AUX OPEL VECTRA 1988 Service Owner's Manual

14Front brake disc shield -
removal and refitting
3
Removal
1Where applicable, remove the wheel trim,
then loosen the relevant front roadwheel bolts
and apply the handbrake. Jack up the front of
the vehicle, and support on axle stands (see
“Jacking and Vehicle Support”) positioned
under the body side members. Remove the
roadwheel.
2Remove the brake disc, as described in
Section 10.
3Using a screwdriver inserted through the
holes in the hub flange, extract the three
screws securing the disc shield to the hub
carrier.
4Using plate shears or an alternative tool, cut
a section of metal from the rear edge of the
shield to enable the shield to be withdrawn
over the hub, then remove the shield (see
illustration).
Refitting
5If a new shield is to be fitted, cut out a
section of metal, as during removal of the old
shield, to enable the shield to be fitted.
Smooth the cut edges, and coat them with
anti-corrosion paint.
6Further refitting is a reversal of removal,
remembering the following points.
7Refit the brake disc, as described in
Section 10.
8Do not fully tighten the roadwheel bolts until
the vehicle is resting on its wheels.
15Master cylinder - removal and
refitting
4
Note: Refer to the note at the beginning of
Section 3 before proceeding
Removal
1Disconnect the battery negative lead.
2Depress the footbrake pedal several times
to dissipate the vacuum in the servo unit.3Disconnect the wiring plug from the brake
fluid level sensor in the reservoir filler cap.
4If possible, use a teat pipette or an old
hydrometer to remove the brake fluid from the
reservoir. This will reduce the loss of fluid later
in the procedure.
5Locate a container beneath the master
cylinder, to catch the brake fluid that will be
released.
6Identify the brake fluid pipes for position,
then unscrew the union nuts and disconnect
the pipes from the master cylinder.
7Unscrew the two securing nuts, and
withdraw the master cylinder from the studs
on the vacuum servo unit (see illustration).
8Clean the external surfaces of the cylinder,
then using a screwdriver carefully prise the
fluid reservoir and its seals from the top of the
cylinder.
9If desired, on models without ABS, the
master cylinder can be overhauled, as
described in Section 16.
10No overhaul of the master cylinder is
possible on models with ABS, see Section 17.
Refitting
11Refitting is a reversal of removal, but use
new seals when fitting the brake fluid
reservoir, and on completion, bleed the
complete brake hydraulic system, as
described in Section 3.
16Master cylinder (non-ABS) -
overhaul
4
Note: Before dismantling the master cylinder,
check that replacement parts can be obtained
and retain the old components to compare
them with the new ones
1With the master cylinder removed as
described in Section 15, continue as follows,
according to type.
GMF type master cylinder
2Clamp the master cylinder in a soft-jawed
vice.
3Where applicable, unscrew the pressure-
proportioning valves from the base of the
cylinder.4Carefully prise out the sealing ring from the
end of the cylinder bore.
5Depress the primary piston slightly using a
piece of wood or plastic. Then hold the piston
in the depressed position by inserting a
smooth pin or rod of 3.0 mm (0.12 in) diameter
through the primary fluid reservoir port in the
cylinder (see illustration).
6Extract the circlip from the end of the
cylinder bore using a screwdriver. Take care
not to damage the piston or cylinder bore.
7Withdraw the pin or rod retaining the piston.
8Withdraw the primary piston assembly from
the cylinder, if necessary tapping the cylinder
on a wooden block to free the piston from the
bore.
9Apply low air pressure - e.g. from a foot
pump - to the front fluid reservoir port in the
cylinder, to eject the secondary piston
assembly.
10Clean all the components, in clean brake
fluid or methylated spirit only, and examine
them for wear and damage. In particular,
check the surfaces of the pistons and cylinder
bore for scoring and corrosion. If the bore
shows signs of wear, renew the complete
master cylinder assembly (see illustration).
11If the cylinder bore is in good condition,
obtain a repair kit, which will contain all the
necessary renewable items. A Vauxhall dealer
will supply a pre-assembled kit of parts, which
should be fitted as follows.
12Lubricate the cylinder bore with clean
brake fluid or brake grease, then clamp the
cylinder in a soft-jawed vice, with the bore
horizontal.
13Remove the plug from the end of the
assembly tube, and insert the short part of the
tube into the cylinder bore as far as the
shoulder on the tube.
14Use a piece of wood or plastic to push the
components out of the tube and into the
cylinder bore. Then hold the primary piston in
the depressed position by inserting the pin or
rod used during dismantling through the
cylinder primary fluid reservoir port.
15Fit a new circlip to the end of the cylinder
bore, ensuring that it seats correctly, and that
the piston is free to move.
16Depress the primary piston, and withdraw
the pin or rod from the fluid reservoir port.
Braking system 9•13
16.5 Holding the primary piston depressed
while extracting the circlip from the
cylinder body - GMF type master cylinder15.7 Master cylinder securing nut
(arrowed)14.4 Cutting a section of metal from a new
front brake disc shield prior to fitting
9

17Fit a new sealing ring to the end of the
cylinder bore.
18Where applicable, screw the pressure-
proportioning valves into the base of the
cylinder.
19Refit the master cylinder, as described in
Section 15.
