Frequently Asked Question
Manifold Pressure always reads too high
Last Updated 2 years ago
MAP will display absolute air pressure. At sea level, it will match the altimeter setting. For every 100 feet above sea level, it will read 0.1" less than the altimeter setting.
The ground for the sensor may be open circuit. To test, turn on the power to the instrument and MAP sensor. Using a voltmeter, touch the black lead to the ground for the airplane. Touch the red voltmeter lead to the metal part of the d-sub connector of the MAP sensor, with the connector plugged into the sensor. You should measure less than 0.020 volts (20 mV). If you measure something in the range of volts, the ground is missing.
The scale factor and/or offset may not be set correctly.