check engine FIAT UNO 1983 Service Manual Online

adjustments described in this sub-Section,
however, will require removal of the
carburettor.
39Disconnect the short, curved diaphragm
hose from the top cover.
40Extract the top cover screws, lift the cover
from the carburettor body, and rotate it in
order to release the cranked choke control
rod from its key hole (photo). Mop out the fuel
and clean the jets.
41Check the jet sizes and other components
against those listed in the Specifications, in
case a previous owner has substituted
incorrect components (photo).
42Overhaul procedures are generally as
given in Chapter 3, Section 14 for the Weber
30/32 DMTR, but use the Specifications listed
in this Chapter. Additional overhaul
procedures are given here.
Fuel inlet needle valve
43If a high float level causing flooding of the
carburettor has been evident, first check that
the inlet valve housing is tight, and its washer
is sealing satisfactorily. A leak here will cause
fuel to bypass the inlet valve.
44If the needle valve is to be renewed,
remove it in the following way.
45Access to the fuel inlet needle valve is
obtained by carefully tapping out the float arm
pivot pin. Take care, the pivot pin pillars are
very brittle (photo).
46Unscrew the fuel inlet valve body and
remove the valve and washer.47When refitting the new valve, always use a
new sealing washer.
Float stroke (travel) - see Fig. 3.10
48The float stroke should be between 42.5
and 43.5 mm when measured from the top
cover gasket. Adjust if necessary by bending
the tab on the end of the arm.
Accelerator pump
49Adjustment of the accelerator pump is
very rarely required, but if performance is
suspect, carry out the following operations.
50Fill the carburettor float chamber and then
operate the throttle valve plate lever several
times to prime the pump.
51Position a test tube under the accelerator
pump jet and give ten full strokes of the
throttle lever, pausing between each stroke to
allow fuel to finish dripping.
52The total volume of fuel collected should
be as specified. Adjust the nut on the pump
control if necessary to increase or decrease
the volume of fuel ejected.
General
53When the stage is reached where the
valve plate spindle bushes have worn, then
the carburettor should be renewed complete.
54When reassembling the carburettor, use
new gaskets which can be obtained in a repair
pack.
Carburettor (Weber 32 ICEV
61/250 and DMTE 30/32,
DMTE 30/150) - general
55These carburettor types are fitted to later
models according to engine type. They are
similar in structure and operation to their
equivalents described in Chapter 3. Reference
can therefore be made to that Chapter for the
description and any operations concerning
them, but refer to Section 2 of this Chapter for
their specifications.
Carburettor (Solex
C 30/32-CIC 8) - description
56This carburettor is fitted as an alternative
to the Weber unit on 1116 cc models
produced for certain markets. The removal,
refitting and overhaul procedures are
essentially the same as described earlier for
the Weber carburettors.
PART C:
BOSCH LE2-JETRONIC
FUEL INJECTION SYSTEM
Description
Warning: Refer to the beginning
of this Section before starting
any work.
1The Bosch LE2-Jetronic fuel injection
system, fitted to the 1301 cc Turbo ie model,
is an electronically controlled multi-point
injection (MPi) system.
2The fuel injectors are fed at constant
pressure in relation to inlet manifold vacuum
pressure.
3The system electronic control unit (ECU)
actuates the injectors for variable duration,
and so supplies the precise volume of fuel
required for any given engine speed and load
condition.
4The ECU also monitors the air induction, air
temperature, coolant temperature and throttle
opening as additional parameters to compute
the required opening of the fuel injectors,
giving maximum power with fuel economy.
Fuel supply system
5The fuel supply system consists of an
electric pump and primary filter, located
adjacent to the fuel tank. A fuel pressure peak
damper is located next to the pump (photo).
6Fuel is then pumped through a filter to the
fuel rail and injectors. The injectors are of the
13•66 Supplement: Revisions and information on later models
9C.5 Electric fuel pump/filter/pressure
damper assembly location on a 1301 cc
Turbo ie model
9B.41 Jets on the Weber 30/32 DMTE
carburettor (top cover removed)
9B.45 Float pivot arrangement and needle
valve on the Weber 30/32 DMTE
carburettor
9B.40 Unscrewing a top cover screw from
the Weber 30/32 DMTE carburettor9B.37F Unscrewing a carburettor fixing nut

solenoid-operated type, actuated from the
ECU.
7Fuel pressure is regulated according to inlet
manifold vacuum pressure by a fuel pressure
regulator. Excess unpressurised fuel is
returned to the fuel tank.
Airflow meter
8This component measures the quantity of
air drawn into the engine, and converts this
into an electric signal which is transmitted to
the ECU.
9The intake air exerts a force on the floating
plate (1) (Fig. 13.39) which is connected to a
potentiometer (2).
