DIESEL INJECTION PRESSURE PUMP ELECTRONIC CONTROL

Description 1060G

1.3 Multijet

Injection control unit (common rail MJD - 6F3 Magneti Marelli)

It is located in the engine compartment.

It is a flash EPROM type control unit, i.e. it can be externally reprogrammed without adjusting the hardware.

The injection control unit incorporates the absolute pressure sensor.

PIN OUT

Connector A (engine side)

1. Cylinder 4 injector negative

2. Not connected

3. Not connected

4. Fuel pressure regulator positive

5. E.G.R. positive

6. Fuel pressure sensor negative

7. Not connected

8. Fuel pressure sensor positive

9. Insufficient engine oil pressure sensor signal

10. Air flow meter temperature signal

11. Not connected

12. Not connected

13. Not connected

14. Flow meter air rate signal

15. EGR solenoid valve negative

16. Cylinder 1 injector negative

17. Cylinder 2 injector negative

18. Not connected

19. Not connected

20. Not connected

21. Timing sensor negative

22. Not connected

23. Supercharging pressure sensor positive

24. Supercharging sensor negative

25. Timing sensor positive

26. Not connected

27. Flow meter negative

28. Not connected

29. Engine coolant temperature sensor earth

30. Waste gate solenoid valve (for versions with DPF)

31. Cylinder 3 injector negative

32. Not connected

33. Not connected

34. Fuel pressure regulator negative

35. Not connected

36. Not connected

37. Not connected

38. Fuel pressure sensor signal

39. Not connected

40. Not connected

41. Turbo pressure signal

42. Not connected

43. Engine rpm sensor positive

44. Not connected

45. Not connected

46. Cylinder 4 injector positive

47. Cylinder 1 injector positive

48. Cylinder 3 injector positive

49. Cylinder 2 injector positive

50. Not connected

51. Not connected

52. Not connected

53. Not connected

54. Engine coolant temperature sensor signal

55. Alternator signal

56. Timing sensor signal

57. Not connected

58. Not connected

59. Rpm sensor negative

60. Not connected

CONNECTOR B (vehicle side)

