1988 OPEL CALIBRA spark plugs

Distributor
Direction of rotor arm rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Anti-clockwise (viewed from cap)
Firing order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-3-4-2 (No 1 cylinder at timing belt end of engine)
Dwell angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Automatically controlled by electronic module (not adjustable)
Ignition timing
14 NV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5°BTDC
16 SV, X 16 SZ, C 16 NZ, C 16 NZ2 and C 18 NZ . . . . . . . . . . . . . . . .10°BTDC *
18 SV and 2.0 litres models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 to 12°BTDC *
* Ignition timing electronically controlled no adjustment possible
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .See Chapter 1 Specifications
Torque wrench settingNmlbf ft
Alternator mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Camshaft phase sensor disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Camshaft phase sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1511
‘Compact’ series alternator lower mounting bolt . . . . . . . . . . . . . . . . . .3526
‘Compact’ series alternator upper mounting bolts . . . . . . . . . . . . . . . . .2015
DIS module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
Inductive pulse pick-up to block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Starter motor mounting bracket-to-cylinder block . . . . . . . . . . . . . . . . .2518
Starter motor mounting:
1.4 and 1.6 litre models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
1.8 and 2.0 litre models:
Engine side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4533
Transmission side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7555
1Electrical system - general
1The electrical system is of the 12 volt
negative earth type, and consists of a 12 volt
battery, alternator with integral voltage
regulator, starter motor, and related electrical
accessories, components and wiring.
2The battery is of the maintenance-free
“sealed for life” type, and is charged by an
alternator, which is belt-driven from the
crankshaft pulley. The starter motor is of the
pre-engaged type, incorporating an integral
solenoid. On starting, the solenoid moves the
drive pinion into engagement with the flywheel
ring gear before the starter motor is
energised. Once the engine has started, a
one-way clutch prevents the motor armature
being driven by the engine until the pinion
disengages from the flywheel.
3It is necessary to take extra care when
working on the electrical system, to avoid
damage to semi-conductor devices (diodes
and transistors), and to avoid the risk of
personal injury. Along with the precautions
given in the “Safety first!” Section at the
beginning of this manual, take note of the
following points when working on the system.4Always remove rings, watches, etc. before
working on the electrical system. Even with
the battery disconnected, discharge could
occur if a component live terminal is earthed
through a metal object. This could cause a
shock or nasty burn.
5Do not reverse the battery connections.
Components such as the alternator, or any
other component having semi-conductor
circuitry, could be irreparably damaged.
6If the engine is being started using jump
leads and a slave battery, connect the
batteries positive to positive and negative to
negative. This also applies when connecting a
battery charger.
7Never disconnect the battery terminals, or
alternator multi-plug connector, when the
engine is running.
8The battery leads and alternator wiring
must be disconnected before carrying out any
electric welding on the vehicle.
9Never use an ohmmeter of the type
incorporating a hand-cranked generator for
circuit or continuity testing.
2Ignition system - general
1The ignition system is responsible for
igniting the air/fuel mixture in each cylinder at
the correct moment, in relation to engine
speed and load. A number of different types
of ignition systems are fitted to models within
the range. Ranging from a basic breakerless
electronic system, to a fully integrated engine
management system controlling both ignition
and fuel injection systems. Each system isdescribed in further detail later in this Section.
2The ignition system is based on feeding low
tension voltage from the battery to the coil,
where it is converted to high tension voltage.
The high tension voltage is powerful enough
to jump the spark plug gap in the cylinders
many times a second under high compression
pressures, providing that the system is in
good condition. The low tension (or primary)
circuit consists of the battery, the lead to the
ignition switch. The lead from the ignition
switch to the low tension coil windings and
the supply terminal on the electronic module.
The lead from the low tension coil windings to
the control terminal on the electronic module.
The high tension (or secondary) circuit
consists of the high tension coil windings, the
HT (high tension) lead from the coil to the
distributor cap, the rotor arm, the HT leads to
the spark plugs, and the spark plugs.
3The system functions in the following
manner. Current flowing through the low
tension coil windings produces a magnetic
field around the high tension windings. As the
engine rotates, a sensor produces an
electrical impulse that is amplified in the
electronic module and used to switch off the
low tension circuit.
4The subsequent collapse of the magnetic
field over the high tension windings produces
a high tension voltage, which is then fed to the
relevant spark plug through the distributor
cap and rotor arm. The low tension circuit is
automatically switched on again by the
electronic module, to allow the magnetic field
to build up again before the firing of the next
spark plug. The ignition is advanced and
retarded automatically, to ensure that the
spark occurs at the correct instant with the
engine speed and load.
5•2Engine electrical systems
Caution: Before carrying out
any work on the vehicle
electrical system, read through
the precautions given in the
“Safety first!” Section at the beginning of
this manual, and in Section 3 of this
Chapter.

HEI (High Energy Ignition)
system
5This comprises of a breakerless distributor
and an electronic switching/amplifier module
along with the coil and spark plugs.