10A compensating butterfly valve (3)
compensates for any reflex pressure which
may occur, and is subject to the braking effect
of the damper chamber (4).
11The idle mixture (air/fuel ratio) is altered by
means of the screw (8), which alters the
cross-section of the bypass channel (7).
12An integral-type temperature sensor is
fitted, the resistance value of which decreases
as the temperature of the intake air increases.
This facility is used to correct the mixture
strength within a pre-determined air
temperature range.
Throttle valve housing
13The housing incorporates a conventional
butterfly-type throttle valve, actuated by
cables and rods from the accelerator pedal.
14The idle bypass channel (2) (Fig. 13.40) is
fitted with an adjustment screw (3) to vary the
idle speed.
15The other screw (4) and locknut are usedto set the closing position of the throttle valve
plate.
Supplementary air valve
16This controls the air volume requirement
during cold starting. Essentially, the valve is an
electrically-heated bi-metallic strip, which rotates
the plate (4) (Fig. 13.41) to vary the volume of air
being drawn in through the aperture (1),
according to the temperature of the engine.
17The requirement for additional air during
cold starting is to dilute the additional fuel,
which is injected and controlled by the ECU
as a result of monitoring the engine coolant
temperature sensor.
Electrical control circuit
18The main components of the system are
the ECU and the system control relay. The
relay incorporates a fuel cut-off facility, which
cuts off the fuel supply in the event of engine
failure, the vehicle turning over, or a fuel line
breaking. The relay energises the following
electrical components.
19Coolant temperature sensor, which
signals the coolant temperature to the ECU.
20Throttle position switch, which signals the
ECU when the throttle valve plate is closed, in
order to actuate the deceleration fuel cut-off
device at speeds above 2500 rpm.21The switch also signals the ECU at full
throttle, so that the mixture can be enriched to
cope with full-power requirements.
22The system control relay also monitors the
engine speed directly from the ignition coil
primary winding.
MaintenanceÁ
23Regularly check the security of all system
hoses, wiring connections and plugs.
24At the intervals specified in Section 3,
renew the fuel filter and the air cleaner element.
Fuel filter - renewalÁ
25This is located within the engine
compartment just above the timing belt cover.
Disconnect the fuel hoses, but be prepared
for loss of fuel (photo).
26When fitting the new filter, make sure that
the arrow stamped on it is pointing towards
the fuel injector rail.
Air cleaner element -
renewal
Á
27Prise back the toggle-type clips and take
off the air cleaner lid. Remove and discard the
element, and wipe any dirt from the inside of
the casing (photos).
28Fit the new element and replace the lid.
Supplement: Revisions and information on later models 13•67
Fig. 13.41 Supplementary air valve -
1301 cc Turbo ie engine (Sec 9C)
1 Aperture
2 Bi-metallic strip
3 Passage
4 Rotating plate (closed position)Fig. 13.40 Sectional view of throttle valve
housing - 1301 cc Turbo ie engine (Sec 9C)
1 Butterfly-type throttle valve
2 Idle bypass channel
3 Idle speed adjusting screw
4 Throttle valve plate setting screwFig. 13.39 Sectional view of airflow meter -
1301 cc Turbo ie engine (Sec 9C)
1 Floating plate
2 Potentiometer
3 Compensating butterfly valve
4 Damper chamber
6 Spring
7 Bypass channel
8 CO adjusting screw
9 Tamperproof plug
Terminals
5, 7, 8, Potentiometer
9 Air temperature sensor
E Sealed (not to be touched)
9C.27A Removing the air cleaner lid9C.25 Secondary fuel filter
13

Idle speed and mixture
adjustment¢
29Before carrying out any adjustments, the
engine must be at operating temperature, the
fan having cut in at second speed and then
switched off.
30Release the locknut and turn the main idle
speed screw in the throttle valve housing until
the engine idles at the specified speed. This
should be all that is necessary to obtain the
correct idle speed, as the throttle valve plate
base setting is set during production.
However, if wear has taken place, or incorrect
adjustment has been carried out previously,
proceed in the following way.
31Disconnect the intake duct from the
throttle valve housing. Release the locknut on
the base (small) adjusting screw, and turn thescrew until there is a clearance between the
lower edge of the throttle valve plate and the
throat wall of between 0.05 and 0.1 mm
(photos).
32With the engine still at operating
temperature, start the engine, and having
released the locknut, turn the main (large) idle
speed screw fully clockwise to close the
bypass passage.
33Now turn the base (small) screw until the
engine idles at between 700 and 800 rpm.
Tighten the locknut.
34Finally, turn the main (large) adjusting
screw to give an idle speed of between 800
and 900 rpm.
