1988 OPEL CALIBRA sensor

28The system also incorporates a separate
ignition amplifier module that transmits
amplified signals from the main system
module to trigger the HT pulse from the
ignition coil. The module is mounted on the
ignition coil’s bracket/baseplate.
29Additionally, the Motronic module
receives information from a cylinder
block-mounted knock sensor, which senses
“knocking” (or pre-ignition) just as it begins to
occur, enabling the module to retard the
ignition timing, thus preventing engine
damage.
Simtec 56.1
30This system uses increased amount of
electronic components instead of mechanical
parts as sensors and actuators with the
Simtec engine management system. This
provides more precise operating data as well
as greater problem free motoring.
31The control unit is equipped with
electronic ignition control. Called ‘Micropro-
cessor Spark Timing System, inductive
triggered’, (or MSTS-i), and means that the
mechanical high voltage distributor is no
longer needed. It is located behind the trim
panel, on the right-hand side footwell (door
pillar).
32The ignition coil is replaced by a dual
spark ignition coil, which is switched directly
by the output stages in the control unit.
33A camshaft sensor will maintain
emergency operation, should the crankshaft
inductive pulse pick-up, malfunction. These
sense TDC (‘Top Dead Centre’), crankshaft
angle and engine speed. The signals are used
by the control unit to calculate ignition point
and for fuel injection.
34The ‘hot film airflow meter’ determines the
mass of air taken in by the engine. The system
uses this information to calculate the correct
amount of fuel needed for injection in the
engine.
35The air inlet temperature sensor (NTC), is
fitted in the air inlet duct between the air
cleaner and the hot mass air flow meter.
36A controlled canister purge valve is
actuated by the system. The tank ventilation is
monitored closely with the Lambda control (or
oxygen sensor) and adaptation by the
computer within the control unit.
37A knock control system is also fitted. This
eliminates the need for octane number
adjustment, as it is performed automatically
through the control unit.
3Electrical system -
precautions
1It 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.
2Always 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.
3Do not reverse the battery connections.
Components such as the alternator, or any
other component having semi-conductor
circuitry, could be irreparably damaged.
4If 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.
5Never disconnect the battery terminals, or
alternator multi-plug connector, when the
engine is running.
6The battery leads and alternator wiring
must be disconnected before carrying out any
electric welding on the vehicle.
7Never use an ohmmeter of the type
incorporating a hand-cranked generator for
circuit or continuity testing.
8Engine management modules are very
sensitive components, and certain
precautions must be taken, to avoid damage
to the module when working on a vehicle
equipped with an engine management
system, as follows.
9When carrying out welding operations on
the vehicle using electric welding equipment,
the battery and alternator should be
disconnected.
10Although underbonnet-mounted modules
will tolerate normal underbonnet conditions,
they can be adversely affected by excess heat
or moisture. If using welding equipment or
pressure washing equipment near the
module, take care not to direct heat, or jets of
water or steam, at the module. If this cannot
be avoided, remove the module from the
vehicle, and protect its wiring plug with a
plastic bag.
11Before disconnecting any wiring, or
removing components, always ensure that the
ignition is switched off.
12Do not attempt to improvise fault
diagnosis procedures using a test lamp or
multimeter, as irreparable damage could be
caused to the module.13After working on ignition/engine
management system components, ensure
that all wiring is correctly reconnected before
reconnecting the battery or switching on the
ignition.
14Any ignition system that uses a
“Hall-effect” generator in the distributor,
cannot be tested. Test equipment that uses
its own power source (e.g. an ohmmeter),
when connected to the distributor or the
“Hall-effect” generator, will be damaged.
4Ignition system testing -
general
3
Note: Refer to Section 3 before proceeding.
Always switch off the ignition before
disconnecting or connecting any component
and when using a multi-meter to check
resistances. Any voltmeter or multi-meter
used to test ignition system components must
have an impedance of 10 meg ohms or
greater
1Electronic ignition system components 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
component failure. 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.