6The electrical impulse that is required to
switch off the low tension circuit is generated
by a magnetic trigger coil in the distributor. A
trigger wheel rotates within a magnetic stator,
the magnetic field being provided by a
permanent magnet. The magnetic field across
the two poles (stator arm and trigger wheel) is
dependent on the air gap between the two
poles. When the air gap is at its minimum, the
trigger wheel arm is directly opposite the
stator arm, and this is the trigger point. As the
magnetic flux between the stator arm and
trigger wheel varies, a voltage is induced in the
trigger coil mounted below the trigger wheel.
This voltage is sensed and then amplified by
the electronic module, and used to switch off
the low tension circuit. There is one trigger arm
and one stator arm for each cylinder.
7The ignition advance is a function of the
distributor, and is controlled both
mechanically and by a vacuum-operated
system. The mechanical governor mechanism
consists of two weights that move out from
the distributor shaft due to centrifugal force as
the engine speed rises. As the weights move
outwards, they rotate the trigger wheel
relative to the distributor shaft and so
advance the spark. The weights are held in
position by two light springs, and it is the
tension of the springs that is largely
responsible for correct spark advancement.
8The vacuum control consists of a
diaphragm, one side of which is connected by
way of a small-bore hose to the carburettor,
and the other side to the distributor.
Depression in the inlet manifold and
carburettor, which varies with engine speed
and throttle position, causes the diaphragm to
move, so moving the baseplate and
advancing or retarding the spark. A fine
degree of control is achieved by a spring in
the diaphragm assembly.
MSTS-i (Microprocessor-
controlled Spark Timing System)
9This system comprises a “Hall-effect”
distributor (or a crankshaft speed/position
sensor on X 16 SZ models), a manifold pressure
sensor, an oil temperature sensor, and a
module, along with the coil and spark plugs.
10On 1.6 litre models, the electrical impulse
that is required to switch off the low tension
circuit is generated by a sensor in the
distributor. A trigger vane rotates in the gap
between a permanent magnet and the sensor.
The trigger vane has four cut-outs, one for
each cylinder. When one of the trigger vane
cut-outs is in line with the sensor, magnetic
flux can pass between the magnet and the
sensor. When a trigger vane segment is in line
with the sensor, the magnetic flux is diverted
through the trigger vane away from thesensor. The sensor senses the change in
magnetic flux, and sends an impulse to the
MSTS-i module, which switches off the low
tension circuit.
11On 1.8 litre models, the electrical impulse
that is required to switch off the low tension
circuit is generated by a crankshaft
speed/position sensor, which is activated by a
toothed wheel on the crankshaft. The toothed
wheel has 35 equally spaced teeth, with a gap
in the 36th position. The gap is used by the
sensor to determine the crankshaft position
relative to TDC (top dead centre) of No 1 piston.
12Engine load information is supplied to the
MSTS-i module by a pressure sensor, which
is connected to the carburettor by a vacuum
pipe. Additional information is supplied by an
oil temperature sensor. The module selects
the optimum ignition advance setting based
on the information received from the sensors.
The degree of advance can thus be constantly
varied to suit the prevailing engine conditions.
Multec, with MSTS-i
13The ignition system is fully electronic in
operation and incorporates the Electronic
Control Unit (ECU) mounted in the driver’s
footwell. A distributor (driven off the camshaft
left-hand end and incorporating the amplifier
module) as well as the octane coding plug,
the spark plugs, HT leads, ignition HT coil and
associated wiring.
14The ECU controls both the ignition system
and the fuel injection system, integrating the
two in a complete engine management
system. Refer to Chapters 4B and 4C for
further information that is not detailed here.
15For ignition the ECU receives information
in the form of electrical impulses or signals
from the distributor (giving it the engine speed
and crankshaft position), from the coolant
temperature sensor (giving it the engine
temperature) and from the manifold absolute
pressure sensor (giving it the load on the
engine). In addition, the ECU receives input
from the octane coding plug (to provide
ignition timing appropriate to the grade of fuel
used) and from, where fitted, the automatic
transmission control unit (to smooth gear
changing by retarding the ignition as changes
are made).
16All these signals are compared by the
ECU with set values pre-programmed
(mapped) into its memory. Considering this
information, the ECU selects the ignition
timing appropriate to those values and
controls the ignition HT coil by way of the
amplifier module accordingly.
17The system is so sensitive that, at idle
speed, the ignition timing may be constantly
changing; this should be remembered if trying
to check the ignition timing.
18The system fitted to C18 NZ models, is
similar to that described above, except that
the amplifier module is separate. The ECU
determines engine speed and crankshaft
position using a sensor mounted in the
right-hand front end of the engine’s cylinderblock; this registers with a 58-toothed disc
mounted on the crankshaft so that the gap left
by the missing two teeth provides a reference
point, so enabling the ECU to recognise TDC.
19Note that this simplifies the distributor’s
function, which is merely to distribute the HT
pulse to the appropriate spark plug; it has no
effect whatsoever on the ignition timing.
DIS (Direct Ignition System)
20On all X16 SZ engines, and on C20 XE
(DOHC) engines from 1993-on, a DIS (Direct
Ignition System) module is used in place of
the distributor and coil. On the X16 SZ engine
the DIS module is attached to the camshaft
housing in the position normally occupied by
the distributor. On the C20 XE engine, a
camshaft phase sensor is attached to the
cylinder head at the non-driven end of the
exhaust camshaft, in the position normally
occupied by the distributor. The DIS module
is attached, by a bracket, to the cylinder head
at the non-driven end of the inlet camshaft.
