Peugeot 405. Manual - part 29

4A

Fuel pump

Type

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mechanical, driven by eccentric on camshaft

Carburettor

Type

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Solex 34-34 Z1, Solex 32-34 Z2 or Weber 36 TLP

Application:

XU engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Solex 34-34Z1 or Solex 32-34 Z2

TU engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Weber 34 TLP

Choke type  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Manual, cable-operated

Solex carburettor

Float height setting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

33.5 mm

Throttle valve fast idle setting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.5 mm

Choke pull-down setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.0 mm

Weber carburettor

Float height setting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

32.0 mm

Choke opening after starting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.0 mm

Recommended fuel

Minimum octane rating:

TU3 (K1G) engine (carburettor)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

97 RON leaded or 98 RON (super) unleaded

All other models (both carburettor and fuel injection)

without a catalytic converter  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

95 RON unleaded* or 97 RON leaded

All other models with a catalytic converter . . . . . . . . . . . . . . . . . . . . .

95 RON unleaded or 98 RON (super) unleaded

*On some early models the ignition timing must be retarded by 3° in order to use 95 RON unleaded fuel - check with your Peugeot dealer.

Torque wrench settings

Nm

lbf ft

Fuel pump retaining bolts  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

12

Inlet manifold retaining nuts  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

6

Exhaust manifold retaining nuts  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

12

Exhaust system fasteners:

Front pipe-to-manifold nuts  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30

22

Front pipe mounting bolt  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

26

Chapter 4  Part A:
Fuel/exhaust systems - carburettor models

Accelerator cable - removal, refitting and adjustment  . . . . . . . . . . . . .7
Accelerator pedal - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . .8
Air cleaner air temperature control system - 

general information and component renewal  . . . . . . . . . . . . . . . . . .3

Air cleaner assembly - removal and refitting  . . . . . . . . . . . . . . . . . . . .2
Air cleaner filter element renewal  . . . . . . . . . . . . . . . . . .See Chapter 1
Carburettor - fault diagnosis, overhaul and adjustments  . . . . . . . . . .13
Carburettor - general information  . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Carburettor - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Choke cable - removal, refitting and adjustment  . . . . . . . . . . . . . . . . .9
Exhaust manifold - removal and refitting  . . . . . . . . . . . . . . . . . . . . . .15

Exhaust system check . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Exhaust system - general information, removal and refitting  . . . . . . .16
Fuel filter renewal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Fuel gauge sender unit - removal and refitting . . . . . . . . . . . . . . . . . . .5
Fuel pump - testing, removal and refitting  . . . . . . . . . . . . . . . . . . . . . .4
Fuel tank - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
General information and precautions  . . . . . . . . . . . . . . . . . . . . . . . . . .1
Idle speed and mixture adjustment  . . . . . . . . . . . . . . . . .See Chapter 1
Inlet manifold - removal and refitting  . . . . . . . . . . . . . . . . . . . . . . . . .14
Unleaded petrol - general information and usage  . . . . . . . . . . . . . . .10

4A•1

Easy, suitable for
novice with little
experience

Fairly easy, suitable
for beginner with
some experience

Fairly difficult,
suitable for competent
DIY mechanic

Difficult, suitable for
experienced  DIY
mechanic

Very difficult,
suitable for expert
DIY or  professional

Degrees of difficulty

Specifications

Contents

1

General information and
precautions

The fuel system consists of a fuel tank

mounted under the rear of the car, a
mechanical fuel pump, and a carburettor. The
fuel pump is operated by an eccentric on the
camshaft, and is mounted on the rear of the
cylinder head. The air cleaner contains a
disposable paper filter element, and
incorporates a flap valve air temperature
control system; this allows cold air from the
outside of the car, and warm air from the
exhaust manifold, to enter the air cleaner in
the correct proportions.

The fuel pump lifts fuel from the fuel tank to

the carburettor via a filter located in the rear of
the engine compartment, and supplies it to the
carburettor via an anti-percolation chamber.
The anti-percolation chamber ensures that the
supply of fuel to the carburettor is kept at a
constant pressure, and is free of air bubbles.
Excess fuel is returned from the anti-
percolation chamber to the fuel tank.

