Air Flow Meter/Sensor: Description and Operation

Fig. 26 Air Flow Meter Inspection:

PURPOSE
Measures quantity of air flowing into engine intake system. Built-in intake air temperature sensor allows PCME to compensate for air mass variations related to temperature.

LOCATION
Left side engine compartment, attached to air cleaner assembly.

OPERATION
Measures airflow with a potentiometer rotated by a spring loaded measuring plate. Incoming air moves the measuring plate in relation to volume (more air, more movement), overriding spring tension. As the measuring plate moves, contacts in the attached potentiometer also move, varying potentiometer resistance and the input voltage signal sent to the PCME.

PCME factors intake air temperature into fuel quantity calculations because density varies with temperature (cold air is denser than warm). With both flow volume (measuring plate and potentiometer) and temperature information, PCME makes precise mixture adjustments.