ATE type master cylinder
20Clamp the master cylinder in a soft-jawed
vice.
21Where applicable, unscrew the pressure-
proportioning valves from the base of the
cylinder.
22Carefully prise out the sealing ring from
the end of the cylinder bore.
23Depress the primary piston slightly using
a piece of wood or plastic, then extract the
circlip from the end of the cylinder bore.
24Withdraw the primary piston assembly,
noting the location of the stop washers.
25Depress the secondary piston, again
using a piece of wood or plastic, and
withdraw the stop screw from the cylinder
body (see illustration).
26Withdraw the secondary piston assembly
from the cylinder, if necessary tapping the
cylinder on a wooden block to free the piston
from the bore.
27Clean all the components, in clean brake
fluid or methylated spirit only, and examine
them for wear and damage. In particular,
check the surfaces of the pistons and cylinder
bores for scoring and corrosion. If the bore
shows signs of wear, renew the complete
master cylinder assembly (see illustration).28If the cylinder bore is in good condition,
obtain a repair kit, which will contain all the
necessary renewable items. A Vauxhall dealer
will supply a complete kit of parts, which
should be fitted as follows.
29Lubricate the cylinder bore with clean
brake fluid or brake grease, then clamp the
cylinder in a soft-jawed vice, with the bore
horizontal.
30Fit a new sealing ring to the stop screw,
then screw it into the cylinder body a little
way, but not so far that it protrudes into the
bore.
31Remove the plugs from the ends of the
assembly tube, then remove all the
components from the short part of the tube,
and push the short part into the long part until
they are flush.
32Insert the assembly tube into the cylinder
bore as far as the collar on the short sleeve.
Then use a piece of wood or plastic to push
the secondary piston assembly into the bore
until it contacts the end of the cylinder.
33Lightly tighten the stop screw, then
withdraw the piece of wood or plastic and the
assembly tube, and fully tighten the stop
screw.
34Reposition the master cylinder in the vice,
with the bore facing upwards.
35Smear the primary piston skirt and the
seal grooves with the special grease provided
in the repair kit. Fit the stop washer to the
piston.
36Adjust the assembly tube so that the end
of the long part is flush with the inner shoulder
of the short part.37Fit the front seal to the primary piston,
with the open end of the seal facing the front
of the master cylinder.
38Place the assembly tube over the cylinder
to compress the seal, insert the piston and
tube part way into the bore, and withdraw the
tube.
39Place the intermediate ring on the primary
piston, then fit the remaining seal using the
assembly tube as described previously.
40Place the stop washer as the primary
piston, then depress the piston slightly using
a piece of wood or plastic, and fit a new circlip
to the end of the cylinder bore. Ensure that the
circlip is correctly seated, and that the piston
is free to move.
41Fit a new sealing ring to the end of the
cylinder bore.
9•14Braking system
16.25 Depressing the secondary piston
while extracting the stop screw - ATE type
master cylinder
16.27 Exploded view of ATE type master
cylinder
1 Filler cap (standard)
2 Strainer
3 Filler cap (with fluid level sensor)
4 Guide sleeve for float
5 Fluid reservoir
6 Cylinder body
7 Sealing ring
8 Fluid reservoir seals
9 Stop screw
10 Repair kit assembly tube
11 Pressure-proportioning valves
16.10 Exploded view of GMF type master
cylinder
1 Filler cap (standard)
2 Filler cap (with fluid level sensor)
3 Fluid reservoir
4 Fluid reservoir retaining clips
5 Fluid reservoir seals
6 Cylinder body
7 Secondary piston and springs
8 Primary piston
9 Circlip
10 Sealing ring
11 Pressure-proportioning valves

16If adjustment is necessary, slacken the
locknut, turn the fork to give the specified
dimension, then tighten the locknut.
17Where applicable, coat the contact faces
of the servo and the mounting bracket with
sealing compound, then refit the bracket to
the servo, and tighten the securing nuts to the
specified torque.
18Coat the threads of the servo securing
bolts with locking fluid, then fit the servo to
the bulkhead and tighten the securing bolts.
19Refit the securing bolt cover plugs to the
cowl panel.
20Refit the master cylinder to the servo, and
tighten the securing nuts to the specified
torque.
21Reconnect the vacuum pipe to the servo.
22Refit the coolant expansion tank, as
described in Chapter 3.
23Refit the windscreen wiper motor and
linkage as described in Chapter 12, then refit
the windscreen cowl panel.
24Further refitting is a reversal of removal.
On completion, test the operation of the
servo, as described in Section 18.
20ABS hydraulic modulator -
removal and refitting
4
Note: Refer to Section 2, and the note at the
beginning of Section 3, before proceeding
Removal
1Disconnect the battery negative lead.
2Remove the brake fluid reservoir cap, and
secure a piece of polythene over the filler
neck with a rubber band, or by refitting the
cap. This will reduce the loss of fluid during
the following procedure.
3Remove the securing screw, and withdraw
the plastic cover from the hydraulic
modulator.
4Remove the two clamp screws, and lift off
the modulator wiring harness clamp (see
illustration).
5Disconnect the modulator wiring plug,
levering it from the socket with a screwdriver if
necessary.6Unscrew the brake fluid pipe union nuts,
and disconnect the pipes from the modulator.