The carburettor is either a Solex 34-34 Z1 or

Solex 32-34 Z2 twin-choke carburettor, or
Weber 36TLP single-choke carburettor (see
Section 11), mixture enrichment for cold starting
is by automatic choke on the Solex carburettor
and a cable-operated choke control on the
Weber carburettor. On the Solex carburettor a
vacuum-operated choke unloader, accelerator
pump and full load enrichener device are fitted
to govern the fuel requirements of the engine
over its full operating range.

The exhaust system consists of three or

four sections according to model. The front
pipe is in one or two sections; where it is in
two sections the rear section may be plain or
include a catalytic converter, where it is in one
section it may include a catalytic converter. All
models are fitted with an Intermediate pipe
and silencer, and a tailpipe and silencer. The
system is suspended throughout its entire
length by rubber mountings.

2

Air cleaner assembly -
removal and refitting

2

Removal

TU engine

1 Slacken the retaining clips (where fitted),
and disconnect the vacuum hose and
breather hose from the front of the air cleaner
housing-to-carburettor duct (see illustration).
Where the crimped-type Peugeot hose clips
are fitted, cut the clips and discard them; use
standard worm-drive hose clips on refitting.
2 Slacken the retaining clips, then lift the duct
off the top of the carburettor and air cleaner
housing. Disconnect the air temperature
control valve hose from the end of the duct,
and remove the duct from the engine
compartment 

(see illustrations). Recover the

rubber sealing ring(s) from the top of the
carburettor and/or air cleaner housing (as
applicable).
3 Disconnect the inlet duct from the front of

the air cleaner housing, and remove the air
cleaner housing from the engine
compartment.
4 To remove the inlet duct assembly, undo
the retaining bolts securing the duct to the
left-hand wing valance, then release the
fastener securing the rear of the duct to the
cylinder head (see illustration). Disconnect
the hot-air inlet hose from the exhaust
manifold shroud, and remove the duct and
hose assembly from the engine compartment.

XU engine

5 Using an Allen key, unscrew the bolt
securing the air inlet duct to the top of the
carburettor. Loosen the clip and disconnect
the duct (see illustration).
6 Loosen the clip and disconnect the air inlet
duct from the filter housing top cover.
7 Release the clips and remove the top cover
from the air filter housing.
8 Remove the filter element from inside the
lower housing.
9 Release the lower housing from the
mounting rubbers then disconnect the inlet
duct and hoses as applicable.

Refitting

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

a) Examine the rubber sealing ring(s) for

signs of damage or deterioration, and if
necessary renew. Note that, on some
models, the carburettor seal is fitted with
an O-ring; this should also be renewed if
it is damaged.

4A•2 Fuel/exhaust systems - carburettor models

2.1  On the TU engine disconnect the

vacuum and breather hoses (arrowed)

from the front of the duct . . .

2.2b  . . . and remove the duct,

disconnecting the air temperature control

valve hose (arrowed)

2.5  On the XU engine unscrew the bolt

securing the air inlet duct, 

then loosen the clip

2.4  Undo the intake duct front bolt then

release the rear fastener, and remove the

duct and hose assembly (TU engine)

2.2a  . . . slacken the retaining clips . . .

Warning: Many of the
procedures in this Chapter
require the removal of fuel lines

and connections, which may result in
some fuel spillage. Before carrying out
any operation on the fuel system, refer to
the precautions given in “Safety first!” at
the beginning of this manual, and follow
them implicitly. Petrol is a highly
dangerous and volatile liquid, and the
precautions necessary when handling it
cannot be overstressed.

b) Where applicable, ensure that the air

cleaner housing locating peg is correctly
engaged with its mounting on the top of
the transmission (see illustration).

c) Prior to tightening the air cleaner-to-

carburettor duct retaining clips, ensure
that the duct is correctly seated on both
the air cleaner housing and carburettor
flanges.