21The DIS module consists of two ignition
coils and an electronic control module housed
in a cast casing. Each ignition coil supplies
two spark plugs with HT voltage. One spark is
provided in a cylinder with its piston on the
compression stroke, and one spark is
provided to a cylinder with its piston on the
exhaust stroke. This means that a “wasted
spark” is supplied to one cylinder during each
ignition cycle, but this has no detrimental
effect. This system has the advantage that
there are no moving parts (therefore there is
no wear), and the system is largely
maintenance-free.
Motronic M4.1 and M1.5
22This system controls both the ignition and
the fuel injection systems.
23The Motronic module receives information
from a crankshaft speed/position sensor, an
engine coolant temperature sensor mounted
in the thermostat housing. A throttle position
sensor, an airflow meter, and on models fitted
with a catalytic converter, an oxygen sensor
mounted in the exhaust system (Chapter 4C).
24The module provides outputs to control
the fuel pump, fuel injectors, idle speed and
ignition circuit. Using the inputs from the
various sensors, the module computes the
optimum ignition advance, and fuel injector
pulse duration, to suit the prevailing engine
conditions. This system gives very accurate
control of the engine under all conditions,
improving fuel consumption and driveability,
and reducing exhaust gas emissions.
25Further details of the fuel injection system
components are given in Chapter 4B.
Motronic M2.5 and M2.8
26The system is similar to that described for
SOHC models, with the following differences.
27Along with the crankshaft speed/position
sensor, a “Hall-effect” distributor is used
(similar to that described in this Section, with
the MSTS-i system).
Engine electrical systems 5•3
5

5If the engine turns over at normal speed but
will not start, check the HT circuit by
connecting a timing light 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.
6If there is a spark, check the fuel system for
faults as far as possible (Chapters 4A or 4B).
7If there is still no spark, check the voltage at
the ignition coil “+” or “15” terminal; it should
be the same as the battery voltage (i.e., at
least 11.7 volts). If the voltage at the coil is
more than 1 volt less than that at the battery,
check the connections back through the
ignition switch to the battery and its earth until
the fault is found. Note, however, that the
ECU controls the coil’s feed; do not attempt
to “test” the ECU with anything other than the
correct test equipment, which will be available
only to a Vauxhall dealer. If any of the wires
are to be checked which lead to the ECU,
always first unplug the relevant connector
from the ECU so that there is no risk of the
ECU being damaged by the application of
incorrect voltages from test equipment.
8If the feed to the ignition coil is sound,
check the coil’s primary and secondary
windings (refer to Section 16). Renew the coil
if faulty, but check the condition of the LT
connections themselves before doing so, to
ensure that the fault is not due to dirty or
poorly fastened connectors.
9If the ignition coil is in good condition, the
fault may be within the amplifier module or the
distributor on the C16 NZ and C16 NZ2
engines, or the amplifier or the crankshaft
speed/position sensor on the C18 NZ engine.
A quick check of these components can be
made by connecting a low-wattage bulb
across the ignition coil’s (disconnected) LT
terminals. If the bulb flickers or flashes when
the engine is turned over, the amplifier and
distributor (C16 NZ and C16 NZ2 engines), or
amplifier and crankshaft speed/position
sensor (C18 NZ engine), are sound.
10If this is the case, the entire LT circuit is in
good condition; the fault, if it lies in the
ignition system, must be in the HT circuit
components. These should be checked
carefully, as outlined above.
11If the indicator or bulb does not flash, the
fault is in either the amplifier or the distributor
(C16 NZ and C16 NZ2 engines), or the
amplifier or crankshaft speed/position sensor
(C18 NZ engine). Owners should note,
however, that by far the commonest cause of
“failure” of either of these is a poor
connection, either between the components
themselves or in the LT circuit wiring
connections. If such a fault is suspected, the
vehicle must be taken to a suitably equipped
Vauxhall dealer for testing; no information is
available to eliminate these components by
other means.12An irregular misfire suggests either a
loose connection or intermittent fault on the
primary circuit, or a HT fault on the coil side of
the rotor arm.
13With 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 in paragraphs 7 to 11
above.
14Check that the HT coil, the distributor cap
and the HT leads are clean and dry. Check the
leads and the spark plugs (by substitution, if
necessary), then check the distributor cap,
carbon brush and rotor arm.
15Regular misfiring is almost certainly due to
a fault in the distributor cap, HT leads or spark
plugs. Use a timing light (paragraph 5, above)
to check whether HT voltage is present at all
leads.
16If HT voltage is not present on any
particular lead, the fault will be in that lead or
in the distributor cap. If HT 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.
17If no HT voltage is present, check the
ignition coil; its secondary windings may be
breaking down under load.
18If all components have been checked for
signs of obvious faults but the system is still
thought to be faulty, take the vehicle to a
Vauxhall dealer for testing on special
equipment.
5Battery - testing and charging
2
Note: Refer to Section 3 before proceeding.
Testing
1Topping-up and testing of the electrolyte in
each cell is not possible. The condition of the
battery can therefore only be tested by
observing the battery condition indicator.
