INTRODUCTION - DIESEL INJECTION PRESSURE PUMP ELECTRONIC CONTROL

1.9 Multijet

INJECTION CONTROL UNIT (EDC 16C39 common rail)

It is fitted in the engine compartnent on the right side panel. The control unit the flash EPROM type, i.e. it can be reprogrammed from the outside without affecting the hardware.

The injection control unit integrates the absolute pressure sensor.

PIN OUT

A01. Bank 2 injector Cylinder 3 "High" control

A02. Bank 2 injector Cylinder 2 "High" control

A03. N.C.

A04. N.C.

A05. N.C.

A06 N.C.

A07. N.C.

A08. Rail pressure sensor earth

A09. N.C.

A10. N.C.

A11. Timing sensor power supply

A12. Engine rpm sensor negative (-) signal

A13. Turbo pressure sensor power supply

A14. N.C.

A15 N.C.

A16. Bank 1 injector Cylinder 1 "High" control

A17. Bank 1 injector Cylinder 4 "High" control

A18. N.C.

A19. High pressure pump flow regulator power supply (BAT+)

A20. Timing sensor earth

A21. Oil level sensor signal input

A22 N.C.

A23. Turbo pressure sensor earth

A24. N.C.

A25. N.C.

A26. N.C.

A27. Engine rpm sensor positive (+) signal

A28. Rail pressure sensor power supply

A29. N.C.

A30. N.C.

A31. Bank 2 injector Cylinder 2 "Low" control

A32. N.C.

A33. Bank 1 injector Cylinder 4 "Low" control

A34. N.C.

A35. N.C.

A36. N.C.

A37. Intake manifold air temperature sensor signal

A38. N.C.

A39. Throttle valve fault diagnosis earth

A40. Turbo pressure signal

A41. Coolant temperature sensor earth

A42. Air flow rate sensor signal

A43. Rail pressure sensor signal

A44. Air flow rate sensor earth

A45. N.C.

A46. Bank 2 injector Cylinder 3 "Low" control

A47. Bank 1 injector Cylinder 1 "Low" control

A48. N.C.

A49. High pressure pump flow regulator control

A50. Timing sensor signal

A51. N.C.

A52. Throttle valve fault diagnosis signal

A53. Turbo air temperature sensor signal

A54. N.C.

A55. N.C.

A56. Oil pressure signal

A57. N.C.

A58. Water temperature sensor signal

A59. Throttle valve actuator

A60. EGR actuator

K01. Battery positive

K02. Battery negative

K03. N.C.

K04. Battery negative

K05. Battery positive

K06. Battery negative

K07. Turbo pressure actuator

K08. Accelerator pedal 2 position sensor earth

K09. Accelerator pedal 1 position sensor signal

K10. Fuel temperature sensor earth

K11. Fuel temperature sensor signal

K12. Air conditioning compressor pressure sensor earth

K13. Air conditioning compressor pressure sensor signal

K14. N.C.

K15. N.C.

K16. N.C.

K17. Brake pedal main switch signal

K18. N.C.

K19. Alternator "L" signal

K20. Low pressure pump relay feed (HSD)

K21. N.C.

K22. Air conditioning compressor pressure sensor power supply

K23. N.C.

K24. N.C.

K25. K line

K26. N.C.

K27. N.C.

K28. Key signal

K29. Air conditioning compressor relay feed

K30. Accelerator pedal 1 position sensor earth

K31. Accelerator pedal 2 position sensor signal

K32. N.C.

K33. N.C.

K34. N.C.

K35. N.C.

K36. N.C.

K37. N.C.

K38. N.C.

K39. N.C.

K40. Clutch pedal switch signal N.C. (+)

K41. N.C.

K42. N.C.

K43. N.C.

K44. N.C.

K45. Accelerator pedal 1 position sensor power supply

K46. Accelerator pedal 2 position sensor power supply

K47. N.C.

K48. N.C.

K49. N.C.

K50. N.C.

K51. Lambda sensor heater control

K52. Preheating control unit fault diagnosis signal

K53. Vehicle speed sensor earth

K54. N.C.

K55. Starter motor relay feed

K56. N.C.

K57. Reversing switch signal

K58. N.C.

K59. N.C.

K60. N.C.

K61. N.C.

K62. N.C.

K63. N.C.

K64. Lambda sensor signal

K65. Lambda sensor signal

K66. N.C.

K67. N.C.

K68. N.C.

K69. Fan 2 relay feed

K70. N.C.

K71. Diagnostic warning light control

K72. Main relay feed

K73. N.C.

K74. Water in fuel signal

K75. Vehicle speed sensor signal

K76. N.C.

