Q: What is the purpose and location of the MAP sensor in Ford Excursion?
A: The MAP sensor is mounted on a bracket in the engine compartment, specifically on a bracket attached to the air conditioning evaporator housing in 7.3L diesel models. On 6.4L engines, the MAP sensor is threaded into the top of the intake manifold. The Manifold Absolute Pressure (MAP) sensor monitors the intake manifold pressure changes resulting from changes in engine load and speed and converts the information into a voltage output. The PCM uses the MAP sensor to control fuel delivery and ignition timing. The PCM will receive information as a voltage signal that will vary from 1.9 to 2.1 volts at closed throttle (high vacuum) and 0.3 to 0.5 volt at wide open throttle (low vacuum). The voltage range values will vary slightly according to changes in altitude. A problem in any of the MAP sensor circuits will set a diagnostic trouble code. Make sure the ignition key is in the OFF position. Disconnect the electrical connector and the vacuum hose from the MAP sensor. Remove the screws that retain the MAP sensor to the bracket. Remove the MAP sensor. Installation is the reverse of removal.