1988 OPEL VECTRA air condition

16 SV engine
Idle speed
Manual transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .925 ±25 rpm
Automatic transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .825 ±25 rpm (in ‘park’ or ‘neutral’)
Idle mixture (CO content) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.5 to 1.5%
Fast idle speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2000 to 2400 rpm
Choke valve gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 to 3.5 mm
Choke pull-down gap:
Up to 1990:
“Small” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.3 to 1.7 mm
“Large” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.9 to 2.3 mm
From 1990:
“Small” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 to 1.7 mm
“Large” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.0 to 2.2 mm
Idle fuel jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
Idle air bleed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132.5
PrimarySecondary
Venturi diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20.0 mm24.0 mm
Main jet:
Up to 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X95X105
From 1990 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X92.5X105
18 SV engine
Idle speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .925 ±25 rpm
Idle mixture (CO content) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.5 to 1.5%
Fast idle speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1900 to 2300 rpm
Choke valve gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 to 3.5 mm
Choke pull-down gap:
“Small” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.2 ±0.2 mm
“Large” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.3 ±0.2 mm
Idle fuel jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42.5
Idle air bleed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132.5
PrimarySecondary
Main jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107.5125
Torque wrench settingsNmlbf ft
Exhaust manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2216
Exhaust downpipe-to-manifold bolts . . . . . . . . . . . . . . . . . . . . . . . . . . .2518
Exhaust fixings except flexible joint bolts . . . . . . . . . . . . . . . . . . . . . . . .2518
Exhaust flexible joint bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129
Fuel pump bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1813
Fuel tank mounting strap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2015
Inlet manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2216
1General description
The fuel system on all carburettor models
comprises a fuel tank, a fuel pump, a vapour
separator (1.6 and 1.8 litre models only), a
downdraught carburettor, and a thermostati-
cally-controlled air cleaner.
The fuel tank is mounted under the rear of
the vehicle, forward of the rear suspension.
The tank is ventilated to the atmosphere, and
has a simple filler pipe and a fuel gauge
sender unit.
The fuel pump is a mechanical diaphragm
type, actuated by a pushrod bearing on the
camshaft.
The fuel vapour separator is used to
stabilise the fuel supply to the carburettor.
Vapour is purged from the carburettor fuel
supply, thus improving hot starting qualities.
The carburettor is a Pierburg 2E3 type, a full
description of which is given in Section 12.The air cleaner has a wax or vacuum-
controlled air inlet supplying a blend of hot
and cold air to suit the prevailing engine
operating conditions. A fuller description is
given in Section 4.
All engines available within the Cavalier
range can be operated on unleaded petrol -
see Chapter 5.
2Fuel system - precautions
1Certain adjustment points in the fuel system
are protected by tamperproof caps, plugs or
seals. In some territories, it is an offence to
drive a vehicle with broken or missing
tamperproof seals. Before disturbing a
tamperproof seal, check that no local or
national laws will be broken by doing so, and
fit a new tamperproof seal after adjustment is
complete, where required by law. Do not
break tamperproof seals on a vehicle that is
still under warranty.2When working on fuel system components,
scrupulous cleanliness must be observed,
and care must be taken not to introduce any
foreign matter into fuel lines or components.
Carburettors in particular are delicate
instruments, and care should be taken not to
disturb any components unnecessarily.
Before attempting work on a carburettor,
ensure that the relevant spares are available.
Full overhaul procedures for carburettors have
not been given in this Chapter. Complete
stripdown of a carburettor is unlikely to cure a
fault that is not immediately obvious, without
introducing new problems. If persistent
problems are met, it is recommended that the
advice of a Vauxhall dealer or carburettor
specialist is sought. Most dealers will be able
to provide carburettor re-setting and servicing
facilities, and if necessary it should be
possible to buy a reconditioned carburettor.
3Refer to Chapter 5, for precautions to be
observed when working on vehicles fitted with
an engine management system.
4A•2Fuel and exhaust systems - carburettor models

3Air cleaner - removal and
refitting
2
Removal
1Remove the air cleaner element, as
described in Chapter 1.
2Release the crankcase ventilation hose
from the plastic clip on the left-hand side of
the air cleaner body.
3Disconnect the inlet duct from the hot air
hose on the exhaust manifold (see
illustration), and lift the air cleaner body from
the carburettor.
4With the body tilted to the rear, disconnect
the crankcase ventilation hose from the stub
on the underside of the body (see
illustration).Where applicable, disconnect
the vacuum hose from the air temperature
control flap thermostat.
