IAFM TMAP Sensor

This IAFM T/MAP sensor is used on the MPI 4.3L, 5.0L and 5.7L engines. The “T”in T/MAP stands for temperature. This sensor measures barometric pressure, intake manifold pressure and intake manifold air temperature. This sensor is a four wire sensor, using the additional wire forthe manifold or intake air temperature signal (MAT or IAT). The IAT shares the sensor return or ground with the MAP. The thermistor for intake air temperature measurement is pictured above. It is yellow in color. See the Intake Air Temperature sensor section for it’s operation.

Speed / Density Fuel System

The solid line in this chart represents the voltage output from a MAP sensor through the whole vacuum range at sea level.

The dotted line represents the same sensor output at a higher altitude. Notice the entire voltage output from the MAP sensor is lower, which means the engine will get less fuel throughout the entire rpm range of the engine.

At altitude, less oxygen in the air means less fuel needed.

The same holds true on days when the atmospheric pressure outside is lower (i.e. a storm is present).

Make a habit of checking MAP key on voltage and key on baro readings to establish what is normal for your area for a particular engine package.

Also compare the “Baro derived from MAP”with a barometer reading to check MAP sensor accuracy.

A MAP sensor that reads baro incorrectly WILL cause a running problem that won’t set a fault code