Ebay fuel sender

Another reason the OEM sender isn't linear is the thermal gauge. Most common is a 20 ohm gauge. It has approx' 13 inches of nickle-chromium resistor wire that measures 1.5 ohms per inch at 68 degrees. As it heats up its per inch resistance changes. This is why half the 80-10 range and needle position is 23 ohms and not 45 ohms.