2The old practice of checking for a spark by
holding the live end of a 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 ignition coil
or amplifier module will be damaged.
Similarly, never try to “diagnose” misfires by
pulling off one HT lead at a time. Note also
that the ECU is at risk if the system is
triggered with an open (i.e., not properly
earthed) HT circuit; ECU’s are very expensive
to replace, so take care!
3If you are in any doubt as to your skill and
ability to test an ignition system component or
if you do not have the required equipment,
take the vehicle to a suitably equipped
Vauxhall dealer. It is better to pay the labour
charges involved in having the vehicle
checked by an expert than to risk damage to
the system or to yourself.
4If 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) and disconnect the
ignition coil HT lead from the distributor cap
and earth. 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,
check the battery, battery connections, starter
motor and charging system.
5•4Engine electrical systems
Warning: The HT voltage
generated by an electronic
ignition system is extremely
high and, in certain
circumstances, could prove fatal. Take
care to avoid receiving electric shocks
from the HT side of the ignition system.
Do not handle HT leads, or touch the
distributor or coil, when the engine is
running. If tracing faults in the HT circuit,
use well-insulated tools to manipulate live
leads

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

been removed, check that No 1 cylinder is on
its firing stroke by removing No 1 cylinder
spark plug and placing a finger over the plug
hole. Turn the crankshaft until compression
can be felt, which indicates that No 1 piston is
rising on its compression stroke. Continue
turning the crankshaft until the relevant timing
marks are in alignment.
11Turn the rotor arm to the position noted in
paragraph 6c, and hold the rotor arm in this
position as the distributor is fitted. Note that
the distributor driveshaft will only engage with
the camshaft in one position. If the original
distributor is being refitted, align the marks
made on the distributor body and camshaft
housing before removal.
12Refit the clamp plate and nut, but do not
fully tighten the nut at this stage.
13On the Bosch distributor, remove the rotor
arm, then refit the plastic shield and the rotor
arm.
14On 14 NV models, reconnect the vacuum
pipe to the diaphragm unit.
15Reconnect the distributor wiring plug.
16Refit the distributor cap as described in
Section 17.
17Reconnect the battery negative lead.
18Check and if necessary adjust the ignition
timing, as described in Section 21.
19Distributor (DOHC models),
where applicable - removal
and refitting
3
Removal
1Disconnect the battery negative lead.
2Remove the distributor cap, as described in
Section 17.
3Disconnect the distributor wiring plug.
4Unscrew the two securing bolts, and
remove the distributor from the cylinder head.
5Examine the O-ring on the rear of the
distributor, and renew if necessary.
Refitting
6Refitting is a reversal of removal. However,
note that the distributor should be fitted so
that the wiring plug is positioned on the upper
left-hand side of the distributor body, when
viewed from the distributor cap end.
20Distributor - dismantling,
inspection and reassembly
3
Note: Before contemplating dismantling of a
distributor, check the cost and availability of
replacement parts. It may prove more
economical to renew the complete distributor
assembly
14 NV models
Dismantling
1With the distributor removed as described
in Section 18, continue as follows.
2Pull off the rotor arm, and remove the
plastic shield.
3The top bearing plate can be removed after
unscrewing the two securing screws, however
(other than the vacuum diaphragm unit), no
spares are available for the distributor and no
adjustments are required.
4If desired, the vacuum diaphragm unit can
be removed by extracting the two securing
screws and unhooking the operating arm from
the distributor baseplate. Note that the
screws are of differing lengths, the longer
screw also secures one of the distributor cap
clips.
Inspection
5The vacuum unit can be tested by applying
suction to the vacuum port, and checking that
the operating rod moves into the unit as
suction is applied. Remove the suction, and
check that the operating rod returns to its
original position. If the operating rod does not
move as described, renew the vacuum unit.
6Check the distributor cap for corrosion of
the segments, and for signs of tracking,
indicated by a thin black line between the
segments. Make sure that the carbon brush in
the centre of the cap moves freely and stands
proud of the surface of the cap. Renew the
cap if necessary.