K77. N.C.

K78. N.C.

K79. N.C.

K80. N.C.

K81. N.C.

K82. N.C.

K83. CAN (low channel)

K84. CAN (high channel)

K85. N.C.

K86. Lambda sensor earth

K87. Lambda sensor signal

K88. N.C.

K89. N.C.

K90. Fan 1 relay feed

K91. N.C.

K92. N.C.

K93 Preheating control unit operation

K94. Fan 3 relay feed

RPM SENSOR

Specifications

It is fitted on the cylinder block/crankcase facing the flywheel on the crankshaft.

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

The injection control unit uses the rpm signal for:

- determining the rotation speed;

- determining the angular crankshaft position

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 send to the electronic control unit provides the latter with an indication of the engine angular speed.

1. Brass bush

2. Permanent magnet

3. Plastic sensor casing

4. Coil reel

5. Polar core

6. Ring gear or flywheel

The recommended distance (gap) between the end of the sensor and the flywheel for obtaining correct signals should be 0.8 - 1.5 mm.

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

CAM ANGLE SENSOR

Specifications

This Hall effect sensor is fitted on the cylinder head facing the camshaft drive pulley.

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

The injection control unit uses the timing sensor signal to identify T.D.C. at the end of compression.

Operation

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

If current intensity 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 with frequency proportional to the speed of magnetic field change.

This change is achieved by making a magnetic ring (internal part of pulley) with an opening pass the sensor.

As it moves, the metal part of the ring covers the sensor to block the magnetic field and thus generate a low ouput signal. Conversely, the sensor generates a high signal when the opening is over the sensor and a magnetic field is present.

Together with the rpm and TDC signal, this signal allows the control unit to identify the cylinders and determine injection point.

1. Pulley ring

2. Magnetic material

EXCESS PRESSURE SENSOR

Specifications

It is fitted on the air intake manifold and the signal sent to the engine management control unit makes it possible to:

- modulate the turbocharger pressure;

- protect the engine from overheating

- diagnose the operation of the air flow meter.

PIN OUT

PRESSURE SENSOR TRANSFER FUNCTION

Sensor specifications

ENGINE COOLANT TEMPERATURE SENSOR

Specifications

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

One NTC thermistor sends the signal to the injection control unit whilst the other sends the signal to the temperature gauge and the warning light in the instrument panel.

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

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

AIR FLOW METER WITH BUILT IN AIR SENSOR

Specifications

The debimeter is located on the air intake sleeve and is hot film type.

The intake air temperature sensor is built into the support for the sensitive element inside the flow meter

1. Electronic circuit cover and measuring duct cover

2. Electronic control circuit

3. Sensitive element with built in intake air temperature sensor

4. Electronic circuit and sensitive element metal support plate

5. Plastic support casing

The air flow meter cannot be disassembled

PIN OUT

1. 12 V power supply

2. Earth

3. Air temperature signal

4. Air mass signal

Operation

The operating principle is based on the heating of a membrane (sensitive element containing two resistances upstream and downstream of the support) in a by-pass duct through which the engine intake air flows.

The hot film membrane is maintained at constant temperature (about 120 °C higher than the incoming air temperature) by the specific heating resistance controlled by the electronics.

Having given off heat to the membrane, the mass of air that passes through the by-pass duct thermally unbalances the two resistances to an extent that is directly proportional to the mass of the incoming fluid, an imbalance that is translated through the control circuit into a resistance variation electronically processed and translated into a frequency value that is sent to the engine management control unit.

The imbalance in the resistance value also makes it possible to determine the direction of the column of air.

As far as the air temperature information is concerned, it is sent to the engine management control unit via a dedicated pin in the form of a duty cycle signal (rectangular wave). The duty value is proportional to the temperature value.

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

FUEL PRESSURE SENSOR

Specifications

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

- modulate the injection pressure;

- regulate the fuel injection duration.

ACCELERATOR PEDAL POTENTIOMETER

Construction specifications

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

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

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 to obtain the injection times and the pressure.

1.3 Multijet

DESCRIPTION OF COMPONENTS

Injection control unit (common rail mjd 6f3 magneti marelli)

It is located in the engine compartment.

The control unit the flash EPROM type, i.e. it can be reprogrammed from the outside without affecting the hardware.

The injection control unit integrates the absolute pressure sensor.

