Opel Corsa B 1993–2000 Service and Repair Manual: Multi-point fuel injection system components (1.8 and 2.0 litre models) - removal and refitting

1.8 litre models

Throttle valve switch

1. Disconnect the battery and proceed as described under the relevant sub-heading.

2. Disconnect the wiring plug from the switch.

3. Remove the two mounting screws and pull the switch off the throttle valve spindle.

4. Refit in the reverse order to removal, adjusting the switch as follows. Release the switch mounting screws and rotate the switch in an anti-clockwise direction until resistance is felt. Tighten the screws (see illustration).

Have an assistant open the throttle valve slightly by depressing the accelerator pedal. A click should be heard from the switch as the throttle opens; another click should be heard when the pedal is released.

Tightening a throttle valve switch screw

Fuel injectors

Early (pre 1990) models

5. Make sure that the engine is cool, and that all sources of external ignition (eg pilot lights) have been extinguished. Disconnect the battery earth lead.

6. Bearing in mind the information given in Section 6, release the hose clamps and withdraw the fuel rail from the injectors (see illustration). Catch as much fuel as possible.

Slackening a fuel rail hose clamp

7. Disconnect the wiring plugs from the injectors.

8. Unscrew the retaining bolts (two per injector) and withdraw the injectors from their holders, being careful not to damage the needle valves (see illustration).

Undoing a fuel injector retaining bolt

9. Refit in the reverse order to removal; renew the injector sealing rings if their condition is at all doubtful.

Later (1990 on) models

10. Refer to paragraphs 5 to 9, noting that the fuel rail is retained by bolts and the injectors are secured to the fuel rail by clips.

Airflow meter

11. The airflow meter is located between the air cleaner and the throttle valve housing.

12. Disconnect the wiring harness plug from the airflow meter. Release the securing band and remove the rubber trunking (see illustration).

Disconnecting the airflow meter trunking

13. Release the spring clips and remove the airflow meter with the upper part of the air cleaner housing.

14. Unbolt the airflow meter from the air cleaner housing (see illustration).

Airflow meter securing bolts (arrowed)

15. Check the meter flap for free movement, without any jerkiness. If necessary, clean away any dirt in the area of the flap using a clean lint-free rag.

16. Refit in the reverse order to removal.

Control unit

Early (pre 1990) models

17. The control unit is located at the side of the front footwell, on the passenger side.

18. Remove the footwell trim panel.

19. Make sure that the ignition is switched off, then release the multi-plug spring clip and disconnect the multi-plug.

20. Remove the three securing screws and withdraw the control unit.

21. Refit in the reverse order to removal, but make sure that the ignition is switched off before reconnecting the multi-plug.

Later (1990 on) models

22. Remove the airflow meter as described earlier.

23. Remove the four screws which secure the cover to the top of the airflow meter (these may be hidden by blanking plugs). Remove the cover and insert, then the control unit.

24. Refitting is the reverse of removal.

Coolant temperature sensor

25. The coolant temperature sensor for the fuel injection system is located near the alternator. Because it is additional to the temperature gauge sensor, it is known as temperature sensor ll.

26. Partially drain the cooling system - about 3 litres should be sufficient.

27. Disconnect the electrical lead and unscrew the sensor.

28. Refit in the reverse order to removal. Use a little sealant on the sensor threads, and refill the cooling system on completion.

Auxiliary air valve

29. The auxiliary air valve is bolted to the side of the camshaft housing.

30. Disconnect the wiring plug from the valve.

31. Release the hose clips and disconnect the air hoses from the valve.

32. Unbolt and remove the valve.

33. The function of the valve may be checked by looking through the hose connecting stubs. A clear passage should exist between the stubs when the valve is cold. As the valve is heated (achieved by connecting its terminals to a 12 volt battery) the regulator disc should move round and block the hole.

34. Refit in the reverse order to removal, using new hose clips if necessary. An air leak on the intake side of the valve will raise the idle speed.

Control relay

35. The control relay is located on the front suspension strut turret. Unplugging the relay disables the fuel pump - this is necessary when performing a compression test.

36. Slacken the securing bolt, remove the relay and its bracket from the turret, and withdraw the relay from the plug (see illustrations).