5Remove the seal from under the air cleaner
body.
Refitting
6Check the hot air hose for condition, and
renew it if necessary.
7Fit a new air cleaner body-to-carburettor
seal.
8Connect the crankcase ventilation hose to
the stub on the underside of the body, and
connect the vacuum hose for the air
temperature control flap.
9Locate the body on the carburettor, and at
the same time locate the inlet duct on the hot
air hose on the exhaust manifold.
10Engage the crankshaft ventilation hose in
the plastic clip.
11Refit the air cleaner element, referring to
Chapter 1 if necessary.
4Air cleaner inlet air
temperature control -
description and testing
3
Description
1The air cleaner is thermostatically-
controlled, to provide air at the most suitable
temperature for combustion with minimum
exhaust emission levels.
2The optimum air temperature is achieved
by drawing in cold air from an inlet at the front
of the vehicle, and blending it with hot airdrawn from a shroud on the exhaust manifold.
The proportion of hot and cold air is varied by
the position of a flap valve in the air cleaner
inlet spout, which is controlled by either a
vacuum diaphragm or wax-type unit. The
vacuum diaphragm type is regulated by a heat
sensor located within the air cleaner body
(see illustration).
Testing
3To check the operation of the air
temperature control, the engine must be cold.
First check the position of the flap valve. On
the vacuum type, remove the air cleaner cover
and check that the flap is open to admit only
cold air from outside the car. Then start the
engine and check that the flap now moves to
admit only hot air from the exhaust manifold.
On the wax type, the flap should already be
positioned to admit only hot air from the
exhaust manifold.
4Temporarily refit the cover on the vacuum
type.
5Run the engine until it reaches its normal
operating temperature.
6On the vacuum type, remove the air cleaner
cover and check that the flap is now
positioned to admit only cold air from outside
the car. In cold weather it should be a mixture
of hot and cold air. Refit the cover after
making the check. On the wax type, use a
mirror to check that the flap is positioned in
the same way as given for the vacuum type.
7If the flap does not function correctly, the
air cleaner casing must be renewed. Note that
the vacuum type thermostat can be renewed
separately if necessary.
5Fuel pump - testing
2
Note: Refer to Section 2 before proceeding
1Disconnect the ignition coil LT lead.
2Place a clean piece of rag under the pump
outlet, then disconnect the pump outlet hose.
Be prepared for fuel spillage, and take
adequate fire precautions.
3Have an assistant crank the engine on the
starter. Well-defined spurts of fuel must be
ejected from the pump outlet - if not, the
pump is probably faulty (or the tank is empty).
Dispose of the fuel-soaked rag safely.
4No spare parts are available for the pump,
and if faulty, the unit must be renewed.
6Fuel pump - removal and
refitting
3
Note: Refer to Section 2 before proceeding
Removal
1The fuel pump is located at the rear right-
hand end of the camshaft housing.
2Disconnect the battery negative lead.
3Disconnect the fuel hoses from the pump
(see illustration). If necessary, label the
hoses so that they can be reconnected to
their correct locations. Be prepared for fuel
spillage, and take adequate fire precautions.
Plug the open ends of the hoses to prevent
dirt ingress and further fuel spillage.
Fuel and exhaust systems - carburettor models 4A•3
3.4 Disconnecting the crankcase
ventilation hose (arrowed)
6.3 Disconnecting a fuel hose from the
fuel pump - 1.6 litre model4.2 Air cleaner flap valve operating
mechanism
1 Flap valve 2 Operating rod
3.3 The air cleaner body locates over the
hot air hose
4A
Warning: Many of the
procedures given in this
Chapter involve the
disconnection of fuel pipes and
system components, which may result in
some fuel spillage. Before carrying out
any operation on the fuel system, refer to
the precautions given in the “Safety first!”
Section at the beginning of this manual
and follow them implicitly. Petrol is a
highly dangerous and volatile substance,
and the precautions necessary when
handling it cannot be overstressed.

4Unscrew the two securing bolts, and
withdraw the pump from the camshaft
housing (see illustration).
5Recover the plastic insulating block.
Refitting
6Refitting is a reversal of removal, but ensure
that the fuel hoses are reconnected to their
correct locations as noted during removal,
and tighten the securing bolts to the specified
torque.
7Run the engine and check for leaks on
completion. If leakage is evident, stop the
engine immediately and rectify the problem
without delay. Note that the engine may take
a longer time than usual to start when the
pump has been removed, as the pump refills
with fuel.
7Fuel tank - removal,
examination and refitting
4
Note: Refer to Section 2 before proceeding
Removal
1Disconnect the battery negative lead.
