881247A 1 Mercury ALTERNATOR

Illustration 1 g06392126
Note: Items in red are mounted off engine.
(1) Fuel Cooler
(2) Injector
(3) Fuel Manifold (Pressure relief valve opens at ( 241 9 MPa (34954 1305 psi))
(4) Rail Pressure Sensor
(5) Stop Cock
(6) Fuel Tank
(7) Pumping Element
(8) Cam Box
(9) Fuel Temperature
(10) Feed Pump
(11) Low-Pressure Regulator (Opens at 25 5 kPa (4 1 psi))
(12) Primary Filter
(13) Transfer Pump (Pressure relief valve. Pump has zero external flow at 450 kPa (65 psi))
(14) Secondary Filter (Max Pressure = 125 kPa (18 psi))
(15) Return Pressure Sensor
(16) Feed Pressure Sensor (If Fitted)Fuel is drawn from the fuel tank through the off engine primary fuel filter to the electronic fuel pump.The fuel flows from the secondary fuel filter to a pressure regulator. A pressure regulator that is installed in the low-pressure fuel system controls the fuel pressure to the fuel injection pump. The pressure regulator regulates the fuel to a pressure of 25 kPa (3.63 psi) to 72 kPa (10.44 psi) when the engine is at idle speed.From the pressure regulator, the fuel flows to the fuel injection pump. The fuel is pumped at an increased pressure up to 200 MPa (29000 psi) to the fuel manifold (rail).Fuel that has too high a pressure from the fuel manifold (rail) returns through the pressure relief valve to the return line. Fuel that is leak off from the electronic unit injectors flows to the return line. The fuel then flows through a fuel cooler on the way back to the fuel tank.Note: All valves in the fuel return line must be open before and during engine operation to help prevent high fuel pressure. High fuel pressure may cause fuel system damage and failure of the high-pressure pump shaft seal.High-Pressure Fuel System
Illustration 2 g06392476
(1) Fuel injection pump
(2) Fuel temperature sensor
(3) Suction control valve for the fuel injection pump
(4) Pressure relief valve
(5) Electronic unit injector
(6) Fuel manifold (rail)
(7) Fuel pressure sensor
(8) Leak Detection SensorThe fuel injection pump (1) feeds fuel to the high-pressure fuel manifold (rail) (6). The fuel is at a maximum pressure of 200 MPa (29000 psi). A pressure sensor (7) in the high-pressure fuel manifold (rail) (6) monitors the fuel pressure in the high-pressure fuel manifold (rail) (6). The ECM controls a suction control valve (3) in the fuel injection pump (1) to maintain the actual pressure in the high-pressure fuel manifold (6) at the desired level. The high-pressure fuel is continuously available at each injector. The ECM determines the correct time for activation of the correct electronic injector (5) which allows fuel to be injected into the cylinder. The leakoff fuel from each injector passes into a drilling which runs along the inside of the cylinder head. A pipe is connected to the rear of the cylinder head to return the leakoff fuel to the fuel tank.Components of the Fuel Injection System
The fuel injection system has the following mechanical components:
Primary filter/water separator
Electric transfer pump
Secondary fuel filter
Fuel injection pump
Fuel injectors
Fuel manifold
Pressure relief valve
Fuel pressure sensor
Fuel temperature sensorThe following list contains examples of both service and repairs when you must prime the system:
A fuel filter is changed.
A low-pressure fuel line is replaced.
The fuel injection pump is replaced.For the correct procedure to prime the fuel system, refer to Systems Operation, Testing and Adjusting, "Fuel System - Prime".Primary Filter/Water Separator
Illustration 3 g03879983The primary filter/water separator (1) is located off the engine between the fuel tank and on engine fuel lift pump.Secondary Fuel Filter
Illustration 4 g03879871The secondary fuel filter (1) is on the left side of the engine after the electric transfer pump.Fuel Pump Assembly
Illustration 5 g03875270
(1) Suction Control Valve
(2) Fuel Temperature Sensor
(3) Fuel Injection PumpThe fuel pump assembly consists of a low-pressure transfer pump and a high-pressure fuel injection pump. The pump assembly is driven from a gear in the front timing case at engine speed. The fuel injection pump (3) has three plungers that are driven by a camshaft. The fuel injection pump (3) delivers a volume of fuel three times for each revolution. The stroke of the plungers are fixed.The injector will use only part of the fuel that is delivered by each stroke of the pistons in the pump. The suction control valve (1) for the fuel injection pump (3) is controlled by the ECM. This maintains the fuel pressure in the fuel manifold (rail) at the correct level. A feature of the fuel injection pump (1) allows fuel to return to the tank continuously.The fuel temperature sensor (2) measures the temperature of the fuel. The ECM receives the signal from the fuel temperature sensor (2). The ECM calculates the volume of fuel.The fuel injection pump has the following operation:
Generation of high-pressure fuelThe fuel output of the fuel injection pump is controlled by the ECM in response to changes in the demand of fuel pressure.Shutoff
The engine shuts off by preventing the electronic unit injectors from injecting. The ECM then closes the suction control valve to prevent the pressure in the fuel manifold (rail) from increasing.Control
The ECM determines the quantity, timing, and pressure of the fuel to be injected into the fuel injector.The ECM uses input from the sensors on the engine. These sensors include the speed/timing sensors and the pressure sensors.The ECM controls the timing and the flow of fuel by actuating the injector solenoid.The amount of fuel is proportional to the duration of the signal to the injector solenoid.The ECM controls the fuel pressure by increasing or decreasing the flow of fuel from the fuel injection pump.Fuel Injectors