1. Control unit power earth

2. Control unit power earth

3. Control unit power earth

4. 12 V control unit power supply

5. 12 V control unit power supply

6. 12 V control unit power supply

7. Fan 1st speed control (-)

8. Fan 2nd speed control (-)

9. Not connected

10. Air conditioning compressor linear sensor negative

11. Particulate filter temperature sensor earth (for versions with DPF)

12. Lambda sensor heating (-) (for versions with Lambda sensor)

13. Fuel temperature sensor earth

14. Particulate filter differential pressure sensor power supply (for versions with DPF)

15. Track 2 positive on accelerator pedal potentiometer

16. Not connected

17. Not connected

18. Not connected

19. Not connected

20. Not connected

21. Not connected

22. Clutch pedal switch

23. Ignition-operated power supply

24. Not connected

25. Not connected

26. Not connected

27. Not connected

28. Not connected

29. Not connected

30. Not connected

31. Not connected

32. Accelerator potentiometer track 2 negative

33. Particulate filter differential pressure sensor earth (for versions with DPF)

34. Not connected

35. Accelerator potentiometer track 1 negative

36. Not connected

37. Air conditioning compressor linear sensor positive

38. Not connected

39. Not connected

40. High speed CAN 1 line

41. Accelerator potentiometer track 2 signal

42. Not connected

43. Not connected

44. Lambda sensor signal (for versions with Lambda sensor)

45. Lambda sensor signal (for versions with Lambda sensor)

46. Lambda sensor reference earth (for versions with Lambda sensor)

47. Lambda sensor (for versions with Lambda sensor)

48. Not connected

49. Particulate filter differential pressure sensor signal (for versions with DPF)

50. Direct power supply from battery

51. Not connected

52. Not connected

53. Not connected

54. Not connected

55. Not connected

56. Not connected

57. Not connected

58. Not connected

59. Not connected

60. Not connected

61. Fuel temperature sensor signal

62. Not connected

63. Not connected

64. High speed CAN 1 line H

65. Accelerator potentiometer track 1 signal

66. Not connected

67. Not connected

68. Not connected

69. Not connected

70. Preheating control unit diagnostic input

71. Not connected

72. Not connected

73. Not connected

74. Heater plugs relay control

75. Not connected

76. Not connected

77. Not connected

78. Not connected

79. Air conditioning compressor control

80. Main relay feed

81. Brake light switch

82. Not connected

83. Accelerator potentiometer track 1 power supply

84. Not connected

85. Fuel pump relay control

86. Not connected

87. Climate control linear sensor signal

88. Not connected

89. Not connected

90. Water in diesel filter sensor signal

91. Particulate filter temperature sensor signal (for versions with DPF)

92. Not connected

93. Not connected

94. Reversing switch

RPM SENSOR - SPECIFICATIONS

It is fitted on the crankcase and faces the phonic wheel on the flywheel.

It is inductive, i.e. its operation is determined by magnetic field changes generated by the teeth passing in front of a phonic wheel (60-2 teeth).

The injection control unit uses the rpm sensor signal to:

• determine the engine rotation speed
• determine the crankshaft angular position.

COMPOSITION - SPECIFICATIONS

The rpm sensor components are illustrated in the diagram.

1. Brass bush

2. Permanent magnet

3. Plastic sensor casing

4. Coil reel

5. Polar core

6. Ring gear or flywheel

7. Coaxial paired cable or electrical connection.

PIN OUT

TECHNICAL SPECIFICATIONS

Winding resistance 790 Ohm ± 20%

Winding inductance 680 mH ± 20% (f=1khz)

The recommended distance (gap) between the end of the sensor and the phonic wheel in order to obtain correct signals should be 0.8 - 1.5 mm.

This distance is not adjustable. Therefore, if the gap is found to be outside the tolerance limits, check the condition of the sensor and phonic wheel.

The graph shows the sensor output signal in relation to the horizontal development of the flywheel.

1. Toothed wheel profile

2. Rpm sensor signal

3. Reference tooth

4. TDC detection point

OPERATION

The changeover from full to empty determined by the presence or absence of a gap brings about a magnetic flux change sufficient to generate an induced alternating voltage proportional to the number of teeth on the ring (or phonic wheel).

The frequency and amplitude of the voltage sent to the electronic control unit provides it with details of crankshaft angular speed.

TIMING SENSOR - SPECIFICATIONS

This Hall effect sensor is fitted on the camshaft housing facing the camshafts.

A tooth on the pulley allows the timing sensor to indicate the engine timing position.

The injection control unit uses the timing sensor signal to recognize T.D.C. at the end of the compression and during starting to synchronize the engine management control unit with the engine.

The sensor is fitted by the exhaust side camshaft.

OPERATION

A current-carrying semiconductor layer submerged in a normal magnetic field (with force lines at right angles to the direction of the current) generates a potential difference known as a Hall voltage at the terminals of the semiconductor.

If the intensity of the current remains constant, the generated voltage depends on magnetic field intensity alone. Periodic changes in magnetic field intensity are sufficient to generate a modulated electrical signal whose frequency is proportional to the speed at which the magnetic field changes. To produce this change, a tooth on the inner part of the pulley periodically moves close to the sensor.

PIN OUT

In the specific case of the timing sensor it receives a 5 Volt power supply from the engine management control unit.

All the times the rotor passes in front of the sensor a variation in the actual sensor output voltage is produced through the Hall effect; this variation takes place for the entire duration that the rotor passes in front of the sensor after which the signal returns to the original value (5 V).

SUPERCHARGING PRESSURE SENSOR - SPECIFICATIONS

The supercharging pressure sensor is fitted on the intake manifold and allows intake pressures up to 1.5 bar to be measured (corresponding to 2.5 bar absolute).

The sensitive element comprises a piezoresistive element whose signal is amplified by an electronic circuit built into the sensor. The sensor receives a direct 5 V supply from the electronic control unit and provides an output voltage directly proportional to the supercharging pressure.

