Fuel Gauge Always Reading Full when driving. 1992 Ranger 2.3l

[NickYurt135]

The whole time I have owned this ranger the fuel gauge has never worked. I have put 2 new fuel pump which both had new sending units in, I have put in new fuel gauges themselves and played around with anti slosh module. But nothing has changed it. I remember for a little while my gauge would read 1/4 tank and once it got below that it would be a accurate reading, but after messing around with it, it has gone back to reading full. When the pump is outside of the tank i can move the float and the gauge read accurately but upon reinstallation it does not work. I have also made sure nothing inside the tank is blocking it or binding with the float. Any tips or insight would be awesome, this has been something that has frustrated me for the longest time.

 

[Things2do]

The sending unit is just a variable resistor attached to the float, with fuller being higher in resistance. The gauge passes a voltage across it to measure it. Unless the gauge itself or the sending unit arm is stuck, which yours don't seem to be, then a fuel gauge always pointing at full is usually caused by a break in the electrical continuity somewhere. A broken wire, a bad connector, or something like that.

When it is working outside of the tank, do you have it plugged into the harness under the truck the same as it would be when it's inside of the tank? If so, then unless you are holding it exactly in its usual place under the truck there may be a terminal loose inside of the connector that is being wiggled into making contact with the different stresses from you holding it. Aside from that, you could also check the ground terminal in the connector for continuity to ground and the wire that runs to there from the cluster for the reference voltage, perhaps while wiggling the wires around if they check out at first. I couldn't tell you which wires are for the sender and which wires are for the fuel pump without looking at a diagram, or what voltage you would be looking for, but since it works when the sender is out of the tank then whatever voltage you measure is probably fine as long as it's fairly consistent.

At least that's where I usually start after verifying that the connector on the back of the cluster is plugged in like it should be. I've never had to troubleshoot the gas gauge in a Ranger though, so there might be a specific common issue that's worth checking first.