Map Sensors

The MAP (Manifold Absolute pressure) sensor is a device that converts the inlet manifold pressure to an electrical signal for the ECU. The ECU uses this signal to determine engine load when calculating ignition and fueling requirements.

The output and hence the testing procedures depend upon the type of sensor. There are basically two types of sensor, which have varying voltage signal (GM) or a varying frequency signal (Ford). In both cases testing is a simple matter of comparing vacuum readings to output voltage/signal.

The biggest failing with MAP sensors is the vacuum supply, cracked, blocked or loose fitting vacuum pipes can all cause problems. poor engine condition is a problem that is often overlooked, a worn engine will have a low vacuum. This translates to a rich mixture, use a vacuum gauge and check the engine condition.