7If the metal portion of the rotor arm is badly
burnt or loose, renew it. If slightly burnt or
corroded; it may be cleaned with a fine file.
8Examine the seal ring at the rear of the
distributor body, and renew if necessary.
Reassembly
9Reassembly is a reversal of dismantling,
ensuring that the vacuum unit operating arm
is correctly engaged with the peg on the
baseplate, several attempts may be required
to reconnect it.
10Refit the distributor as described in
Section 18, and then check and if necessary
adjust the ignition timing, as described in
Section 21.
16 SV models
Dismantling
11With the distributor removed as described
in Section 18, pull off the rotor arm and, on
the Bosch distributor, remove the plastic
shield.
12Using a pin punch, carefully drive out the
roll pin securing the plastic drive collar to the
rear of the distributor shaft (see illustration).
13Lift off the drive collar, and remove the
thrustwashers from the end of the shaft (see
illustration).
14Withdraw the shaft, complete with the
trigger vane, from the distributor body, and
recover the thrustwashers from the shaft (see
illustration).
15On the Lucas distributor, extract the
spring clip from inside the body, then
withdraw the terminal block. Pull the small
wiring plug from inside the terminal block (see
illustrations).
16Remove the screws, and lift the sensor
plate from the distributor body (see
illustrations).
5•12Engine electrical systems
20.15A Removing the spring clip . . .20.14 Recovering the thrustwashers from
the shaft - 1.6 litre (Bosch distributor)20.13 Removing the thrustwashers
20.12 Removing the drive collar roll pin -
1.6 litre models (Bosch distributor)

Inspection
17Examine the distributor cap and rotor arm,
as described in paragraphs 6 and 7. Examine
the O-rings at the rear of the distributor body,
and on the rear of the shaft, and renew if
necessary.
Reassembly
18Reassembly is a reversal of dismantling,
ensuring that the thrustwashers are correctly
located. Note that the drive collar should be
refitted so that the drive peg on the collar is
aligned with the groove in the top of the
distributor shaft (it is possible to fit the drive
collar 180°out of position).
19Refit the distributor as described in
Section 18, and then check and if necessary
adjust the ignition timing, as described in
Section 21.
DOHC models (where
applicable)
20The distributor cap and rotor arm can be
examined as described in paragraphs 6 and 7.
21Ignition timing -checking and
adjustment
4
Note: Refer to Section 3 before proceeding. A
tachometer and a timing light will be required
during this procedure. For details of ignition
timing adjustment required to operate vehicles
on unleaded petrol, refer to Section 22.
14 NV and 16 SV models
Checking
1Start the engine and run it until it reaches
normal operating temperature, then switch
off.
2On 14 NV models, disconnect the vacuum
pipe from the distributor vacuum diaphragm
unit.
3On all models use a spanner applied to the
crankshaft pulley bolt to rotate the crankshaft
clockwise until the notch in the pulley’s
inboard rim aligns with the pointer protruding
from the oil pump housing. On 14 NV models,
where two notches (indicating 10°and 5°
BTDC respectively) are found, rotate the
crankshaft until the second notch (in thedirection of rotation -i.e. 5°BTDC) aligns. Use
white paint or similar to emphasise the pointer
and notch, to make them easier to see.
4Connect a timing light to No 1 cylinder
(nearest the timing belt end of the engine) HT
lead, also a tachometer; follow the equipment
manufacturer’s instructions for connection.
5Start the engine and allow it to idle -the
speed should be between 700 and 1000 rpm.
6On 14 NV models, aim the timing light at the
pointer and check that it is aligned with the
crankshaft pulley notch.
7On early 16 SV models, disconnect the
ignition timing basic adjustment coding plug.
