Peugeot 405 Haynes (petrol). Manual - part 18

8 Unscrew the Allen bolts and remove the
throttle housing (see illustration).

Bosch LU2-Jetronic system

9 Release the securing clip, and disconnect
the wiring plug from the throttle position
switch.
10 Loosen the securing clamp, and
disconnect the air trunking from the front of
the throttle body.
11 Disconnect the accelerator cable.
12 Disconnect the vacuum and/or breather
hoses from the throttle body, noting their
locations to ensure correct refitting.
13 Unscrew the three throttle body securing
nuts, and recover the washers. Remove the
throttle cable bracket from the top throttle
body securing stud, noting its orientation.

Bosch Motronic system

14 Slacken the retaining clip, then
disconnect the inlet duct from the throttle
housing and recover the sealing ring.
15 Disconnect the accelerator inner cable
from the throttle cam, then withdraw the outer
cable from the mounting bracket, along with
its flat washer and spring clip.
16 Depress the retaining clip and disconnect
the wiring connector(s) from the throttle
potentiometer, and, where necessary, from
the electric heating element, the air
temperature sensor.
17 Slacken and remove the three retaining
screws and remove the throttle housing from
the inlet manifold. Recover the O-ring from
manifold and discard it; a new one must be
used on refitting.

Magneti Marelli 8P system

18 Remove the air cleaner-to-throttle
housing duct as described in Section 2.
19 As applicable, carefully lever the
accelerator linkage rod off its throttle housing
balljoint, or disconnect the accelerator inner
cable from the throttle cam, then withdraw the
outer cable from the mounting bracket along
with its flat washer and spring clip. Where
necessary, also disconnect the kickdown
cable as described in Chapter 7B (see
illustration).
20 Depress the retaining clips, and
disconnect the wiring connectors from the
throttle potentiometer, the electric heating
element, the air temperature sensor and idle
control stepper motor (as applicable).
21 Release the retaining clips (where fitted),
and disconnect all the relevant vacuum and
breather hoses from the throttle housing. Make
identification marks on the hoses, to ensure
they are connected correctly on refitting.
22 Slacken and remove the three retaining
screws, and remove the throttle housing from
the inlet manifold. Remove the O-ring from the
manifold, and discard it - a new one must be
used on refitting.

Refitting

23 Refitting is a reversal of the removal
procedure, noting the following points:

a) Fit a new O-ring to the manifold, then refit

the throttle housing and securely tighten
its nuts or screws (as applicable).

b) Ensure all hoses are correctly reconnected

and, where necessary, are securely held in
position by the retaining clips.

c) Ensure all wiring is correctly routed, and

the connectors are securely reconnected.

d) On completion, adjust the accelerator

cable as described in Section 3 and,
where necessary, the kickdown cable as
described in Chapter 7B.

13 Electronic control unit -

removal and refitting

Removal

1 With the exception of the Bosch L3.1-
Jetronic system, the electronic control unit is

located behind the engine compartment
bulkhead on the left-hand side. On the L3.1
system it is located on the air cleaner cover
and is removed by removing the cover as
described in Section 2. Proceed as follows for
other models.
2 To remove the unit first disconnect the
battery negative lead.
3 Open the bonnet and unclip the cover from
the top of the engine compartment bulkhead.
4 Release the clip, and disconnect the wiring
plug from the electronic control unit.
5 Unscrew the clamp bolts or nuts, as
applicable, securing the ECU to the housing,
then carefully withdraw the unit from its
location. On some models, it may be
necessary to disconnect the control unit
wiring harness earth lead before the unit can
be withdrawn.
6 Where applicable, separate the control unit
from its mounting bracket.

Refitting

7 Refitting is a reversal of removal, ensuring
that the wiring harness earth lead is correctly
reconnected where applicable.

14 Bosch L3.1-Jetronic system

components - removal,
refitting and adjustments

Throttle initial position

1 Disconnect the accelerator cable and
throttle switch.
2 Loosen the throttle switch unit mounting
bolts and turn the unit fully anti-clockwise,
then tighten the mounting bolts.