3

Air cleaner air temperature
control system - information
and component renewal

2

General information

TU engine

1 The system is controlled by a heat-sensitive
vacuum switch, mounted in the end of the air
cleaner housing-to-carburettor duct. When
the engine is started from cold, the switch is
open, allowing inlet manifold depression to
act on the air temperature control valve
diaphragm in the inlet duct. This vacuum
causes the diaphragm to rise, drawing a flap
valve across the cold-air inlet, thus allowing
only (warmed) air from the exhaust manifold to
enter the air cleaner.
2 As the temperature of the exhaust-warmed
air in the air cleaner-to-carburettor duct rises,
the wax capsule in the vacuum switch
deforms and closes the switch, cutting off the
vacuum supply to the air temperature control
valve assembly. As the vacuum supply is cut,
the flap is gradually lowered across the hot-air

inlet until, when the engine is fully warmed-up
to normal operating temperature, only cold air
from the front of the car is entering the air
cleaner.
3 To check the system, allow the engine to
cool down completely, then slacken the
retaining clip and disconnect the inlet duct
from the front of the control valve assembly;
the flap valve in the duct should be securely
seated across the hot-air inlet. Start the
engine; the flap should immediately rise to
close off the cold-air inlet, and should then
lower steadily as the engine warms up, until it
is eventually seated across the hot-air inlet
again.
4 To check the vacuum switch, disconnect
the vacuum pipe from the control valve when
the engine is running, and place a finger over
the pipe end. When the engine is cold, full
inlet manifold vacuum should be present in
the pipe, and when the engine is at normal
operating temperature, there should be no
vacuum in the pipe.
5 To check the air temperature control valve
assembly, slacken the retaining clip and
disconnect the inlet duct from the front of the
valve assembly; the flap valve should be
securely seated across the hot-air inlet.
Disconnect the vacuum pipe, and suck hard
at the control valve stub; the flap should rise
to shut off the cold-air inlet.
6 If either component is faulty, it must be
renewed.

XU engine

7 Cold air is drawn into the system from the
inlet duct fitted to the front panel.

8 Hot air is drawn from the collector plate
over the exhaust manifold. These two ducts
join together at the air inlet mixer housing
which contains a control flap operated by a
wax thermostat (see illustrations).
9 When the engine is cold the thermostat
contracts and the control flap closes off the
cold air duct and opens the hot air duct. As
the air being collected from the exhaust
manifold becomes warmer, so the thermostat
progressively closes off the warm air duct and
opens the cold air duct.
10 If the thermostat should fail, renew the
mixer housing.
11 All the ducts are held by worm drive clips.
12 Additional breather pipes are connected
to the air filter housing on certain models.

Vacuum switch 
(TU engine) - renewal

13 Remove the air cleaner housing-to-
carburettor duct, as described in para-
graphs 1 and 2 of Section 2.
14 Bend up the tangs on the switch retaining
clip, then remove the clip, along with its seal,
and withdraw the switch from inside the duct
(see illustrations). Examine the seal for damage
or deterioration, and renew if necessary.
15 On refitting, ensure that the switch and
duct mating surfaces are clean and dry, and
position the switch inside the duct.
16 Fit the seal over the switch unions, and
refit the retaining clip. Ensure that the switch
is pressed firmly against the duct, and secure
it in position by bending down the retaining
clip tangs. Refit the duct as described in
Section 2.

Fuel/exhaust systems - carburettor models  4A•3

3.8b  Wax thermostat on the air inlet mixer

housing (XU engine)

3.14c  . . . then withdraw the vacuum

switch from inside the duct

3.14b  . . . and seal . . .

3.14a  Remove the retaining clip . . .