SPECIFICATIONS

Excess pressure sensor pin out

COOLANT TEMPERATURE SENSOR - SPECIFICATIONS

This is fitted to the thermostat cup and detects coolant temperature by means of an NTC thermistor with negative resistance coefficient.

SPECIFICATIONS

Engine coolant temperature sensor specifications

FLOW METER - SPECIFICATIONS

The air flow meter is located on the air intake sleeve and is a hot film type meter.

There is an arrow on the outer casing showing the direction of the air flow.

Air flow meter pin out

The air flow meter cannot be disassembled.

OPERATION

This component works on the basis of a membrane positioned within a measurement channel that carries air into the engine.

The hot film membrane is maintained at a constant temperature (about 120°C higher than the incoming air temperature) by the heating coil.

The air mass that flows through the measurement channel tends to remove heat from the membrane. A certain amount of current must therefore flow through the heater coil in order to maintain the membrane at a constant temperature.

The main diagram for the flow meter sensitive element is illustrated.

The platinum hot film sensor is a PTC (positive temperature coefficient) type thermal resistance, in other words a resistance whose value increases as the temperature rises.

As the quantity of intake air increases, the quantity of heat removed from the sensor increases, therefore there is a decrease in the resistance of the actual sensor. As it is inserted in a "bridge" measurement electric circuit, it causes an increase in the output voltage, measured by the ECU to calculate the volume of the air drawn in by the engine.

The flow meter is also capable of discerning the direction of the air flow, therefore the information is relative to the effective quantity of air drawn in by the engine, not affected by possible turbulence.

The air flow meter measures the air mass (not the volume) directly to eliminate problems of temperature, altitude, pressure etc.

FUEL TEMPERATURE SENSOR - SPECIFICATIONS

It is incorporated in the fuel heater assembly and measures the temperature of the fuel by means of a dual NTC thermistor with negative resistance coefficient.

Fuel temperature sensor pin out

Fuel temperature sensor specifications

The sensor is designed using semiconductor technology. In other words, the resistance level drops if sensor element temperature increases with increasing fuel emperature.

Because the resistance does not change in linear fashion as the temperature increases, it is relatively higher at low temperatures than at high temperatures.

FUEL PRESSURE SENSOR - SPECIFICATIONS

It is fitted at the end of the common rail and its function is to provide the injection control unit with a feedback signal to enable it to:

• modulate injection pressure;
• regulate fuel injection duration.

The sensor receives a direct power supply from the engine management control unit at a voltage of 5V. The output voltage varies in a linear fashion between 0.5V (0 bar) and 4.5V (1500 bar).

Fuel pressure sensor pin out

CONSTRUCTION SPECIFICATIONS

The sensor consists of a case secured to the accelerator pedal; the case contains an axially-located shaft connected to two potentiometers: a main one and a safety one.

A coil spring on the shaft ensures the correct amount of resistance to pressure while a second spring ensures return following release.

The redundant signal reading makes it possible to continuously monitor the plausibility of the readings in order to guarantee complete safety whilst driving even if there is a failure.

OPERATION

The accelerator pedal position is converted into an electrical voltage signal and sent to the injection control unit by the potentiometer connected to the pedal.

The accelerator pedal position signal is processed together with the information relating to the engine rpm in order to obtain the injection times and the pressure.

POTENTIOMETER TECHNICAL SPECIFICATIONS

The potentiometer settings are illustrated in the graph below.

P1. Track n°1

P2. Track n°2

A. Maximum throttle opening

B. Pedal stop on cap

C. Pedal stop on support

FUEL PRESSURE REGULATOR - CONSTRUCTION SPECIFICATIONS

The fuel pressure regulator is fitted on the rail and regulates the fuel pressure on the basis of the commands from the engine management control unit through a ball valve that drains the fuel along the low pressure line directly into the tank.

There is a solenoid inside the fuel pressure regulator that is controlled by the engine management control unit through a PWM technique (capacity 1 kHz). When the duty cycle is set at 0% the solenoid does not receive a power supply: there is a mimimum pressure in the rail due to the pre-loading of the ball valve spring.

