Fuel Gauge Question

[Hoehne]

I have a 1949 Willys pickup. I am replacing the fuel gauge. Does it matter which gauge post is connected to the ignition and which post is connected to the tank sender? The pickup is a 6 volt negative ground and the gauge is a KS Distometer.

[bmorgil]

LarrBeard will know for sure but, usually the sender wire goes to the post on the "Empty" side of the gauge. If you reverse it from the way it should be, it will read full when its empty and empty when its full. It is basically a volt meter.

[LarrBeard]

"Does it matter which gauge post is connected to the ignition and which post is connected to the tank sender?"

I believe the gauges on the early trucks were thermal gauges - they were not polarity sensitive. I agree with Bob - power to F side, sender to E side. Leave a little slack in the wires, and if you get it backwards - just swap the wires.

Now - a bit of discussion. Modern senders and old gauges don't match up all that well. If you have the tank off the truck, it would be a good idea to do some calibration before you put everything back together (I wish I had thought of that when I replaced the tank and sender on the '48).

Set the empty tank off to one side on a bench, sawhorses or whatever. Rig a wire from the sender terminal to the fuel gauge and connect a good ground from the tank to the vehicle frame. Install the sender in the tank and see what the fuel gauge reads. It should read close to E. If it is pegged way below E or if it reads upscale from E you will need to do some bending of the float arm to get it close. (I don't remember which way to bend it to get which way - just bend and try a bit.)

Someone on one of the forums a while back suggested that you put a gallon or two of water in the tank and set the float to read E with a 1 or 2-gallon reserve. There is almost no chance that the float/gauge pair will read F when the tank is just exactly Full. If it runs over I know it's full, I just really want to know when it's about empty.

Good Luck - and show us some pictures of the '49. (You show me yours, I'll show you mine ....). There aren't many flat fender trucks about any more.

[Hoehne]

Thank you for your info. The gauge is the thermal type. I will try to attach some pictures.