35It is unlikely that the mixture will require
alteration, but if it does, connect an exhaust
gas analyser to the car in accordance with the
equipment manufacturer’s instructions.
36With the engine at operating temperature,
prise out the tamperproof cap, and turn the
mixture screw, which is located in the airflow
meter, until the CO level is as given in the
Specifications. Turning the screw clockwise
richens the mixture, turning it anti-clockwise
weakens the mixture. Use a close-fitting Allen
key for the adjustment (photo).
Fuel injection system -
electrical testsª
37When carrying out checks to trace a fault
in the system, an ohmmeter should be used
for the following tests.
38Disconnect the multipin connector from
the ECU, and also the one from the system
control relay, and apply the probes of the
ohmmeter in accordance with the following
sequence to check for continuity in thecables. The component wiring plug will of
course be disconnected for the test.
ECU connector Component connector
plug terminal plug terminal
1 1 of ignition coil
2 2 of throttle position
switch
3 3 of throttle position
switch
4 50 of ignition switch
5 Earth
5 5 of airflow meter
7 7 of airflow meter
8 8 of airflow meter
9 9 of airflow meter
9 9 of throttle position
switch
9 18 of supplementary air
valve
9 87 main relay socket
10 10 of coolant temperature
sensor
12 Injector terminals
13 Earth
System control Component connector
relay connector plug terminal
plug terminal
1 1 of ignition coil
15 15 of ignition switch
30 Battery positive
31 Earth
50 50 of ignition switch
87 Injector terminals
87 18 of throttle position
switch
87 9 of ECU multipin socket
87b Fuel pump (fused)
13•68 Supplement: Revisions and information on later models
Fig. 13.42 ECU and component connector plug terminals - 1301 cc Turbo ie engine (Sec 9C)
For colour code see main wiring diagrams
9C.31C Checking throttle valve plate
opening with a feeler blade
9C.36 Using an Allen key to adjust the
mixture (CO level)
9C.31B Idle speed base setting screw (1)
and main adjustment screw (2)9C.31A Disconnecting the throttle valve
housing intake duct9C.27B Removing the air cleaner element

39Now use the ohmmeter to check the
resistance of the following components.
Supplementary air valve
40Resistance between the terminals should
be between 40 and 60 ohms at 20ºC (68ºF).
Airflow meter
41Resistance between terminals 5 and 8 of
the potentiometer should be between 330 and
360 ohms at 20ºC (68ºF).
42Resistance between terminals 8 and 9 of
the internal circuit should be between 190 and
210 ohms at 20ºC (68ºF) and between 170
and 190 ohms at 60ºC (140ºF).
Coolant temperature sensor
43At 20ºC (68ºF) the resistance should be
between 2 and 4 k ohms. At 50ºC (122ºF) the
resistance should be between 600 and
900 ohms. At 90ºC (194ºF) the resistance
should be between 100 and 300 ohms.
Fuel injectors
44The winding resistance should be
between 15 and 17 ohms at 20ºC (68ºF).
Throttle position switch
45With the throttle butterfly valve closed,
there should be continuity between ter-
minals 18 and 2, and with the valve fully open,
there should be no continuity between
terminals 18 and 3.
46The throttle position switch should not be
disturbed unless absolutely necessary. If it
has to be removed, then refit it so that themicroswitch is heard to click immediately the
throttle butterfly is opened.
Fuel injection system -
mechanical tests ª
Fuel pump
47To test the pressure of the fuel pump, a
pressure gauge will be required, connected
into the fuel delivery hose.
48Remove the multipin plug from the system
control relay and bridge terminals 87b and 30.
49Turn the ignition switch on. The pump
should operate and indicate a pressure of
between 2.8 and 3.0 bars (40 and 44 lbf/in
2).
50To check the operation of the peak
pressure regulator, pinch the fuel return hose.
If the fuel pressure increases, the regulator
must be faulty, and should be renewed.
51Check that the fuel pressure increases
when, with the engine idling, the accelerator is
depressed sharply.
Supplementary air valve
52With the engine at normal operating
temperature and idling, pinch the
supplementary air valve hose using a pair of
pliers. The engine speed should not drop by
more than 50 rpm. If it does, renew the valve.
Fuel injection system
components -
removal and refitting
ª
53Disconnect the battery before carrying out
any of the following operations.
Air cleaner
54Remove the cover and filter element as
previously described.
55Disconnect the duct from the air cleaner
casing, and then unbolt and remove the
casing. Note that the lower bracket bolt need
not be completely removed, only unscrewed,
due to the design of the bracket. The air
cleaner metal duct is routed over the top of
the radiator (photos).
Airflow meter
56Release the securing clip and disconnect
the air intake duct (photo).
57Release the securing clip and disconnect
the air outlet duct (photo).
58Disconnect the wiring plug.
