Peugeot 405. Manual - part 39

5B

System type

Carburettor, L3.1-Jetronic and LU2-Jetronic models  . . . . . . . . . . . . . .

Breakerless electronic ignition system

Other models except XU10J4 (16-valve)  . . . . . . . . . . . . . . . . . . . . . . . .

Integral ignition system controlled by engine management ECU

XU10J4 (16-valve) models  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Direct ignition system controlled by engine management ECU

Firing order

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

1-3-4-2 (number 1 cylinder at transmission end)

Ignition timing

Carburettor models*:

TU3 engine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8° BTDC at 750 rpm

XU5 (B2A) and XU9 (D2H) engines  . . . . . . . . . . . . . . . . . . . . . . . . . . .

10° BTDC at 750 rpm

Fuel injection models*:

L3.1-Jetronic fuel injection models . . . . . . . . . . . . . . . . . . . . . . . . . . .

5° BTDC at 900 rpm

LU2-Jetronic fuel injection models  . . . . . . . . . . . . . . . . . . . . . . . . . . .

10° BTDC at 850 rpm

All other fuel injection models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ECU controlled (non-adjustable)

*Note: If unleaded fuel is used in the following engines, the ignition timing must be retarded by 3° - check with your Peugeot dealer.

a) TU3 (K1A)
b) TU3A (K1G)
c) XU92C (D2D)
d) XU9J2 (D6A)
e) XU9J4 (D6C)
f) XU52C (B2A)

Ignition HT coil resistances*:

Primary windings  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.7 ohms

Secondary windings  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.6 K ohms

Impulse generator resistance  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

300 ohms

*The above specifications are approximate values and are accurate only when the coil is at 20°C. See text for further information

Torque wrench settings

Nm

lbf ft

Distributor mounting nuts  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

5

Chapter 5  Part B:
Ignition system

Distributor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Ignition HT coil(s) - removal, testing and refitting  . . . . . . . . . . . . . . . . .3
Ignition system - general information  . . . . . . . . . . . . . . . . . . . . . . . . . .1
Ignition system - testing  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Ignition system amplifier unit(s) - removal and refitting  . . . . . . . . . . . .5
Ignition system check  . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1
Ignition timing - checking and adjustment  . . . . . . . . . . . . . . . . . . . . . .6
Spark plugs  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1

5B•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

Ignition system - 
general information

Breakerless 
Electronic ignition system

All carburettor models, and models fitted

with the Bosch L3.1-Jetronic and Bosch LU2-
Jetronic fuel injection systems are equipped

with a breakerless electronic ignition system
is used. The system comprises solely of the
HT ignition coil and a distributor mounted on
the left-hand end of the cylinder head and
driven by the camshaft. On carburettor
models the coil is mounted on a bracket
attached to the cylinder block, and on models
fitted with L3.1 and LU2 systems it is mounted
on the inlet manifold.

The distributor contains a reluctor mounted

onto its shaft and a magnet and stator fixed to

its body. The ignition amplifier unit is also
mounted onto the side of the distributor body.
The system operates as follows.

When the ignition is switched on but the

engine is stationary the transistors in the
amplifier unit prevent current flowing through
the ignition system primary (LT) circuit.

As the crankshaft rotates, the reluctor

moves through the magnetic field created by
the stator. When the reluctor teeth are in
alignment with the stator projections a small

AC voltage is created. The amplifier unit uses
this voltage to switch the transistors in the
unit and complete the ignition system primary
(LT) circuit.

As the reluctor teeth move out of alignment

with the stator projections the AC voltage
changes and the transistors in the amplifier
unit are switched again to interrupt the
primary (LT) circuit. This causes a high voltage
to be induced in the coil secondary (HT)
windings which then travels down the HT lead
to the distributor and onto the relevant spark
plug.

A TDC sensor is fitted to the rear of the

flywheel but the sensor is not part of the
ignition system. It is there to be used for
diagnostic purposes only.

Integral ignition/
fuel injection system

On fuel-injected models except the L3.1

and LU2 systems, the ignition system is
integrated with the fuel injection system to
form a combined engine management system
under the control of one ECU (See the
relevant Part of Chapter 4 for further
information).