Primary barrel

3 Prise out the tamperproof cap from the
throttle stop screw and loosen the screw until it
is clear of the throttle lever (see illustration).
4 Place a 0.05 mm feeler blade between the
lever and the screw and tighten the screw
until it just contacts the feeler blade without
trapping it (see illustration). The throttle lever
must not be moved.

14.4 Adjusting the throttle initial position

4C•6 Fuel/exhaust systems - multi-point fuel injection models

12.8 Removing the throttle housing

14.3 Tamperproof cap covering primary

throttle stop screw (arrowed)

12.19 Accelerator cable and kickdown

cable connections on the throttle housing

(Magneti Marelli 8P fuel injection system)

5 Remove the feeler blade then turn the
screw in by a further quarter turn. Fit a new
tamperproof cap.

Secondary barrel

6 The procedure is as described for the
primary barrel but using the secondary throttle
adjustment screw (see illustrations).
7 On completion of the adjustment, apply a
drop of thread locking compound to the head
of the adjustment screw.
8 Adjust the throttle switch.
9 Reconnect the throttle switch and
accelerator cable.

Throttle switch

10 To remove the unit, disconnect the multi-
plug and unbolt the unit from the throttle
housing.
11 To adjust the switch proceed as follows.
12 The throttle valve initial opening position
must be correctly adjusted.

Idling switch

13 Loosen the switch bolts and turn it
clockwise as far as it will go, then bring it back
until the switch can be heard to operate (see
illustration).
14 Tighten the mounting bolts with the
switch held in this position.
15 To check that the adjustment is correct,
disconnect the multi-plug and connect an
ohmmeter to terminals 2 and 18 on the
switch.
16 The ohmmeter should read zero ohms.
17 Fully depress the accelerator pedal, when
the ohmmeter should read infinity.
18 If these readings are incorrect, re-adjust
the switch.

Full load switch

19 Connect the ohmmeter to terminals 3 and
18 on the switch. The reading should indicate
infinity.
20 Fully depress the accelerator pedal, when
the reading should be zero ohms.
21 If these readings are incorrect, renew the
throttle switch.
22 Reconnect the multi-plug.

Airflow meter and ECU

23 The airflow meter and ECU are removed
as described in Section 2.

Fuel rail and injectors

Note: Refer to the warning note in Section 1
before proceeding.
Note: If a faulty injector is suspected, before
condemning the injector, it is worth trying the
effect of one of the proprietary injector-
cleaning treatments.
24 Depressurise the fuel system.
25 Disconnect the sensor pipe on the fuel
pressure regulator and remove the bolt from
the regulator support bracket on the inlet
manifold.
26 Number the injector electrical plugs then
disconnect them from the injectors.
27 Disconnect the inlet and outlet fuel hoses,
being prepared for any fuel spillage.
28 Unbolt the fuel rail and pull it and the
injectors upward to release them from the
cylinder head (see illustrations).
29 Pull out the clips securing the injectors to

the fuel rail and pull out the injectors. Number
them for refitting in the same positions (see
illustration).
30 Check the condition of the O-ring seals
and renew them as necessary (see
illustration).
31 Clean the injector nozzles using injector
cleaning fluid. Note: Fouling of the injector
nozzles can cause the following symptoms.

a) Difficult hot starting.
b) Persistent stalling.
c) Misfiring when cold.
d) Misfire when hot between 1000 and

2000 rpm.

e) Loss of performance.

32 Refitting is a reversal of removal.

Fuel pressure regulator

33 Depressurise the system.
34 Disconnect the sensor pipe.
35 Disconnect the fuel hose.

Fuel/exhaust systems - multi-point fuel injection models 4C•7

14.13 Throttle switch unit mounting bolts

(A) and plug terminal numbers

14.29 Removing an injector

from the fuel rail

14.28b . . . and pulling up the rail and

injectors

14.28a Removing a fuel rail bolt . . .