59Unscrew the fixing screws and remove
the airflow meter from its mounting bracket.
Supplement: Revisions and information on later models 13•69
9C.55B Removing the air cleaner casing
upper bracket9C.55A Disconnecting the duct from the air
cleanerFig. 13.43 System control relay connector
plug terminals 1301 cc Turbo ie engine
(Sec 9C)
9C.57 Air outlet duct securing clip removal
from airflow meter
9C.55C Air cleaner casing lower bracket
and bolt (arrowed)
9C.56 Air intake duct at airflow meter
(securing clip arrowed)9C.55D Air cleaner metal duct over
radiator
13

PART D:
BOSCH MONO-JETRONIC
FUEL INJECTION SYSTEM
Warning: Refer to the beginning
of this Section before starting
any work.
Description
1The Bosch Mono-Jetronic fuel injection
system fitted to the 1372 cc ie engine and
later 999/1108 ‘FIRE’ models is an electroni-
cally-controlled single point injection (SPi)
system. The SPi system is a compromise
between a conventional carburettor fuel
supply system and a multi-point fuel injection
(MPi) system.
2Compared with a conventional carburettor,
the SPi unit is a relatively simple device. Fuel
is pumped to the SPi unit and then injected
into the inlet system by a single solenoid valve
(fuel injector), mounted centrally on top of the
unit. The injector is energised by an electrical
signal sent from the electronic control unit
(ECU), at which point the injector pintle is
lifted from its seat and atomised fuel is
delivered into the inlet manifold under
pressure. The electrical signals take two forms
of current; a high current to open the injector
and a low current to hold it open for the
duration required. At idle speed the injector
is pulsed at every other intake stroke rather
than with every stroke as during normal
operation.
3The air-to-fuel mixture ratio is regulated by
values obtained from the ignition coil (engine
speed), engine coolant temperature sensor,
throttle position switch, and the Lambda
sensor in the exhaust system. No adjustments
to the fuel mixture are possible.
4The throttle position switch enables the
ECU to compute both throttle position and its
rate of change. Extra fuel can then be
provided for acceleration when the throttle is
suddenly opened. Throttle position
information, together with the idle tracking
switch, provide the ECU with the closed
throttle position information.
5The 1372 cc ie system layout and principal
components are shown in Figs. 13.44 and13.45. Note that the Digiplex 2 electronic
ignition, is not fitted to FIRE models
(999/1108 cc).
6The fuel system pump is immersed in the
fuel tank and forms a combined unit with the
fuel level sender unit. A cartridge type in-line
fuel filter is fitted to the fuel line, and is located
in the engine compartment.
7The fuel pressure in the system is
controlled by a mechanical diaphragmregulator in the injection unit turret. High
pressure in the system causes the diaphragm
to operate and excess fuel is returned to the
fuel tank.
8The air intake temperature and volume is
regulated to ensure the correct mixture ratio
under all operating conditions. The
temperature of the air passing through the
injection unit is measured by a sensor which
transmits such information to the ECU for the
Supplement: Revisions and information on later models 13•73
9C.101 Fuel tank anti-blow-back
compartment (arrowed)9C.99D Throttle cable balljoint retaining
spring clip (arrowed)9C.99C Throttle cable nipple (arrowed) in
throttle linkage cut-out
Fig. 13.44 Bosch Mono-Jetronic fuel injection system components and layout on the
1372 cc ie engine (Sec 9D)
1 Fuel pump relay
2 Injection system relay
3 Fuel pump fuse
4 Ignition coil
5 Digiplex 2 ECU
6 Battery
7 Idle speed check actuator
8 Injector connector9 Fuel pressure regulator
10 Injector
11 Throttle position switch
12 Ignition switch
13 Coolant temperature
sensor
14 Engine speed and TDC
sensor15 Secondary fuel filter
16 Fuel supply pipe
17 Fuel return pipe
18 Diagnostic socket
19 Fuel injection ECU
20 Fuel pump/level sender
unit13

necessary processing (photo). A conventional
paper type air filter element is used and this
must be renewed at the specified intervals.
9The ECU is specific to the model type, its
function being to control the fuel system
under all operating conditions, including
starting from cold - it richens the fuel mixture
as required but at the same time prevents
flooding. As the engine temperature rises, the
injection impulses are progressively reduced
until the normal operation temperature is
reached.
10An integral emergency system enables
the fuel injection system to remain operational
in the event of any of the following
components malfunctioning. These items are
the coolant temperature sensor, the air intake
sensor, the Lambda sensor, the idle speed
check actuator and the throttle position
switch. In the event of the throttle position
switch malfunctioning, the fuel system
becomes automatically inoperative.
11The catalytic converter fitted in the
exhaust system minimises the amount of
pollutants which escape into the atmosphere.