This can be identified by a length of Black
wire joining Brown/Red and Brown/Yellow
wires in a connector plug clipped to the wiring
or heater/cooling system hoses beneath the
battery/ignition coil (see illustration, 16.1). This
causes the MSTS-i module to adopt its basic
adjustment mode, sending a constant firing
signal corresponding to 10°BTDC and
eliminating any advance below 2000 rpm. Aim
the timing light at the pointer and check that it
is aligned with the crankshaft pulley notch.
8On later 16 SV, C 16 NZ and C 16 NZ2
models, the coding plugs are no longer fitted.
For accurate checking, special Vauxhall test
equipment must be used which causes the
MSTS module to adopt its basic adjustment
mode.
9Without access to such equipment, it is
possible to check and adjust the ignition
timing, accurate results cannot be
guaranteed. Owners are therefore advised to
have this work carried out by a suitably
equipped Vauxhall dealer; at the very least,
make the initial setting yourself and then have
it checked as soon as possible.
10If you do attempt to check the ignition
timing yourself, note that the fixed reference
mark is now an extended line embossed on
the timing belt lower outer cover.
Adjustment
11If the notch and pointer are not aligned,
loosen the distributor clamp nut and turn the
distributor body slightly in the required
direction to align.
12Tighten the distributor clamp nut, and
check that the notch and pointer are still
aligned. 13Stop the engine, and disconnect the
timing light and tachometer.
14On 16 SV models, reconnect the basic
adjustment coding plug. On 14 NV models,
reconnect the vacuum pipe to the distributor
vacuum diaphragm unit.
Other models
15No adjustment of the ignition timing is
possible on 1.8 and 2.0 litre models, as the
adjustment is carried out automatically by the
electronic control module.
16The ignition timing can be checked by a
Vauxhall dealer using specialist dedicated test
equipment, if a fault is suspected.
22Ignition timing -adjustment
for use with unleaded petrol
3
14 NV models
1All models with the 14 NV engine have the
ignition timing adjusted for use with 95 RON
unleaded petrol before they leave the factory,
and no further adjustment is required.
2Leaded petrol (98 RON) can be used if
desired, with no adverse effects.
1.6, 1.8 and 2.0 SOHC models
Note: Models equipped with a catalytic
converter must be operated on 95 R0N
unleaded petrol at all times, and although an
octane coding plug may be fitted, it should
not be tampered with
3Models, other than 14 NV, are equipped
with an octane coding plug, which is located
Engine electrical systems 5•13
20.16B . . .and withdraw the sensor plate -
1.6 litre (Bosch distributor)
20.16C Sensor plate screw (arrowed) -
1.6 litre (Lucas distributor)
20.16A Remove the securing screws . . .20.15B . . .and disconnecting the small
wiring plug - 1.6 litre (Lucas distributor)
5

in a clip at the left-hand rear of the engine
compartment (see illustration).
4The plug is reversible in its connector, and
is marked either “A” or “98” on one side,
which corresponds to the position for use with
98 RON leaded petrol. On the other side either
“B” or “95”, which corresponds to the position
to use with 95 RON unleaded petrol. All
vehicles are set for use with 95 RON unleaded
petrol before they leave the factory.
5To change the coding for use with a
different type of petrol, first allow the fuel tank
to become practically empty.
6Fill the fuel tank with the required type of
petrol.
7Ensure that the ignition is switched off, then
remove the coding plug from its clip and
disconnect the wiring connector.
8Rotate the plug through 180°, so that the
appropriate octane mark is uppermost (see
paragraph 4), then reconnect the wiring
connector and refit the plug to its clip.
9Note that using petrol with a higher octane
rating than that set will not cause damage, but
petrol with a lower octane rating than that set
must not be used.
20 XE, C20 XE and X20 XEV
models
10The ignition coding plug found on these
models is not an octane coding plug
(although its method of operation is similar)
and must not be altered from its factory
setting. Its purpose is to ensure that the
Motronic module uses the correct information,
pre-programmed (or “mapped”) into its
memory, to enable the vehicle to comply with
the relevant national noise and exhaust
emission legislation.