2Siphon out any remaining fuel in the tank
through the filler pipe. Siphon the fuel into a
clean metal container that can be sealed.
3Chock the front wheels, then jack up the
rear of the vehicle, and support securely on
axle stands (see “Jacking and Vehicle
Support”) placed under the body side
members.
4Disconnect the exhaust system front
flexible joint. Suspend the front section of the
exhaust system with wire or string from the
underbody.
5Disconnect the rear section of the exhaust
system from its rubber mountings, and allow it
to rest on the rear suspension torsion beam. It
is advisable to support the rear section of the
exhaust at its front end, with wire or string
from the underbody, to avoid straining the
system.
6Unclip the handbrake cable from the
bracket on the left-hand fuel tank securing
strap.
7Disconnect the fuel hoses from the fuel
level sender unit located in the right-hand side
of the fuel tank. Make a note of the hosepositions 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.
8Disconnect the wiring plug from the fuel
level sender unit.
9Disconnect the filler and vent hoses from
the rear of the fuel tank.
10Support the weight of the fuel tank on a
jack with an interposed block of wood.
11Unscrew the securing bolts from the tank
mounting straps, then remove the straps and
lower the tank sufficiently to enable the
disconnection of the remaining vent hose.
12With the aid of an assistant, withdraw the
tank sideways from the right-hand side of the
vehicle. Note that as the tank is withdrawn,
some residual fuel may be released.
Examination
13If 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 level sender unit, as
described in Section 8. 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.
14Any repairs to the fuel tank should be
carried out by a professional. Do not under
any circumstances attempt to weld or solder a
fuel tank. Removal of all residual fuel vapour
requires several hours of specialist cleaning.
Refitting
15Refitting is a reversal of removal, ensuring
that all hoses are reconnected to their correct
locations as noted during removal.
16On 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. Note that
the engine may take a longer time than usual
to start when the fuel tank has been removed,
as the pump refills with fuel.
8Fuel level sender unit -
removal and refitting
3
Note: Refer to Section 2 before proceeding
Removal
1Disconnect the battery negative lead.
2Siphon out any remaining fuel in the tank
through the filler pipe. Siphon the fuel into a
clear metal container that can be sealed.
3Chock the front wheels, then jack up the rear
of the vehicle, and support securely on axle
stands (see “Jacking and Vehicle Support”)
placed under the body side members.
4The sender unit is located in the right-hand
side at the fuel tank.
5Make alignment marks on the sender unit
and the fuel tank, so that the sender unit can
be refitted in its original position.6Disconnect the fuel hoses from the sender
unit. 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.
7Disconnect the wiring plug from the fuel
level sender unit.
8To remove the sender unit, engage a flat
piece of metal as a lever between two of the
slots on the sender unit rim, and turn it anti-
clockwise.
9Withdraw the unit carefully, to avoid
bending the float arm.
10Recover the sealing ring.
Refitting
11Refitting is a reversal of removal,
remembering the following points.
12Examine the condition of the sealing ring,
and renew if necessary.
13Ensure that the marks made on the
sender unit and fuel tank before removal are
aligned.
14Ensure that the 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. Also check
that the fuel gauge reads correctly. If leakage
is evident, stop the engine immediately and
rectify the problem without delay. Note that
the engine may take a longer time than usual
to start when the sender unit has been
removed, as the fuel pump refills with fuel.
9Fuel vapour separator (1.6
and 1.8 litre models) -
removal and refitting
3
Note: Refer to Section 2 before proceeding
Removal
1The fuel vapour separator is located on a
bracket attached to the side of the
carburettor.
2Note the locations of the three fuel hoses,
labelling them if necessary for use when
refitting, then disconnect the hoses from the
vapour separator. Be prepared for fuel
spillage, and take adequate fire precautions.
Plug the open ends of the hoses, to prevent
dirt ingress and further fuel spillage.
3Remove the two securing screws, and lift
the vapour separator from its bracket.
4Check the body of the separator for cracks
or leaks before refitting, and renew if
necessary.
Refitting
5Refitting is a reversal of removal, but ensure
that the three fuel hoses are connected to
their correct locations as noted during
removal.
6Run the engine and check the hose
connections for leaks on completion. If
leakage is evident, stop the engine
immediately and rectify the problem without
delay.
4A•4Fuel and exhaust systems - carburettor models
6.4 Withdrawing the fuel pump and plastic
insulating block - 1.6 litre model

2A separate idle system operates
independently from the main jet system,
supplying fuel by way of the mixture control
screw.