Be prepared for fluid spillage, and plug the
open ends to prevent dirt ingress and further
fluid loss. Move the pipes just clear of the
modulator, taking care not to strain them.
7Unscrew the three modulator securing nuts
(see illustration), then tilt the modulator
slightly, and withdraw it upwards from its
bracket, sufficiently to gain access to the
earth lead securing nut at the front lower edge
of the modulator.
8Unscrew the securing nut and disconnect
the earth lead, then withdraw the modulator
from the vehicle, taking care not to spill brake
fluid on the vehicle paintwork.
9If a new modulator is to be fitted, pull the
two relays from the top of the old modulator,
and transfer them to the new unit. No attempt
must be made to dismantle the modulator.
Refitting
10Before refitting the modulator, check that
the bolts securing the mounting bracket to the
body panel are tight, and that the modulator
rubber mountings are in good condition.
Renew the rubber mountings if necessary.
11Refitting is a reversal of removal,
remembering the following points.
12Make sure that the earth lead is
reconnected before fitting the modulator to its
mounting bracket.13On completion, remove the polythene
sheet from the brake fluid reservoir filler neck,
and bleed the complete brake hydraulic
system, as described in Section 3.
14Check that the ABS warning lamp
extinguishes when first starting the engine
after the modulator has been removed. At the
earliest opportunity, take the vehicle to a
Vauxhall dealer, and have the complete
system tested, using the dedicated ABS test
equipment.
21ABS wheel sensors - removal
and refitting
3
Note: Refer to Section 2 before proceeding
Front wheel sensor
Removal
1Disconnect the battery negative lead.
2Where applicable, remove the wheel trim,
then loosen the relevant front roadwheel bolts
and apply the handbrake. Jack up the front of
the vehicle, and support on axle stands (see
“Jacking and Vehicle Support”) positioned
under the body side members. Remove the
roadwheel.
3Unclip the sensor wiring connector from the
retaining clip under the wheel arch, then
separate the two halves of the wiring
connector, prising them apart with a
screwdriver if necessary (see illustration).
4Using a Allen key or hexagon bit, unscrew
the bolt securing the wheel sensor to its
mounting bracket, then carefully lever the
sensor from the bracket using a screwdriver
(see illustration). Recover the seal ring.
Refitting
5Examine the condition of the seal ring, and
renew if necessary.
6Refitting is a reversal of removal,
remembering the following points.
7Smear a little grease on the sensor casing
before fitting it to the bracket.
8Do not fully tighten the roadwheel bolts until
the vehicle is resting on its wheels.
9Check that the ABS warning lamp
extinguishes when first starting the engine
after a wheel sensor has been removed. At
9•16Braking system
20.4 ABS hydraulic modulator (cover
removed)
1 Wiring harness
clamp screws2 Earth lead
3 Relays
21.3 Front wheel sensor wiring under
wheelarch - DOHC model
1 ABS sensor connector
2 Disc pad wear sensor wiring connector
21.4 ABS front wheel sensor securing bolt
(arrowed) - DOHC model20.7 ABS hydraulic modulator securing
screws (arrowed)

the earliest opportunity, take the vehicle to a
Vauxhall dealer, and have the complete
system tested, using the dedicated ABS test
equipment.
Rear wheel sensor
Removal
10Disconnect the battery negative lead.
11Where applicable, remove the wheel trim,
then loosen the relevant rear roadwheel bolts
and chock the front wheels. Jack up the rear
of the vehicle, and support on axle stands
(see “Jacking and Vehicle Support”)
positioned under the body side members.
Remove the roadwheel.
12Unclip the sensor wiring connector from
the retaining clip on the rear underbody, then
separate the two halves of the wiring
connector, prising them apart with a
screwdriver if necessary (see illustration).
13Note the routing of the sensor wiring, and,
where applicable, release it from the clips on
the underbody.
14Using a Allen key or hexagon bit, unscrew
the bolt securing the wheel sensor to the
trailing arm (or the mounting bracket on
DOHC models), then carefully lever the sensor
from its location using a screwdriver (see
illustration). Recover the seal ring.
Refitting
15Proceed as described in paragraphs 5 to 9
inclusive.
22ABS electronic control
module - removal and refitting
3
Note: Refer to Section 2 before proceeding
ABS-2E systems
Removal
1Ensure that the ignition is switched off, then
disconnect the battery negative lead.
2The control module is located under a
cover in the passenger sill, to the left-hand
side of the seat.
3Extract the three securing screws, and lift
the cover from the control module. Note that
two of the screws are covered by plastic trim
plugs. 4Lift the control module from its recess, then
release the retaining clip and disconnect the
module wiring plug. Withdraw the module
(see illustrations).
Refitting
5Refitting is a reversal of removal.
6Check that the ABS warning lamp
extinguishes when first starting the engine
after the module has been removed. At the
earliest opportunity, take the vehicle to a
Vauxhall dealer, and have the complete
system tested, using the dedicated ABS test
equipment.
ABS-2EH systems
Removal
7Ensure that the ignition is switched off, then
disconnect the battery negative lead.
8Remove the cover from the hydraulic
modulator.
9Disconnect both the wiring harness and
solenoid valve connectors.
10Relays can only be removed from control
units that have slanted covers (see
illustration). The relays for the solenoid valve
and pump motor, if removable, can now be
removed. If the unit has a flat cover, and is
faulty, the whole unit will have to be replaced.