PIN OUT

CONNECTOR A

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. Fuel flow rate regulator negative (90 CV only)

20. Fuel flow rate regulator positive (90 CV only)

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. Variable geometry turbine solenoid valve (90 CV only)

31. Cylinder 3 injector negative

32. Not connected

33. Not connected

34. Fuel pressure regulator negative

35. Not connected

36. Not connected

37. Supercharging temperature

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

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 3rd speed control (-)

9. Not connected

10. Air conditioning compressor linear sensor negative

11. Not connected

12. Lambda sensor heating (-)

13. Fuel temperature sensor earth

14. Not connected

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. Engine oil level sensor

27. Not connected

28. Not connected

29. Not connected

30. Fan 2nd speed control

31. Not connected

32. Accelerator potentiometer track 2 negative

33. Not connected

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

45. Lambda sensor signal

46. Lambda sensor reference earth

47. Lambda sensor

48. Not connected

49. Not connected

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. Starter motor relay control

74. Heater plugs relay control

75. Not connected

76. Fuel heater relay control

77. Not connected

78. Brake light switch

79. Air conditioning compressor control

80. Main relay control

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. Speedometer impulse generator

90. Water in diesel filter sensor signal

91. Not connected

92. Not connected

93. Not connected

94. Reversing switch

Rpm sensor

Specifications

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

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

The injection control unit uses the rpm signal for:

- determining the engine speed of rotation

- determining the angular crankshaft position

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

PIN OUT

Technical specifications

Winding resistance 790 Ohm +/- 20%

Winding resistance 680 mH +/- 20% (f=1khz)

The recommended distance (gap) between the end of the sensor and the flywheel for obtaining correct signals should be 0.8 - 1.5 mm.

This distance is not adjustable. 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.

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 send to the electronic control unit provides the latter with an indication of the engine angular speed.

Cam angle 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 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 immersed in a normal magnetic field (force lines at right angles to current direction) generates a potential difference known as a Hall voltage at its terminals.

If current intensity 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 with frequency proportional to the speed of magnetic field change.

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).

Pressure relief sensor - for the 75 cv version

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.

PIN OUT

Pressure relief and air temperature sensor - for the 90 cv version

It is fitted on the air intake manifold and the signal sent to the engine management control unit makes it possible to:

- regulate the turbocharger pressure;

- protect the engine against overheating;

- diagnose the operation of the air flow meter.

PIN OUT

Sensor specifications

Engine coolant temperature sensor

Specifications

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

Specifications

Fuel pressure sensor

Specifications

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

- modulate the injection pressure;

- regulate the fuel injection duration.

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

Pin out

Accelerator pedal potentiometer

Construction specifications

The sensor is secured to the accelerator pedal; inside it contains an axially-located shaft connected to two potetiometers: a main one and one 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 to obtain the injection times and the pressure

PIN OUT

Bosch sensor technical specifications

Supply voltage: 5 V +/- 0.3 V

Resistance at potentiometer cursor terminals: 1 Kohm +/- 0.4 kOhm

Track 1 resistance: 1.2 Kohm +/- 0.4 kOhm

Track 2 resistance: 1.7 Kohm +/-0.8 kOhm

Hella sensor technical specifications

Supply voltage: 5 V +/- 0.3 V

Resistance at potentiometer cursor terminals: 1 kOhm +/- 0.4 kOhm

Track 1 resistance: 0.9 kOhm +/- 35%....1.4 kOhm +/- 35%

Track 2 resistance: 1.2 kOhm +/- 35%....2.0 kOhm +/- 35%.

Air flow meter with built in air sensor

Specifications

The debimeter is located on the air intake sleeve and is hot film type.

The intake air temperature sensor is built into the air flow meter on the same support as the sensitive element.

1. Electronic circuit cover and measuring duct cover

2. Electronic control circuit

3. Sensitive element with intake air temperature sensor incorporated

4. Electronic circuit metal support plate and sensitive element

5. Plastic support casing

The air flow meter cannot be dismantled

PIN OUT

1. 12 V power supply

2. Earth

3. Air temperature signal

4. Air mass signal

Operation

The operating principle is based on the heating of a diaphragm (sensitive element containing two resistances upstream and downstream of the support) in a by-pass duct through which the engine intake air flows.

The hot film membrane is maintained at constant temperature (about 120 °C higher than the incoming air temperature) by the specific heating resistance controlled by the management electronics.

The mass of air passing through the by-pass duct, giving off heat to the membrane, thermally unbalances the two resistances to an extent directly proportional to the mass of the incoming fluid, an imbalance that is translated through the control circuit into a resistance variation, electronically processed and translated into a frequency value to be sent to the engine management control unit.

The imbalance in the resistance value also makes it possible to determine the direction of the column of air.

As far as the air temperature information is concerned, it is sent to the engine management control unit via a dedicated pin in the form of a duty cycle signal (rectangular wave). The value of the duty is proportional to the value of the temperature.

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