FB/EK Fuel gauge - Dash and Tank Units

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rosco
Posts: 2569
Joined: Wed Feb 04, 2004 8:34 pm
State: VIC
Location: Melbourne

FB/EK Fuel gauge - Dash and Tank Units

Post by rosco »

This is a transcribe from the EK workshop manual.......

Dash and Tank Units

The fuel gauge consists of two units: the dash unit located in the instrument carrier panel, and the tank unit located in the fuel tank.

One terminal of the dash unit is connected to the ignition/starting switch so that the unit registers only when the ignition switch is turned on.
The dash unit is grounded to the instrument panel.
The other terminal of the dash unit is connected by a single wire (originally brown) to the tank unit, which is grounded on the tank to complete the circuit.

(Insert diagram 12F-1 here)

The dash unit pointer is moved by changing the magnetic pull of two coils in the unit.
The magnetic pull is controlled by the action of the tank unit, which contains a variable rheostat,the value of which varies with the movement of a float and arm.

The tank unit is mounted in the tank so that the float rises and falls on the surface of the fuel near the middle of the tank.

If the fuel gauge does not operate correctly, the dash unit, tank unit wiring , and tank unit should be tested separately to determine which is at fault.

A tester may be made from a new fuel gauge tank unit.

Attach a 5 foot piece of red coloured insulated wire (18 gauge) to the terminal post of the test tank unit, and attach a similar piece of black wire to the flange of the unit.

Attach a spring clip to the free end of each wire.

Test of Dash Unit

1. With the ignition/starting switch turned off, remove the instrument panel and disconnect the tank wire (brown) from the dash unit terminal.
Connect the red tester wire to this terminal and connect the black tester wire to a good ground (earth) on the vehicle.
Make sure that the other wire attached to the dash unit has a tight connection.

2. Turn the ignition switch "on" then move the tester arm up and down against the stops.
If the dash unit is sound, the pointer will move freely from Empty to Full with movement of the tester arm, indicating that the fault is in the wiring or tank unit.
If the pointer does not move, or only moves part way, the dash unit is faulty and should be replaced.

3. Turn the ignition switch off.
If the dash unit is sound, re-connect the wire to the terminal stud, being careful that the terminal of this wire does not come in contact with the other dash unit terminal, which would result in damage to the rheostat in the tank unit.

4. Install the instrument carrier panel assembly.


Test of Tank Unit Wiring

1. On models 219, 229, 2104 & 2106 - access to the tank unit may be gained by removing the spare wheel and on models 215 & 225 - by removing the rear compartment floor mat.

2. With the ignition switch off, remove the tank unit protector cap and disconnect the wire from the tank unit.
Connect the red wire of the test tank unit to the wire running to the dash unit (brown), and connect the black tester wire to ta good ground (earth) on the vehicle.

3. Turn the ignition switch on then move the tester arm up and down against the stops, while the dash unit is being observed.
If the wiring is sound, the dash unit pointer will move freely from "Empty" to "Full" with movement of the tester arm, indicating that the fault is in the tank unit.

4. If, during the test, the dash unit reads "Empty" at all times or the reading is noticeably lower than during the test of the dash unit - look for a ground in the wiring between the dash unit and the tank unit.
If the dash unit reads above "Full" at all times or if it reads higher at "Empty" and "Full" then the readings obtained during the dash unit test, look for points of high resistance, such as dirty connections, broken wire stands or an open circuit.

Test of Tank Unit

1. If the tests given above in dicate that the fault is in the tank unit, remove the fuel gauge tank unit so that it may be cleaned and tested.

2. Before removing the unit from the fuel tank, clean away any dirt that may have collected around the tank unit recess and note whether the insulation was in its correct position over the terminal and wire.
Road dirt, particularly calcium chloride, may have caused an electrical leak which threw the tank unit out of calibration.

3. After a thorough cleaning of the recess and removal of the tank unit, connect it to ground (earth) and to the wire leading to the dash unit, and test in the same manner when using the tester.
If one tank unit tests satisfactorily, it should be re-installed in the tank, otherwise it should be replaced with a new unit.

4. Install the tank unit protector cap and stick down the luggage compartment mat or replace the spare wheel.
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