3The main jets are calibrated to suit engine
requirements at mid-range throttle openings.
To provide the necessary fuel enrichment at
full throttle, a vacuum-operated power valve is
used. The valve provides extra fuel under the
low vacuum conditions associated with wide
throttle openings.
4To provide an enriched mixture during
acceleration, an accelerator pump delivers
extra fuel to the primary main venturi. The
accelerator pump is operated mechanically by
a cam on the throttle linkage.
5A fully automatic choke is fitted, operated
by a coolant and electrically heated bi-metal
coil. When the engine is cold, the bi-metal coil
is fully wound up, holding the choke plate
(fitted to the primary barrel) closed. As the
engine warms up, the bi-metal coil is heated
and therefore unwinds, progressively opening
the choke plate. A vacuum operated pull-
down system is employed, whereby, if the
engine is under choke but is only cruising (i.e.
not under heavy load) the choke plate is
opened against the action of the bi-metal coil.
The pull-down system prevents an over-rich
mixture, which reduces fuel economy and
may cause unnecessary engine wear when
the engine is cold. A secondary pull-down
solenoid is fitted, which operates in
conjunction with the main diaphragm unit to
modify the pull-down characteristics,
improving fuel economy.
61.8 litre models are fitted with an idle cut-off
solenoid. This is an electrically operated valve,
which interrupts the idle mixture circuit when
the ignition is switched off, this preventing
engine “run-on”.13Carburettor - removal,
overhaul and refitting
3
Note: Refer to Section 2 before proceeding.
New gasket(s) must be used when refitting the
carburettor. A tachometer and an exhaust gas
analyser will be required to check the idle
speed and mixture on completion
Removal
1Disconnect the battery negative lead.
2Remove the air cleaner, on early models.
On later models, disconnect the air trunking
from the air cleaner, then disconnect the
vacuum pipe and breather hose from the air
box. Extract the three securing screws and lift
off the air box, complete with air trunking.
3On 1.4 litre models, disconnect the fuel
supply hose from the carburettor, and on 1.6
and 1.8 litre models, disconnect the fuel
supply and return hoses from the vapour
separator. Be prepared for fuel spillage, and
take adequate fire precautions. Plug the ends
of the hoses, to prevent dirt ingress and
further fuel spillage.
4Extract the clip from the throttle cable end
fitting at the bracket on the carburettor, then
slide the cable end grommet from the bracket,
and slide the cable end from the throttle valve
lever.
5Disconnect the coolant hoses from the
automatic choke housing noting their
locations, as an aid to refitting. Be prepared
for coolant spillage, and plug the hoses, or
secure them with their ends facing upwards,
to prevent further coolant loss.
6Disconnect the vacuum pipes from the front
of the carburettor, noting their locations and
routing for use when refitting (see
illustration).
7Disconnect the choke heater wire and any
additional wiring.8Unscrew the three securing nuts, and
withdraw the carburettor from the inlet
manifold studs.
9Recover the gasket(s) and insulator block
that fit between the carburettor and the inlet
manifold.
Overhaul
10With the carburettor removed from the
vehicle, drain the fuel from the float chamber
and vapour separator (where applicable).
Clean the outside of the carburettor, then
remove the top cover (Section 15).
11Blow through the jets and drillings with
compressed air, or air from a foot pump - do
not probe them with wire. If it is wished to
remove the jets, unscrew them carefully with
well-fitting tools.
12Remove the fuel filter gauze from the inlet
union, refer to Section 21, for details. Vauxhall
recommend that it is renewed whenever the
carburettor is cleaned.
4A•6Fuel and exhaust systems - carburettor models
12.1B Side view of carburettor, showing automatic choke
housing (1), vapour separator (2) and secondary throttle valve
vacuum diaphragm (3)12.1C Side view of carburettor, showing secondary choke pull-
down solenoid (1) and power valve (2)
13.6 Disconnecting the air box vacuum
pipe from the carburettor - 1.6 litre model
Aerosol cans of carburettor
cleaner are widely available
and can prove useful in
helping to clean internal
passages of stubborn obstructions.

13Clean any foreign matter from the float
chamber. Renew the float, the float needle
valve and seat if wear is evident, or if the float
is punctured or otherwise damaged. Check
that the needle valve closes completely before
the float reaches the top of its movement. See
Section 15, for details of float level checking.
14Renew the diaphragms in the part-load
enrichment valve and in the accelerator pump.
If additional pump or valve parts are supplied
in the overhaul kit, renew these parts also.
15Further dismantling is not recommended.