14.6b . . . and viewed from underneath

14.6a Secondary throttle adjusting screw

(arrowed) . . .

14.30 Injector O-ring seals (arrowed)

36 Remove the bolt from the support bracket
on the inlet manifold.
37 Unbolt and remove the regulator from the
fuel rail (see illustration).
38 Refit in reverse order.

Fuel pump damper

39 Depressurise the fuel system.
40 Disconnect the fuel hose unions from the
damper (see illustration).
41 Unscrew the nut securing the damper to
the support bracket and remove the damper.
42 Refit in reverse order.

Supplementary air device

43 Disconnect the battery then remove the
battery and battery tray.
44 Remove the nuts securing the water
housing to the cylinder head.
45 Disconnect the wiring and air hoses from
the air device (see illustration).
46 Tilt the water housing to gain access to
the air device securing bolts and remove the
bolts and air device.
47 Refit in reverse order.

Injection thermistor

48 Disconnect the wiring from the thermistor
on the water housing (see illustration).
49 Drain the cooling system.
50 Unscrew the thermistor from the water
housing.
51 Refit in reverse order, using a new sealing
washer.
52 Top-up and bleed the cooling system.

Fuel filter

53 Disconnect the battery negative lead.
54 Depressurise the fuel system.
55 Disconnect the inlet and outlet hoses from
the filter (see illustration).
56 Loosen the rubber mounting strap clamp
nut and slide the filter from the clamp.
57 Refit in reverse order, ensuring any
directional arrows on the filter are facing the
direction of fuel flow.

15 Bosch LU2-Jetronic system

components - removal,
refitting and adjustments

Throttle initial position

1 The throttle initial position is set in
production, and will not normally require
adjustment unless the throttle housing has
been tampered with. Adjustment should be
entrusted to a Peugeot dealer.

Throttle switch unit

2 Disconnect the battery negative lead.
3 Disconnect the wiring plug from the switch.
4 Remove the two securing screws, and
withdraw the switch from the throttle body.
5 Commence refitting by initially adjusting the
switch as described later.
6 Refitting is reversal of removal, but ensure
that the switch wiper engages correctly with
the flats on the end of the throttle spindle.
7 The throttle initial position must be correctly

adjusted before attempting to adjust the
throttle switch.
8 Slacken the throttle switch securing screws.
9 Turn the switch unit fully clockwise, then
turn it slowly back until the idling contacts are
heard to close.
10 Tighten the securing screws.
11 Pull the wiring from the switch, then
connect an ohmmeter between terminals 2
and 18 in the switch - the ohmmeter should
read zero.
12 Operate the throttle linkage, and the
ohmmeter should read infinity.
13 If the readings are not correct, repeat the
adjustment.
14 Connect an ohmmeter between switch
terminals 3 and 18 - the ohmmeter should
read infinity.
15 Fully open the throttle, and the ohmmeter
should read zero.
16 If the specified readings cannot be
obtained, renew the switch.
17 Reconnect the switch wiring plug on
completion.

Airflow meter

18 The airflow meter is removed as
described in Section 2.

Electronic control unit (ECU)

19 Refer to Section 13.

Fuel injectors

Note: Refer to the warning note in Section 1
before proceeding.
Note: If a faulty injector is suspected, before
condemning the injector, it is worth trying the
effect of one of the proprietary injector-
cleaning treatments.
20 Depressurise the fuel system.
21 Disconnect the battery negative lead.
22 Disconnect the wiring plugs from the fuel
injectors, labelling them if necessary to ensure
correct refitting.
23 Disconnect the vacuum hose from the top
of the fuel pressure regulator.
24 Unscrew the four bolts securing the fuel
rail to the inlet manifold then carefully lift the
rail, complete with pressure regulator and fuel
injectors, from the inlet manifold, taking care
not to strain any of the hoses or pipes.

