Fuel gauge Q

[Postie Bob]

For some time now my fuel gauge would go straight to F when ign turned on.
It now goes to 1/4 , ign on , with tank  empty .
I,ve noticed the electrical terminal in the centre of the tank unit is pointing to the left of the vehicle and according to my` Bedford Bible` it should be facing the front.   Would this be the cause of my grief?
I,ve been playing around with the electrics .. the dash printed circuit had blown where the oil pressure bulb fits ( earth side ) . I flattened out some resin cord solder and jammed it in the bulb holder and now I have oil pressure light & temp gauge .  Would that part of the circuit have anything to do with my fuel gauge?
Any assist greatly appreciated .
Cheers, Bob.

[Marishka]

Ive had the same drama with fuel gauge senders in the past,
And have found when ive removed them and inspected that the bit
with the thin wire wrapped, has been broken/worn away thus not giving a full electrical
Circuit.
Check out your sender before anything else.
I dont think it matters witch way its installed/pointing.


Ive used a tiny bit of steel wool to the same as you have
with the printed circuit dash pannel, 

DO NOT = Never use a 22 bullet as a fuze! I seen it on mythbusters the other week that they can go
off n shoot u in the leg!
Lol, ouch, 

[Marishka]

Im thinking 1 of these might replace the old buga,d one?

http://www.ebay.co.uk/itm/FUEL-SENDER-UNIVERSAL-TOP-MOUNT-230mm-deep-tank-/370406363677?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item563df0921d

[Postie Bob]

Have removed sender unit and my ohm meter is all over the place when I move the float up & down.
My book says ohms should be from 1 - 30 .   The ohms on the pic you sent are from 3 - 150 .
Does  the sender unit have to match the gauge ?
Wish I could just bung a dipstick in the tank  .

[Postie Bob]

ERRR.... Just checked the live wire that goes to the sender and all I`m getting is 4.5 volts
Where`s a good place to start looking where the rest has gone ?
With my ohm meter , what setting do I put it on to check sender ohms?
An electrical genius I`m not  .

[Marishka]

I think thats about right,
You dont want 12v down there unless you want your fuel tank
To be a time bomb?
 

[cfjeff]

gidday,

going back to your original fault, "when you turn it on the gauge reads full," this is caused by a short to earth in the sender wire or the sender. To find out which is at fault, unplug the sender wire from the sender and turn on the ignition, if it still goes to full then the fault is with the wiring loom (sender wire) if not then the fault is with the sender.

hope this helps
Cheers Jeff
 

[Postie Bob]

The gauge goes to full with the sender wire disconnected .
Where does that wire get it`s power ( 4.5v )  .  Is it connected to the printed circuit ?
Can I run a new cable from somewhere to over-ride it?
`Tis gettin to be a real can`o`worms 

[Marishka]

Yeah their supposed to go to full when disconnected
, dont ask me why but every time ive checked them by
removing the wire its gone to full like yours.

Disconnect your sender wire and Get a piece of wire about 4 ft long and connect it to your sender wire ( make sure its connected good and wrap that connection with electrical tape)
Try get a hold of a sender (preferably bedford one) ( but if unavailable try hz holden ute or any similar) and connect  a sender to that wire .
Walk over to the dash holding the sender and earth the sender body to a good ground,
Then turn on the ignition.
 While looking at the dash fuel gauge move the float up and down watching the reaction on the gauge.
Watching the sender position Stopping at 1/4, 1/2, 3/4, and full

This might shed some light on the problem.

Note= most times the sender will fault at 1/4 to 3/4 as that part of the sender wears out due to petrol sloshing sround while driving thus wearing the center of the sender wrap wiring ( this area is not visible untill sender is dismantled)

[Rogerfied]

 the only power supply is to one side of the fuel gauge at the dash, the fuel tank sender is a fluctuating earth, the position of the float changes the resistance in the earth (ohms) which is read by the dash gauge. Some tanks have an earth wire from the tank to the vehicle body then another from the tank sender to the dash gauge