Mass Air Meter

[87_5.0]

Can someone please explain the mass air meter thing to me, im new to this because i have an 87, but im in the process of getting an 89, so i want to look for some mods before i get it. thanks,

Brent

 

[jrichker]

Can someone please explain the mass air meter thing to me, im new to this because i have an 87, but im in the process of getting an 89, so i want to look for some mods before i get it. thanks,

Brent

Mass Air Flow is used to help the computer measure the amount of air entering the intake so that it knows how much fuel the engine needs to perform properly. Mass air flow measures not only the amount of air, but to a limited extent, also its density. Changes in humidity, barometric pressure and inlet air temperature also affect air density. The Manifold Atmospheric Pressure or MAP sensor measures the barometric air pressure. The ACT sensor measures the inlet air temperature. Using the input from these two other sensors helps the computer actually calculate the air density, The air/fuel ratio is calculated on the basis of air density, so the MAF. MAP & ACT work together to make it happen.

The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.

At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element casing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).