Manifold Air Temperature (Mat) Sensor; Mat Sensor Removal And Installation - Mercury 25 EFI Service Manual

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DMT 2004 Digital Multimeter

Manifold Air Temperature (MAT) Sensor

The manifold intake air temperature sensor is a thermistor that controls a signal voltage to the ECM. It is located near the air

entrance of the throttle body. It informs the ECM of the air temperature before the air enters the intake manifold. The ECM

adjusts the fuel injection duration needed to run the engine at optimum efficiency according to the MAT information. When

intake air is cold, the sensor resistance is high. As the air temperature rises, resistance lowers.

MAT Sensor Removal

Remove the two bolts securing the electrical cover. Do not lose the spacers.

Remove the electrical cover from the grommets in the intake manifold.

Pull the MAT sensor out of the rubber grommet.

Remove the engine harness connector from the MAT sensor.

90-8M0105568 eng MARCH 2016

Meter Test Leads

Oil pressure switch metal body

91‑892647A01

Grommets in the intake manifold

Bolts securing the electrical cover (2)

19.3 ‑ 27.5 kPa (2.8 ‑ 4.0 PSI)

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