3.8a  Hot-air collector plate on exhaust

manifold (XU engine)

4A

2.10  Air cleaner housing peg and

mounting rubber (arrowed)

Air temperature control valve
(TU engine) - renewal

17 Disconnect the vacuum pipe from the air
temperature control valve, then slacken the
retaining clips securing the inlet ducts to the
valve (see illustration).
18 Disconnect both inlet ducts and the hot-
air inlet hose from the control valve assembly,
and remove it from the vehicle.
19 Refitting is the reverse of the removal
procedure, noting that the air temperature
control valve assembly can only be renewed
as a complete unit.

4

Fuel pump - 
testing, removal and refitting

2

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

Testing

1 To test the fuel pump on the engine,
disconnect the outlet pipe which leads to the
carburettor. Hold a wad of rag by the pump
outlet while an assistant spins the engine on
the starter. Keep your hands away from the
electric cooling fan. Regular spurts of fuel
should be ejected as the engine turns. Be
careful not to spill fuel onto hot engine
components.
2 The pump can also be tested by removing
it. With the pump outlet pipe disconnected
but the inlet pipe still connected, hold the wad
of rag by the outlet. Operate the pump lever
by hand, moving it in and out; if the pump is in
a satisfactory condition, the lever should
move and return smoothly, and a strong jet of
fuel should be ejected.

Removal

3 Identify the pump inlet and outlet hoses,
and slacken both retaining clips (see
illustration). Where the crimped-type
Peugeot hose clips are fitted, cut the clips and
discard them; use standard worm-drive hose
clips on refitting. Place wads of rag beneath
the hose unions to catch any spilled fuel, then
disconnect both hoses from the pump; plug
the hose ends to minimise fuel loss.

TU engine

4 Where fitted remove the insulating cover
from the fuel pump, then slacken and remove
the bolts securing the pump to the rear of the
cylinder head. Remove the pump along with
its insulating block. Check the block and
renew it if necessary.

XU engine

5 Unscrew the nuts securing the pump to the
distributor end of the cylinder head and lift off
the pump (see illustration).
6 Remove the insulating block from the studs
on the cylinder head.

Refitting

7 Ensure that the pump and cylinder head
mating surfaces are clean and dry, then offer
up the insulating block and refit the pump to
the cylinder head. Tighten the pump retaining
bolts/nuts to the specified torque, then refit
the pump insulating cover where fitted
8 Reconnect the inlet and outlet hoses to the
relevant pump unions, and securely tighten
their retaining clips.

5

Fuel gauge sender unit -
removal and refitting

3

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

Removal

1 Disconnect the battery negative lead.

2 For access to the sender unit, fold the rear
seat cushion forwards or remove the rear
seats as described in Chapter 11.
3 Using a screwdriver, carefully prise the
plastic access cover from the floor to expose
the sender unit (see illustration).
4 Disconnect the wiring connector from the
sender unit (see illustration).

5 Mark the hoses for identification purposes,
then slacken the feed and return hose clips.
Where the crimped-type Peugeot hose clips
are fitted, cut the clips and discard them; use
standard worm-drive hose clips on refitting.
Disconnect both hoses from the top of the
sender unit, and plug the hose ends.
6 Noting the alignment marks on the tank,
sender unit and the locking ring, unscrew the
ring and remove it from the tank. This is best
achieved by using a screwdriver on the raised
ribs of the locking ring, as follows. Carefully
tap the screwdriver to turn the ring anti-
clockwise until it can be unscrewed by hand.
7 Carefully lift the sender unit from the top of
the fuel tank, taking great care not to bend the
sender unit float arm, or to spill fuel onto the
interior of the vehicle. Recover the rubber
sealing ring and discard it - a new one must
be used on refitting. If necessary remove the
filter from the bottom of the unit and wash it in
clean fuel.

4A•4 Fuel/exhaust systems - carburettor models

3.17  Air temperature control valve

assembly (TU engine)

4.5  Removing the fuel pump (XU engine)

5.4  Electrical plug (A) and fuel hose

connections (B) on fuel gauge sender

5.3  Remove the plastic access cover . . .

4.3  Arrows on raised fuel pump unions

indicate the direction of fuel flow

Tape the connector to the
vehicle body, in order to
prevent it from disappearing
behind the tank .