11On these models, the knock sensor circuit
allows the Motronic module to compensate
for differences in the octane value of the
petrol used, without the need for manual
intervention. Remember, however, that all
catalytic converter-equipped vehicles must
use unleaded petrol only. This means that
these models can use any grade of unleaded
petrol on sale in the UK without the need for
adjustment.
23Electronic modules - removal
and refitting
3
Note: Refer to Section 3 for precautions to be
observed when working with electronic
modules. Heat sink compound must be used
when refitting the module.
HEI module (14 NV models)
Removal
1The module is mounted on a metal plate,
beneath the ignition coil, on the left-hand side
of the engine compartment.
2Remove the ignition coil as described in
Section 16, and slide the coil from its clamp.
3The module can be removed from the
mounting plate by unscrewing the two
securing screws.
4Before refitting the module, heat sink
compound should be applied to the mounting
plate to improve heat dissipation. If a new
module is being fitted, it should be supplied
with heat sink compound. Similar compounds
can be bought from DIY electrical shops.
Refitting
5Refitting is a reversal of removal.
MSTS-i module (1.6 and 1.8 litre
models)
Removal
6The module is mounted on the engine
compartment bulkhead, above the steering
rack (see illustration).
7Disconnect the battery negative lead.
8If desired, for improved access, remove the
air box from the top of the carburettor.
9Disconnect the wiring plug from the
module.
10Unscrew the two securing nuts, and
withdraw the module from the bulkhead.
Refitting
11Refitting is a reversal of removal.
Motronic module
Removal
12The module is mounted in the driver’s
footwell, behind the side trim panel.13Disconnect the battery negative lead.
14Remove the driver’s footwell side trim
panel, as described in Chapter 11.
15Unscrew the three module securing
screws, two at the top of the module, and a
single screw at the bottom, and lower the
module from the footwell (see illustration).
16Release the retaining clip, and disconnect
the module wiring plug (see illustration).
17Withdraw the module, noting the plastic
insulating sheet on its rear face.
Refitting
18Refitting is a reversal of removal, but
ensure that the insulating sheet is in place on
the rear face of the module.
24MSTS-i components -
removal and refitting
3
Note: Refer to Section 3 before proceeding.
Procedures for removal and refitting of the
ignition system components and electronic
module are given elsewhere in the relevant
Sections of this Chapter
Manifold pressure sensor
Removal
1The sensor is located on the engine
compartment bulkhead, to the left of the
MSTS-i module, under the edge of the
windscreen cowl panel (see illustration).
2Disconnect the battery negative lead.
5•14Engine electrical systems
22.3 Octane coding plug (arrowed) -
2.0 litre model
23.15 Lowering the Motronic module from
the footwell - 2.0 litre model23.16 Releasing the Motronic module
wiring plug clip - 2.0 litre model
23.6 MSTS-i module location -
1.6 litre model

3Lift up the edge of the windscreen cowl
panel for access to the sensor.
4Disconnect the sensor wiring plug, and the
vacuum pipe.
5Pull the pressure sensor upwards to release
it from its bracket, and withdraw it from the
vehicle.
Refitting
6Refitting is a reversal of removal. However,
on Multec models no fuel vapour trap is fitted.
It is therefore essential that the sensor
vacuum hose is routed so that it falls steadily
from the sensor to the throttle body. This
precaution prevents any fuel droplets being
trapped in the sensor or hose, and allows
them to drain into the inlet port.
Oil temperature sensor
Removal
7The sensor is screwed into the inlet
manifold side of the cylinder block, next to the
starter motor’s right-hand end.
8The sensor can be reached quite easily
from above, but if it is to be removed from
beneath, ensure that the handbrake is
applied, and that the vehicle is securely
supported on axle stands (see “Jacking and
Vehicle Support”).
9Disconnect the battery negative lead.
10Disconnect the sensor wiring plug.
11Using a spanner, unscrew the sensor and
remove it (see illustration). Be prepared for
oil spillage, and plug the hole in the cylinder
block to prevent dirt ingress and further oil
loss.
