Fuel injection system components - removal and refitting

Fuel system: single-point injection models / Fuel injection system components - removal and refitting

Warning: Observe the
precautions in Section 1 before working on any component in the fuel system.

Throttle body
Removal
1 Refer to Section 2 and remove the air cleaner/throttle body air box.

2 Refer to Section 9 and depressurise the fuel system, then disconnect the battery negative cable and position it away from the terminal.

3 Disconnect the fuel supply and return hoses from the ports on the side of the throttle body. Note the arrows that denote the direction of fuel flow, and mark the hoses accordingly (see illustration).

5.3 Throttle body fuel supply and return hoses and ports

4 Unplug the wiring harness from the throttle body at the connectors, labelling them to aid correct refitting later. Similarly, disconnect all vacuum hoses from the throttle body and label them carefully; it is essential that the hoses are reconnected to the correct vacuum ports on reassembly.

5 Refer to Section 4 and disconnect the accelerator cable from the throttle body.

6 Remove the through-bolts and lift the upper and lower sections of the throttle body away from the inlet manifold.

7 The lower section of the throttle body may be separated from the upper section by releasing the clips. If required, the inter-mediate flange may be detached from the inlet manifold by removing the nuts from the four through-bolts.

Refitting
8 Refitting is a reversal of removal; renew all gaskets where appropriate. Finally, check and if necessary adjust the accelerator cable.

Fuel injector
Removal
9 Refer to Section 2 and remove the air cleaner housing.

10 Refer to Section 9 and depressurlse the fuel system, then disconnect the battery negative cable and position it away from the terminal.

11 Unplug the wiring harness from the injector at the connector(s), labelling them to aid correct refitting later.

12 Remove the screw and lift off the injector retaining cap/inlet air temperature sensor housing (see illustration)

5.12 Exploded view of the throttle body upper section and fuel injector

13 Lift the injector out of the throttle body, recovering the O-ring seals. Check the injector electrical resistance using a multimeter and compare the result with the Specifications .

Refitting
14 Refit the injector by following the removal procedure in reverse, renewing all O-ring seals. Tighten the retaining screw to the specified torque.

Inlet air temperature sensor 15 The inlet air temperature sensor is an integral part of the fuel injector retaining cap.

Removal is as described in the previous sub- Section. Its electrical resistance may be checked using a multimeter (refer to illustration 5.12).

Fuel pressure regulator
16 The fuel pressure regulator components are matched to the upper section of the throttle body and can only be renewed as part of a complete assembly.

Throttle valve positioning module Removal
17 Disconnect the battery negative cable and position it away from the terminal. Remove the air cleaner/throttle body air box, with reference to Section 2.

18 Refer to Section 4 and disconnect the accelerator cable from the throttle body.

19 Unplug the connector from the side of the throttle valve positioning module.

20 Remove the retaining screws and lift the module together with the accelerator cable outer mounting bracket away from the throttle body.

Refitting
21 Refitting is a reversal of removal. Check that the idle switch plunger lines up with the plastic stop on the lower section of the throttle body. If necessary, adjust the position of the throttle valve positioning module bracket after loosening the mounting screws.

Throttle valve potentiometer 22 Refer to the relevant sub-Section and remove the throttle body. The throttle valve potentiometer is an integral part of the lower section of the throttle body and cannot be renewed separately.

Idle switch
23 Refer to the relevant sub-Section and remove the throttle valve positioning module.

The idle switch is an integral part of the module and cannot be renewed separately.

Lambda sensor
Removal
24 The lambda sensor is threaded into the exhaust pipe, at the front of the catalyst.

25 Disconnect the battery negative cable and position it away from the terminal, then unplug the wiring harness from the lambda sensor at the connector, located at the rear of the engine, beneath the throttle body.

26 Note: As a flying lead remains connected to the sensor after is has been disconnected, if the correct size spanner is not available, a slotted socket will be required to remove the sensor. Working under the vehicle, slacken and withdraw the sensor, taking care to avoid damaging the sensor probe as it is removed.

Refitting
27 Apply a little anti-seize grease to the sensor threads - take care to avoid contaminating the probe tip.

28 Refit the sensor to its housing, tightening it to the correct torque. Restore the harness connection.

Coolant temperature sensor Removal
29 Disconnect the battery negative cable and position it away from the terminal, then refer to Chapter 3 and drain approximately one quarter of the coolant from the engine.

30 The temperature sensor is located on the left hand side of the cylinder head, under the heater coolant outlet elbow (see illustration).

There are two sensors fitted; the one colour coded blue serves the engine management system, the black one produces a signal for the instrument panel temperature gauge.

5.30 Two coolant temperature sensors are fitted; the one colour-coded blue (arrowed) serves the engine management system

31 Unplug the wiring harness from the sensor at the connector, then extract the clip and lift the sensor from its housing, recovering the Oring - be prepared for an amount of coolant loss.

Refitting
32 Refit the sensor by reversing the removal procedure, using a new O-ring. Refer to Chapter 1 and top-up the cooling system.

Electronic Control Unit (ECU) Removal
Caution: Electronic Control Units (ECUs) contain components that are sensitive to the levels of static electricity generated during normal activity. Once the multiway harness connector has been unplugged, the exposed ECU connector pins can freely conduct stray static electricity to these components, damaging or even destroying them - the damage will be invisible and may not manifest itself immediately. Expensive repairs can be avoided by observing the following basic handling rules: a) Handle a disconnected ECU by its case only; do not allow fingers or tools to come into contact with the pins.

b) When carrying an ECU around, “ground” yourself from time to time, by touching a metal object such as an unpainted water pipe, this will discharge any potentially damaging static that may have built up.

c) Do not leave the ECU unplugged from its connector for any longer than is absolutely necessary.

d) Make no attempt to ‘test’ the ECU using multimeters or other non-dedicated test equipment.

33 The ECU is located on the engine bulkhead, beneath a water shield.

e) Only unplug the ECU multiway connector after the battery supply has been disconnected.

34 Disconnect the battery negative cable and position it away from the terminal.

35 Remove the clips and lift off the water shield.

37 Remove the securing screws and lift the ECU away from the mounting bracket.

36 Release the spring clip and unplug the multiway connector from the ECU.

Refitting
38 Refitting is a reversal of removal.

Hall effect sensor
39 This sensor is an integral part of the ignition HT distributor assembly. It can be removed and renewed separately, but dismantling of the distributor will be necessary. It is therefore recommended that this operation is entrusted to a automotive electrical specialist.

Relays
Fuel pump relay
40 The fuel pump relay is located on the engine bulkhead, beneath a water shield. It is the lower of the two relays mounted on the same bracket as the engine management system ECU (see illustration).

5.40 Location of engine management system ECU and relays

1 Bosch Mono-Motronic ECU 2 Multiway harness connector 3 Mounting bracket
4 Fuel injection pump relay 5 Inlet manifold pre-heater relay

41 Disconnect the battery negative cable and position it away from the terminal.

42 Remove the clips and lift off the water shield.

43 Pull the relay from its socket.

44 Refitting is a reversal of removal.

Inlet manifold preheater relay 45 The manifold preheater relay is located on the engine bulkhead, beneath a water shield.

It is the upper of the two relays, mounted on the same bracket as the engine management system ECU (refer to illustration 5.40).

46 Disconnect the battery negative cable and position it away from the terminal.

47 Remove the clips and lift off the water shield.

48 Pull the relay from its socket.

49 Refitting is a reversal of removal.