2The battery condition indicator is fitted in
the top of the battery casing, and indicates
the condition of the battery from its colour. If
the indicator shows green, then the battery is
in a good state of charge. If the indicator turns
darker, eventually to black, then the battery
requires charging, as described later in this
Section. If the indicator shows clear/yellow,
then the electrolyte level in the battery is too
low to allow further use, and the battery
should be renewed.
Charging
3Do not attempt to charge, load or jump start
a battery when the indicator shows
clear/yellow. If the battery is to be charged,
remove it from the vehicle and charge it as
follows.
4The maintenance-free type battery takes
considerably longer to fully recharge than the
standard type, the time taken being
dependent on the extent of discharge.5A constant-voltage type charger is required,
to be set, when connected, to 13.9 to 14.9
volts with a charger current below 25 amps.
6If the battery is to be charged from a fully
discharged state (less than 12.2 volts output),
have it recharged by a Vauxhall dealer or
battery specialist, as the charge rate will be
high and constant supervision during charging
is necessary.
6Battery - removal and refitting
2
Note: Refer to Section 3 before proceeding.
Removal
1The battery is located at the left-hand front
corner of the engine compartment.
2Disconnect the lead(s) at the negative
(earth) terminal by unscrewing the retaining
nut and removing the terminal clamp.
3Disconnect the positive terminal lead(s) in
the same way.
4Unscrew the clamp bolt sufficiently to
enable the battery to be lifted from its
location. Keep the battery in an upright
position, to avoid spilling electrolyte on the
bodywork.
Refitting
5Refitting is a reversal of removal, but smear
petroleum jelly on the terminals when
reconnecting the leads, and always connect
the positive lead first and the negative lead
last.
7Alternator - description
1A Delco-Remy or Bosch alternator may be
fitted, depending on model and engine
capacity. The maximum output of the
alternator varies accordingly.
2The alternator is belt-driven from the
crankshaft pulley. Cooling is provided by a
fan, mounted outside the casing on the end of
the rotor shaft. An integral voltage regulator is
incorporated, to control the output voltage.
3The alternator provides a charge to the
battery even at very low engine speed, and
consists of a coil-wound stator in which a
rotor rotates. The rotor shaft is supported in
ball-bearings, and slip rings are used to
conduct current to and from the field coils
through the carbon brushes.
4The alternator generates ac (alternating
current), which is rectified by an internal diode
circuit to dc (direct current) for supply to the
battery.
5Later models are fitted with a Delco-Remy,
‘compact’ series alternators (see illustration).
They use a ribbed V-belt type drivebelt with
automatic tensioner. They are rigidly mounted
to the engine.
Engine electrical systems 5•5
5

models so equipped). On 14 NV, 16 SV and
18 SV models, the ignition amplifier module is
mounted on the coil’s bracket or baseplate
(see illustration).
2Disconnect the battery negative lead.
3Carefully note the LT wiring connections
before disconnecting them (see illustration).
4Note that on models with power steering,
one of the coil securing bolts also secures the
power steering fluid reservoir bracket.
5Remove the coil.
6On models with a cylindrical type coil, the
mounting clamp can be removed from the coil
by loosening the clamp nut.
Testing
7To test the coil, first disconnect the LT
wiring and the HT lead. Test the coil’s primary
windings by connecting a multi-meter across
the LT terminals (“+” or “15” and “-” or “1”).Then the secondary windings by testing
across the HT terminal (“4”) and one of the LT
terminals (usually the “-/1” terminal, although
in some cases, either terminal may serve). On
20 XEJ models, results should closely
approximate the specified values. On all other
models, typical primary resistances are less
than 1 ohm, while secondary resistances can
be expected to be in the 4000 to 12 000 ohms
range.
8If the results obtained differ significantly
from those given, showing windings that are
shorted or open circuit, the coil must be
renewed.
Refitting
9Refitting is a reversal of removal, however
ensure correct connections. Usually they are
physically different to prevent incorrect
refitting. If not, use the terminal marks ornumbers in conjunction with the relevant
wiring diagram at the back of this manual to
ensure that the connections are correctly
remade. If the connections are reversed, so
will the coil’s polarity be. While the engine
may still run, spark plug life will be reduced
and poor starting and/or misfiring may follow.
10Where applicable, ensure that the coil
suppresser is in position before refitting the
coil securing bolts.
17Distributor cap and rotor
arm -removal and refitting
3
Note: Refer to Section 3 before proceeding
Removal
14 NV and 16 SV models
1Disconnect the battery negative lead.
2Identify each HT lead for position, so that
the leads can be refitted to their correct
cylinders, then disconnect the leads from the
spark plugs by pulling on the connectors, not
the leads. Similarly, disconnect the HT lead
from the coil. Pull the leads from the clips on
the camshaft cover.
3On the Bosch distributor, prise away the
two spring clips with a screwdriver, and lift off
the distributor cap. On the Lucas distributor,
unscrew the two small bolts and lift off the
cap (see illustrations).
4The rotor arm is a push fit on the end of the
distributor shaft.
5If needed, on the Bosch distributor, the
plastic shield can be pulled from the end of
the distributor, to allow examination of the
distributor components (see illustration).
Other models, where applicable
6Proceed as described in paragraphs 1 and 2.