Removing the control relay and bracket

Unplugging the control relay

37. Refit in the reverse order to removal.

Fuel pressure regulator

38. The fuel pressure regulator is located between injectors 3 and 4 (see illustration).

Fuel pressure regulator

39. Disconnect the battery earth lead and take appropriate fire precautions.

40. Clamp the fuel hoses to minimise fuel loss, using self-locking grips with suitably protected jaws.

41. Disconnect the fuel and vacuum hoses form the pressure regulator and remove it. Be prepared for fuel spillage.

42. Refit in the reverse order to removal.

2.0 litre models

Idle speed adjuster

43. Refer to the information given earlier for the 1.8 litre models, information for additional components is as follows

44. Note the routing and positioning of the air hoses, then disconnect the multi-plug and the air hoses from the idle speed adjuster (see illustrations). On the 16-valve engine the adjuster is located below the inlet manifold; access is not good but is easier from below.

Disconnect the idle speed adjuster multi-plug . . .

. . . and the air hoses (arrowed)

45. Refitting is the reverse of the removal procedure.

Control unit

46. The control unit is located behind the side trim panel in the driver's footwell. To remove the trim panel, first remove the front two screws from the driver's 'kick plate' and peel back the door surround strip in the area next to the side trim panel (see illustrations).

Remove the kick plate screws . . .

. . . and peel back the door surround strip

47. Open the access panel in the side trim.

Prise out the plastic retaining clips and withdraw the side trim panel (see illustration).

Prise out the clips to release the trim panel

48. Remove the retaining screws to release the control unit (see illustration). Release the multi-plug catch and disconnect the multi-plug. Handle the control unit with care if it is to be re-used.

Motronic control unit location

49. Refitting is the reverse of the removal procedure.

Inductive pulse sensor

50. Refer to Chapter 5.

Fuel injectors - Motronic ML4.1 and M1.5

51. Remove the idle speed adjuster.

52. Disconnect the wiring plugs from the fuel injectors.

53. Unbolt the fuel rail from the inlet manifold, bearing in mind the information in Section 6.

54. Remove the clips which secure the injectors to the fuel rail by prising them out.

55. Disconnect the brake servo hose from the throttle body housing.

56. Unbolt the fuel supply hose bracket.

57. Carefully lift the fuel rail away from the manifold and pull out the injectors.

58. Refitting is the reverse of the removal procedure. If the old injectors are being refitted, use new sealing rings.

Fuel injectors - Motronic M2.5

59. Remove the pre-volume chamber as described earlier.

60. Bearing in mind the information, clean around the unions on the fuel rail, then disconnect the supply and return hoses from it (see illustration). Be prepared for fuel spillage.

Disconnecting the fuel supply line from the fuel rail

61. Disconnect the two crankcase ventilation hoses from the camshaft cover. To improve access, remove the larger of the two hoses completely.

62. Disconnect the vacuum hose from the fuel pressure regulator.

63. Disconnect the multi-plugs from the air mass meter and from the throttle valve switch.

64. Unbolt the throttle cable bracket and move it aside.

65. Remove the nuts securing the earth straps at each end of the fuel rail (see illustration).

One of the earth straps on the fuel rail

66. The injector multi-plugs must now be disconnected. Each plug is secured by a spring clip, which must be levered out with a small screwdriver or long-nosed pliers. With all the multi-plugs released, cut or undo cable ties as necessary and move the wiring rail forwards so that it rests on the camshaft cover (see illustrations).

Removing the spring clip from an injector multi-plug

Lifting the wiring rail off the injectors

67. Remove the two bolts which secure the fuel rail to the inlet manifold.

68. Pull the rail and injectors away from the manifold.

69. Individual injectors may now be removed from the rail by removing their retaining clips and pulling them from the rail (see illustrations).

Remove the retaining clip

. . . and pull out the injector

70. Refitting is the reverse of the removal procedure. If the old injectors are being refitted, use new sealing rings.

Throttle valve potentiometer - Motronic M1.5

71. The throttle valve potentiometer is removed and refitted in the same way as the throttle valve switch (which it replaces) on earlier models. There is no need for adjustment.

Fuel pressure regulator - Motronic M1.5 and 2.5

72. On Motronic M2.5 systems, remove the pre-volume chamber.

73. Bearing in mind the information in Section 6, disconnect the fuel return union from the pressure regulator (see illustration). Be prepared for fuel spillage.