Refitting
12Refitting is a reversal of removal.
Crankshaft speed/position
sensor (1.8 litre models)
Removal
13The sensor is located on the exhaust
manifold side of the engine, in the lower
cylinder block behind the oil pump.
14Disconnect the battery negative lead.
15Release the relevant outer timing belt
cover securing clips, and unclip the sensor
wiring from the timing belt cover.
16Disconnect the sensor wiring connector,
noting its location.
17Unscrew the securing bolt, and withdraw
the sensor from the cylinder block (see
illustration).
18Examine the sensor sealing ring, and
renew if necessary (see illustration).
Refitting
19Refitting is a reversal of removal, ensuring
that the sensor wiring is correctly located on
the timing belt cover, and that the wiring
connector is correctly located.
25Motronic system
components - removal and
refitting
3
Note: Refer to Section 3 before proceeding.
Procedures for removal and refitting of the
ignition system components and electronic
module are given elsewhere in the relevant
Sections of this Chapter. Removal and
refitting procedures for all fuel injection
system components are given in Chapter 4B
Coolant temperature sensor
Removal
1On all except 20 XEJ models, the sensor is
located in the end of the thermostat housing,
on the inlet manifold side of the engine.
2On 20 XEJ models, the sensor is located in
the thermostat housing, on the exhaust
manifold side of the engine.
3Disconnect the battery negative lead.
4Partially drain the cooling system, as
described in Chapter 3. 5Disconnect the sensor wiring plug (see
illustration).
6Using a spanner, unscrew the sensor and
withdraw it from the thermostat housing.
Refitting
7Refitting is a reversal of removal.
8On completion, top-up the cooling system,
as described in Chapter 3.
Knock sensor (DOHC models)
Removal
9The sensor is located at the lower inlet
manifold side of the cylinder block, below the
idle speed adjuster, and is only accessible
from below the vehicle.
10Disconnect the battery negative lead.
11Apply the handbrake, then jack up the
front of the vehicle, and support securely on
axle stands (see “Jacking and Vehicle
Support”) placed under the body side
members.
12Remove the engine undershield, as
described in Chapter 11.
13Disconnect the sensor wiring plug.
14Unscrew the securing bolt, and withdraw
the sensor from the cylinder block.
Refitting
15Refitting is a reversal of removal, but note
that the mating faces of the sensor and
cylinder block must be cleaned thoroughly
before fitting the sensor.
Engine electrical systems 5•15
24.17 Unscrewing the crankshaft
speed/position sensor securing bolt -
1.8 litre model
25.5 Disconnecting the coolant
temperature sensor wiring plug - 2.0 litre
model (alternator removed)24.18 Examine the crankshaft
speed/position sensor sealing ring -
1.8 litre model
24.11 Unscrewing the MSTS-i oil
temperature sensor - 1.6 litre model
(engine removed)24.1 MSTS-i manifold pressure sensor -
1.6 litre model
5

26DIS module - removal and
refitting
3
Note: Refer to Section 3 before proceeding.
Removal
1Disconnect the battery negative lead.
2Disconnect the HT leads from the module
terminals noting their locations to ensure
correct refitting. Note that the HT lead cylinder
numbers are stamped on the module, next to
each terminal, and similar numbers appear on
each HT lead.
3Disconnect the module wiring plug.
4On X16 SZ engines, undo the three screws
and remove the module from the camshaft
housing. On C20 XE engines, undo the bolts
securing the DIS module mounting bracket tothe cylinder head and remove the module and
bracket. Note the installed position of DIS
module on its mounting bracket, undo the four
securing screws and separate the module
from the bracket.
Refitting
5Refitting is a reversal of removal.
27Camshaft phase sensor (C20
XE engine) -removal and
refitting
3
Note: Refer to Section 3 before proceeding.
Removal
1The camshaft phase sensor is mounted on
the end of the cylinder head in the position
normally occupied by the distributor.2Disconnect the battery negative lead.