11Undo fixing bolts and remove the control
unit.
Refitting
12Refitting is a reversal of removal. Refer
also to paragraph 6.
23ABS relays (ABS-2E systems
only) - removal and refitting
2
Note: Refer to Section 2 before proceeding.
For ABS-2EH system relays, refer to
paragraphs 7 to 12, in Section 22.
Solenoid valve and pump motor
relays
Removal
1The solenoid valve and pump motor relays
are mounted on the hydraulic modulator.
2Disconnect the battery negative lead.
3Remove the securing screw and withdraw
the plastic cover from the hydraulic
modulator.
4Pull out the appropriate relay. The small
relay is for the solenoid valve, and the large
relay is for the pump motor.
Refitting
5Refitting is a reversal of removal.
6Check that the ABS warning lamp
extinguishes when first starting the engine
after a relay has been removed. At the earliest
opportunity, take the vehicle to a Vauxhall
dealer, and have the complete system tested,
using the dedicated ABS test equipment.
Surge arrester relay
Removal
7The surge arrester relay is located in the
relay box at the left rear of the engine
compartment.
Braking system 9•17
22.4A Lift out the ABS control module . . .22.10 ABS-2EH control unit
1 Slanted cover type 2 Flat cover type22.4B . . . and release the wiring plug
retaining clip - ABS-2E system
21.14 ABS rear wheel sensor (arrowed) -
DOHC model21.12 ABS rear wheel sensor wiring
connectors (arrowed) on rear underbody -
DOHC model`
9

8Disconnect the battery negative lead.
9Unclip the lid and open the relay box, then
pull out the relay (see illustration).
Refitting
10Refitting is a reversal of removal, with
reference to paragraph 6.
24Rear brake pressure-
proportioning valves -
removal and refitting
4
Note: Refer to the note at the beginning of
Section 3 before proceeding. Note also that
the valve must only be renewed in pairs, and
both valves must be of the same calibration.
Ensure that correct type of valves are fitted.
The bodies have been stamped for easier
identification.
Master cylinder-mounted valves
Removal
1Remove the brake fluid reservoir cap, and
secure a piece of polythene over the filler
neck with a rubber band, or by refitting the
cap. This will reduce the loss of fluid during
the following procedure.
2Locate a container beneath the master
cylinder, to catch the brake fluid that will be
released.
3Identify the two lower brake pipes for
position, then unscrew the union nuts and
disconnect the pipes from the proportioning
valves in the base of the master cylinder. Plug
the open ends of the pipes to prevent dirt
ingress.
4Unscrew the proportioning valves from the
master cylinder, and plug the open ends of
the cylinder to prevent dirt ingress.
Refitting
5Refitting is a reversal of removal, but on
completion, remove the polythene from the
brake fluid reservoir filler neck, and bleed the
complete hydraulic system, as described in
Section 3.
Rear underbody-mounted valves
Removal
6Proceed as described in paragraph 1.
7Chock the front wheels, then jack up the
rear of the vehicle, and support securely on
axle stands (see “Jacking and Vehicle
Support”) positioned under the body side
members.
8Working under the rear of the vehicle,
unscrew the union nut and disconnect the
brake pipe from one of the valves. Be
prepared for fluid spillage, and plug the open
end of the pipe to prevent dirt ingress and
further fluid spillage.
9Similarly, disconnect the flexible hose from
the valve.
10Pull the valve retaining clip from the
bracket on the underbody, noting that on
certain models, the retaining clip also secures
the ABS sensor wiring, and withdraw the valve
(see illustration).
11Repeat the procedure for the other valve.
Refitting
12Proceed as described in paragraph 5.
25Brake fluid pipes and hoses
- general, removal and refitting
4
Note: Refer to the note at the beginning of
Section 3, before proceeding.
General
1When checking the condition of the
system’s pipes and/or hoses, carefully check
that they do not foul other components such
as the power steering gear pipes (where
applicable), so that there is no risk of the
pipes chafing. If necessary use clips or ties to
secure braking system pipes and hoses well
clear of other components.
Rigid pipes
Removal
2Some of the commonly used brake pipes
can be obtained from Vauxhall parts dealers,
ready-formed and complete with unions, but
other brake pipes must be prepared using
4.75 mm (0.19 in) diameter brake pipe. Kits for
making the brake pipes can be obtained from
certain motor accessory shops.
3Before removing a brake pipe, remove the
brake fluid reservoir cap, and secure a piece
of polythene over the filler neck with a rubber
band, or by refitting the cap. This will reduce
the loss of fluid when the pipe is
disconnected.4Jack up the vehicle, and support securely
on axle stands (see “Jacking and Vehicle
Support”) positioned under the body side
members.
5To remove a brake pipe, unscrew the
unions at each end, and release the pipe from
the retaining clips.
Refitting
6Refitting is a reversal of removal, taking
care not to overtighten the unions.
7On completion, remove the polythene from
the brake fluid reservoir filler neck, and bleed
the relevant hydraulic circuit(s), as described
in Section 3.
Flexible hoses
Removal
8Proceed as described previously for the
rigid pipes, but note that a flexible pipe must
never be installed twisted, although a slight
“set” is permissible to give it clearance from
adjacent components.
