B150 1/2 Ton Van V6-239 3.9L (1989)
Manifold Pressure/Vacuum Sensor: Description and Operation
Fig. 3 Manifold Absolute Pressure (MAP) sensor location
The MAP sensor, Fig. 3, is mounted in the engine compartment on the dash panel and monitors intake manifold vacuum through a line connected to
the throttle body. The sensor converts manifold vacuum (negative pressure) and barometric pressure into electrical signals and transmits these signals to
the SMEC. The SMEC uses these signals to monitor engine load and atmospheric conditions in order to determine the correct air/fuel mixture for vehicle
operating conditions.