42253 Mercruiser BOLT, BOOSTER CYLINDER (LATER STYLE)

Sensor Locations for the C3.6 Engine
The illustrations in this section show the typical locations of the sensors for the industrial engine. Specific engines may appear different from the illustration due to differences in applications.
Illustration 1 g06484809
Typical example
(1) Temperature sensor for the NOx Reduction System (NRS)
(2) Aftercooler out temperature sensor
(3) Inlet manifold temperature and pressure sensor
(4) Exhaust gas valve for the NOx Reduction System (NRS)
(5) Fuel pressure sensor
(6) Coolant temperature sensor
(7) Suction control valve for the fuel injection pump
(8) Fuel temperature sensor
(9) Camshaft speed/timing sensor
Illustration 2 g06484819
Typical example
(10) Electronic actuated Turbocharger Wastegate (EWG)
(11) Electronic unit injector
(12) Crankshaft speed/timing sensor
(13) Engine oil pressure switch
(14) Electronic Control Module (ECM)
(15) Inlet air temperature sensor
(16) Water in fuel switchSensor Locations for the C2.8 Engine
The illustrations in this section show the typical locations of the sensors for the industrial engine. Specific engines may appear different from the illustration due to differences in applications.
Illustration 3 g06517718
Typical example
(1) Inlet manifold temperature sensor
(2) Inlet manifold pressure sensor
(3) Fuel pressure sensor
(4) Exhaust gas valve for the NOx Reduction System (NRS)
(5) Coolant temperature sensor
(6) Suction control valve for the fuel injection pump
(7) Fuel temperature sensor
(8) Camshaft speed/timing sensor
(9) Temperature sensor for the NOx Reduction System (NRS)
Illustration 4 g06517734
Typical example
(10) Electronic unit injector
(11) Crankshaft speed/timing sensor
(12) Engine oil pressure switch
(13) Electronic Control Module (ECM)
(14) Inlet air temperature sensor
(15) Water in fuel switchECM
Illustration 5 g06163526
Typical example
The Electronic Control Module (ECM) (1) functions as a governor and a computer for the fuel system. The ECM receives signals from the sensors to control the timing and the engine speed.The electronic system consists of the ECM, the engine sensors, and inputs from the parent machine. The ECM is the computer. The personality module is the software for the computer. The personality module contains the operating maps. The operating maps define the following characteristics of the engine:
Engine rating
Torque curves
High and low idle speed (rpm)
Emissions
Injection timingThe factory passwords restrict changes to authorized personnel. Factory passwords are required to clear any event code. Refer to 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 programmable software contains all the fuel setting information. The information determines the engine performance.Flash programming is the method of programming or updating the programmable software. Refer to Troubleshooting, "Flash Programming" for the instructions on the flash programming of the programmable software.The ECM is sealed and the ECM needs no routine adjustment or maintenance.Engine Speed
The electronic controls determine the injection timing, the amount of fuel that is delivered to the cylinders and the intake manifold pressure if an electronically controlled wastegate is installed. These decisions are based on the actual conditions and the desired conditions at any given time.The ECM has software that compares the desired engine speed to the actual engine speed. The actual engine speed is determined through the crankshaft speed/timing sensor and the camshaft speed/timing sensor. If the desired engine speed is greater than the actual engine speed, the ECM will instruct the electronic unit injector to inject more fuel to increase engine speed.Timing Considerations
Once the ECM has determined the amount of fuel that is required, the software must determine the timing of the fuel injection. Fuel injection timing is determined by the ECM after considering input from the following components:
Engine coolant temperature sensor
The sensor for the inlet manifold temperature and pressureAt start-up, the ECM determines the TOP CENTER position of the number 1 cylinder from the secondary speed/timing sensor on the camshaft. The ECM decides when fuel injection should occur relative to the TOP CENTER position. The ECM optimizes engine performance by control of each of the electronic unit injectors so that the required amount of fuel is injected at the precise cycle of the engine. The electronic unit injectors are supplied high-pressure fuel from the fuel manifold. The ECM also provides the signal to the solenoid in the fuel injection pump. The solenoid in the fuel injection pump controls a valve in the fuel injection pump. This valve controls the volume of fuel that enters the plungers. By controlling the volume of fuel that enters the plungers, this controls the pressure in the fuel manifold. Fuel that is not required for the engine is diverted away from the fuel injection pump back to the fuel tank.The ECM adjusts injection timing and fuel pressure for the best engine performance, the best fuel economy, and the best control of exhaust emissions.Fuel Injection
The programmable software inside the ECM sets certain limits on the amount of fuel that can be injected.The FRC Limit is a limit that is based on intake manifold air pressure and engine rpm. The FRC Limit is used to control the air/fuel ratio to control the exhaust emissions of the engine. When the ECM senses a higher int