ECO mode FIAT UNO 1983 Service Manual PDF

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)

optimum engine operating efficiency. In the
event of a system sensor malfunction, errors
in data passed to the ECU are overcome by
an emergency operation, whereby the ECU
supplies the injectors with one of two set
injection periods independent of the sensors.
One period (2.2 ms) is for idle speed and the
other (2.5 ms) is for speeds above idle
(actuated when the idle speed contact is
opened).
4An injection system relay and a fuel pump
relay are fitted and are located in the engine
compartment, adjacent to the ECU on the left-
hand inner wing panel. In the event of the
engine not being started within two seconds of
the ignition being switched to the “ON”
position, the fuel pump relay is deactivated.
The fuel pump circuit fuse is located in the
main fuse block located under the facia within
the car. Note: To avoid possible damage to the
ECU, it is essential that the ignition is switched
off before disconnecting (or connecting) the
wiring multi-plug from the ECU.A Lambda (or
oxygen) sensor is fitted to L3.2 equipped
models, to measure exhaust gas oxygen
content. In sending signals to the ECU,
optimum catalyst operation is maintained.
Fuel system -
depressurisationÁ
5The 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.
6The fuel pump relay is located next to the
ECU and airflow meter in the engine
compartment. Carefully pull free the fuel
pump relay, then start the engine and run it
until it stops. The fuel system is now
depressurised. Turn the ignition off before
removing/dismantling any components.
7Do 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.
MaintenanceÁ
8Regularly check the condition and security
of the system hoses and connections. Also
check the system wiring connections for
condition and security.9At the specified intervals, renew the air
cleaner element and the fuel filter.
Fuel filter - renewalÁ
10This is located in the engine compartment
on the right-hand side. Disconnect the fuel
inlet and outlet hoses, but be prepared for the
loss of fuel. Loosen off the clamp and remove
the filter.
11Reverse the removal procedure to fit the
new filter, but ensure that the arrow indicating
fuel flow is pointing towards the fuel injector rail.
Air cleaner element -
renewalÁ
12Prise free the four retaining clips, then
remove the cover and the air cleaner element.13Wipe clean the inside surfaces of the air
cleaner housing, then insert the new element,
refit the cover and secure it with the four
retaining clips.
Checks and adjustments°
Engine idle speed and mixture
adjustment
14Before carrying out any adjustments, the
engine must be at its normal operating
temperature, the cooling fan having cut into
Supplement: Revisions and information on later models 13•79
Fig. 13.49 Fuel injection system components layout in engine compartment on the
1372 cc Turbo ie engine (Sec 9E)
1 ECU
1A Diagnostic socket
2 Ignition system relay and
fuel pump relay
7 Coolant temperature
sensor10 Supplementary air valve
11 Throttle position switch
11A Throttle housing
12 Airflow meter
13 Fuel pressure regulator
15 Secondary fuel filter16 Injectors
17 Injector cooling fan
18 Thermostatic switch (to
engage injector cooling
fan)
Fig. 13.52 Idle speed adjustment screw (1)
on the 1372 cc Turbo ie engine (Sec 9E)
Note method of compressing the
supplementary air valve pipe (arrowed)
Fig. 13.51 Air cleaner cover securing clips
(arrowed) on the 1372 cc Turbo ie engine
(Sec 9E)Fig. 13.50 Secondary fuel filter with arrows
indicating direction of flow - 1372 cc Turbo
ie engine (Sec 9E)
13

