Removal/refitting

The air flow meter quantifies the flow of air taken in by the engine through the throttle valve controlled by the accelerator cable and sends a signal to the control unit on the basis of which the fuel injection time is determined.

The air flow meter functions according to the principle of the fluctuating throttle valve: a spiral spring acts as an acting force on the throttle valve itself so that, with a certain quantity of air, a precise angular position will be obtained. Compensation for the pressure oscillations arising from the piston strokes is carried out by a compensation throttle valve closely connected to the measuring throttle valve. The electric signal is generated by the trailing of a potentiometer fixed to the shaft of the fluctuating throttle valve.

The intake air temperature sensor is located inside the air flow meter and is realized with a negative resistance coefficient (NTC) (i.e. able to reduce its resistance in proportion to the rise in temperature) connected to the control unit.

This sensor enables the control unit to take into account the variations in air density during the injection phase.

REMOVAL/REFITTING

• Disconnect the negative cable from the battery.

1. Disconnect the electrical connection from the air flow meter.

1. Unscrew the screws securing the air cleaner cover.
2. Unscrew the screw securing the air flow meter support bracket.
3. Disconnect the corrugated sleeve from the air flow meter after loosening the relative clamp.

1. Remove the air cleaner cover-air flow meter assembly.