7On DOHC models (except X20 XEV),
unscrew the two securing bolts and withdraw
the spark plug cover from the camshaft cover.
8Using a Torx socket, unscrew the three
captive securing screws and withdraw the
distributor cap (see illustration).
9Withdraw the plastic shield from the rotor
arm housing. The shield is fitted in the
housing, with an O-ring seal located in a
groove in its periphery. Ease out the shield,
taking care not to damage the rotor arm (see
illustration).
5•10Engine electrical systems
16.1 Ignition coil - 1.6 litre models - note
ignition timing basic adjustment coding
plug (arrowed)
17.3A Removing the distributor cap -
1.6 litre model (Bosch distributor) . . .
17.9 Removing the plastic shield from the
rotor arm housing - 2.0 litre model17.8 Unscrewing a distributor cap
securing screw - 2.0 litre model17.5 Removing the rotor arm and plastic
shield - 1.6 litre model (Bosch distributor)
17.3B . . .and 1.6 litre models (Lucas
distributor)
16.3 Disconnecting the coil LT wiring plug
- 2.0 litre model

b)Always keep the ignition and fuel systems
well maintained according to the
manufacturers schedule (see “Routine
maintenance” and the relevant Chapter).
In particular, ensure that the air cleaner
filter element, the fuel filter and the spark
plugs are renewed at the correct intervals.
If the inlet air/fuel mixture is allowed to
become too rich due to neglect, the
unburned surplus will enter and burn in
the catalytic converter, overheating the
element and eventually destroying the
converter.
c)If the engine develops a misfire, do not
drive the vehicle at all (or at least as little
as possible) until the fault is cured. The
misfire will allow unburned fuel to enter
the converter, which will result in its
overheating, as noted above.
d)The engine control indicator (the outline
of an engine with a lightning symbol
superimposed), will light when the ignition
is switched on and the engine is started,
then it will go out. While it may light briefly
while the engine is running, it should go
out again immediately and stays unlit. If it
lights and stays on while the engine is
running, seek the advice of a Vauxhall
dealer as soon as possible. A fault has
occurred in the fuel injection/ignition
system that, apart from increasing fuel
consumption and impairing the engine’s
performance, may damage the catalytic
converter.
e)DO NOT push or tow-start the vehicle.
This will soak the catalytic converter in
unburned fuel causing it to overheat when
the engine does start see (b) above.
f)DO NOT switch off the ignition at high
engine speeds. If the ignition is switched
off at anything above idle speed,
unburned fuel will enter the (very hot)
catalytic converter, with the possible risk
of its igniting on the element and
damaging the converter.
g)DO NOT use fuel or engine oil additives.
These may contain substances harmful to
the catalytic converter.
h)DO NOT continue to use the vehicle if the
engine burns oil to the extent of leaving a
visible trail of blue smoke. The unburned
carbon deposits will clog the converter
passages and reduce its efficiency; in
severe cases the element will overheat.
i)Remember that the catalytic converter
operates at very high temperatures hence
the heat shields on the vehicle’s under-
body and the casing will become hot
enough to ignite combustible materials
that brush against it. DO NOT, therefore,
park the vehicle in dry undergrowth, over
long grass or over piles of dead leaves.
j)Remember that the catalytic converter is
FRAGlLE. Do not strike it with tools during
servicing work. Take great care when
working on the exhaust system. Ensure
that the converter is well clear of any
jacks or other lifting gear used to raise thevehicle. Do not drive the vehicle over
rough ground, road humps, etc., in such a
way as to ground the exhaust system.
k)In some cases, particularly when the
vehicle is new and/or is used for
stop/start driving, a sulphurous smell (like
that of rotten eggs) may be noticed from
the exhaust. This is common to many
catalytic converter-equipped vehicles and
seems to be due to the small amount of
sulphur found in some petrol’s reacting
with hydrogen in the exhaust to produce
hydrogen sulphide (CS) gas. While this
gas is toxic, it is not produced in sufficient
amounts to be a problem. Once the
vehicle has covered a few thousand miles
the problem should disappear. In the
meanwhile a change of driving style or of
the brand of petrol may effect a solution.
l)The catalytic converter, used on a
well-maintained and well-driven vehicle,
should last for between 50 000 and 100
000 miles. From this point on, careful
checks should be made at all specified
service intervals of the CO level to ensure
that the converter is still operating
efficiently. If the converter is no longer
effective it must be renewed.
11Carbon canister - removal
and refitting
3
Removal
1Apply the handbrake, then jack up the front
of the vehicle, and support securely on axle
stands placed under the body side members
(see “Jacking and Vehicle Support”).
2Remove the front right hand wheel and
wheel arch liner.
3Note the hose and pipe connections to the
canister, or label them, to ensure that they are
reconnected to their original unions, then
disconnect them (see illustration). Unscrew
the two nuts securing the canister mounting
bracket to the vehicle body.
Refitting
4Refitting is a reversal of removal, however
ensure correct fitment of hose and pipes.
12Oxygen sensor (catalytic
converter models) - removal
and refitting
3
Note: This sensor is also known as a Lambda
sensor.
Removal
1Disconnect the battery negative lead.