4C•8 Fuel/exhaust systems - multi-point fuel injection models

14.37 Regulator-to-fuel rail bolts (arrowed)

- assembly removed for clarity

14.45 Disconnecting the supplementary

air device plug

14.55 Fuel filter showing fuel hoses (A)

and clamp bolt (B)

14.48 Disconnecting the injection

thermistor wiring

14.40 Fuel pump damper showing fuel

hose connections

25 To remove a fuel injector from the fuel rail,
carefully remove the metal securing clip, then
pull the injector from the rail. Be prepared for
fuel spillage.
26 Refitting is a reversal of removal, but use
new injector O-rings.

Fuel pressure regulator

Note: Refer to the warning note in Section 1
before proceeding.
27 For improved access to the regulator
lower securing nut, remove the fuel rail.
28 If not already done, disconnect the
vacuum hose from the top of the pressure
regulator.
29 Slacken the hose clip, and disconnect the
fuel return hose from the bottom of the
pressure regulator. Be prepared for fuel
spillage.
30 Unscrew the two bolts securing the
pressure regulator to the fuel rail bracket
assembly, whilst counterholding the nuts.
Note that on some models a hose bracket is
secured by the upper bolt.
31 Pull the regulator from the end of the fuel
rail, and recover the O-ring.
32 Refitting is a reversal of removal, but use a
new O-ring when refitting the pressure
regulator to the fuel rail, and where applicable,
use new injector O-rings.

Oxygen sensor

33 The sensor is located in the exhaust
downpipe. When handling the sensor, note
that it is fragile; take care not to drop it, and
do not allow it to contact fuel or silicone
substances.
34 Start the engine and run it until it reaches
normal operating temperature, then switch off
and disconnect the battery negative lead.
35 If access is required from below, jack up
the front of the car and support it on axle
stands (see “Jacking and Vehicle Support).
36 Release the securing clips, and separate
the two halves of the sensor wiring connector.
37 Using a suitable spanner, unscrew it from
the exhaust downpipe.
38 Refitting is a reversal of removal, bearing
in mind the following points.

a) Apply anti-seize compound to the threads

of the sensor.

b) The sensor must be tightened securely;

this will require the use of either a deep
socket, slotted to allow for the sensor
wiring, or of a spanner.

16 Bosch Motronic system

components - removal,
refitting and adjustments

Fuel rail and injectors

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 crimped-
type 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 right-
hand 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

Fuel/exhaust systems - multi-point fuel injection models 4C•9

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.

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.

17 Magneti Marelli system

components - removal,
refitting and adjustments

1.8 litre models

Fuel 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.
1 Disconnect the battery negative terminal.
2 Remove the air cleaner-to-throttle housing
duct as described in Section 2.
3 Undo the two bolts securing the wiring tray
to the top of the manifold, and position the
tray clear of the injectors.
4 Depress the retaining clip(s) and disconnect
the wiring connector(s) from the injector(s).
5 Slacken the retaining screw and remove the
injector retaining plate; Nos 1 and 2 injectors
are retained by one plate, Nos 3 and 4 by
another.
6 Place a wad of clean rag over the injector,
to catch any fuel spray which may be
released, then carefully ease the relevant
injector(s) out of the manifold. Remove the O-
rings from the end of each disturbed injector,
and discard them - these must be renewed
whenever they are disturbed.
7 On refitting the injectors, fit new O-rings to
the end of each injector. Apply a smear of
engine oil to the O-ring, to aid installation,
then ease the injector(s) back into position in
the manifold.
8 Ensure each injector connector is correctly
positioned, then refit the retaining plate and
securely tighten its retaining screw.
Reconnect the wiring connector(s) to the
injector(s).
9 Refit the wiring tray to the top of the
manifold and securely tighten its retaining
bolts.
10 Refit the air cleaner-to-throttle body duct
and reconnect the battery. Start the engine
and check the injectors for signs of leakage.

