Mass Air Flow Sensor
Automotive experts say that the amount of air-fuel mixture should always be right, but how do you really know if the mixture amount is right? Well, that's the reason your auto has the air mass meter. This metering device measures the mass of air flowing into the engine. Based on this measurement, the engine computer unit (ECU) bases its calculations as to the amount of fuel the injector will atomize into the intake valve. Turns out, an efficiently working air mass flow meter equals better MPG and fuel economy.
An air mass meter is a plastic tube mounted right after the air box and through which the filtered air freely flows. As the air passes through it, a sensor measures the air mass. Electrical wires attached to the meter then transmit the measurement to the ECU for calculation. This meter is crafted to last the life of a vehicle, but micro particulates seeping through, coming together with the filtered air, may build up in and around it over time and render it useless.
There are different air mass meters for different applications: vane meter, cold wire, membrane, and hotwire meter. Among these, only the last three directly measure the mass of air going into the engine. The vane meter measures air volume, temperature, and pressure to determine density. Air mass is then calculated from the result. Whichever air mass meter is mounted in your auto, see to it that you keep it in shape for a long and reliable service.