2Disconnect the oxygen sensor wiring plug,
which is located behind the coolant expansion
tank.
3Apply the handbrake, then jack up the front
of the vehicle, and support securely on axle
stands placed under the body side members.
4On DOHC models, remove the engine
undershield, as described in Chapter 11.
5On models fitted with Multec injection
system, the sensor is screwed into the
exhaust manifold. Trace the wiring from the
sensor itself to the connector (either clipped
to the radiator cooling fan shroud or behind
the coolant expansion tank). Release it from
any clips or ties; disconnect the wiring before
unscrewing the sensor.
6On other models, unscrew the oxygen
sensor from the front section of the exhaust
system (see illustration). It is advisable to
wear gloves, as the exhaust system will be
extremely hot.
7Withdraw the oxygen sensor and its wiring,
taking care not to burn the wiring on the
exhaust system. If the sensor is to be re-used,
take care that the sealing ring is not lost, and
that the sensor is not dropped.
Refitting
8If a new sensor is being fitted, it will be
supplied with the threads coated in a special
grease to prevent it seizing in the exhaust
system.
9If the original sensor is being refitted,
ensure that the screw thread is clean. Coat
the thread with a lithium based copper grease
(i.e. Vauxhall Part No. 90295397).
10Refitting is a reversal of removal. Check
the exhaust system for leakage when the
engine is re-started.
4C•4Fuel and exhaust systems - exhaust and emissions
12.6 Oxygen sensor location in front
section of exhaust system - DOHC models
11.3 Charcoal canister
A Vent to atmosphere
B Vapour feed hose from filler pipe
C Vapour exhaust hose to inlet tract
D Control valve vacuum pipe from
throttle body

13Exhaust manifold - removal
and refitting
3
Note:New manifold-to-cylinder head, and
manifold-to-downpipe, gaskets must be used
on refitting. Exhaust manifolds on DOHC
models are of tubular design, which form part
of the front section of the exhaust.
Removal
1Disconnect the battery negative lead.
2Disconnect the HT leads from the spark
plugs, if necessary labelling them to ensure
refitting to the correct cylinders.
3Loosen the clamp screw and disconnect
the air cleaner hot air tube from the shroud on
the manifold, if fitted. Remove the securing
screws and withdraw the hot air shroud from
the manifold.
4Working under the manifold, unscrew and
remove the four bolts securing the exhaust
downpipe to the manifold.
5If fitted, disconnect the oxygen sensor
wiring
6Separate the downpipe from the manifold,
and support with wire or string. Do not allow
the front section of the exhaust system to hang
under its own weight. Recover the gasket.
7Unscrew the securing nuts, and withdraw
the manifold from the cylinder head (see
illustration). Recover the gasket.
8It is possible that some of the manifold
studs may be unscrewed from the cylinder
head when the manifold securing nuts are
unscrewed. In this event, the studs should be
screwed back into the cylinder head once the
manifold has been removed, using two
manifold nuts locked together.
Refitting
9Refit the manifold using a new gasket, and
tighten the securing nuts to the specified
torque.
10Reconnect the exhaust downpipe to the
manifold, using a new gasket and tighten the
securing bolts to the specified torque.
11Further refitting is a reversal of removal.
14Exhaust system - checking,
removal and refitting
2
Note: All relevant gaskets and/or sealing rings
should be renewed on refitting
Checking
1Periodically, the exhaust system should be
checked for signs of leaks or damage. Also
inspect the exhaust system rubber
mountings, and renew if necessary.
2Small holes or cracks can be repaired using
proprietary exhaust repair products, but
where more serious corrosion or damage is
evident, renewal will be necessary.
Removal
3The original factory-fitted exhaust system
consists of four separate sections, all of which
can be renewed individually.
4On models fitted with a catalytic converter,
an oxygen sensor is fitted to the front section
of the exhaust. The catalytic converter is fitted
in place of the front expansion box in the
conventional exhaust system. The
manufacturers do not specify any renewal
intervals for the catalytic converter.
5Before renewing an individual section of the
exhaust system, it is wise to inspect the
remaining sections. If corrosion or damage is
evident on more than one section of the
system, it may prove more economical to
renew the entire system.
6Individual sections of the exhaust system
can be removed as follows.
Front section - SOHC models
7On models with a catalytic converter,
disconnect the battery negative lead, and
disconnect the oxygen sensor wiring plug,
which is located behind the coolant expansion
tank.
8Raise the vehicle, and support securely on
axle stands placed under the body side
members (see “Jacking and Vehicle
Support”).
9Unscrew the two securing bolts, and
disconnect the exhaust front section from the
front expansion box or catalytic converter (as
applicable) at the flexible joint. Recover the
sealing ring and the springs (see illustration).10Unbolt the exhaust front section from the
bracket on the cylinder block (see
illustration).
11Unscrew and remove the four bolts
securing the downpipe to the exhaust
manifold, and withdraw the exhaust front
section (see illustration). Recover the
downpipe-to-manifold gasket.
Refitting
12Refitting is a reversal of removal, but use a
new gasket when reconnecting the downpipe
to the manifold, and a new sealing ring when
connecting the flexible joint. Tighten all fixings
to the specified torque.
Front section - DOHC models
Removal
13Proceed as described in paragraphs 7
and 8.