The Lambda sensor in the exhaust system
provides the fuel injection system ECU with
constant feedback which enables it to adjust
the mixture to provide the best possible
conditions for the converter to operate. The
fuel tank ventilation is contained within the
system. This is done by feeding any excess
vapours through a carbon filter back into the
engine intake, using solenoids and valves, as
shown in Fig. 13.46.
MaintenanceÁ
12Regularly check the condition and
security of the system hoses and
connections. Also check the system wiring
connections for condition and security.
13At the specified intervals, renew the air
cleaner element and the fuel filter.
Fuel filter - renewalÁ
14The in-line fuel filter is secured to the
right-hand suspension turret in the engine
compartment. To remove the filter, first
depressurize the fuel in the system as
described later in this Part.
13•74 Supplement: Revisions and information on later models
Fig. 13.46 Fuel evaporation control system (Sec 9D)
1 Fuel tank
2 Two-way safety valve
3 Throttle body4 Two-way vapour vent
valve
5 Vapour cut-off solenoid6 Carbon filter
7 Elbi solenoid
8 ECU
9D.8 Atmospheric air intake for air
temperature sensor (1). Also shown are the
supply and return fuel line connections (2
and 3) and the throttle position sensor (4)
Fig. 13.45 Mono-Jetronic fuel injection component locations in the engine compartment
- 1372 cc ie engine (Sec 9D)
1 Injector resistor
2 Lambda sensor signal connector
3 Lambda sensor heating connector
4 Secondary fuel filter
5 Fuel return pipe
6 Fuel supply pipe
7 Coolant temperature sensor
8 ECU9 Injector holder turret
10 Lambda sensor
11 Nut for adjusting accelerator cable
12 Engine speed and TDC sensor connector
13 Ignition control unit
14 Ignition coil
15 Diagnostic socket
16 Fuel pump relay and system relay

15Undo the retaining strap bolt and
withdraw the filter from its location bracket.
Disconnect the inlet and supply hose from the
filter. If crimp connectors are fitted they will
have to be cut free and new screw type clips
fitted (photo).
16Connect the hoses to the new filter
ensuring that the filter is correctly orientated
(the arrow mark on the body indicates the
direction of fuel flow). Ensure that the hose
clips are secure before refitting the filter into
the retaining strap and securing the retaining
bolt. When the engine is restarted, check the
hose connections to ensure that there is no
fuel leakage from them.
Air cleaner element -
renewalÁ
17Release the spring clip each side at the
front of the air cleaner, then unscrew and
remove the two screws from the top front face
of the housing. Withdraw the end cover and
element from the filter unit (photos).18Wipe any dirt from within the casing then
locate the new element and refit it together
with the end cover.
Idle speed and mixture
adjustment°
19No manual idle speed and/or mixture
adjustments to this type of fuel system are
necessary or possible. Any such adjustments
are automatically made by the ECU. If the
engine idle speed and/or mixture adjustment
is suspect, it must be checked using CO
measuring equipment; a task best entrusted
to a FIAT dealer or a competent garage. The
most probable cause of a malfunction is likely
to be a defective sensor or incorrectly
adjusted accelerator control cable.
Accelerator control system
- check and adjustment#
20To check the adjustment of the
accelerator control system, it is essential thatthe engine is at its normal operating
temperature. This is achieved by running the
engine for a period of about fifteen minutes,
by which time the cooling fan should have cut
into operation several times. At this point,
stop the engine, turn the ignition key to the
OFF position and proceed as follows.
21Remove the air cleaner unit.
22Place a 10 mm shim (X) between the
adjustment screw and the cam lever (between
items 1 and 2 in Fig. 13.47), on the throttle
body. This will open the thottle butterfly by
20º.
23Loosen off the locknuts (C1 and C2) from
each linkage end. Insert another 10 mm
shim (Y) between the cable support bracket
and the nut (C1). Carefully tighten the nut
against the shim, ensuring that the cam does
not move whilst making the cable slightly taut.
24Remove the shim (Y) and carefully tighten
the nut (C2) against the bracket without
allowing the nut (C1) to move. Remove the
shim (X) and release the accelerator pedal.
Check that the butterfly is completely open
when the the pedal is fully depressed.
Fuel system
depressurisationÁ
Warning: Refer to the beginning
of this Section before starting
any work.
25The fuel system should always be
depressurised whenever any fuel hoses
and/or system components are disconnected
and/or removed. This can easily be achieved
as follows.