Pay particular attention to the throttle opening
mechanism arrangement if it is decided to
dismantle it; the interlocking arrangement is
important.
16Reassemble in the reverse order to
dismantling. Use new gaskets and seals
throughout; lubricate linkages with a smear of
molybdenum based grease.
Refitting
17Carry out the following procedure before
refitting.
a)Position the fast idle adjustment screw on
the highest step of the fast idle cam.
b)Use a gauge rod or twist drill of the
specified diameter to measure the
opening of the primary throttle valve.
c)Adjust if necessary at the fast idle
adjustment screw.
d)Note that this is a preliminary adjustment;
final adjustment of the fast idle speed
should take place with the engine running.
18Refitting is a reversal of removal, but
renew the gasket(s).
19After refitting, carry out the following
checks and adjustments.
20Check the throttle cable free play and
adjust if necessary, as described in Section 11.
21Check and if necessary top-up the
coolant level, as described in Chapter 3.
22Check and if necessary adjust the idle
speed and mixture, as described in Section 14.
14Idle speed and mixture -
adjustment
3
Note: Refer to Section 2 before proceeding.
To carry out the adjustments, an accurate
tachometer and an exhaust gas analyser (CO
meter) will be required
1To check the idle speed and mixture
adjustment, the following conditions must be
met:
a)The engine must be at normal operating
temperature
b)All electrical consumers (cooling fan,
heater blower, headlamps, etc.) must be
switched off
c)The ignition timing and spark plug gaps
must be correctly adjusted - see Chapters
1 and 5
d)The throttle cable free play must be
correctly adjusted - see Section 11
e)The air inlet trunking must be free from
leaks, and the air filter must be cleanf)On automatic models, always select
position, “P”.
2Connect a tachometer and an exhaust gas
analyser to the vehicle, according to the
equipment manufacturer’s instructions.
3Start the engine, and run it at 2000 rpm for
approximately 30 seconds, then allow it to
idle. If the idle speed is outside the specified
limits, adjust by means of the throttle stop
screw (see illustration).
4When the idle speed is correct, check the
CO level in the exhaust gas. If it is outside the
specified limits, adjust by means of the idle
mixture adjustment screw. In production, the
screw is covered by a tamperproof plug;
ensure that no local or national laws are being
broken before removing the plug (see
illustration).
5On automatic models, when position “D” is
selected (all electrical systems switched off),
the idle speed should not drop perceptibly. If
it does, the vehicle should be taken to a
Vauxhall dealer for the idle-up system to be
checked using special Vauxhall test
equipment.
6With the idle mixture correct, readjust the
idle speed if necessary.
7If the cooling fan cuts in during the
adjustment procedure, stop the adjustments,
and continue when the cooling fan stops.
8When both idle speed and mixture are
correctly set, stop the engine and disconnect
the test equipment.
9Fit a new tamperproof plug to the idle
mixture adjustment screw, where this is
required by law.
15Needle valve and float -
removal, inspection and
refitting
4
Note: Refer to Section 2 before proceeding. A
new carburettor top cover gasket must be
used on reassembly. A tachometer and an
exhaust gas analyser will be required to check
the idle speed and mixture on completion
Removal
1Disconnect the battery negative lead.
2Remove the round air cleaner, on
applicable models. On other models,
disconnect the air trunking from the air
cleaner, then disconnect the vacuum pipe and
breather hose from the air box. Extract the
three securing screws and lift off the air box,
complete with air trunking.
3Thoroughly clean all external dirt from the
carburettor.
4Disconnect the fuel supply hose at the
carburettor. Be prepared for fuel spillage, and
take adequate fire precautions. Plug the end
of the hose, to prevent dirt ingress and further
fuel spillage.
5Identify the automatic choke coolant hose
locations as an aid to refitting, then
disconnect the hoses. Be prepared for
coolant spillage, and either plug the hoses, or
secure them with their ends facing upwards,
to prevent further coolant loss.
6Disconnect the choke heater wiring plug.
7Disconnect the lower vacuum hoses from
the choke pull-down unit.
8Remove the four carburettor top cover
securing screws, noting their locations, as two
lengths of screw are used (see illustration).
9Lift off the top cover and recover the
gasket.
Inspection
10Hold the cover vertically, so that the float
is hanging from its pivot. Then tilt the cover
until the float needle valve is just closed - the
needle spring must not be compressed by the
weight of the float.