Fuel pressure regulator

11 Refer to Section 13.

Throttle potentiometer

12 The throttle potentiometer is fitted to the
right-hand side of the throttle housing. To
remove the potentiometer, first disconnect the
battery negative terminal.
13 Depress the retaining clip and disconnect
the potentiometer wiring connector.
14 Slacken and remove the two retaining
screws, and remove the potentiometer from
the throttle housing.
15 Refitting is the reverse of removal,
ensuring that the potentiometer is correctly
engaged with the throttle valve spindle.

Electronic Control Unit (ECU)

16 Refer to Section 13.

Idle speed control stepper motor

17 The idle speed control stepper motor
is located on the front of the throttle
housing assembly. Before removing the
motor, first disconnect the battery negative
terminal.
18 Release the retaining clip and disconnect
the wiring connector from the motor.
19 Slacken and remove the two retaining
screws, and withdraw the motor from the
throttle housing.
20 Refitting is a reversal of the removal
procedure.

Manifold absolute pressure (MAP)
sensor

21 Refer to Section 13.

Coolant temperature sensor

22 Refer to Chapter 3.

Inlet air temperature sensor

23 The inlet air temperature sensor is located
in the throttle housing.
24 To remove the sensor, first remove the
throttle potentiometer as described in
paragraphs 12 to 14.
25 Depress the retaining clip and disconnect
the wiring connector from the air temperature
sensor.
26 Remove the screw securing the sensor
connector to the top of the throttle housing,
then carefully ease the sensor out of position
and remove it from the throttle housing.
Examine the sensor O-ring for signs of
damage or deterioration, and renew if
necessary.
27 Refitting is a reversal of the removal
procedure, using a new O-ring where
necessary, and ensuring that the throttle
potentiometer is correctly engaged with the
throttle valve spindle.

Crankshaft sensor

28 Refer to Section 13.

Fuel injection system relay unit

29 Refer to Section 13.

Throttle housing heating element

30 The throttle housing heating element is
fitted to the top of the throttle housing. To
remove the element, first disconnect the
battery negative terminal.

31 Depress the retaining tangs and
disconnect the wiring connector from the
heating element.
32 Undo the screw(s) securing the wiring
connector to the throttle housing, then
displace the connector and carefully withdraw
the heating element from the throttle housing
(see illustration). Examine the element O-ring
(where fitted) for signs of damage or
deterioration, and renew if necessary.
33 Refitting is a reversal of the removal
procedure, taking great care to ensure that
the element wiring does not become trapped
as the wiring connector bolt(s) are tightened.

2.0 litre models

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.
34 Disconnect the battery negative terminal.
35 Remove the air cleaner-to-throttle housing
duct, using the information in Section 2.
36 Disconnect the vacuum pipe from the fuel
pressure regulator.
37 Release the retaining clip and free the
various hoses from the top of the fuel rail.
38 Bearing in mind the information given in
Section 7, slacken the retaining clip, and
disconnect the fuel feed and return hoses
from the ends of the fuel rail. Where the
original crimped-type Peugeot hose clips are
still fitted, cut them off and discard them; use
standard worm-drive hose clips on refitting.
39 Depress the retaining clips and
disconnect the wiring connectors from the
four injectors.
40 Slacken and remove the three fuel rail
retaining bolts, 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; these must be
renewed whenever they are disturbed.
41 Slide out the retaining clip(s) and remove
the relevant injector(s) from the fuel rail.
Remove the upper O-ring from each injector
as it is removed, and discard it; all O-rings
must be renewed once they have been
disturbed.

4C•10 Fuel/exhaust systems - multi-point fuel injection models

17.32 Throttle housing heating element

42 Refitting is a reversal of the removal
procedure, noting the following points:

a) Fit new O-rings to all disturbed injectors.
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

43 Refer to Section 13.

Throttle potentiometer

44 Remove the throttle housing as described
in Section 12.
45 Undo the two retaining screws and
remove the potentiometer from the base of
the throttle housing.
46 On refitting, ensure that the potentiometer
is correctly engaged with the throttle valve
spindle, and securely tighten its retaining
screws.
47 Refit the throttle housing as described in
Section 12.

