48409 Mercury SCREW, MERCURY SWITHCH TO EXHAUST COVER (5/8")

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Schematic of the electronic control
(1) Connector for fuel injection pump
(2) ECM
(3) Voltage load protection module
(4) Service tool connector
(5) Timing wheel
(6) Speed/timing sensor
(7) Machine interface connector
(8) Boost pressure sensor
(9) Engine coolant temperature sensor
(10) Engine oil pressure sensor
(11) Air inlet temperature sensor The electronic control system has the following components:
ECM
Pressure sensors
Temperature Sensors
Speed/timing sensor
Voltage load protection moduleECM
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ECM
The ECM functions as the governor and the computer for the fuel system. The ECM receives all the signals from the sensors in order to control the timing and the engine speed.The reasons for having passwords in an ECM are the following reasons:
Reprogramming that is unauthorized
Erasing of logged events that is unauthorized
Allow the customer to control certain programmable engine parameters.The factory passwords restrict changes to authorized personnel. Factory passwords are required to clear any event code. Refer to the following Troubleshooting, "Factory Passwords" For more information on the passwords.The ECM has an excellent record of reliability. Any problems in the system are most likely to be the connectors and the wiring harness. The ECM should be the last item in troubleshooting the engine.The personality module contains the software with all the fuel setting information. The information determines the engine performance. The personality module is installed behind the access panel on the ECM. Flash programming is the method of programming or updating the personality module. Refer to the following Troubleshooting, RENR2417, "Flashing Programming " for the instructions on the flash programming of the personality module. The ECM is sealed and the ECM needs no routine adjustment or maintenance.Speed/Timing Sensor
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Timing wheel on crankshaft
The primary engine position is a passive sensor. The timing wheel is located on the crankshaft. The speed/timing sensor receives a signal from the teeth on timing wheel. The extra space on the timing wheel gives one revolution per space. The space is oriented so that the space is 40 degrees after top center.
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Schematic for speed/timing sensor
When the engine is cranking, the ECM uses the signal from the speed/timing sensor in the fuel injection pump. When the engine is running the ECM uses the signal from the speed/timing sensor on the crankshaft. This speed/timing sensor is the primary source of the engine position.Pressure Sensors
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Schematic for pressure sensors
The boost pressure sensor and the engine oil pressure sensor are active sensors.The boost pressure sensor provides the ECM with a measurement of inlet manifold pressure in order to control the air/fuel ratio. This will reduce the engine smoke during transient conditions.The operating range for the boost pressure sensor ... 55 kPa to 339 kPa (8 psi to 50 psi)The engine oil pressure sensor provides the ECM with a measurement of engine oil pressure. The ECM can warn the operator of possible conditions that can damage the engine. This includes the detection of an oil filter that is blocked.The operating range for the engine oil pressure sensor ... 55 kPa to 339 kPa (8 psi to 50 psi)Temperature Sensors
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Schematic for the temperature sensors
The air inlet temperature sensor and the coolant temperature sensor are passive sensors. Each sensor provides a temperature input to the ECM. The ECM controls following operations:
Fuel delivery
Injection timingThe operating range for the sensors ... −40 °C to 150 °C (−40 °F to 302 °F)The sensors are also used for engine monitoring.Voltage Load Protection Module
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Voltage load protection module
The voltage load protection module monitors the voltage of the system. The voltage load protection module will shut down the fuel injection pump if there is a high voltage on the system.