Refitting
9When reconnecting a flexible hose to a
front brake caliper, note that the sealing rings
on the union bolt must be renewed.
26Handbrake - adjustment
2
Models with rear drum brakes
1The handbrake will normally be kept in
correct adjustment by the self-adjusting
action of the rear brake shoes. However, due
to cable stretch over a period of time, the
travel of the handbrake lever may become
excessive, in which case the following
operations should be carried out.
2Chock the front wheels, jack up the rear of
the vehicle, and support securely on axle
stands (see “Jacking and Vehicle Support”)
positioned under the body side members.
3Fully release the handbrake.
4Turn the knurled nut on the cable adjuster
(mounted on the torsion beam), until the brake
shoes can just be heard to rub when the rear
wheels are turned by hand in the normal
direction of rotation (see illustration).
9•18Braking system
23.9 ABS surge arrester relay (arrowed)
26.4 Handbrake cable adjuster. Knurled
nut arrowed - all SOHC models24.10 Brake pressure-proportioning valve
on rear underbody - DOHC model
1 Valve 2 Retaining clip

4B
cruising and accelerating. The injector earth is
also switched off on the overrun to improve
fuel economy and reduce exhaust emissions.
Additionally, on the X16 SZ engine, the ECU
also controls the operation of the charcoal
canister purge valve in the evaporative
emission control system.
10The oxygen sensor screwed into the
exhaust manifold provides the ECU with a
constant feedback signal. This enables it to
adjust the mixture (closed-loop control) to
provide the best possible conditions for the
catalytic converter to operate effectively.
11Until the oxygen sensor is fully warmed up
it gives no feedback so the ECU uses
pre-programmed values (open-loop control) to
determine the correct injector pulse width.
When the sensor reaches its normal operating
temperature, its tip (which is sensitive to
oxygen) sends the ECU a varying voltage
depending on the amount of oxygen in the
exhaust gases. If the inlet air/fuel mixture is too
rich, the exhaust gases are low in oxygen so the
sensor sends a low-voltage signal. The voltage
rises as the mixture weakens and the amount of
oxygen rises in the exhaust gases. Peak
conversion efficiency of all major pollutants
occurs if the inlet air/fuel mixture is maintained
at the chemically correct ratio for the complete
combustion of petrol of 14.7 parts (by weight) of
air to 1 part of fuel (the “stoichiometric” ratio).
The sensor output voltage alters in a large step
at this point, the ECU using the signal change
as a reference point and correcting the inlet
air/fuel mixture accordingly by altering the fuel
injector pulse width.
12In addition, the ECU senses battery
voltage, incorporates diagnostic capabilities,
and can both receive and transmit information
by way of the diagnostic connector, thus
permitting engine diagnosis and tuning by
Vauxhall’s TECH1, test equipment.
Motronic system
13The Motronic type is available in several
different versions, depending on model. The
system is under the overall control of the
Motronic engine management system (Chapter
5), which also controls the ignition timing.
14Fuel is supplied from the rear-mounted
fuel tank by an electric fuel pump mounted
under the rear of the vehicle, through a
pressure regulator, to the fuel rail. The fuel rail
acts as a reservoir for the four fuel injectors,
which inject fuel into the cylinder inlet tracts,
upstream of the inlet valves. On SOHC
engines, the fuel injectors receive an electrical
pulse once per crankshaft revolution, which
operates all four injectors simultaneously. On
DOHC engines, sequential fuel injection is
used, whereby each injector receives an
individual electrical pulse allowing the four
injectors to operate independently, which
enables finer control of the fuel supply to each
cylinder. The duration of the electrical pulse
determines the quantity of fuel-injected, and
pulse duration is computed by the Motronic
module, based on the information received
from the various sensors.15On SOHC engines, inlet air passes from
the air cleaner through a vane type airflow
meter, before passing to the cylinder inlet
tracts through the throttle valve. A flap in the
vane airflow meter is deflected in proportion
to the airflow; this deflection is converted into
an electrical signal, and passed to the
Motronic module. A potentiometer screw
located on the airflow meter provides the
means of idle mixture adjustment, by altering
the reference voltage supplied to the Motronic
module.
16On DOHC engines, inlet air passes from
the air cleaner through a hot wire type air
mass meter, before passing to the cylinder
inlet tracts through a two-stage throttle body
assembly. The electrical current required to
maintain the temperature of the hot wire in the
air mass meter is directly proportional to the
mass flow rate of the air trying to cool it. The
current is converted into a signal, which is
passed to the Motronic module. The throttle
body contains two throttle valves that open
progressively, allowing high torque at part
throttle, and full-throttle, high-speed
“breathing” capacity. A potentiometer screw
located on the air mass meter provides the
means of idle mixture adjustment, by altering
the reference voltage supplied to the Motronic
module.
17A throttle position sensor enables the
Motronic module to compute the throttle
position, and on certain models, its rate of
change. Extra fuel can thus be provided for
acceleration when the throttle is opened
suddenly. Information from the throttle
position sensor is also used to cut off the fuel
supply on the overrun, thus improving fuel
economy and reducing exhaust gas
emissions.