3Disconnect the wiring plug then undo the
phase sensor securing bolts.
4Withdraw the phase sensor from the
cylinder head, then undo the bolt and remove
the phase sensor disc from the end of the
camshaft.
Refitting
5Refitting is a reversal of removal.
5•16Engine electrical systems

4C
Torque wrench settingsNm lbf ft
AIR non-return valve to pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 22
AIR pipe support bracket to manifold . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6
AIR pipe to manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
AIR pipe to support bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6
AIR pump bracket to protective shield . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7
AIR pump to wheel arch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
AIR pump to insulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7
AIR valves to bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3
Carbon canister . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3
EGR valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
Heat shield . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 6
Oxygen sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 22
Chapter 4 Part C:
Fuel and exhaust systems - exhaust and emissions
AIR cut-off valve - removal, testing and refitting . . . . . . . . . . . . . . . . .7
AIR pipe and non-return valve - removal and refitting . . . . . . . . . . . . .9
AIR pump assembly (Simtec system) - removal and refitting . . . . . . . .6
AIR switchover valve - removal and refitting . . . . . . . . . . . . . . . . . . . .8
Carbon canister - removal and refitting . . . . . . . . . . . . . . . . . . . . . . .11
Catalytic converter - description, general and precautions . . . . . . . .10
EGR module (X 16 SZ models) - removal and refitting . . . . . . . . . . . . .5EGR valve (Multec system models) - testing, removal and refitting . . .3
EGR valve (Simtec system) - testing, removal and refitting . . . . . . . . .4
Emissions control systems - general . . . . . . . . . . . . . . . . . . . . . . . . . .1
Exhaust gas recirculation (EGR) system - general . . . . . . . . . . . . . . . .2
Exhaust manifold - removal and refitting . . . . . . . . . . . . . . . . . . . . . .13
Exhaust system - checking, removal and refitting . . . . . . . . . . . . . . .14
Oxygen sensor (catalytic converter models) - removal and refitting .12
4C•1
Specifications Contents
1 Emissions control systems -
general
General
Multec system
1An evaporative emissions control system is
fitted to minimise the escape into the
atmosphere of unburned hydrocarbons.
2The fuel tank filler cap is sealed and a
charcoal canister is mounted under the
right-hand front wing to collect the petrol
vapours generated in the tank when the
vehicle is parked. It stores them until they can
be purged from the canister into the inlet tract
to be burned by the engine during normal
combustion. The canister’s control valve (on
the top of the canister) is opened by a vacuum
pipe from the front of the throttle body on C16
NZ, C16 NZ2 and C18 NZ engines. On X16 SZ
it’s opened by an electronically activated
purge valve, mounted on the camshaft
housing.
Motronic system
3The system is as described in Chapter 4B,
except that the charcoal canister is purged
under the control of the fuel injection/ignition
system module through the fuel tank vent
valve. To ensure that the engine runs correctly
when it is cold and/or idling, and to protect
the catalytic converter from the effects of an
over-rich mixture, the valve is not opened by
the module until the engine is under partial or
full load. The valve solenoid is then modulated
on and off to allow the stored vapour to pass
into the inlet tract.
4Canister removal and refitting is as
described in Section 11.
5On C20 NE engines, the vent valve is
mounted above the injectors for cylinders 2
and 4. To remove it, disconnect the battery
negative lead and the valve wiring plug, then
disconnect the two vent hoses having made
note of their connections. Either remove the
valve from its mounting bracket, or unbolt the
bracket, as required.
6On C20 XE engines, the vent valve is
mounted on the left-hand end of the engine,underneath the end of the fuel injector wiring
harness housing (see illustration). Removal
and refitting is as described in the previous
paragraph.
Simtec system
7For information refer to “General
description”, in Chapter 4B. Note that “AIR”,
is an abbreviation for the secondary Air
Injection Reactor system used on this model.
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321
1.6 Disconnecting the fuel tank vent valve
wiring