The Bosch Motronic ML4.1 and Fenix 1B

systems retain the distributor cap and rotor
arm assembly in order to distribute the spark
to the cylinders, together with a conventional
ignition coil.

All other models use a static (distribu-

torless) ignition system, consisting only of a
four output ignition coil. The ignition coil
actually consists of two separate HT coils
which supply two cylinders each (one coil
supplies cylinders 1 and 4, and the other
cylinders 2 and 3). Under the control of the
ECU, the ignition coil operates on the “wasted
spark” principle, ie. each spark plug sparks
twice for every cycle of the engine, once on
the compression stroke and once on the
exhaust stroke - the spark on the exhaust
stroke has no effect on the running of the
engine, and is therefore “wasted”. The ECU
uses its inputs from the various sensors to
calculate the required ignition advance setting
and coil charging time.

On some models a knock sensor is

incorporated into the ignition system. The
sensor is mounted onto the cylinder head and
prevents the engine “pinking” under load. The
sensor is sensitive to vibration and detects the
knocking which occurs when the engine starts
to “pink” (pre-ignite). The knock sensor sends
an electrical signal to the ECU which in turn
retards the ignition advance setting until the
“pinking” ceases.

Direct ignition system

The ignition system on 1998 cc XU10J4

(16-valve) models is of the “direct” type. The
system components consist of two amplifier
modules, four ignition HT coils, and a knock
sensor. The ignition system is integrated with
the fuel injection system, to form a combined
engine management system under the control

of one ECU via the ignition amplifier modules.

Each ignition amplifier module operates two

HT coils; the ignition HT coils are integral with
the plug caps, and are pushed directly onto
the spark plugs, one for each plug. This
removes the need for any HT leads
connecting the coils to the plugs. The ECU
uses the inputs from the various sensors to
calculate the required ignition advance setting
and coil charging time.

The knock sensor is mounted onto the

cylinder head, and prevents the engine
“pinking” under load. The sensor detects
abnormal vibration, and is thus able to detect
the knocking which occurs when the engine
starts to “pink” (pre-ignite). The knock sensor
sends an electrical signal to the ECU, which in
turn retards the ignition advance setting until
the “pinking” ceases.

2

Ignition system - testing

2

Breakerless 
Electronic ignition system

Note: Refer to the precautions given in
Section 1 of Part A of this Chapter before
starting work. Always switch off the ignition
before disconnecting or connecting any
component and when using a multi-meter to
check resistances.

General

1 The components of electronic ignition
systems are normally very reliable; most faults
are far more likely to be due to loose or dirty
connections or to “tracking” of HT voltage
due to dirt, dampness or damaged insulation
than to the failure of any of the system’s
components.  Always

check all wiring

thoroughly before condemning an electrical
component and work methodically to
eliminate all other possibilities before deciding
that a particular component is faulty.
2 The old practice of checking for a spark by
holding the live end of an HT lead a short
distance away from the engine is not
recommended; not only is there a high risk of
a powerful electric shock, but the HT coil or
amplifier unit will be damaged. Similarly,
never try to “diagnose” misfires by pulling off
one HT lead at a time.

Engine will not start

3 If the engine either will not turn over at all,
or only turns very slowly, check the battery
and starter motor. Connect a voltmeter across
the battery terminals (meter positive probe to
battery positive terminal), disconnect the
ignition coil HT lead from the distributor cap
and earth it, then note the voltage reading
obtained while turning over the engine on the
starter for (no more than) ten seconds. If the
reading obtained is less than approximately
9.5 volts, first check the battery, starter motor
and charging system as described in the
relevant Sections of this Chapter.
4 If the engine turns over at normal speed but
will not start, check the HT circuit by
connecting a timing light (following the
manufacturer’s instructions) and turning the
engine over on the starter motor; if the light
flashes, voltage is reaching the spark plugs,
so these should be checked first. If the light
does not flash, check the HT leads
themselves followed by the distributor cap,
carbon brush and rotor arm using the
information given in Chapter 1.
5 If there is a spark, check the fuel system for
faults referring to the relevant part of Chapter
4 for further information.
6 If there is still no spark, check the voltage at
the ignition HT coil “+” terminal; it should be
the same as the battery voltage (ie, at least
11.7 volts). If the voltage at the coil is more
than 1 volt less than that at the battery, check
the feed back through the fusebox and
ignition switch to the battery and its earth until
the fault is found.
7 If the feed to the HT coil is sound, check the
coil’s primary and secondary winding
resistance as described later in this Section;
renew the coil if faulty, but be careful to check
carefully the condition of the LT connections
themselves before doing so, to ensure that
the fault is not due to dirty or poorly-fastened
connectors.
8 If the HT coil is in good condition, the fault
is probably within the amplifier unit or
distributor stator assembly. Testing of these
components should be entrusted to a
Peugeot dealer.