18Idle speed is controlled by a variable-
orifice solenoid valve, which regulates the
amount of air bypassing the throttle valve. The
valve is controlled by the Motronic module;
there is no provision for direct adjustment of
the idle speed.
19Additional sensors inform the Motronic
module of engine coolant temperature, air
temperature, and on models fitted with a
catalytic converter, exhaust gas oxygen
content.
20A fuel filter is incorporated in the fuel
supply line, to ensure that the fuel supplied to
the injectors is clean.
21A fuel pump cut-off relay is controlled by
the Motronic module, which cuts the power to
the fuel pump should the engine stop with the
ignition switched on, if there is an accident. All
1993-onwards models equipped with
Motronic systems, have their fuel pump
located inside the fuel tank.
22The later M2.8 system is basically the
same as the earlier M2.5 system apart from
the following:
a)Hot Film Mass Airflow Meter - The hot
wire type unit used previously is replaced
on the M2.8 system by a hot film mass
airflow meter. The operation is the sameexcept that a thin, electrically heated plate
rather than a wire is used. The plate is
maintained at a constant temperature by
electric current as the inlet air mass
passing over the plate tries to cool it. The
current required to maintain the
temperature of the plate is directly
proportional to the mass flow rate of the
inlet air. The current is converted to a
signal that is passed to the Motronic
module.
b)Inlet Air Temperature Sensor -The sensor
is located in the hose between the hot
film mass airflow meter and the air cleaner
for precise monitoring of inlet air
temperature. Signals from the sensor are
used in conjunction with other sensors to
indicate the occurrence of a hot start
condition. The Motronic module then
interprets these signals to alter injector
duration accordingly.
c)Throttle Valve Potentiometer -On the
M2.8 system a throttle valve
potentiometer replaces the throttle valve
switch used previously.
Simtec system
23An increased amount of electronic
components are used 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.
24The 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).
25The ignition coil is replaced by a dual
spark ignition coil, which is switched directly
by the output stages in the control unit.
26A 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.
27The ‘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.
28The air inlet temperature sensor (NTC), is
fitted in the air inlet duct between the air
cleaner and the hot mass air flow meter.
29A 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.
30A knock control system is also fitted. This
eliminates the need for octane number
adjustment, as it is performed automatically
through the control unit.
Fuel and exhaust systems - fuel injection models 4B•3

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.

9Fuel filter (‘Out-of-tank’ fuel
pump models) - removal and
refitting
3
Note: Refer to Section 2 before proceeding
Removal
1The fuel filter is located on the fuel pump
bracket under the rear of the vehicle. Either on
the right-hand side of the spare wheel well or
in front of the fuel tank, depending on model
(see illustrations).
2Disconnect the battery negative lead.
3Have a container to hand, to catch the fuel
that will be released as the filter is removed.
4Clamp the fuel hoses on either side of the
filter, to minimise fuel loss when the hoses are
disconnected.
5Loosen the clamp screws, and disconnect
the fuel hoses from the filter. Be prepared for
fuel spillage, and take adequate fire
precautions.
6Loosen the clamp bolt(s), and withdraw the
fuel filter from its bracket. Note the orientation
of the flow direction arrow on the body of the
filter, and the position of the “AUS” (out)
marking on the filter end face.
Refitting
7Refitting is a reversal of removal, ensuring
that the flow direction markings are correctly
orientated.
8Run the engine and check for leaks on
completion. If leakage is evident, stop the
engine immediately, and rectify the problem
without delay.
10Fuel filter (‘In-tank’ fuel
pump models) - removal and
refitting
3
Note: Refer to Section 2 before proceeding
Removal
1Depressurise the fuel system (Section 8).
2Chock the front wheels, jack up the rear of
the vehicle and support it on axle stands
placed under the body side members. (see
“Jacking and Vehicle Support”). The fuel filter
is located at the rear of the fuel tank, on the
right-hand side.3Unclip the fuel hose from the filter mounting
bracket.
4Note carefully any markings on the fuel filter
casing. There should be at least an arrow
(showing the direction of fuel flow) pointing in
the direction of the fuel supply hose leading to
the engine compartment. There may also be
the words “EIN” (in) and “AUS” (out)
embossed in the appropriate end of the
casing.
5Clamp the fuel filter hoses, then slacken the
clips and disconnect the hoses.
6Undo the single screw to release the
mounting bracket, then open the clamp with a
screwdriver to remove the fuel filter (see
illustration).
Refitting
7Fit the new fuel filter using a reversal of the
removal procedure, but ensure that the fuel
flow direction arrow or markings point in the
correct direction. Switch on the ignition and
check carefully for leaks; if any signs of
leakage are detected, the problem must be
rectified before the engine is started.
11Fuel pump - testing
2
Testing
1If the fuel pump is functioning, it should be
possible to hear it “buzzing” by listening
under the rear of the vehicle when the ignition
is switched on. Unless the engine is started,
the fuel pump should switch off after
approximately one second. If the noise
produced is excessive, this may be due to a
faulty fuel flow damper. The damper can be
renewed referring to Section 18, if necessary.
2If the pump appears to have failed
completely, check the appropriate fuse and
relay.
3To test the fuel pump, special equipment is
required, and it is recommended that any
suspected faults are referred to a Vauxhall
dealer.
