System Configuration of Common-rail EFI-diesel


System configuration of common-rail EFI-diesel

1. Sensors

2. Actuator

3. ECU and other parts

Layout of components (1CD-FTV E/G)

1. Sensor

(1) Air flow meter

Detects the intake air volume.

(2) Accelerator pedal position sensor

Detects the accelerator opening angle and idling conditions.

(3) Camshaft position sensor

Identifies the cylinders.

(4) Intake air temperature sensor

Detects the intake air temperature.

(5) Turbo pressure sensor

Detects the intake manifold pressure.

(6) Water temperature sensor

Detects the coolant temperature.

(7) Crankshaft position sensor

Detects the rotational angle of the crankshaft.

(8) Fuel pressure sensor

Detects the fuel pressure in the common-rail.

(9) Fuel temperature sensor

Detects the fuel temperature.

2. Actuator

(1) Injector

Injects fuel in accordance with signals.

(2) EGR valve

(Exhaust Gas Recirulation valve)

Opens and closes in accordance with the signals from the ECU to recirculate the exhaust gases in order to reduce the amount of emissions.

(3) SCV

(Suction Control Valve)

Mounted on the supply pump, the SCV regulates the volume of fuel that is drawn into the supply pump.

3. ECU and Other parts

(1) ECU (Electronic Control Unit)

Determines the operating conditions based on the signals from various sensors in order to send optimal control signals to the engine.

(2) EDU

Amplifies the ECU signals to actuate the injectors.

(3) Common-rail

Stores the fuel that has been compressed by the supply pump to a pressure that is required for injection.

(4) Supply pump

Increase the pressure of the fuel required for injection and feeds the fuel to the common-rail.

(5) Fuel filter and sedimenter

Removes foreign particles and water from the fuel.

4. Flow of fuel and signals in common-rail EFI-diesel

(1) Flow of fuel and signal in common diesel

The feed pump in the supply pump draws up the fuel from the fuel tank. The fuel that has been pressurized by the supply pump to reach the proper injection pressure is fed into the common-rail where it is stored. The stored fuel is distributed via the injection pipes to the injectors of the cylinders, and when the injectors are operated, the fuel is injected.

(2) Flow of signal

The ECU collects information from the sensors and sends signals to the SCV in order to attain the target fuel pressure. In addition, the pressure signal from the common-rail is fed back into the ECU. The ECU sends signals to the EDU to operate the injectors, the EDU applies the raised voltage to the injectors, and the injectors inject the fuel.


The fuel return circuit from the injector, supply pump or common-rail is not illustrated at left, but the fuel return circuit is attached to the actual fuel system.

Timing Gear Installation

Reinstall the injection pump by aligning the marks on the crankshaft timing gear, idler gear, and the pump drive gear in order to match the phase of the pump and the engine.

Common-rail EFI-diesel Timing Belt Installation

Also on the common-rail EFI-diesel, align the matching marks on the pulleys in a similar manner. The SCV and the plunger in the pump can be synchronized by aligning the position of the pump pulley.

Nozzle Leakage Pipe Leak Inspection

Perform a leak check after reinstalling the nozzle leakage pipe. After installing the nozzle leakage pipe to the cylinder head (on some models), attach the turbo pressure gauge (SST) to the pipe, pressurize it, and make sure that there are no leaks.

Basic Control Items

Functions controlled by the ECU in conventional EFI-diesel and common-rail EFI-diesel:

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