11Measure the distance, dimension x (see
illustration),from the bottom of the float to
the gasket surface on the top cover’s
Fuel and exhaust systems - carburettor models 4A•7
15.8 Carburettor top cover securing
screws (arrowed)14.4 Tamperproof plug (arrowed) covering
idle mixture adjustment screw
14.3 Carburettor idle speed adjustment
(throttle stop) screw (arrowed)
4A

4If adjustment is necessary, release the
clamp screw and turn the cam plate in the
desired direction. Tighten the clamp screw,
and recheck the pump delivery (see
illustration).
Removal
5Proceed as described in Section 17,
paragraphs 1 and 2.
6Thoroughly clean all external dirt from the
area around the accelerator pump housing.
7Remove the four securing screws and lift off
the accelerator pump cover. Recover the
diaphragm, spring, valve retainer and valve.
Note the orientation of the valve retainer.
Refitting
8Clean the mating faces of the cover and
housing.
9Check the condition of the valve, and renew
if necessary.
10Begin refitting by locating the valve, valve
retainer and spring in the housing. Note that
the valve retainer can only be fitted in one
position. The larger diameter of the spring
should rest against the valve retainer.
11Locate the diaphragm on the housing,
ensuring that the spring is correctly seated,
and refit the cover. Tighten the cover securing
screws progressively to avoid distorting the
diaphragm (see illustration).
12Further refitting is a reversal of removal.
19Automatic choke unit -
removal, refitting and
adjustment
3
Note: Refer to Section 2 before proceeding. A
tachometer and an exhaust gas analyser will
be required to check the idle speed and
mixture on completion. If the coolant housing
is removed, new O-rings will be required for
refitting
Removal
1Proceed as described in Section 17,
paragraphs 1 and 2.
2Note the position of the bi-metal housing
alignment marks as an aid to refitting, if
necessary making additional marks for clarity,
then remove the three securing screws and lift
off the bi-metal housing. Place the housing to
one side, taking care not to strain the coolant
hoses or electric choke heater wiring.
3Remove the three screws securing the
choke housing to the carburettor body, and
withdraw the choke assembly, taking care not
to bend the choke operating rod.
4If it is necessary to remove the bi-metal
housing for renewal, continue as follows;
otherwise go on to paragraph 8.
5Identify the automatic choke coolant hose
locations as an aid to refitting, then
disconnect the hoses. Be prepared for
coolant spillage, and either plug the hoses, or
secure them with their ends facing upwards,
to prevent further loss of coolant.
6Disconnect the wiring from the electric
choke heater, and withdraw the bi-metal
housing.
7The coolant housing can be separated from
the bi-metal housing by unscrewing the
central securing bolt. Recover the O-rings
from under the bolt head, and from the rim of
the coolant housing.
Refitting
8Begin refitting by locating the choke
assembly on the carburettor body, ensuring
that the lever on the choke assembly engages
with the choke operating rod. Tighten the
three securing screws.
9Check and if necessary adjust the choke
valve gap and the fast idle cam position, as
described in paragraphs 15 to 19, of this
Section.10Connect the bi-metal spring to the choke
lever, position the bi-metal housing on the
choke housing, and loosely fit the securing
screws. Align the marks on the bi-metal
housing and the choke housing as noted
during removal, then tighten the securing
screws.
11Where applicable, refit the coolant
housing to the bi-metal housing, using new O-
rings if necessary, and reconnect the coolant
hoses and electric choke heater wiring.
12Further refitting is a reversal of removal,
remembering the following points.
13If the coolant hoses have been
disconnected, check the coolant level, as
described in Chapter 3.
14Check and if necessary adjust the fast idle
speed, as described in paragraphs 25 to 34,
of this Section.
Adjustment
Choke valve gap
15With the bi-metal housing removed as
described in paragraphs 2 to 4, of this
Section, continue as follows.
16Press the choke operating lever fully
clockwise, and retain it in position with a
rubber band.
17Move the throttle lever to the fully open
position, and measure the choke valve gap
between the lower side of the choke plate and
the wall of the primary barrel. Check that the
gap is as given in the Specifications.
18If necessary, adjust the choke valve gap
by bending the “adjuster segment (2)” If the
gap is too small, enlarge gap “B”, by levering
with a screwdriver. If the gap is too large,
decrease gap “B” using a pair of pliers (see
illustration).
19If no further adjustments are to be carried
out, refit the bi-metal housing, as described in
paragraphs 10 to 14, of this Section.
Fuel and exhaust systems - carburettor models 4A•9
18.11 Carburettor accelerator pump components
1 Cover with operating lever
2 Diaphragm
3 Spring4 Valve
5 Air passage
18.4 Accelerator pump delivery adjustment: “+” to
increase, “-” to reduce
4A

1General information and
precautions
The electrical system is of 12-volt negative
earth type. Power for the lights and all
electrical accessories is supplied by a
lead/acid type battery, which is charged by
the alternator.