Supplement: Revisions and information on later models 13•75
9D.17B . . . remove the cover and extract
the element9D.17A Release the air cleaner end cover
retaining clips . . .9D.15 Secondary fuel filter element
9D.22 Accelerator control rod and cable
connections
A Cable
B Bracket
C1 Locknut
C2 Locknut
D PulleyE Pawl
H Protection
K Pedal
R BushX Shim
Y Shim
1 Adjustment screw
2 Cam lever
13
Fig. 13.47 Accelerator linkage and butterfly control lever - SPi models (Sec 9D)

26Loosen off the knurled retaining nut and
remove the cover from the fuel pump relay.
This is located on the left-hand suspension
turret in the engine compartment (photo).
27Carefully pull free the fuel pump relay,
then start the engine and run it until it stops
(photo). The fuel system is now
depressurised. Turn the ignition off before
removing/dismantling any components.
28Do not refit the fuel pump relay or turn the
ignition on until the system is fully
reconnected. When the engine is ready to be
restarted, refit the relay and its cover, then
restart the engine in the normal manner.
Fuel pump and supply
system checks°
29Specialised equipment is required to
undertake accurate tests in the fuel supply
system and such checks must therefore be
entrusted to a FIAT dealer or a fuel injection
specialist. If the fuel pump is suspected of
malfunction, a basic check can be made by
removing the fuel filler cap then listening
through the filler pipe, get an assistant to turn
on the ignition whilst you listen to hear if the
pump is heard to operate in the tank. If the
pump fails to operate, check that the pump
fuse is sound and that its connection (and
also that of the relay) are clean and secure.
30The pump can be further checked by first
depressurising the fuel system as described in
the previous sub-Section, then disconnect the
fuel supply pipe at the injector unit and locateit in a suitable container. With the fuel pump
relay removed, connect up a suitable test lead
with a 7.5 amp (10 amp on models with
catalyst) fuse, in series, to the relay terminals
30 and 87, and check that fuel flows into the
container from the supply pipe (photo). If a
suitable pressure gauge is available for
connecting into the fuel line between the
engine compartment fuel filter and the
injection unit, check that the fuel pressure is
as specified at the beginning of this Chapter.
31If the pump fails to operate, check that the
battery is in good condition and that the pump
wiring connections are clean and secure
before condemning the pump. To remove the
pump unit from the fuel tank, proceed as
described in the following sub-Section.
Fuel pump -
removal and refittingÁ
32Release the pressure from the fuel system
as described previously.
33Move the front seats forward, then tilt the
rear seat cushions forward. Peel back the
luggage area floor cover from the right-hand
side towards the centre to expose the access
cover above the pump/sender unit in the floor.
Remove the access cover.
34Detach the wiring connectors from the
pump unit and the fuel level sender unit.
35Loosen off the hose retaining clips and
detach the fuel supply and return hoses from
the pump unit connections. Mark the hosesfor identity to avoid incorrect attachment
during refitting.
36Unscrew the retaining nuts then carefully
lift out and withdraw the fuel pump/level
sender unit from the fuel tank.
37Refitting is a reversal of the removal
procedure. A new seal gasket must be used
and it is important to ensure that all
connections are securely and correctly made.
Injector unit -
removal and refittingÁ
38Depressurise the fuel system as
described previously, then disconnect the
battery negative lead.
39Remove the air cleaner unit and the
rubber seal (photo).
40Disconnect the engine idle speed check
actuator lead and the throttle position switch
lead from the side faces of the injector unit.
41Undo the retaining clips and detach the
fuel supply and return hose from the injector
unit. If crimped type retaining clips are fitted,
they will have to be carefully cut free and new
screw type clips obtained to replace them.
Take care not to cut into the hoses when
releasing the crimped type clips.
42Detach the crankcase ventilation hose
from the fuel injector unit.
43Disconnect the accelerator linkage at the
throttle lever on the injector unit.
44Undo the four retaining screws and lift the
injector unit from the inlet manifold. Remove
the gasket (photo).
45Clean the injector unit and the inlet
manifold mating faces.
46Refit in the reverse order of removal.
Intake air temperature
sensor - removal and
refitting
Á
47The air temperature sensor is located in
the top of the injector unit. It is basically a
resistor which varies its value in accordance
with the air temperature entering the induction
circuit from the air filter. The sensor can then
transmit the registered air temperature at this
point to the ECU temperature sensor (2).
48Remove the air cleaner unit and its
mounting bracket in the injector.
49Disconnect the wiring connector from the
13•76 Supplement: Revisions and information on later models
9D.44 Injector unit retaining screws
(arrowed)9D.39 Removing the filter seal from the
injector unit
9D.30 Test lead connected to relay
terminals 30 and 879D.27 Fuel pump relay removal9D.26 Fuel pump relay (1), injection control
relay (2), Lambda sensor fuse (3) and pump
fuse (4) with cover (5) removed

air temperature sensor. Undo the retaining
screw and remove the sensor from the
injector unit (photo).