14Remove the engine undershield, as
described in Chapter 11.
15Proceed as described in paragraphs 9
and 10.
16Working in the engine compartment,
remove the bolts securing the exhaust
manifold heat shield to the cylinder head.
17Unscrew the two lower exhaust manifold
securing nuts that also secure the heat shield
brackets, and withdraw the heat shield (see
illustration).
18Unscrew the remaining manifold securing
nuts, then withdraw the manifold/exhaust
front section from the vehicle. Recover the
manifold gasket.
Fuel and exhaust systems - exhaust and emissions 4C•5
14.10 Exhaust front section support
bracket - SOHC models
14.11 Unscrewing a downpipe-to-exhaust
manifold bolt - SOHC models
14.9 Exhaust front section flexible joint -
SOHC models13.7 Unscrewing an exhaust manifold
securing nut - SOHC models
4C

31This engine is also fitted with an EGR
(exhaust gas recirculation) valve and
secondary air injection (AIR - Air Injection
Reactor), to conform to the latest European
exhaust emission limits (as from 1996). The
EGR returns a specific amount of exhaust gas
into the combustion process. This in turn
reduces the formation of nitrogen oxides
(No
x). The secondary air injection system has
an electrically driven air pump that injects air
into the exhaust manifold, reducing the
amount of CO and HC emissions.
2Fuel injection system -
precautions
The fuel injection system is pressurised,
therefore extra care must be taken when
disconnecting fuel lines. When disconnecting
a fuel line union, loosen the union slowly, to
avoid a sudden release of pressure that may
cause fuel to spray out.
Fuel pressure checking must be entrusted
to a Vauxhall dealer, or other specialist, who
has the necessary special equipment.
3System testing - general
3
General
1Apart from basic electrical tests, there is
nothing that can be done by the owner to test
individual fuel system components.2If a fault arises, check first that it is not due
to poor maintenance. Check that the air
cleaner filter element is clean, the spark plugs
are in good condition and correctly gapped.
Check also that the engine breather hoses are
clear and undamaged and that the throttle
cable is correctly adjusted. If the engine is
running very roughly, check the compression
pressures (Chapter 1) and remember the
possibility that one of the hydraulic tappets
might be faulty, producing an incorrect valve
clearance.
3If the fault is thought to be due to a dirty
injector, it is worth trying one of the
established injector-cleaning treatments
before renewing, perhaps unnecessarily, the
injector.
4If the fault persists, check the ignition
system components (as far as possible).
5If the fault is still not eliminated, work
methodically through the system, checking all
fuses, wiring connectors and wiring, looking
for any signs of poor connections, dampness,
corrosion, dirt or other faults.
6Once the system components have been
checked for signs of obvious faults, take the
vehicle to a Vauxhall dealer for the full system
to be tested on special equipment.
7Do not attempt to “test” any component,
but particularly the ECU, with anything other
than the correct test equipment, available at a
Vauxhall dealer. If any of the wires to be
checked lead to a component such as the
ECU, always first unplug the relevant
connector from the system components so
that there is no risk of the component being
damaged by the application of incorrect
voltages from test equipment.
4Air cleaner - removal and
refitting
2
Note:If ‘round type’ air filter is fitted, follow
procedure in Chapter 4A.
Removal
1Unclip the coolant expansion tank hose
from the air cleaner cover, and move it to one
side out of the way.2Loosen the clamp screw and disconnect
the air trunking from the airflow meter (see
illustration).
3Disconnect the battery negative lead, then
disconnect the wiring plug from the airflow
meter.
4Release the two securing clips from the left-
hand side of the air cleaner cover, and
unscrew the two captive securing screws
from the right-hand side, then lift off the
cover.
5Lift out the filter element.
6Loosen the preheat hoses, fastening nuts.
7Undo the nuts securing the 2 rubber block
studs which are secured through the lower
half of the air cleaner housing.
8Some models are fitted with an inlet air
resonance box, to reduce induction noise.
This box is located under the wheel arch, and
connects to a pipe on the air inlet tube.
9The resonance box must be removed
before the air inlet tube can be removed. To
do this, first apply the handbrake, then jack up
the front of the vehicle, and support securely
on axle stands placed under the body side
members.
10Remove the securing screws, and
withdraw the lower splash shield from the
wing to expose the resonance box.
11Unscrew the single securing screw, and
pull the resonance box from the connector
tube (see illustrations).
12If desired, the air inlet tube can be
removed after pulling off the connector tube
from under the wing (see illustration).
4B•4Fuel and exhaust systems - fuel injection models
4.12 Removing the resonance box
connector tube4.11B . . . and withdraw the resonance box4.11A Remove the securing screw . . .
4.2 Loosening the air trunking clamp
screw at the airflow meter
Warning: Many of the
procedures in this sub-Section
require the removal of fuel lines
and connections that 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.

4B
4Clamp the fuel hoses on either side of the
damper, to minimise fuel loss when the hoses
are disconnected.
5Loosen the clamp screws, and disconnect
the fuel hoses from the damper. Be prepared
for fuel spillage, and take adequate fire
precautions.
6Unscrew the securing nut, and withdraw
the damper from the bracket.
Refitting
7Refitting is a reversal of removal.
