Removal and installation, checking of fuel level sensor (BMW 5 Series E34)

When the fuel level in the fuel tank drops, the float of the fuel reserve sensor drops. At the same time, the resistance of the sensor, taken from the sliding contact engine, increases. As a result, the voltage supplied to the fuel reserve indicator decreases and the indicator arrow shifts in the "empty" direction.

As the float continues to lower, the contact of the indicator closes and the warning light for remaining fuel lights up on the instrument panel.

Removal

Warning: Do not make an open fire! Fire hazard! When removing the fuel level sensor, the fuel tank must not be completely filled. Therefore, pump out the fuel into a suitable container. Fuel vapors are toxic, do not inhale fuel vapors. If possible, carry out work outdoors or provide sufficient ventilation.

Disconnect the positive and ground wires from the battery.

Remove the luggage compartment floor trim.



Loosen the screws and remove the cover.



Mark fuel hoses 2 with adhesive tape and disconnect them from fuel level sensor 1 by loosening the clamps.

Caution: The fuel system is under pressure, so disconnect the hoses slowly and wipe off any leaking fuel with a rag.

Disconnect connector 4. To do this, move the metal bar to the side and disconnect the connector.

Carefully knock off the union nut - three blows to the left. For this purpose, BMW service stations use tool 161020. This can also be done with a hardwood rod or a large screwdriver.



Lift the fuel gauge 1, tilt it to the side and pull it out. At the same time, put a rag and wipe off the leaking fuel.

If only the fuel level sensor is being removed, mark the fuel lines with tape before disconnecting them.

Examination

List of contacts of the fuel tank pump connector and the fuel level sensor:

• 1 Fuel level sensor mass
• 2 Control lamp
• 3 Fuel level sensor
• 4 Fuel pump weight
• 5 Fuel pump 1

Connect the ohmmeter to the fuel level sensor to terminals G and 31. On the connector these are contacts 1 and 3.

Keep the fuel gauge in the set position, the float is at the bottom, when the indicator on the car would show "reserve". Set value: 86.7±2.5 Ohm.

Turn the sensor 180°, the float is in the upper position, when the indicator on the car would show "full". The specified value: 3.2±0.7 Ohm.

Check the fuel level indicator contact: Connect an ohmmeter to terminals W and 31 of the fuel level sensor. The specified value with the sensor in the operating position: 0 Ohm; when turned 180°: infinity.

Installation

Connect the fuel pump fuel hoses to the fuel level sensor.

Insert the fuel level sensor with a new gasket. First insert the sealing ring into the hole in the fuel tank, and then insert the sensor.

Position the fuel gauge so that the connectors face the fuel hoses.

Screw on and tighten the union nut.

Connect the fuel hoses and secure them with new clamps.

Connect the connector and secure it with a metal bracket.

Install and tighten the cover screws, ensuring that the gasket is properly seated.

Connect the positive and ground wires to the battery.

Check the fuel level indicator on the instrument panel.