Fuel Gauge Indication Problem

The previous owner of my 710K Pinz installed a VDO fuel gauge on the dash. The problem I am seeing is that the gauge is indicating empty at half tank. I do not think the sender was changed. So could the problem be is it is a 12VDC gauge?

Any guesses and what should I look for?

Mike

Las Vegas NM

At half tank or 1/4 tank?
As a European vehicle, it goes to "R" when there is about 70Km of fuel left. That's their Reserve setting. There is no "Empty" mark.

At half tank. When the gauge is registering empty it takes 10 gallons to fill the tank up to the filler neck.

Finally got out to look at mine with a volt meter. As you can see, it is just a bit over 1/2 tank and the gauge has 3.18 volts to the sense line.

Finally got out to check mine with a volt meter. At a bit over 1/2 tank, the sense line has 3.18 volts.

I just installed a VDO guage in mine. There is a small screw on side of guage to adjust it. Use plastic insulated screwdriver. The sending unit should be 0-100 ohms depending on full or empty. That can be checked with multimeter.