Engine misfires

9 An irregular misfire suggests either a loose
connection or intermittent fault on the primary
circuit, or an HT fault on the coil side of the
rotor arm.
10 With the ignition switched off, check
carefully through the system ensuring that all
connections are clean and securely fastened.
If the equipment is available, check the LT
circuit as described above.
11 Check that the HT coil, the distributor cap
and the HT leads are clean and dry. Check the
leads themselves and the spark plugs (by
substitution, if necessary), then check the
distributor cap, carbon brush and rotor arm as
described in Chapter 1.
12 Regular misfiring is almost certainly due to
a fault in the distributor cap, HT leads or spark

5B•2 Ignition system

Warning: Voltages produced by
an electronic ignition system
are considerably higher than
those produced by conventional

ignition systems. Extreme care must be
taken when working on the system with
the ignition switched on. Persons with
surgically-implanted cardiac pacemaker
devices should keep well clear of the
ignition circuits, components and test
equipment.

plugs. Use a timing light (paragraph 4 above)
to check whether HT voltage is present at all
leads.
13 If HT voltage is not present on any
particular lead, the fault will be in that lead or
in the distributor cap. If HT voltage is present
on all leads, the fault will be in the spark
plugs; check and renew them if there is any
doubt about their condition.
14 If no HT voltage is present, check the HT
coil; its secondary windings may be breaking
down under load.

Integral and 
Direct ignition systems

15 If a fault appears in the engine
management (fuel injection/ignition) system
first ensure that the fault is not due to a poor
electrical connection or poor maintenance; ie,
check that the air cleaner filter element is
clean, the spark plugs are in good condition
and correctly gapped, that the engine
breather hoses are clear and undamaged,
referring to Chapter 1 for further information.
Also check that the accelerator cable is
correctly adjusted as described in the relevant
part of Chapter 4. If the engine is running very
roughly, check the compression pressures
and the valve clearances as described in
Chapter 2A.
16 On systems with a distributor cap and
rotor arm, check these items as described in
the previous sub-section.
17 If these checks fail to reveal the cause of
the problem the vehicle should be taken to a
suitably equipped Peugeot dealer for testing.
A wiring block connector is incorporated in

the engine management circuit into which a
special electronic diagnostic tester can be
plugged. The tester will locate the fault quickly
and simply alleviating the need to test all the
system components individually which is a
time consuming operation that carries a high
risk of damaging the ECU.
18 The only other ignition system checks
which can be carried out by the home
mechanic are those described in Chapter 1,
relating to the spark plugs, and the ignition
coil test described in this Chapter. If
necessary, the system wiring and wiring
connectors can be checked as described in
Chapter 12 ensuring that the ECU wiring
connector(s) have first been disconnected.

3

Ignition HT coil(s) - 
removal, testing and refitting

2

Removal

Breakerless Electronic ignition system

1 On early models the coil is mounted either
on the cylinder block above the starter motor
or on the inlet manifold. On later models it is
mounted on the left-hand end of the cylinder
head. First disconnect the battery negative
terminal.
2 Where necessary, disconnect the hot air
inlet hose from the exhaust manifold shroud
and air temperature control valve and remove
it from the engine. Release the inlet duct
fastener and position the duct clear of the coil.

