4 replies to this topic

[danb69]

Hi guy on my1989 mini some reason my fuel gauge isn't going up, its fill as well but nothing, I have checked if there is power going to the fuel tank but power keeps going on and off like flashing Should it do that? Need help

[Ethel]

Earth the green wire at the tank and the gauge should climb up to show full. If it does, earth it via the the black wire on the tank - if it doesn't do the same the black (earthing) wire is at fault.

[dklawson]

The "on-off" thing is normal and to be expected.  It is the voltage stabilizer operating.

 

As Ethel said, earth the green/black sending unit wire with the ignition on.  If the needle climbs to full, the gauge is working.  Now connect the green/black wire to the black wire on the sending unit and the needle should again go to full.  If it doesn't, that says the far end of the black wire has lost its earth connection.  If for BOTH tests, the gauge goes to full, that says the sending unit has failed and needs to be replaced.

[danb69]

I put them both together and the gauge went full but I put back on went straight back down I tried putting them on the other way on the tank and the gauge went up??

[dklawson]

Switching the two wire connections is not the answer.  The sending unit is a variable resistor situated between the car's chassis (earth) and the fuel gauge.  By hooking the wires up to the "wrong" terminals, what you have done is bypass the sending unit and connect the gauge directly to earth.  It will always read above full when this is done.

 

What you have learned from your test by holding the green/black wire's terminal to earth is that the gauge and voltage stabilizer (that powers the gauge) is/are working.  The problem is that your car needs a new sending unit.  This is easily replaced.  Drive the car until using a flashlight through the tank's filler neck you can see that the level of fuel is below the circular hole the sending unit is installed in.  Buy a new sending unit AND new sealing rubber gasket.  Disconnect the sending unit wires and use a flat bladed screwdriver and small hammer to tap the sending unit locking ring counterclockwise.  There are 3 ears on the locking ring.  Tap each one lightly working around in a circle until the locking ring releases the sending unit.  Reverse these steps to install your new sending unit after replacing the rubber seal.