Map Sensor Test - Mercury 150 EFI Service Manual

FUEL INJECTION
PRESSURE TEST
IMPORTANT: When testing TPS voltage, do not move the drive mechanism (rotor/
wiper).
1. Connect DDT and rotate the key to the "ON" position.
2. Set DDT to read TPS voltage; expand the screen to show Now/Min/Max.
NOTE: Test accuracy is improved when TPS is at its lowest voltage reading; this may be
idle or WOT depending on model year.
3. Clear the minimum/maximum values on the DDT – press the "0" button.
4. Watch the DDT readings while pressing below the electrical connection point on the
TPS cover.
a -
5. Voltage reading should change:
Less than a couple of digits (i.e. 1.90 v to 1.92 v)
NOTE: Version 5.0 cartridge gives 3 decimal point (millivolts) accuracy if below 1 volt.
Less than 10 millivolts (i.e. 0.293 v to 0.285 v)
Replace any TPS that fails either test.

MAP Sensor Test

a -
Purpose: Determines whether the Manifold Absolute Pressure (MAP) Sensor is functioning properly through
the use of the Digital Diagnostic Terminal (DDT).
1. Place outboard in water, connect Digital Diagnostic Terminal (DDT) to engine.
NOTE: If MAP sensor is not functioning, #4 LED indicator light on DDT will be illuminated.
2. Start engine, allow to warm up. Using DATA MONITOR portion of DDT, access MAP
PSI.
Results: As throttle is advanced, numerical value on DDT display should increase. As throttle is retarded,
numerical value should decrease indicating MAP sensor is functioning. If numerical value does not
change as throttle setting varies, MAP sensor is defective. The ECM would revert to a default of
approximately 14.7 PSI (near sea level) should it not receive a signal from the MAP sensor.
Page 3B-34
a
Press on cover below electrical connection
MAP Sensor
a
58898
90-883728 JULY 2001