Peugeot 405 Manual

Bosch Motronic system components - removal, refitting and adjustments
Fuel/exhaust systems - multi-point fuel injection models / Bosch Motronic system components - removal, refitting and adjustments


Fuel rail and injectors Note: Refer to the warning note in Section 1 before proceeding. If a faulty injector is suspected, before condemning the injector, it is worth trying the effect of one of the proprietary injector-cleaning treatments.

Warning: During the procedure described in this Section it is very important not to allow fuel to spill into the engine, otherwise a hydraulic lock may occur causing extensive engine damage.

1 Disconnect the battery negative terminal.

2 Disconnect the vacuum pipe from the fuel pressure regulator, then slacken and remove the retaining nut and bolt and release the wiring/hose retaining clip from the end of the fuel rail.

3 Bearing in mind the information given in Section 7, slacken the retaining clips and disconnect the fuel feed and return hoses from the fuel rail. Where the original crimpedtype Peugeot hose clips are still fitted, cut them and discard; replace them with standard worm-type hose clips on refitting.

4 Depress the retaining tangs and disconnect the wiring connectors from the four injectors.

5 Slacken and remove the fuel rail retaining bolts and nuts, then carefully ease the fuel rail and injector assembly out from the inlet manifold and remove it from the vehicle.

Remove the O-rings from the end of each injector and discard them; they must be renewed whenever they are disturbed.

6 Slide out the retaining clip(s) and remove the relevant injector(s) from the fuel rail.

Remove the upper O-ring from each disturbed injector and discard; all disturbed O-rings must be renewed.

7 Refitting is a reversal of the removal procedure, noting the following points.

a) Fit new O-rings to all disturbed injector unions.

b) Apply a smear of engine oil to the O-rings to aid installation, then ease the injectors and fuel rail into position ensuring that none of the O-rings are displaced.

c) On completion, start the engine and check for fuel leaks.

Fuel pressure regulator
Note: Refer to the warning note in Section 1 before proceeding.

8 Disconnect the vacuum pipe from the regulator. Note that access to the regulator is poor with the fuel rail in position, if necessary, remove the fuel rail as described earlier, then remove the regulator.

9 Place a wad of rag over the regulator, to catch any fuel spray which may be released, then remove the retaining clip and ease the regulator out from the fuel rail.

10 Refitting is a reversal of the removal procedure. Examine the regulator seal for signs of damage or deterioration and renew if necessary.

Throttle potentiometer
11 Disconnect the battery negative terminal.

12 Depress the retaining clip and disconnect the wiring connector from the throttle potentiometer.

13 Slacken and remove the two retaining screws, then disengage the potentiometer from the throttle valve spindle and remove it from the vehicle.

14 Refitting is a reversal of the removal procedure ensuring that the potentiometer is correctly engaged with the throttle valve spindle.

Electronic Control Unit (ECU) 15 Refer to Section 13.

Idle speed auxiliary air valve 16 The auxiliary air valve is mounted onto the underside of the inlet manifold.

17 To remove it, first disconnect the battery negative terminal.

18 Depress the retaining clip and disconnect the wiring connector from the air valve.

19 Slacken the retaining clips and disconnect both vacuum hoses from the end of the auxiliary air valve.

20 Slide the valve out from its mounting rubber and remove it from the engine compartment.

21 Refitting is a reversal of the removal procedure. Examine the mounting rubber for signs of deterioration and renew it if necessary.

Manifold absolute pressure (MAP) sensor
22 The MAP sensor is situated on the righthand side of the engine compartment where it is mounted onto the wing valance. To remove it, first disconnect the battery negative terminal.

23 Undo the retaining nut and free the MAP sensor from the body.

24 Disconnect the wiring connector and vacuum hose and remove the MAP sensor from the engine compartment.

25 Refitting is the reversal of the removal procedure.

Coolant temperature sensor 26 Refer to Chapter 3.

Inlet air temperature sensor 27 The inlet air temperature sensor is screwed into the top of the air cleaner housing. To remove the sensor first disconnect the battery negative terminal.

28 Disconnect the wiring connector, then unscrew the sensor and remove it from the vehicle.

29 Refitting is the reversal of removal.

Crankshaft sensor
30 The crankshaft sensor is situated on the front face of the transmission clutch housing.

31 To remove the sensor, first disconnect the battery negative terminal.

32 Trace the wiring back from the sensor to the wiring connector and disconnect it from the main harness.

33 Prise out the rubber grommet, then undo the retaining bolt and withdraw the sensor from the transmission.

34 Refitting is reversal of the removal procedure ensuring that the sensor retaining bolt is securely tightened and the grommet is correctly seated in the transmission housing.

Fuel injection system relay unit 35 The relay unit is mounted onto the rear of the ECU plastic box which is situated directly behind the battery.

36 To remove the relay unit, first disconnect the battery.

37 Undo the retaining nut, then disconnect the wiring connector and remove the relay unit from the vehicle.

38 Refitting is the reverse of removal, ensuring that the relay unit is securely clipped in position.


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