Air Flow Meter/Sensor: Description and Operation

Fig. 41 Air Flow Meter.:

The air flow meter measures the quantity of intake air, and sends a signal to the control unit so that the base pulse width can be determined for the correct fuel injection by the injector. The air flow meter is equipped with a flap in the air passage. As air flows through the passage, the flap rotates and its angle of rotation electronically signals the control unit.
During idle operation when there is less intake air, the air flows parallel with the flap through the by-pass port so that the specified intake air flow can be provided correctly.
An air temperature sensor is located in the air passage. The by-pass port has the air by-pass screw which regulates the idle mixture ratio. The air by-pass screw is preset and sealed at the factory.