3 Disconnect the wiring connector from the
capacitor mounted on the coil mounting
bracket and where necessary release the TDC
sensor wiring connector from the front of the
bracket (see illustration).
4 Disconnect the HT lead from the coil then
depress the retaining clip and disconnect the
coil wiring connector (see illustrations).
5 Slacken and remove the two retaining bolts
and remove the coil and mounting bracket.
Where necessary, slacken and remove the
four screws and nuts and separate the HT coil
and mounting bracket (see illustrations).

Integral ignition models

6 Disconnect the battery negative terminal.
The ignition HT coil is mounted on the left-
hand end of the cylinder head.
7 Depress the retaining clip and disconnect
the wiring connector from the HT coil.

Ignition system  5B•3

3.4b  . . . and wiring connector (arrowed)

from the ignition HT coil

3.5c  Coil mounting bolts (arrowed) on

Bosch L3.1 system

3.5b  . . . and remove the coil and mounting

bracket from the cylinder head

3.5a  Undo the two retaining bolts

(arrowed) . . .

3.4a  . . . then disconnect the HT lead . . .

3.3  On breakerless ignition models,

disconnect the capacitor wiring connector,

and release the TDC sensor connector . . .

5B

3.5d  Removing the ignition coil and

bracket on the Motronic ignition system

8 Make a note of the correct fitted positions
of the HT leads then disconnect them from
the coil terminals.
9 Undo the four retaining screws securing the
coil to its mounting bracket and remove it
from the engine compartment.

Direct ignition models

10 Disconnect the battery negative terminal.
There are four separate ignition HT coils, one
on the top of each spark plug.
11 To gain access to the coils, undo the eight
bolts, noting the correct fitted position of the
wiring clip, and remove the access cover from
the centre of the cylinder head cover.
12 To remove an HT coil, depress the
retaining clip and disconnect the wiring
connector, then pull the coil off the spark plug
and remove it along with its rubber seal.

Testing

13 Testing of the coil consists of using a
multimeter set to its resistance function, to
check the primary (LT “+’“to “-” terminals) and
secondary (LT “+” to HT lead terminal)
windings for continuity, bearing in mind that
on the four output, static type HT coil there
are two sets of each windings. Compare the
results obtained to those given in the Specifi-
cations at the start of this Chapter. Note the
resistance of the coil windings will vary slightly
according to the coil temperature, the results
in the Specifications are approximate values
for when the coil is at 20°C.
14 Check that there is no continuity between
the HT lead terminal and the coil body/
mounting bracket.

15 If the coil is thought to be faulty, have your
findings confirmed by a Peugeot dealer before
renewing the coil.

Refitting

16 Refitting is a reversal of the relevant removal
procedure, ensuring the wiring connectors are
securely reconnected and, where necessary, the
HT leads are correctly connected.

4

Distributor - 
removal and refitting

3

Removal

Breakerless ignition system

1 Disconnect the battery negative terminal.
Where necessary, to improve access to the
distributor, remove the ignition HT coil as

described in Section 3 and the inlet duct as
described in the relevant Part of Chapter 4.
2 Peel back the waterproof cover then
slacken and remove the distributor cap
retaining screws. Remove the cap and
position it clear of the distributor body (see
illustrations). Recover the seal from the cap.
If necessary disconnect the HT leads from the
spark plugs after noting their positions.
3 Depress the retaining clip and disconnect
the wiring connector from the distributor.
Disconnect the hose from the vacuum
diaphragm unit (see illustrations).
4 Check the cylinder head and distributor
flange for signs of alignment marks. If no
marks are visible, using a scriber or suitable
marker pen, mark the relationship of the
distributor body to the cylinder head. Slacken
and remove the two mounting nuts and
withdraw the distributor from the cylinder
head (see illustrations). Remove the O-ring

4.2a  Peel back the 

waterproof cover . . .

4.2b  . . . then undo the 

retaining screws . . .

5B•4 Ignition system

4.2c  . . . and remove the cap from the end

of the distributor

4.3b  . . . and the vacuum diaphragm hose

4.4c  . . . and withdraw the distributor from

the cylinder head

4.4b  Unscrew the retaining nuts . . .

4.4a  Alignment marks across the

distributor and cylinder head housing

4.3a  Disconnect the distributor 

wiring connector . . .