17886 1 Mercury THROTTLE CAM

Illustration 1 g00281158
(1) Oil pressure sensor
(2) Air temperature sensor for the inlet manifold
(3) Air pressure sensor for the inlet manifold
(4) Atmospheric pressure sensor
(5) Coolant temperature sensor
(6) Primary speed/timing sensor
(7) Backup speed/timing sensor
(8) Fuel pressure sensor
(9) Fuel temperature sensor Failure of Sensors
All Sensors
A failure of any of the sensors may be caused by one of the following malfunctions:
Sensor output is open.
Sensor output is shorted to "- battery" or "+ battery".
Measured reading of the sensor is out of specification.Atmospheric Pressure Sensor
Atmospheric pressure sensor (4) measures the atmospheric pressure in the crankcase. A signal is sent to the Electronic Control Module (ECM).
Table 1
Atmospheric Pressure Sensor
Operating pressure range for the atmospheric pressure sensor 0 to 116 kPa (0 to 16.8 psi) Coolant Temperature Sensor
The coolant temperature sensor (5) monitors engine coolant temperature. This feature is used for engine system diagnostics with an output from the Electronic Control Module (ECM). The output of the ECM can indicate a high coolant temperature through a relay or a lamp. In addition, the sensor activates the cold start strategy which improves the startability of the engine.The minimum coolant temperature that will activate the alarm is 106°C (223°F). The switch opens as the coolant cools. A resetting procedure is not required.Failure of the Coolant Temperature Sensor
If one of the following conditions exist, a failure of the coolant temperature sensor may have occurred:
Sensor output is open.
Sensor output is shorted to ground or supply.
Measured reading of the coolant temperature is out of specification.The ECM will detect the failure of the coolant temperature sensor. The diagnostic lamp will warn the operator about the status of the coolant temperature sensor. The coolant temperature related strategies will be disabled. The failure of the coolant temperature sensor will not cause a shutdown of the engine or any horsepower change.Engine Oil Pressure Sensor
The engine oil pressure sensor (1) can detect engine oil pressure for diagnostic purposes. The engine oil pressure sensor sends a signal to the Electronic Control Module (ECM).Low Oil Pressure Warning
The setpoint is dependent upon the engine rpm. The fault will be active and logged only if the engine has been running for more than 15 seconds. Very Low Oil Pressure Warning
The very low oil pressure setpoint is dependent upon the engine rpm. If the customer specified parameter is selected, the ECM will derate the engine power. The engine horsepower will be limited.Failure of the Engine Oil Pressure Sensor
If one of the following conditions exist, a failure of the engine oil pressure sensor may have occurred:
The engine oil pressure sensor is open.
The engine oil pressure sensor is shorted to ground or supply.
Measured reading of the oil pressure is out of specification.The ECM will detect the failure of the engine oil pressure sensor. The diagnostic lamp warns the user about the status of the engine oil pressure sensor. The oil pressure related strategies will be disabled. The failure of the engine oil pressure sensor will not cause a shutdown of the engine or any horsepower change.Engine Speed/Timing Sensor
If the ECM does not receive a signal from engine speed/timing sensor (6) and (7), the "DIAGNOSTIC" lamp will indicate a diagnostic fault code which will be logged in the ECM memory.Intermittent failure of the sensor will cause erratic engine control.Fuel Pressure Sensor
Fuel pressure sensor (8) monitors the fuel filter outlet pressure. Low fuel pressure or high fuel pressure will not cause a shutdown of the engine or any horsepower change. Fuel pressure that is outside of the normal range will affect the engine performance. If the fuel filter outlet pressure is low, the fuel filter may need to be replaced.
Table 2
Fuel Pressure Sensor
Minimum allowable pressure of the fuel transfer pump at full load speed 415 kPa (60 psi)
Minimum allowable pressure in the fuel manifold at full load speed 276 kPa (40 psi) Fuel Temperature Sensor
Fuel temperature sensor (9) monitors the fuel temperature. Fuel temperature is monitored in order to adjust the fuel rate so that the engine will deliver consistent power. The fuel temperature sensor can also be used to warn the operator of excessive fuel temperature. A high fuel temperature can adversely affect the engine performance.
Table 3
Fuel Temperature Sensor
Operating range of the fuel temperature sensor for activation of the power correction by the ECM 30 to 70°C (86 to 158°F) Air Temperature Sensor for the Inlet Manifold
The air temperature sensor for the inlet manifold (2) measures the inlet manifold air temperature. The Electronic Control Module (ECM) monitors the signal from the air temperature sensor for the inlet manifold. The output of the ECM can indicate high inlet manifold air temperature through a relay or a lamp. The air temperature sensor for the inlet manifold will not cause a shutdown of the engine or any horsepower change.Note: The air temperature sensor for the inlet manifold will be affected by the heat that is conducted from the inlet manifold. This is true when the engine is idling and after the engine is shut off. This warm-up is due to the lack of coolant circulation through the engine. The reading from the air temperature sensor for the inlet manifold may be significantly higher than the actual temperature of the air inside the inlet manifold until the inlet manifold cools.Air Pressure Sensor for the Inlet Manifold
The air/fuel ratio control utilizes actual engine speed and actual boost pressure (inlet manifold air pressure) in order to control the transient smoke level. When the throttle is increased and when the engine demands more fuel, the fuel limit is controlled in order to reduce overall smoke levels of the engine exhaust.The Electronic Control Module (ECM) controls injection timing and the amount of fuel that is injected.Note: The air pressure sensor for the inlet manifold (3) is located on the top right side of the engine. The sensor is located in front of the air pressure sensor for the inlet manifold.