Fuel Gauge Freaking Out

[eastendmedic]

Any pointers as to why my fuel gauge will show a full tank when the truck is filled up but then within a few miles of driving drops down to empty....will occasionally go up to a 1/2 tank...then drop down again? Newbie here...any pointers for a fix. Thanks.

 

[FJ40Jim]

bad sender connection

Look at the wiring on top of the fuel tank at the sender. It tends to get dirty and corroded up there, but there's no way to clean it from outside.

Fortunately, there is a access hatch under the rear carpet to get at the connection and clean the green corrosion off the tabs.

Just remove the rear carpet trim molding. Roll up carpet, remove 2 phillips screws on access panel. Pry up panel. Sometimes it is very stuck to the weatherstripping.

You will see the wires to the sender unit now. Remove connector, clean connection with sandpaper, emory board, x-acto knife, whatever... Blow it clean w/ brake cleaner and compressed air. Reconnect, turn key to run position, watch fuel gage.

If gage still doesn't work, repeat as necessary.

 

[eastendmedic]

Thanks Jim!!!

As a newbie....Thanks A lot....not too many cruiser guys around my area...this place is an invaluable resource. I will give it a go and see what happens!

 

[lunyou]

i was told the truck i acquired used to do this but he did what FJ40Jim said and it works fine now.

lunyou

 

[Live to Ski]

Is the temp guage going wacky too? If so, the fuel level guage and temp guage share a ground. It's written up here in a few threads.

 

[eastendmedic]

Wacky

No, Just the fuel gauge....it seems to be when the tank drops below 3/4 of a tank...then it goes to E....I cleaned the contacts with contact cleaner, emory paper, and emory board....still doing it? Bad float?

 

[jclark]

Access panel

Jim,

I have this issue and my former mechanic said only some LC's have this access panel, otherwise you have to drop the gas tank to get at the sensor.

Do you know anything about certain years having this access panel and other's not? My former mech said mine did not and quoted me a grip of cash to drop the tank and replace the sensor.

 

[FJ40Jim]

I have this issue and my former mechanic said only some LC's have this access panel, otherwise you have to drop the gas tank to get at the sensor.
Do you know anything about certain years having this access panel and other's not? My former mech said mine did not and quoted me a grip of cash to drop the tank and replace the sensor.

All 40 and 60 series have the access panel to get to the fuel sender.

Can't remember seeing an access panel in the back of the FJ55's.

 

[eastendmedic]

Tried it all...no worky!

Okay,
so I did what you guys said again.....still no luck.....if the tank is full it says full on the gauge however after driving for a day it drops to E.....so a took out a test light and when grounded to the frame or even the top of the tank and contact is made with the terminal it lights up an flashes...low and behold the gauge goes to full.....should I assume that the sending unit is bad.....is this easy to change as my 60 has a access panel.....the gauge works fine....the terminals have been cleaned and it still doesn't work....what do you guys think...any assistance appreciated.

 

[FJ40Jim]

The sending unit should give 17 ohms full and 120 ohms empty.

Pull it out, test, replace as necessary.