Manifold Absolute Pressure (Map) Sensor
This sensor monitors all changes in manifold pressure resulting from engine load, speed, and atmospheric pressure variations. The ECA applies a 9-volt reference voltage to sensor and monitors resultant output voltage to determine part throttle spark advance and EGR flow rate. The MAP sensor is mounted on the left rocker arm cover. See Figure.
NOTE:
A running change was made in the 1978 EEC I system. The Barometric Pressure Sensor and the Manifold Absolute Pressure Sensor were combined in a single housing.