Opel Corsa B 1993–2000 Service and Repair Manual: Single-point fuel injection system components (1.4 and 1.6 litre models) - removal and refitting

1. Disconnect the battery negative lead and proceed as described under the relevant subheading (see illustration).

Single-point fuel injection system components and location on 1.4 litre model

1. Throttle valve injection housing
2. Fuel pump sensor
3. Filter
4. Fuel pressure regulator
5. Injection valve
6. Throttle valve (potentiometer)
7. Idle air stepper motor
8. Inlet manifold pressure sensor
9. Coolant temperature sensor
10. Road speed sensor
11. Octane number plug (95/91)
12. Unheated oxygen sensor
13. Ignition distributor (Hall)
14. Engine telltale
15. ALDL plug
16. Wiring harness
17. Control unit
18. Three-way catalytic converter
19. Exhaust system
20. Heat shield
21. Tank filler neck
22. Damping control system

Throttle body/injector housing unit components

2. The following items can be removed from the throttle body/injector housing unit for inspection and where necessary, renewal. If the unit is in position in the car, first remove the air cleaner unit to allow suitable access to the appropriate component (see illustration).

Exploded view of the throttle body/injector housing assembly - 1.4 and 1.6 litre models

1. Air filter seal
2. Injection valve
3. Injection valve holder
4. Upper O-ring
5. Lower O-ring
6. Upper housing
7. Seal
8. Fuel inlet connector
9. Fuel inlet seal
10. Fuel return connector
11. Fuel pressure regulator diaphragm
12. Fuel pressure regulator spring
13. Fuel pressure regulator spring seat
14. Fuel pressure regulator cover
15. Connecting cable grommet
16. Throttle body
17. Potentiometer (throttle valve)
18. Idle air stepper motor
19. O-ring
20. Idle adjustment screw
21. Idle adjustment screw spring
22. Cap
23. Vacuum connections flange
24. Vacuum connections flange seal
25. Injector housing- inlet manifold seal

Throttle valve potentiometer

3. Disconnect the wiring connector from the potentiometer, then undo the retaining screws and remove the potentiometer from the throttle housing (see illustrations).

Detach the wiring connector from the throttle valve potentiometer

Throttle valve potentiometer removal

4. Refitting is a reversal of the removal procedure. Ensure that the throttle valve is fully shut as the potentiometer is fitted into position and that the pick-up is properly seated on the throttle spindle. Tighten the retaining screws to the specified torque setting.

5. Reconnect the wiring plug and refit the air cleaner unit.

Injection valve

6. Disconnect the wiring plug. Undo the retaining screw then carefully lever the injection valve free using a suitable screwdriver. Remove the injection valve together with its holder (see illustrations).

Disconnect the wiring connector . . .

. . . undo the retaining screw . . .

. . . and remove the injector

7. Refit in the reverse order of removal.

Always renew the seal rings and as the injection unit is pressed into position, ensure that the wiring connector is facing up (towards the retaining screw). If the retaining screw was fitted with a washer, discard the washer and apply a suitable locking compound to the screw threads before screwing it into position.

Throttle body upper injector housing

8. Detach the wiring connector, undo the retaining screws and lift the upper injector housing clear of the main body. Remove the seal.

9. Unscrew the union nuts and detach the fuel lines from the injector housing.

10. Refit in the reverse order of removal.

Remove the seal located between the upper housing and the main body. Where the retaining screws were fitted with washers, discard the washers and coat the threads of the screws with a suitable locking compound. Tighten the retaining screws to the specified torque to secure the upper body to the main body.

Idle air stepper motor

11. Detach the wiring connector, undo the retaining screws and withdraw the idle air stepper motor unit from the injector unit housing (see illustrations).

Detach the wiring connector . . .

. . . undo the retaining screws . . .

. . . and remove the idle air stepper motor

12. Refit in the reverse order of removal. To avoid damaging the injector housing as the motor unit is refitted, press the cone in against its stop and check that the top of the cone to the mating flange face is within 28 mm (see illustration).

Idle air stepper motor cone tip-toflange distance should be as specified

Throttle body/injector housing unit

13. Disconnect the wiring connectors from the throttle body/injector housing.

14. Disconnect the operating rod, then unscrew and remove the two retaining nuts from the studs and carefully lift the throttle body/injector housing from the inlet manifold.

Remove the gasket and clean the mating surfaces.

15. Refit in the reverse order of removal, but be sure to fit a new gasket between the manifold and the throttle body/injector unit.

Tighten the retaining nuts to the specified torque setting.

Pressure regulator

16. Prior to removal of the regulator unit, a new diaphragm must be obtained as this must be renewed whenever the cover is removed.

Release the pressure in the fuel system.

17. Undo the four retaining screws and carefully withdraw the regulator unit cover, spring and diaphragm (see illustrations).

Undo the retaining screws . . .

. . . and remove the pressure regulator cover, spring and diaphragm

18. Refit in the reverse order of removal.

Ensure that the new diaphragm and its seatings are clean. Note that no adjustment to the regulator unit is necessary (or possible).

Inlet manifold pressure sensor

19. This unit is located on the engine side of the bulkhead. Disconnect the wiring connector and the vacuum hose, then detach and remove the unit from the bulkhead.

20. Refit in the reverse order of removal, ensuring that the vacuum hose and wiring plug are securely reconnected. Position the vacuum hose so that it progressively slopes down between the inlet manifold pressure sensor and the throttle housing.

Control unit

21. Detach and remove the trim panel from the right-hand footwell to gain access to the control unit.

22. Disconnect the wiring multi-plug connectors, undo the retaining screw then release and remove the control unit.

23. The control unit also contains a programmable memory (PROM) unit in which the engine/vehicle data and calibration are stored. If this unit is known to be faulty it can be removed from the control unit and renewed separately. If the control unit is at fault, the PROM unit should be removed from it, the control unit alone renewed and the original PROM unit fitted to the new control unit.

24. To separate the PROM from the control unit, detach and withdraw the cover from the end of the control unit, then press back the retaining clips, unplug and withdraw the PROM unit from the control unit. When removed, no attempt must be made to open and/or tamper with the PROM unit. Ensure that its plug contacts are clean and in good condition.

25. If renewing the control unit it is important that the part number/code sticker label is transferred to the new unit.

26. Refit in the reverse order of the removal procedure. On completion, switch on the ignition and check for satisfactory operation.

Coolant temperature sensor

27. Partially drain the cooling system to allow the temperature sensor to be removed without excessive coolant loss.

28. Disconnect the multi-plug from the temperature sensor, then unscrew the sensor.

Note the position of the sealing ring.

29. Refitting is a reversal of the removal procedure, using a new sealing ring and tightening the sensor securely.

Road speed sensor

30. Unclip the road speed sensor multi-plug, located near the base of the speedometer cable, and disconnect it. Unscrew and detach the speedometer cable from the sensor.

31. Unscrew the road speed sensor from its gearbox location and remove it.

32. Refitting is the reverse to removal.