operation twice. Also prior to making
adjustments ensure that the supplementary
air valve pipe is in good condition, with no
leaks. Compress the air valve pipe using a
pair of grips to prevent incorrect adjustment
caused by a defective supplementary air
valve.
15The air cleaner must be connected when
checking and/or adjusting the engine idle
speed. To adjust, turn the adjuster screw in
the required direction to set the engine idle
speed to that specified.
16It is unlikely that the mixture will require
adjustment and unless this is proven by
measuring the exhaust gases using a CO
content analyser, its setting should not be
altered. As with idle speed adjustment, the
engine must be at its normal operating
temperature when making this check and
adjustment. It is also necessary to ensure that
the ignition idle advance is as specified.
Checking and adjustment must not be made
with the engine cooling fan, air conditioning
(where fitted) or other related items switched
on.
17If adjustment to the mixture is required,
prise free the tamperproof plug from the front
of the mixture adjustment screw in the control
unit, then turn the screw as required. Turn the
screw inwards (clockwise) to increase the CO
content or outwards (anti-clockwise) to
weaken it.
Throttle position switch adjustment
18This switch will not normally require
adjustment having been set during
production. The switch should not be
loosened off or reset unless absolutely
necessary.
19If a new switch is fitted it can be set by
loosely fitting the securing bolts, turning the
switch fully anti-clockwise, then clockwise
until one of the internal contacts is felt to click
into engagement. Hold the switch in this
position and tighten the retaining screws.
Reconnect the wiring multiplug to the switch.
Accelerator cable adjustment
20If the accelerator cable is removed or
detached from the support bracket at the
throttle control housing at any time, care must
be taken to adjust it correctly. When the inner
cable is connected to the throttle quadrant,
set the outer cable in the bracket so that the
inner cable has a minimal amount of free play,
yet does not prevent the throttle valve from
fully closing.
21When the engine is restarted, check that
the engine idle speed is as specified and that
the action of the accelerator is satisfactory.
Fuel pump and supply system checks
22Although the following basic checks can
be made to the fuel pump and fuel supply
system, specialised equipment is required to
undertake full and accurate tests of the fuel
supply system. Such checks must therefore
be entrusted to a FIAT dealer or a fuel
injection specialist.
23If the fuel pump is suspected of
malfunction, a basic check can be made by
turning the ignition on and listening around
the area of the pump unit to hear if it is
operating. The pump is located on the
underside of the car, just forward of the fuel
tank. If the pump fails to operate, check thatthe pump fuse is sound and that its
connection (and also that the relay) are clean
and secure.
24The pump can be further checked as
described previously for the LE2 fuel injection
system fuel pump in Part C of this Section.
Supplementary air valve check
25With the engine at its normal operating
temperature, allow it to idle, then pinch the
supplementary air valve hose using suitable
pliers as shown in Fig. 13.52 and check to see
if the engine speed drops by more than 50
rpm. If it does, the supplementary air valve is
defective and in need of renewal.
Injection system
components -
removal and refitting
Á
Warning: Refer to the beginning
of this Section before starting
any work.
26With the exception of the items mentioned
below, the various components of the fuel
injection system are removed in the same
manner as that described for the equivalent
items in Part C of this Chapter.
27Disconnect the battery negative lead
before carrying out any of the removal and
refitting operations. Where fuel lines are to be
disconnected it will first be necessary to
depressurise the injection system.
Airflow meter
28Release the retaining clips and detach the
air intake and outlet ducts from the airflow
meter.
29Ensure that the ignition is switched off,
then disconnect the multiplug from the ECU.
Unscrew the retaining bolts and remove the
airflow meter complete with the ECU.
30If required, the ECU can be separated
from the airflow meter by undoing the
securing bolts.
Throttle valve housing/inlet manifold
31Loosen off the retaining clip and detach
the air intake duct from the throttle housing,
the air cooling hoses for the injectors and the
supplementary air valve.
32Detach the accelerator cable from the
throttle linkage.
13•80 Supplement: Revisions and information on later models
Fig. 13.56 Disconnecting the injector air
cooling hoses and the supplementary air
valve hose on the 1372 cc Turbo ie engine
(Sec 9E)Fig. 13.55 Disconnecting the air intake
duct and accelerator cable from the
throttle housing on the 1372 cc Turbo ie
engine (Sec 9E)
Fig. 13.54 Accelerator cable adjustment
on the 1372 cc Turbo ie engine (Sec 9E)
1 Adjuster 3 Quadrant support
2 Inner cableFig. 13.53 Mixture adjustment screw
location on the 1372 cc Turbo ie engine
(Sec 9E)