Disconnecting the fuel return line from the fuel pressure regulator

74. Disconnect the vacuum hose from the regulator (see illustration).

Disconnecting the vacuum hose

75. Remove the four Torx screws which secure the pressure regulator to the fuel rail. A small E6 Torx spanner will be needed for access to the screws. If this is not available the fuel rail will have to be removed so that the screws can be undone with a socket or (at a pinch) self-locking pliers. With the screws removed, the pressure regulator can be removed from the rail.

76. Refitting is the reverse the removal.

Pre-volume chamber - Motronic M2.5

77. Remove the four Allen screws which secure the pre-volume chamber to the throttle housing (see illustration). On some models there is a fifth screw to the left which must also be removed.

Removing a pre-volume chamber screw

78. Release the hose clip which secures the air mass meter to the pre-volume chamber.

79. Lift the pre-volume chamber slightly and disconnect the idle speed adjuster hose from the left-hand end (see illustration). Remove the pre-volume chamber.

Idle speed adjuster hose attachment to pre-volume chamber

80. Refitting is the reverse of the removal procedure, but note that it is important that the ring which seals the throttle body to the pre-volume chamber is not displaced during fitting. Air leaks at this point will weaken the mixture and dirt may enter. Secure the ring to the chamber if necessary with a few dabs of sealant (see illustration).

Pre-volume chamber sealing ring

Throttle valve switch - Motronic M 2.5

81. Remove the pre-volume chamber and the air mass meter.

82. Disconnect the multi-plug from the switch (see illustration). Remove the two screws and withdraw the switch.

Disconnecting the throttle valve switch multi-plug

83. Refitting is the reverse of the removal procedure. Adjust the switch before tightening the screws as described in paragraph 4 of this Section.

Air mass meter - Motronic M2.5

84. Disconnect the multi-plug from the air mass meter (see illustration).

Disconnecting the multi-plug from the air mass meter

85. Release the hose clips from each end of the meter and remove it. Do not drop it, it is fragile.

86. Refitting is the reverse of the removal procedure.

Coolant temperature sensor - Motronic M2.5

87. Partially drain the cooling system at the radiator bottom hose to bring the coolant level below the level of the thermostat housing.

88. Disconnect the multi-plug from the sensor on the thermostat housing. The Motronic sensor is the larger of the two the smaller one feeds the temperature gauge. Unscrew the sensor and remove it.

89. Refitting is the reverse of the removal procedure, noting the following points:

1. Use a new sealing ring on the sensor, and apply a little sealant to its threads.
2. Refill the cooling system.

Knock sensor - Motronic M2.5

90. The knock sensor is on the rear of the cylinder block. Unless the inlet manifold has been removed, access is easiest from below.

91. Disconnect the multi-plug (coloured red or orange) from the knock sensor. Remove the securing screw and the sensor (see illustration).

Knock sensor multi-plug (arrowed) seen from below

92. Refitting is the reverse of the removal procedure, but make sure that the sensor and its seat are perfectly clean and that the sensor is secured firmly. Failure to observe these points could lead to damage to the engine, because a poorly mounted sensor will not pick up knocking (pinking) and the appropriate ignition correction will not be applied.

Oxygen sensor - models with a catalytic converter

93. Bring the engine to operating temperature, then switch it off and disconnect the battery.

94. Disconnect the oxygen sensor multi-plug, which is located near the right-hand suspension turret (see illustration). Free the wiring leading to the sensor.

Disconnecting the oxygen sensor multi-plug

95. Working under the vehicle, unscrew the sensor from the exhaust manifold (see illustration).

Removing the oxygen sensor

96. Refitting is the reverse of the removal procedure. Note that the makers specify the use of a special anti-seize compound made of graphite and glass beads. New sensors are provided with their threads already coated with this compound. When refitting a used sensor, obtain some of the special compound from a Vauxhall dealer.

Carbon canister - 16-valve models with a catalytic converter

97. Raise the front of the vehicle and remove the left-hand roadwheel.

98. Slacken the canister clamp nut. Release the canister from the clamp, disconnect the hoses from it and remove it (see illustrations). Treat the canister with the same precautions as would apply to a fuel tank - it may be full of vapour.

Canister clamp nut (arrowed)

Disconnecting a hose from the canister

99. Refitting is the reverse of the removal procedure.

Vent valve - 16-valve models with a catalytic converter

100. Disconnect the multi-plug and the hoses from the vent valve (see illustration). Unbolt the valve bracket and remove the valve and bracket.

Disconnecting the vent valve multi-plug

101. Refitting is the reverse of the removal procedure.