Checking the fuel gauge (BMW 3 Series E36)

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. The microprocessor in the instrument panel calculates the fuel level based on the resistance of the sensors and other parameters of the car, which is indicated on the instrument panel.

Both sensors have the same potentiometers, the test for both sensors is the same. Fuel pump (in the right fuel sensor) can only be checked at the service station in the removed state. Check the pump performance in the installed position using the above method.

Examination

Remove the fuel level sensor.

Connect an ohmmeter to the terminals of the fuel level sensor connector, see the figures in the subsection "Removal and installation the fuel level sensor".

Keep the fuel gauge in the working position, the float is at the bottom, and in this position the indicator on the instrument panel would show "reserve". The specified value is 10 + 2 ohms.

Turn the fuel gauge 180°, the float is on top, and in this position the indicator on the dashboard would show "full". The specified value is 250 + 5 ohms.

Replace the defective fuel level sensor unit as a set.

Please note: Fuel sensors are supplied as complete kits only, individual parts cannot be replaced.

(The original is located on the internet portal «bmwman.ru»)