780 V6-2849cc 2.8L SOHC B280F (1987)
Mass Air Flow Sensor: Description and Operation
Air Mass Meter
PURPOSE AND LOCATION
The air mass meter (located in engine compartment behind air filter housing) sends a signal (current) to the fuel injection ECU. The ECU can now
calculate the air mass entering the engine and adjust fuel injection duration as needed.
The air mass meter is of the hot-wire sensor type. Factors such as ambient temperature, humidity and pressure (altitude) are taken into consideration
with this type of air meter.
OPERATION
The measurement sensor (inside the meter housing) consists of a wire (hot-wire) which is maintained at 215°F (100°C) higher than the air entering the
engine. As the air mass passes over the hot-wire, wire resistance decreases and more current is required to maintain the correct temperature. The amount
of current required is used to calculate the air mass entering the engine.
When the engine is turned off, any dirt on the wire is burned off electrically by a one second burn off cycle that heats the wire to 1800°F (1000°C). Any
dirt remaining on the hot-wire can cause it to sent a faulty signal to the ECU.