12Fuel pump (‘Out-of-tank’ fuel
pump models) - removal and
refitting
3
Note: Refer to Section 2 before proceeding
Removal
1The fuel pump is located on a bracket
under the rear of the vehicle, either on the
right-hand side of the spare wheel well or in
front of the fuel tank on other models.
2Disconnect the battery negative lead.
3Have a container to hand, to catch the fuel
that will be released as the damper is
removed.
4Disconnect the wiring plug(s) from the fuel
pump (see illustration).
5Clamp the fuel hoses on either side of the
damper, to minimise fuel loss when the hoses
are disconnected.
6Loosen the clamp screws, and disconnect
the fuel hoses from the pump. Be prepared for
fuel spillage, and take adequate fire
precautions.
7Loosen the clamp bolt, and slide the pump
from its bracket.
Refitting
8Refitting is a reversal of removal, ensuring
that the pump is fitted the correct way round
in its bracket. Push the pump into the rubber
clamping sleeve as far as the rim on the pump
body (see illustration).
4B•6Fuel and exhaust systems - fuel injection models
9.1A Fuel filter (arrowed) - ‘out of tank’,
fuel pump models10.6 Fuel filter - ‘in tank’, fuel pump type
A Clamp screwB Hose clips
12.4 Disconnecting a fuel pump wiring
plug - ‘out of tank’, fuel pump model
9.1B Fuel component assembly - ‘out of
tank’, fuel pump models
1 Fuel filter
2 Fuel flow damper3 Fuel pump

4B
9Run the engine and check for leaks on
completion. If leakage is evident, stop the
engine immediately, and rectify the problem
without delay.
13Fuel pump (‘In-tank’ fuel
pump models) - removal and
refitting
3
Removal
1Depressurise the fuel system (Section 8),
then remove and refit the fuel filler cap to
ensure that the pressure is equalised inside
and outside the tank.
2Disconnect the battery negative terminal.
3Fold forwards the rear seat cushion. Peel
back the floor covering beneath it, then
remove the cover plug from the vehicle floor
to reach the pump mountings (see
illustration).
4Noting exactly how it is connected, and
making your own marks or notes to ensure
that it can be reconnected the same way
round, disconnect the wiring plug from the
pump.
5Release the securing clip and disconnect
the fuel hose from the pump. Clamp or plug
the hose to prevent the loss of fuel and the
entry of dirt.
6Undo the pump mounting bracket screws,
then withdraw the mounting bracket and
pump assembly from the tank. Note the
position of the sealing ring and discard it, then
cover the tank opening as a safety measure
and to prevent the entry of dirt.
7If the pump is to be renewed, first move it to
a clean working area and carry out the
following.
8Prise off the filter at the base of the pump
assembly, then release the securing clamp
and disconnect the mounting
bracket-to-pump fuel hose.
9Making your own marks or notes to ensure
that they can be reconnected the same way
round, unsolder the wires connecting the
pump to the mounting bracket.
10Press the pump out of the rubber sleeve.
Refitting
11Reassembly and refitting are the reverse
of the removal and dismantling procedures,
noting the following points.a)Ensure that the pump is seated correctly
in the sleeve and that the hose is securely
fastened.
b)Ensure that the wires are correctly
reconnected and securely soldered.
c)Always renew the pump mounting
bracket’s sealing ring.
d)Apply a few drops of sealing compound
(i.e. Vauxhall part no. 90485251) to the
threads of the screws, then tighten them
securely, but take care not to distort the
sealing ring.
14Fuel pump relay - renewal
2
The relay is mounted in the engine
compartment relay box (Chapter 12). Where
more than one relay is fitted, the fuel pump
relay is the one with the black base.
15Fuel tank filler pipe - removal
and refitting
3
Removal
1Syphon out any remaining fuel in the tank
into a clean container that is designed for
carrying petrol and is clearly marked as such.
2Raise the bottom edge of the seal
surrounding the filler neck and undo the single
securing screw beneath.
3Chock the front wheels, jack up the rear of
the vehicle and support it securely on axle
stands (see “Jacking and Vehicle Support”)
placed under the body side members.
4Unscrew the single filler pipe mounting bolt
from the underbody, then work along the
length of the pipe, cutting or releasing any
clips or ties securing other pipes or hoses to
it. Releasing their clips, disconnect the filler
and vent hoses from the pipe’s lower end and
the small-bore vent hoses from the unions at
its upper end.
5Having ensured that all components have
been removed or disconnected which mightprevent its removal, manoeuvre the pipe away
from the vehicle’s underside.
6To check the operation of the pipe’s
anti-leak valve, invert the filler pipe and fill the
lower union (now uppermost) with petrol. If
the valve is functioning correctly, no petrol will
leak from the other union. If petrol leaks from
the other union the valve is faulty and the
complete filler pipe must be renewed.
Refitting
7Refitting is the reverse of the removal
procedure, noting the following.
a)Check the condition of all hoses and
clips, renewing any components that are
found to be worn or damaged
b)When reconnecting the small-bore vent
hoses to the unions at the pipe’s upper
end, connect the hose from the charcoal
canister to the uppermost union and the
vent hose from the tank itself to the lower
union (see illustration).
c)Replacing any that were cut on removal
use the clips or ties provided to secure
any other pipes or hoses to the filler pipe.
d)Check carefully for signs of leaks on
refilling the tank; if any signs of leakage
are detected, the problem must be
rectified immediately.