Electronic control unit (ECU)

48 The ECU is situated inside its own
protective compartment in the battery tray. To
remove the ECU, first disconnect the battery
negative terminal.
49 Unclip the lid from the plastic box and
disconnect the wiring connector from the
ECU.
50 Slide the ECU out of the box and, if
necessary, undo the retaining nuts and
separate it from its mounting plate.
51 Refitting is the reverse of removal,
ensuring that the wiring connector is securely
reconnected.

Idle speed control stepper motor

52 Refer to the information given in
paragraphs 17 to 20 of this Section.

Manifold absolute pressure (MAP)
sensor

53 The MAP sensor is situated on the right-
hand side of the engine compartment,
mounted on the front suspension mounting
turret. To remove the sensor, first disconnect
the battery negative terminal.
54 Undo the three retaining nuts and free the
sensor from the underside of the mounting
bracket.
55 Depress the retaining clip, disconnect the
wiring connector and vacuum hose from the
sensor, and remove the sensor from the
engine compartment.
56 Refitting is a reversal of the removal
procedure.

Coolant temperature sensor

57 Refer to Chapter 3.

Inlet air temperature sensor

58 The inlet air temperature sensor is located
in the base of the throttle housing.
59 To remove the sensor, first remove the
throttle housing as described in Section 12,

then undo the two retaining screws and
remove the throttle potentiometer from the
base of the housing.
60 Trace the wiring back from the sensor to
its wiring connector, and remove the screw
securing the connector to the throttle housing.
61 Carefully ease the sensor out of position,
and remove it from the throttle housing.
Examine the sensor O-ring for signs of
damage or deterioration, and renew if
necessary.
62 Refitting is a reversal of removal, using a
new O-ring where necessary.

Crankshaft sensor

63 Refer to Section 13.

Fuel injection system relay unit

64 Refer to Section 13.

Throttle housing heating element

65 Refer to the information given in
paragraphs 30 to 33 of this Section.

Vehicle speed sensor

66 The vehicle speed sensor is an integral
part of the transmission speedometer drive
assembly. Refer to Chapter 7A for removal
and refitting details.

Knock sensor

67 The knock sensor is screwed onto the
rear face of the cylinder block.
68 To gain access to the sensor, firmly apply
the handbrake, then jack up the front of the
vehicle and support it on axle stands (see
“Jacking and Vehicle Support”). Access to the
sensor can then be gained from underneath
the vehicle.

69 Trace the wiring back from the sensor to
its wiring connector, and disconnect it from
the main loom.
70 Slacken and remove the bolt securing the
sensor to the cylinder block, and remove it
from underneath the vehicle.
71 Refitting is a reversal of the removal
procedure, ensuring that the sensor wiring is
correctly routed and its retaining bolt securely
tightened.

18 Inlet manifold -

removal and refitting

Removal

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

Bosch L3.1-Jetronic system

2 Remove the fuel rail as described
previously. There is no need to disconnect
any fuel hoses. Lay the rail to one side.
3 Disconnect the brake servo vacuum hose
(see illustration).
4 Remove the throttle housing as described
previously.
5 Disconnect and unbolt the ignition coil.
6 Disconnect the supplementary air device air
hose from the manifold (see illustration).
7 Remove the bolt from the starter bracket
(see illustration).
8 Unbolt the oil filler tube support bracket
(see illustration).

Fuel/exhaust systems - multi-point fuel injection models 4C•11

18.8 Oil filler tube support bracket

18.7 Removing the bolt from the

starter bracket

18.6 Supplementary air device air hose

connection on inlet manifold

18.3 Disconnecting the brake servo

vacuum hose

9 Remove the manifold securing bolts and
the two 5 mm Allen bolts (a long Allen key is
required).
10 Lift off the manifold.