This Chapter covers repair and service
procedures for the various electrical
components not associated with engine.
Information on the battery, alternator and
starter motor can be found in Chapter 5.
It should be noted that, before working on
any component in the electrical system, the
battery negative terminal should first be
disconnected, to prevent the possibility of
electrical short-circuits and/or fires.
Whenever the occasion arises, carefully
check the routing of the wiring harness,
ensuring that it is correctly secured by the
clips or ties provided so that it cannot chafe
against other components. Carefully check
points such as the clutch cable bracket,
clutch housing and harness support bracket,
the inlet manifold, the horn mounting bracket,
the starter motor terminals, and the rear
bumper and number plate lamp.
If evidence is found of the harness having
chafed against other components, repair the
damage and ensure that the harness is
secured or protected so that the problem
cannot occur again.
2Electrical fault-finding -
general information
Note:Refer to the precautions given in “Safety
first!” (at the beginning of this manual) and to
Section 1 of this Chapter before starting work.
The following tests relate to testing of the main
electrical circuits, and should not be used to
test delicate electronic circuits (such as anti-
lock braking systems), particularly where an
electronic control module is used.
A typical electrical circuit consists of an
electrical component, any switches, relays,
motors, fuses, fusible links or circuit breakers
related to that component, and the wiring and
connectors that link the component to boththe battery and the chassis. To help to
pinpoint a problem in an electrical circuit,
wiring diagrams are included at the end of this
Chapter.
Before attempting to diagnose an electrical
fault, first study the appropriate wiring
diagram, to obtain a complete understanding
of the components included in the particular
circuit concerned. The possible sources of a
fault can be narrowed down by noting
whether other components related to the
circuit are operating properly. If several
components or circuits fail at one time, the
problem is likely to be related to a shared fuse
or earth connection.
Electrical problems usually stem from
simple causes, such as loose or corroded
connections, a faulty earth connection, a
blown fuse, a melted fusible link, or a faulty
relay (refer to Section 3 for details of testing
relays). Visually inspect the condition of all
fuses, wires and connections in a problem
circuit before testing the components. Use
the wiring diagrams to determine which
terminal connections will need to be checked,
to pinpoint the trouble-spot.
The basic tools required for electrical fault-
finding include the following:
a)a circuit tester or voltmeter (a 12-volt bulb
with a set of test leads can also be used
for certain tests).
b)a self-powered test light (sometimes
known as a continuity tester).
c)an ohmmeter (to measure resistance).
d)a battery.
e)a set of test leads.
f)a jumper wire, preferably with a circuit
breaker or fuse incorporated, which can
be used to bypass suspect wires or
electrical components.
Before attempting to locate a problem with
test instruments, use the wiring diagram to
determine where to make the connections.
To find the source of an intermittent wiring
fault (usually due to a poor or dirty
connection, or damaged wiring insulation), a
“wiggle” test can be performed on the wiring.
This involves wiggling the wiring by hand, to
see if the fault occurs as the wiring is moved.
It should be possible to narrow down the
source of the fault to a particular section of
wiring. This method of testing can be used in
conjunction with any of the tests described in
the following sub-Sections.
Apart from problems due to poor
connections, two basic types of fault can
occur in an electrical circuit - open-circuit, or
short-circuit.
Open-circuit faults are caused by a break
somewhere in the circuit, which prevents
current from flowing. An open-circuit fault will
prevent a component from working, but will
not cause the relevant circuit fuse to blow.
Short-circuit faults are caused by a “short”
somewhere in the circuit, which allows the
current flowing in the circuit to “escape” along
an alternative route, usually to earth. Short-
circuit faults are normally caused by abreakdown in wiring insulation, which allows a
feed wire to touch either another wire, or an
earthed component such as the bodyshell. A
short-circuit fault will normally cause the
relevant circuit fuse to blow.
Finding an open-circuit
To check for an open-circuit, connect one
lead of a circuit tester or voltmeter to either
the negative battery terminal or a known good
earth.
Connect the other lead to a connector in
the circuit being tested, preferably nearest to
the battery or fuse.
Switch on the circuit, remembering that
some circuits are live only when the ignition
switch is moved to a particular position.
If voltage is present (indicated either by the
tester bulb lighting or a voltmeter reading, as
applicable), this means that the section of the
circuit between the relevant connector and
the battery is problem-free.
