78 Toyota Hilux. The fuel reader is not accurate any more. When I fill up the tank it reads full tank if I drive around for a day or 2 maybe 25 miles on the high side. The fuel level reads under 1/4 of a tank, and it will stay there until I fill back up again. I test it out by putting 7 gallons in it and it read around 1/2 a tank then when I stopped the truck and restarted it read 1/4 again. What could be causing this?

 

You probably need to pull the fuel level sender/float out of the tank and check the ohms value at different setting on the wiper. Most all the older models need the wiper cleaned or repaired. I repaired mine in my ‘81

 

argh I dont want to drop that tank again. I want to change the fuel gage to a more modern one, and change its place I will wait till then and see what fun will be to match a new gauge with a new fuel sending unit.

@Lons81 When you checked of ohms on your what were the readings?

 

This may help, but I'll double check the FSM. This is from another post

Fuel Tank Sender Low (ohms) 110 = Empty High (ohms) Sender 3 = Full