You guys have inspired me to get off my butt and fix all the little things wrong on my 63 PV544. Saturday I finally installed a starter push button to save the ignition key. Now I'm ready for the next challenge. The fuel gauge has always read full(ignition on, any amount of fuel in the tank)since I purchased the car. Is it possible the previous owner connected some wires incorrectly or should I be looking for something else.
Thanks in advance,
Alan

Alan,
You mentioned installing a push-button starter. How did you do it? and where did you get a push button switch?
Harley

Harley, I followed the advice from a previous posting. The momentary switch I used was from a 122s parts car but there is nothing special about it. It's just a spring loaded push button momentary switch with 2 terminals. 1 terminal is wired to the hot terminal on the ignition switch (passenger side terminal of ignition switch)and 1 is connected to the wire that goes to the starter soleniod (top center terminal ignition switch, green wire). Disconnect the soleniod wire from the ignition switch and connect it to the momentary switch.
I made a mounting plate for the new switch from a small piece of aluminum angle. I used the 2 screws that hold the ignition switch in place to attach the aluminum angle. No new holes needed to be drilled into the dash.

The fuel gauge is working again. The sending unit and wire to the gauge were fine. The gauge terminals were clean but the paprer gasket surrounding the gauge mounting surface was only half in place. I replaced it with a rubber gasket from the 122s parts car fuel gauge and reinstalled. It works but I'm not really sure why. I suspect the gauge was touching somewhere it shouldn't have. Anyway on to the heater switch that will not close completely.
Thanks for all the replies
Alan

My experience has been that the gauge reading full with the ignition on indicated an open circuit, rather than a short. Usually has been a corroded
terminal on the back of the gauge, as pointed out by jmenacker.

The fuel gauge needle tends to stick on full on my '63 also. A rap on the dashboard with a rubber mallet when the tank is not full frees the needle on mine. I have been using the car as a daily driver for about nine months now. It seems to stick on full less and less the more the car is used.

The electrical connections on the back of the gauge had plenty of oxidation on them. Cleaning the connectors and threaded posts with a wire brush helped gauge reliability a lot.

Best regards,

Joe

If the gauge returns to empty with the key off then the problem probably lies in the sendaer on top of the tank (trunk floor). The gauge grounds through the varying resistance of the sender. So if the wire is inadvertantly grounded somewhere or the sender has developed a short somehow it will always get a full ground and read full. Try unhooking the wire from the sender and see if it reads empty. If if still reads full there is probably some short on the wire somewhere between the tank and the gauge. If it reads empty (and nothing looked funny with the way the wire was hooked to the sender - i.e. it should be insulated and isolated to the sender terminal) then take out the sender and give it a look. Be careful about sparks around gas vapors.

The gauge does return to empty with the ignition off. I disconnected the wire from the sending unit and the gauge remained at full. If I cannot track down the short could I simply run a new wire to the gauge from the sending unit?

Hi,

I also had a problem with the fuel gauge of my 544C for a while. The first thing I checked was the sender unit - and voila - the only mecanical part in the system caused al the trouble.
You can check the sender without removing it from the tank with a resistance meter. If the tank is full, you should read app. 200 ohms beetween the wire connection point and the car body, app. 10 ohm when the tank is empty. If you read an enormously high resistance you can be sure that the resistance wire in the sender is broken - then it is time to have a closer look at it. For those who just wonder how the sender looks like, I have taken some photos on my website www.oldie-werkstatt.de --> Tipps Technik --> Tankanzeige (sorry, german only)

Regards, Martin "McOldie"

Worst case - yes. But I'd do a little chacking on the gauge itself first, just to make sure no one has done anything creative witht he wiring there either. The gas gauge has 2 terminals. The positive side is used as a distribution point for various other devices that need a switched positive feed - so there are 3 or 4 (usually red) wires hooked to that side. The other terminal should only have the brown wire that leads to the sender. Before thinking about running a new wire just try unhooking the brown wire at the gauge, and see if that makes the gauge return to empty. If so then there definately is a short somewhere along the wire. If the gauge STILL stays on full when the key is turned on then there is probably some sort of short grounding that terminal somehow, so take the gauge out and give it a look.