50Refit in the reverse order of removal.
Fuel injector -
removal and refittingÁ
51Depressurise the fuel system as
described previously, then disconnect the
battery negative lead.
52Remove the air cleaner unit.
53Release the injector feed wiring mutliplug
and detach it from the injector.
54Bend over the locking tabs retaining the
injector screws, then undo and remove the
screws. Withdraw the injector retaining collar,
then carefully withdraw the injector (noting its
orientation) followed by its seal.
55Refit in the reverse order of removal.
Always use new seals in the unit and the
retaining collar and lightly lubricate them with
clean engine oil prior to assembly. Take care
not to damage the seals when fitting and also
when the injector is fitted; check that it
engages correctly.
Fuel injection electronic
control unit (ECU) -
removal and refitting
Á
56The control unit is located under the facia
on the driver’s side of the vehicle. Commence
by disconnecting the battery negative lead.
57To gain access to the control unit, detach
and remove the trim panel from the underside
of the facia on the driver’s side of the car.
58Disconnect the wiring multiplug from the
control unit, then undo the retaining screw
and remove the unit from the car (photos).
59Refit in the reverse order of removal.
Inlet manifold -
removal and refittingÁ
60Remove the fuel injector unit as described
previously.
61Drain the cooling system as described in
Section 8 of this Chapter.
62Detach the coolant hose and coolant
temperature sensor from the inlet manifold.
63Unbolt and remove the accelerator
cable/throttle linkage support bracket from
the top of the inlet manifold. The cable can be
left attached to the bracket.64Detach the brake servo vacuum hose
from the connector on the manifold.
65Unscrew and remove the inlet manifold
securing bolts and nuts and remove the
manifold from the cylinder head. As they are
removed, note the location of the fastenings
and their spacers.
66Remove the gasket and clean the mating
faces of the manifold and the cylinder head.
The gasket must be renewed when refitting
the manifold.
67Refitting is a reversal of the removal
procedure. Ensure that the spacers are
correctly located (where applicable) and
tighten the retaining bolts and nuts to the
specified torque settings.
Exhaust manifold -
removal and refittingÁ
68Remove the inlet manifold as described
previously (1372 cc models only).
69Disconnect the Lambda sensor lead
(photo).
70Raise and support the car at the front end
on axle stands to allow sufficient clearance to
work underneath the car and disconnect the
exhaust downpipe from the manifold.
71Straighten the tab washers, then unscrew
and remove the exhaust downpipe-
to-manifold retaining nuts (photo). Detach the
downpipe from the manifold. Support the
downpipe so that the Lambda sensor will not
get knocked and/or damaged.72Undo the manifold-to-cylinder head
securing bolts/nuts and withdraw and remove
the manifold and heat shield.
73Remove the gasket and clean the mating
faces of the manifold, cylinder head and
downpipe flange. The gasket must be
renewed when refitting the manifold.
74Refitting is a reversal of the removal
procedure. Tighten the retaining bolts/nuts to
the specified torque setting.
Catalytic converter -
general information
75The catalytic converter is a reliable and
simple device which needs no maintenance in
itself, but there are some facts of which an
owner should be aware if the converter is to
function properly for its full service life.
a) DO NOT use leaded petrol in a car
equipped with a catalytic converter - the
lead will coat the precious metals,
reducing their converting efficiency and
will eventually destroy the converter.
b) Always keep the ignition and fuel systems
well-maintained in accordance with the
maintenance schedule - particularly, en-
sure that the air cleaner filter element the
fuel filter and the spark plugs are renewed
at the correct interval - if the intake air/fuel
mixture is allowed to become too rich due
to neglect, the unburned surplus will enter
and burn in the catalytic converter,
overheating the element and eventually
destroying the converter.
Supplement: Revisions and information on later models 13•77
9D.58B . . . for access to the ECU retaining
screw (arrowed)9D.58A Detach the multiplug (arrowed) . . .9D.49 Fuel injector unit sensor retaining
screw (1). Also shown is the intake air
temperature sensor (2)
9D.71 Exhaust downpipe to manifold
flange connection showing retaining nuts
and locktabs9D.69 Lambda sensor in exhaust
downpipe
13

c) If the engine develops a misfire, do not
drive the car at all (or at least as little as
possible) until the fault is cured - the
misfire will allow unburned fuel to enter
the converter, which will result in its
overheating, as noted above.
d) DO NOT push- or tow-start the car - this
will soak the catalytic converter in
unburned fuel, causing it to overheat
when the engine does start - see b)
above.
e) DO NOT switch off the ignition at high
engine speeds - if the ignition is switched
off at anything above idle speed,
unburned fuel will enter the (very hot)
catalytic converter, with the possible risk
of its igniting on the element and
damaging the converter.
