map sensor

[miami man]

i was on the megasquirt homepage and it talks about a 3 bar and 4 bar map sensor. what is a map sensor on a car?

[floydiancomplex]

Manifold Absolute Pressure. It is used in place of the airflow meter. It determines fuel requirements based on
intake manifold pressure instead of the MAF to measure how much air the motor is getting. If you install a
megasquirt or any other aftermarket EMS you will use this and can ditch your restrictive MAF. Basically
your intake will look like a Honda intake with a filter, tube to the throttle body and nothing else in between.

[miami man]

thanks for the info