Bosch LU2-Jetronic, Motronic and
Magneti Marelli systems

11 The procedure is similar to that described
above, noting the following points.

a) Note that vacuum, coolant hose and

wiring connections to the manifold and
associated components vary depending
on model. When disconnecting any pipes,
hoses, or wires, take note of their
locations to ensure correct refitting.

b) Where applicable, ignore the references

to the coil, supplementary air device
and/or starter bracket.

c) Ensure that any disturbed gaskets are

renewed.

d) Note that not all manifolds are secured by

Allen bolts.

Refitting

12 Refitting is a reversal of removal using a
new gasket/seal or jointing compound as
necessary. Ensure that the locating dowels
are in position and tighten all bolts to their
specified torque (see illustrations).
Note: The engine gasket kit contains gaskets
for both carburettor and injection type
manifolds. The injection type gasket has cut-
outs for the injector ports. Ensure that the
correct gasket is fitted. The carburettor type
will partially obstruct the injector ports causing
erratic running and loss of power.

19 ACAV inlet system (16-valve

models) - general information,
removal and refitting

General information

1 To ensure optimum efficiency at high
engine speeds, and maximum torque at lower
engine speeds, 16-valve models have an inlet
manifold with a variable inlet tract system. The
system is called ACAV (variable acoustic
characteristic induction).
2 The inlet manifold is divided into two tracts
of different length and diameter; a long tract
(for low-speed torque) which is 650 mm long,
diameter 36 mm, and a short tract (for high-
speed power) which is 370 mm long, diameter
45 mm.
3 Situated between the manifold and the
cylinder head is a line of four butterfly valves,
mounted in an alloy housing. Mounted on
either end of the housing is a vacuum
diaphragm assembly. Each diaphragm is
connected to the butterfly valve spindles via a
pushrod. The vacuum diaphragms are
connected to an electrically-operated
solenoid valve, which is in turn connected to
the braking system vacuum pump. The pump
is mounted on the end of the cylinder head,
and is driven off the left-hand end of the inlet
camshaft.
4 At engine speeds below 1800 rpm and
above 5080 rpm, the ECU closes the solenoid
valve, shutting off the vacuum supply to the
diaphragms, and the butterfly valves are

closed. With the valves closed, the short inlet
tracts are closed, and the incoming air flows
only through the long inlet tract, boosting the
torque output.
5 At engine speeds between 1800 rpm and
5080 rpm, the ECU opens the solenoid valve.
The vacuum present in the pump is then
allowed to act on the vacuum diaphragms,
which draws the pushrods into the diaphragm
bodies, and opens up the four butterfly valves.
With the valves open, the incoming air is
allowed to flow through both the short and
long inlet tracts, for maximum power.
6 To check the system, start the engine and
allow it to idle. Slowly increase the engine
speed, whilst observing the vacuum
diaphragm pushrods. At approximately 1800
rpm, the pushrods should be drawn into the
diaphragm bodies (valves open). Release the
throttle cam, and allow the engine to idle
again; the pushrods should extend from the
diaphragms (valves closed).
7 To check the operation of the solenoid
valve, disconnect the vacuum pipe from the
diaphragm. Start the engine, and allow it to
idle. Place your finger over the end of the
pipe; no vacuum should be present in the
pipe. Slowly increase the engine speed; at
approximately 1800 rpm, vacuum should be
felt in the pipe. Allow the engine to idle again,
and check that the vacuum supply is switched
off. If this is not the case, either the solenoid
valve or its supply voltage is at fault.
8 To check the operation of either vacuum
diaphragm assembly, disconnect the vacuum
pipe, and suck hard at the control valve stub;
the pushrod should be drawn into the
diaphragm body, and the valve should open.
If this is not the case, the vacuum diaphragm
is faulty.