Continue to check the remainder of the
circuit in the same fashion.
When a point is reached at which no
voltage is present, the problem must lie
between that point and the previous test point
with voltage. Most problems can be traced to
a broken, corroded or loose connection.
Finding a short-circuit
To check for a short-circuit, first disconnect
the load(s) from the circuit (loads are the
components that draw current from a circuit,
such as bulbs, motors, heating elements, etc.).
Remove the relevant fuse from the circuit,
and connect a circuit tester or voltmeter to the
fuse connections.
Switch on the circuit, remembering that
some circuits are live only when the ignition
switch is moved to a particular position.
If voltage is present (indicated either by the
tester bulb lighting or a voltmeter reading, as
applicable), this means that there is a short-
circuit.
If no voltage is present, but the fuse still
blows with the load(s) connected, this indicates
an internal fault in the load(s).
Finding an earth fault
The battery negative terminal is connected
to “earth” (the metal of the
engine/transmission and the car body), and
most systems are wired so that they only
receive a positive feed. The current returning
through the metal of the car body. This means
that the component mounting and the body
form part of that circuit. Loose or corroded
mountings can therefore cause a range of
electrical faults, ranging from total failure of a
circuit, to a puzzling partial fault. In particular,
lights may shine dimly (especially when
another circuit sharing the same earth point is
in operation). Motors (e.g. wiper motors or the
radiator cooling fan motor) may run slowly,
and the operation of one circuit may have an
affect on another. Note that on many vehicles,
earth straps are used between certain
components, such as the engine/transmission
and the body, usually where there is no metal-
12•2Body electrical systems
Warning: Before carrying out
any work on the electrical
system, read through the
precautions given in “Safety
first!” at the beginning of this manual, and
in Chapter 5.
Caution:If the radio/cassette player fitted
to the vehicle is one with an anti-theft
security code, as the standard unit is, refer
to “Radio/cassette player anti-theft system
- precaution”in the Reference Section of
this manual before disconnecting the
battery.

12•22Body electrical systems
Explanations of abbreviations used in wiring diagrams
ABSAnti-lock braking system
ACAir conditioning
AZVTrailer hitch
ATAutomatic transmission
ATCAutomatic temperature control
BRTrip (on-board) computer
CCCheck control system
CRCCruise control
DDiesel
DSTheft protection
DTTurbo Diesel
DWAAnti-theft warning system
DZMTachometer
EFCElectric folding roof (Convertible)
EKSPinch guard (electric windows)
EMPRadio
EUREuronorm (emission control standard)
engine
EZ + ElPlus ignition system (with self-
diagnosis)
EZVEcotronic
FHElectric windows
GBGreat Britain
HSHeated rear window
HWRear window wiper
HZGHeating
HRLLuggage compartment lampINSInstrument panel
IRLCourtesy lamps
KATCatalytic converter
KBSWiring harness
KVContact breaker distributor
L3.1Bosch Jetronic fuel injection system
LCDLiquid crystal display (LCD)
instruments
LHDLeft-hand drive
4WDFour-wheel-drive
LWRHeadlamp aim adjustment
M1.5Bosch Motronic M1.5 engine
management system
M2.5Bosch Motronic M2.5 engine
management system
MOTMotronic (general)
MTManual gearbox
MULMultec fuel injection system
NNorway
NSFront foglamps
NSLRear foglamps
OELOil level/pressure check system
OPTOptional equipment
PBSLPark and brake shift block
(automatic transmission, selector
lever in position ‘P’)P/NPark/neutral (automatic transmission)
POTPotentiometer
RCRear suspension level control
system
RFSReversing lamps
RHDRight-hand drive
SSweden
SDSunroof
SHHeated seats
SRAHeadlamp washers and wipers
TANKFuel level sender unit
TDTurbo Diesel
TEMPTemperature gauge
TFLDaytime driving lamps
TKSCourtesy lamp (door pillar) switches
TSZITransistorised ignition (inductive-
triggered) system
VGSCarburettor
WEGOdometer frequency/roadspeed
sensor
WHRRear suspension level control
system
WSWarning buzzer
ZVCentral locking
ZYLCylinder
Colour codes
BLBlue
HBLLight blue
BRBrown
GEYellow
GRGrey
GNGreenRTRed
WSWhite
SWBlack
LILilac
VIViolet
Wiring identification
Example: GEWS 1.5
GE -Wire basic colour
WS -Wire tracer colour
1.5 -Wire cross-section in mm
2
Note: Not all items shown are fitted to all models. Refer to Section 62 (Chapter 12) for details of diagram usage.