16Fuel tank - removal and
refitting
4
Note: Refer to Section 2 before proceeding
Removal
SOHC models
1The procedure is similar as for models with
carburettors. Refer to Chapter 4A, however
note the following:
a)Depressurise the fuel system (Section 8).
b)On models with C16 NZ and X16 SZ
engines, disconnect the exhaust system
from the manifold.
c)When working on the fuel tank sender
unit, note that there is only one hose to be
disconnected.
Fuel and exhaust systems - fuel injection models 4B•7
15.7 Vent hose connections at fuel tank
filler pipe
A Charcoal canister hose
B Tank vent hose
13.3 Fuel pump - ‘in-tank’, fuel pump
model
A Wiring connector
B Fuel hose clampC Mounting bracket
screws
12.8 Fuel pump clamping sleeve should
rest against rim (arrowed)

d)Disconnect the fuel pump hose and wiring
as described in Section 12.
e)When releasing the tank mounting straps,
note that the fuel filter must either be
moved aside or removed completely,
whichever is most convenient
f)One of the fuel hoses connects to a pipe
in the side of the tank.
DOHC models
2Disconnect the battery negative lead.
3Siphon out any remaining fuel in the tank
through the filler pipe. Siphon the fuel into a
clean metal container that can be sealed.
4Chock the front wheels, then jack up the
rear of the vehicle, and support on axle stands
placed under the body side members (see
“Jacking and Vehicle Support”).
5Open the fuel filler flap, then pull back the
rubber seal to expose the fuel filler pipe
securing screw (see illustration). Remove the
screw.
6Release the fuel tank vent hoses from the
clips on the underbody.
7Support the weight of the fuel tank on a
jack, with an interposed block of wood.
8Unscrew the securing bolts from the tank
mounting straps. Then remove the straps and
lower the tank sufficiently to enable the fuel
hoses, vent hoses and fuel tank sender unit
wiring to be disconnected (see illustration).
9Disconnect the vent hoses and the fuel tank
sender unit wiring. Note the positions of the
vent hoses as an aid to refitting.
10Disconnect the fuel hoses from the tank and
the fuel tank sender unit, making a note of the
hose positions for use when refitting. Be
prepared for fuel spillage, and take adequate fire
precautions. Plug the open ends of the hoses, to
prevent dirt ingress and further fuel loss.
11Lower the fuel tank, and withdraw it from
under the vehicle.
12If the tank contains sediment or water, it
may be cleaned out using two or three rinses
with clean fuel. Shake vigorously using
several changes of fuel, but before doing so,
remove the fuel tank sender unit, as described
in Section 17. This procedure should be
carried out in a well-ventilated area, and it is
vital to take adequate fire precautions - refer
to the “Safety first!” Section at the beginning
of this manual for further details.
Refitting
13Any repairs to the fuel tank should be
carried out by a professional.
14Refitting is a reversal of removal, ensuring
that all hoses are reconnected to their correct
locations as noted during removal.
15On completion, fill the fuel tank, then run
the engine and check for leaks. If leakage is
evident, stop the engine immediately, and
rectify the problem without delay.
17Fuel tank sender unit -
removal and refitting
3
Note:Refer to Section 2 before proceeding
Removal
SOHC models
1Remove the fuel tank, (refer to Section 16),
if necessary. Note that there is only one hose
connected to the sender unit. This must also
be disconnected from the union on the inside
of the unit before it can be withdrawn
completely from the tank (see illustration).
DOHC models
2Remove the fuel tank, as described in
Section 16.
3Make alignment marks on the sender unit
and the fuel tank so that the sender unit can
be refitted in its original position.
4To remove the sender unit, an improvised
tool must be used which engages with thecut-outs in the sender unit retaining ring. The
Vauxhall special tool KM-673 for this purpose
is shown (see illustration).
5Withdraw the unit carefully, to avoid
bending the float arm.
6Recover the sealing ring.
Refitting
7Refitting is a reversal of removal,
remembering the following points.
8Renew the sealing ring.
9Ensure that the marks made on sender unit
and fuel tank before removal are aligned.
10Refit the fuel tank, (Section 16).
18Fuel flow damper - removal
and refitting
3
Note:Refer to Section 2 before proceeding
Removal
1The fuel flow damper is located on the fuel
pump bracket under the rear of the vehicle, on
the right-hand side of the spare wheel well or
in front of the fuel tank, depending on model
(see illustration). The damper is positioned in
the fuel feed line between the fuel pump and
the fuel filter, and its purpose is to reduce
pressure fluctuations in the fuel return line,
thus reducing noise levels.
2Disconnect the battery negative lead.
3Have a container to hand, to catch the fuel
that will be released as the damper is
removed.
4B•8Fuel and exhaust systems - fuel injection models
16.5 Fuel filler pipe securing screw
(arrowed) - models with semi-trailing arm
rear axles17.1 Fuel level sender unit - models with
semi-independent rear axles
18.1 Fuel flow damper - models with semi-
trailing arm rear axles17.4 Vauxhall special tool KM-673 for
removing fuel level sender units
16.8 Fuel tank mounting - models with
semi-trailing arm rear axles
1 Strap securing bolt 2 Vent hose securing