Removal and refitting

ACAV valve assembly

9 Remove the inlet manifold as described in
Section 18.
10 Bearing in mind the information given in
Section 7, slacken the retaining clip, and
disconnect the fuel feed and return hoses
from their unions on the fuel rail. Where the
original crimped-type Peugeot hose clips are
still fitted, cut them off and discard them; use
standard worm-drive hose clips on refitting.
11 Depress the retaining tangs, and
disconnect the wiring connectors from the
four injectors. To avoid the possibility of the
wiring connectors being incorrectly
reconnected on refitting, mark each
connector with its relevant cylinder number
(No 1 is at the transmission end of the engine).
12 Disconnect the vacuum hoses from the
fuel pressure regulator and the ACAV
diaphragm hose T-piece.
13 Slacken and remove the nuts and three
bolts securing the valve assembly to the
cylinder head, then slide the assembly off its
mounting studs and remove it from the engine
compartment. Remove the valve assembly

4C•12 Fuel/exhaust systems - multi-point fuel injection models

18.12a Applying jointing compound to the

inlet manifold

18.12c Fitting the inlet manifold

18.12d Tightening the manifold

securing bolts

18.12b Ensure locating dowels (arrowed)

are in position

gasket from the head, and discard it - a new
one must be used on refitting.
14 Examine the assembly, checking that the
butterfly valves open freely and close
smoothly. If not, the assembly must be
renewed. The only components available
separately are the vacuum diaphragm units -
if either one is faulty, it must be renewed as
described below.
15 Refitting is a reverse of the removal
procedure, noting the following points:

a) Ensure that the valve assembly and

cylinder head mating surfaces are clean
and dry, and fit the new manifold gasket
over the studs. Refit the valve assembly,
and securely tighten its retaining nuts and
bolts.

b) Ensure that all relevant hoses are

reconnected to their original positions,
and are securely held (where necessary)
by the retaining clips.

c) Refit the inlet manifold as described in

Section 18.

d) On completion, check the operation of

the ACAV system as described above.

Vacuum diaphragm unit

16 Disconnect the vacuum hose from the

diaphragm unit. Using a suitable flat-bladed
screwdriver, carefully lever the unit pushrod
off the valve linkage balljoint (see
illustration).
17 Slacken and remove the two bolts
securing the diaphragm unit mounting bracket
to the valve assembly, and remove the
diaphragm from the engine.
18 Refitting is a reversal of the removal
procedure, ensuring that the diaphragm
pushrod is clipped firmly onto the linkage
balljoint.

Solenoid valve

19 The solenoid control valve is mounted on
the left-hand end of the cylinder head
(see illustration). Before removing the valve,
first disconnect the battery negative terminal,
and position it away from the battery.
20 Depress the retaining clip, and disconnect
the wiring connector from the valve.
21 Undo the nut securing the valve to the
cylinder head, then withdraw the valve,
disconnecting its vacuum hoses as they
become accessible.
22 Refitting is a reversal of the removal
procedure. Test the system on completion, as
described above.

20 Exhaust manifold -

removal and refitting

Removal

1 Refer to Chapter 4A, Section 15, noting that
where applicable the lambda (oxygen) sensor
wiring connectors should be disconnected.
Alternatively, care must be taken to support
the front pipe, to avoid any strain being
placed on the sensor wiring. Where
applicable, jack up the front of the car and
support on axle stands (see “Jacking and
Vehicle Support”).

Refitting

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

a) Examine all the exhaust manifold studs for

signs of damage and corrosion; remove
all traces of corrosion, and repair or
renew any damaged studs.

b) Ensure that the manifold and cylinder

head sealing faces are clean and flat, and
fit the new manifold gaskets. Tighten the
manifold nuts to the specified torque.

c) Reconnect the front pipe to the manifold

using the information given in Section 18.

21 Exhaust system -

general information,
removal and refitting

Refer to Chapter 4A, Section 16, however

note that it will be necessary to disconnect
the lambda (oxygen) sensor wiring connectors
in order to remove the front pipe/complete
system. On refitting, ensure that the sensor
wiring is retained by all the relevant retaining
clips so that it is in no danger of contacting
the hot exhaust/engine.

Fuel/exhaust systems - multi-point fuel injection models 4C•13

19.19 ACAV solenoid valve

retaining nut (1), wiring connector (2)

and hose connections (3)

19.16 ACAV vacuum diaphragm unit

Content .. 16 17 18 19 ..