8Run the engine and check for leaks on
completion. If leakage is evident; stop the
engine immediately, and rectify the problem
without delay.
19Throttle cable - removal,
refitting and adjustment
3
Removal
1This procedure is basically the same as
described in Chapter 4A, but note the
following.
2Not all models are fitted with an air box.
Ignore references to it, if not applicable.
3For “carburettor” substitute “throttle body”,
and note that the cable bracket is bolted to
the inlet manifold.
4The throttle cable end may connect to a
balljoint on the throttle valve lever, which is
retained by a clip (see illustration).
5If fitted, remove the air box. Refer to
Section 5, if necessary.
6Where fitted, use a pair of needle-nosed
pliers to extract the wire spring clip securing
the cable end balljoint to the throttle linkage.
Prise the cable end off the linkage.
7Withdraw the clip and pull the cable outer
seating grommet out of the cable bracket,
then release the cable as far as the bulkhead
(see illustration).
8Working inside the passenger
compartment, remove the driver’s footwell
trim panel, refer to Chapter 11, if necessary.
9Release the end of the cable’s inner wire
from the “keyhole” fitting at the top of the
throttle pedal by easing back the spring and
prising the cable end out of the slot.10Prise the grommet out of the bulkhead
and tie a length of string to the cable.
11Noting carefully its routing, withdraw the
cable through the bulkhead into the engine
compartment; untie the string, leaving it in
place, when the pedal end of the cable
appears.
Refitting
12Refitting is the reverse of the removal
procedure, noting the following points.
a)First ensure that the cable is correctly
routed, then draw it through the bulkhead
aperture using the string.
b)Ensure that the bulkhead grommet is
correctly seated.
c)Connect the cable end to the throttle
linkage. Seat the cable outer grommet in
the bracket and pull it through so that the
cable inner wire is just taut when the
throttle linkage is held fully closed. Fit the
clip to secure the cable outer in that
position.
d)Check the throttle operation and cable
adjustment, as described below.
Adjustment
13Refer to Chapter 4A, but for “carburettor”
substitute “throttle body”. If applicable, the air
box must be removed.
14First check that the pedal is at a
convenient height for the driver. This setting
can be adjusted by turning the pedal stop
screw (it will be necessary to remove the
footwell trim panel to reach the screw).
Remember that the pedal must be left with
enough travel for the throttle valve to open
fully. Also check that the pedal pivot bushes
are in good condition.
15Returning to the engine compartment,
check that the linkage pivots and balljoints are
unworn and operate smoothly throughout
their full travel. When the throttle valve is fully
closed and the throttle pedal is released, there
should be hardly any free play in the cable
inner wire.
16If adjustment is required, extract the clip
securing the cable outer seating grommet in
the cable bracket and replace it in the
appropriate groove, so that the cable outer is
repositioned correctly.17With an assistant operating the throttle
pedal from the driver’s seat. Check that when
the pedal is fully depressed, the throttle valve
is fully open. If there is insufficient pedal travel
to permit this, unscrew the pedal stop screw,
then reset the cable at the throttle linkage.
18When cable adjustment is correct, refit all
disturbed components.
20Idle mixture - checking and
adjustment
3
Note: No adjustment of idle mixture is
possible on models fitted with a catalytic
converter, and no adjustment of idle speed is
possible with the Motronic system. Refer to
Section 2 before proceeding. A tachometer
and an exhaust gas analyser (CO meter) will be
required to carry out adjustment on models
fitted with Motronic systems.
Multec systems
Checking
1If the CO level reading is incorrect (or if any
other symptom is encountered which causes
you to suspect a fault) always check first that
the air cleaner element is clean. Check also
that the spark plugs are in good condition and
correctly gapped. Ensure that the engine
breather and vacuum hoses are clear and
undamaged. Check that there are no leaks in
the air inlet trunking. Check the throttle body
and the manifolds for damage. Ensure that the
throttle cable is correctly adjusted (see Section
19). If the engine is running very roughly, check
the compression pressures (Chapter 2A) and
remember the possibility that one of the
hydraulic tappets might be faulty, producing
an incorrect valve clearance. Check also that
all wiring is in good condition, with securely
fastened connectors. Check that the fuel filter
has been renewed at the recommended
intervals and that the exhaust system is
entirely free of air leaks which might upset the
operation of the catalytic converter, if fitted.
Adjustment
2The idle mixture is controlled entirely by the
ECU and there is no provision at all for any
form of adjustment. Furthermore, accurate
checking is not possible without the use of
Vauxhall test equipment in conjunction with a
good-quality, carefully calibrated exhaust gas
analyser.
3While it may be possible for owners with
access to such analysers to check the
mixture, the results should be regarded as no
more than a rough guide. If the mixture is
thought to be incorrect, the vehicle should be
taken to a Vauxhall dealer for checking. If the
CO level exceeds the specified value the
system must be checked thoroughly by an
experienced mechanic using the Vauxhall test
equipment until the fault is eliminated and the
defective component renewed.
Fuel and exhaust systems - fuel injection models 4B•9
19.7 Throttle cable end grommet in
bracket on inlet manifold19.4 Disconnecting the throttle cable end
from the throttle valve lever - SOHC model