ELECTRICAL SPECIFICATIONS

Resistance: 2.07 - 2.53 (ohm) at 20 °C

Maximum current 2.5 A

Minimum pressure not supplied 50 bar

ELECTRIC FUEL PUMP - CONSTRUCTION SPECIFICATIONS

The electric fuel pump has the task of supplying the high pressure pump. It is completely submerged in the fuel inside the tank. The pump assembly is created in such a way that the fuel level is maximum in the draught area.

This function is achieved by means of a venturi in the return pipe to the draught in relation to the one in the tank. The pumping unit is the roller type and allows a flow rate of 160 litres per hour.

The pump incorporates an electric motor with permanent magnets which receives a continuous power supply when the engine is on. The fuel sent to the high pressure pump that has not been used flows to the tank via an excess pressure valve fitted on the filter assembly.

The pump assembly has another excess pressure valve, in order to prevent damage to the pumping unit in case the supply pipe is blocked.

TECHNICAL SPECIFICATIONS

Capacity > = 130 l/h

Operating pressure 2.6 bar

HEATER PLUGS CONTROL UNIT - CONSTRUCTION SPECIFICATIONS

The device is interfaced and controlled by the engine management control system in accordance with the EOBD protocol. It has been designed to carry out all the operating and monitoring functions for the operating status of the individual heater plugs during the diesel engine pre-heating stage.

The control unit includes protection against high currents and excess voltage and has a control logic which, if there is any fault, behaves like a proper self-repairing electronic fuse.

The device may be fitted directly in the engine compartment given its thermal properties and resistance to external agents.

The control unit is protected at all the terminals from possible electrical connections with reversed battery polarity and is constructed in such a way as to be able to withstand all the stresses on the vehicle.

The unit has the following connection terminals:

FUEL MANIFOLD (RAIL) CONSTRUCTION SPECIFICATIONS

The rail comprises a forged steel pipe resistant to the high operating pressures of the high pressure system.

The internal volume of the rail is 20 cc: this volume has been selected in order to minimize the pressure peaks due to the injection process without slowing down the fuel pressure variation commands set by the engine management control unit in order to ensure optimum combustion.

The fuel from the high pressure pump arrives at the rail and is then directed to the injectors. A pressure sensor and a high pressure regulator are fitted on the rail.

HIGH PRESSURE FUEL PUMP - CONSTRUCTION SPECIFICATIONS

The high pressure pump is the CP1 Compact type with three radial pistons. The capacity is 567 mm3/rev and as it is fitted on the camshaft the rotation speed is half that of the rotation speed of the crankshaft (reduction ratio 2:1). The pump is lubricated and cooled by the flow of fuel passing through it: the required capacity is provided by the low pressure pump. The latter supplies the pump with an amount of fuel that is always higher than the engine requirements in order to create a recirculation of fuel to the tank, thereby ensuring the (priority) lubrication and cooling of the pump.

The movement of the pistons is determined by a cam on the pump shaft: this operates a polygonal ring which acts on the foot of the piston.

Each pumping unit is equipped with an intake valve and a supply ball valve.

The pump has a valve known as a shut off valve: this allows the pump to be protected if there is a low flow rate from the low pressure supply, allowing the lubrication of the pumping units and the cam mechanism to be maintained.

TECHNICAL SPECIFICATIONS

Radial Pump with 3 pumping elements

Capacity 567 [mm3/rev]

Output: > 79% at 1350 bar at 1000 giri/min

Maximum rotation speed 3000 rpm

Nominal Pressure: 1350 bar

1. Fuel intake

2. Fuel return to the tank

3. Fuel supply to the rail

SENSOR FOR PRESENCE OF WATER IN DIESEL FILTER - CONSTRUCTION SPECIFICATIONS

Inserted in the diesel filter casing, in the lower part, it signals the presence of water through the dedicated warning light in the instrument panel.

1. Water presence sensor

2. Diesel filter container

3. Filter element