f) DO NOT use fuel or engine oil additives -
these may contain substances harmful to
the catalytic converter.
g) DO NOT continue to use the car if the
engine burns oil to the extent of leaving a
visible trail of blue smoke - the unburned
carbon deposits will clog the converter
passages and reduce its efficiency; in
severe cases the element will overheat.
h) Remember that the catalytic converter
operates at very high temperatures and
the casing will become hot enough to
ignite combustible materials which brush
against it. DO NOT, therefore, park the car
in dry undergrowth, over long grass or
piles of dead leaves.
i) Remember that the catalytic converter is
FRAGILE - do not strike it with tools
during servicing work, take great care
when working on the exhaust system,
ensure that the converter is well clear of
any jacks or other lifting gear used to raise
the car and do not drive the car over
rough ground road humps, etc., in such a
way as to ground the exhaust system.
j) In some cases, particularly when the car is
new and/or is used for stop/start driving, a
sulphurous smell (like that of rotten eggs)
may be noticed from the exhaust. This is
common to many catalytic
converter-equipped cars and seems to be
due to the small amount of sulphur found
in some petrols reacting with hydrogen in
the exhaust to produce hydrogen sulphide
(H
2S) gas; while this gas is toxic, it is not
produced in sufficient amounts to be a
problem. Once the car has covered a few
thousand miles the problem should
disappear - in the meanwhile a change of
driving style or of the brand of petrol used
may effect a solution.
k) The catalytic converter, used on a
well-maintained and well driven car,
should last for at least 50 000 miles
(80 000 km) or five years - from this point
on, careful checks should be made at all
specified service intervals on the CO level
to ensure that the converter is still
operating efficiently - if the converter is no
longer effective it must be renewed.
Fuel evaporation control system
- general
76As mentioned earlier, fuel evaporation is
contained within the system. In high outdoor
temperatures, when the vehicle is parked for a
period of time, the fuel in the tank evaporates,
building up pressure. When the pressure builds
up to a predetermined level a vent valve opens
to allow the vapours to pass on to and absorbed
by a carbon filter. However, if extreme pressure
or vacuum should build up, a two way safety
valve opens to allow external venting.
77If the safety valve needs replacing, note
that it must be fitted correctly. The black end
should be connected to the fuel tank and the
blue to the carbon filter.
78The vapours in the carbon filter are
flushed by warm air passing through the filter
on to a ECU controlled vapour cut-off
solenoid.
79The cut-off solenoid is closed when
starting the engine and opens to allow
vapours to be drawn into the inlet manifold,
through a second solenoid. If the cut-off
solenoid needs replacing ensure that the
black arrow on the casing is pointing towards
the inlet manifold.
80The second solenoid, known as an Elbi
solenoid, is closed when the engine is turned
off, thus preventing engine run-on. The side
facing connection is for the inlet manifold
pipe.
PART E:
BOSCH L3.1/2 JETRONIC
FUEL INJECTION SYSTEMS
Warning: Refer to the beginning
of this Section before starting
any work.
Description
1A Bosch L3.1 (or L3.2, as fitted from 1992)
Jetronic fuel injection system is fitted to the
1372 cc Turbo ie engine. The system circuit
and main component locations are shown in
Figs. 13.48 and 13.49.
2The L3.1/2 Jetronic system is a multi-point
fuel injection (MPi) system. It operates in a
similar manner to that of the LE2-Jetronic
system fitted to the 1301 cc Turbo ie engine
described in Part C of this Section. The L3.1/2
system is more sophisticated and has the
ability to provide reasonably efficient engine
operation when system sensors malfunction.
As with the LE2 system, the fuel and air
supply mixture circuits are regulated in
accordance with the electronic control unit
(ECU), but on the L3.1/2 system the control
unit is attached to the upper part of the
airflow meter.
3The ECU analyses the information passed
to it from the system sensors. These signals
are then processed and the air/fuel mixture is
constantly adjusted as required to provide the
13•78 Supplement: Revisions and information on later models
Fig. 13.48 Bosch L3.1 Jetronic fuel injection system - 1372 cc Turbo ie engine (Sec 9E)
1 ECU
1A Diagnostic socket
2 Injection system relay and
fuel pump relay
3 Ignition switch
4 Battery
5 Fuel tank
6 Fuel pump
6A Primary fuel filter7 Coolant temperature
sensor
8 Intake air cooling radiator
(intercooler)
9 Air cleaner
10 Supplementary air valve
11 Throttle position switch
11A Throttle housing
12 Airflow meter12A Intake air temperature
sensor
13 Fuel pressure regulator
14 Fuel rail (to injectors)
15 Secondary fuel filter
16 Injectors
17 Injector cooling fan
18 Thermostatic switch (to
engage injector cooling fan)