doing it also, that would be something between where the yellow wire leaves the back of the gauge and the float of the sending unit. It probably isn't the float, since they normally either float or don't float. I never saw one with variable buoyancy. Typically, a sending unit will be consistent in it's reading. It might be wrong, but it will always tell the same lie every time. That leaves the wire itself. It could be making poor contact at the sending unit or the gauge because of corrosion or something, or it might have a bad spot somewhere along its length that grounds itself out on the car occasionally as it gets bounced around going down the road. I would start by checking the wire. Again, this is all with the assumption that the water temp gauge isn't doing that also.

[kelmcmillan]

I am not using the temp gauge, I have an aftermarket under the dash for that. I will check the wiring. Thanks

[Veronica]

Hi again. If you aren't using the factory water temp gauge, that adds another section of wiring that could be responsible for what you're experiencing. There's a green wire with a black stripe that comes off of the back of the ignition switch and supplies power to the instrument cluster voltage regulator. From there, the wire splits to supply power to the two gauges. If the wire that used to supply power to the water temp gauge is doing doing something stupid, like shorting itself out on the car, that could cause your fuel gauge to do strange things. Good luck.

[kelmcmillan]

The gauge was alway off before, it would not go all the way to full. I put in the the new regulator at the same time.

[60's Refugee]

Given a new gauge and a new regulator that leaves the float. If it was the wire, it would be more likely to just turn off the gauge. Probably more often off than on. The float is actually a potentiometer and it is from there that the gas gauge gets the ability to go up or down based on the resistance created by the position on the float arm. Since the float wasn't replaced then that is where I'd look next. If the float sinks it will usually stay sunk. I bet it's the reostat part of the float going bad.

Wish I had enough gas to tell if mine works or not!

Good luck!

Harry