protective shield to gain access to the pump
which is located forward of the fuel tank.
60Disconnect the fuel hoses and the wiring
connector, release the retaining clamp and
withdraw the pump unit.
Refitting all components
61Refitting of all components is a reversal of
the removal procedure, but note the following
specific points.
62Ensure that all components are clean prior
to refitting and where applicable, use new
seals and gaskets. Ensure that all connectionsare securely and correctly made.
63Do not reconnect the battery until all the
refitting procedures are complete.
64When the engine is restarted, check
around the fuel injection system for any signs
of leakage from the fuel supply and return
components.
Lambda sensor - general
65The sensor is screwed into the exhaust in
front of the catalytic converter.
66A faulty sensor can damage the converter,
therefore it must be checked regularly (see
Maintenance schedule, Section 3) by a dealer
using special equipment.
67Use of leaded fuel will also damage this
sensor, as well the converter.
PART F:
TURBOCHARGER SYSTEM
Description
1A turbocharger is fitted to certain 1301 and
1372 cc ie engines. The accompanying
photographs are all taken from a 1301 cc
engine, but the system is much the same for
both engine types.
2The turbocharger is basically a shaft with an
exhaust gas-driven turbine at one end, and a
compressor located at the other end which
draws in outside air and forces it into the inlet
manifold. By compressing the incoming air, a
larger charge can be let into each cylinder,
and greater power output is achieved than
with normal aspiration.3Lubrication of the turbocharger shaft
bearings is provided by pressurised engine
oil, and the unit is cooled by the coolant from
the engine cooling system.
4A wastegate valve is incorporated in the
turbocharger to divert excessive exhaust gas
pressure from the turbine into the exhaust
pipe at a predetermined pressure level.
5A maximum air pressure switch is located in
the inlet manifold. Its purpose is to cut the
ignition system off when the turbocharger
system pressure continues to increase
beyond 0.86 bars (12.5 lbf/in
2). This would
otherwise damage the engine, due to high
combustion temperatures and pressures
(photo).
6An intercooler (heat exchanger) is located
between the turbocharger and the inlet
manifold. Its function is to cool the inlet
charge, thus increasing its density, to provide
greater power output.
7A mechanical bypass valve is located
between the low-pressure pipe (downstream)
and the high-pressure pipe (upstream), which
reduces the inherent noise from the
turbocharger when the accelerator pedal is
released (photo).
8None of the components of the
turbocharger system can be repaired and
parts are not available. Any fault will therefore
mean that the turbocharger or associated
assemblies will have to be renewed complete.
Precautions
9The following precautions should be
observed when using a turbocharged vehicle.
a) Never operate the engine without the air
cleaner fitted.
b) Never switch off the engine before its
speed has dropped to idling. If the car
has been driven hard, allow it to idle for a
few minutes before switching off. Failure
to observe these recommendations can
cause damage to the turbocharger due to
lack of lubrication.
10Always keep the fuel injection system
well-maintained and tuned. Operating on a
weak mixture can cause overheating of the
turbocharger.
Turbocharger
(1301 cc ie engine) -
removal and refitting
Á
11Disconnect and remove the airflow meter
as described in Section 9C.
12Disconnect the spiral-wound hose from
the fuel injector cooling duct.
13Remove the turbocharger air hoses from
within the left-hand side of the engine
compartment. Note particularly their routing.
14Remove the throttle housing/inlet
manifold as described in Section 9C, also the
fuel rail, injectors and inlet manifold branch
pipe stubs. Remove the alternator heat shield
(photo).
15Remove the exhaust heat shield.
16Unscrew the turbocharger-to-exhaust
pipe flange nuts (photos).
13•82 Supplement: Revisions and information on later models
9F.16A Turbocharger-to-exhaust flange
nut (arrowed)9F.14 Alternator heat shield
9F.7 Bypass valve9F.5 Maximum air pressure switch
(arrowed)
Fig. 13.63 Fuel pump and sender unit
location on the 1372 cc Turbo ie engine
(Sec 9E)
1 Fuel level gauge sender connector
2 Fuel pump connector
3 Fuel return hose
4 Fuel supply hose

6On 999, 1108 and 1372 cc engines, the
distributor is driven from the rear end of the
camshaft.
7On the 1116 and 1299/1301 cc engines, the
distributor is driven from an extension of the
oil pump driveshaft which is geared to the
auxiliary shaft.
8The distributor contains a reluctor mounted
on its shaft, and a magnet and stator fixed to
the baseplate.
9Ignition advance is controlled in the
conventional way mechanically by centrifugal
weights and a diaphragm unit for vacuum
advance.
10Instead of the conventional method of
interrupting the low tension circuit to generate
high tension voltage in the coil by means of a
mechanical contact breaker, when the
electronic ignition is switched on, the
switching of the transistors in the electronic
control unit (ECU) prevents current flow in the
coil primary windings.
11Once the crankshaft rotates, the reluctor
moves through the magnetic field created by
the stator and when the reluctor teeth are in
alignment with the stator projections a small
AC voltage is created. The ECU amplifies this
voltage and applies it to switch the transistors
and so provide an earth path for the primary
circuit.
12As the reluctor teeth move out of
alignment with the stator projections the AC
voltage changes, the transistors in the ECU
are switched again to interrupt the primary
circuit earth path. This causes a high voltage
to be induced in the secondary winding.
Distributor
(breakerless type) -
removal and refitting
#
13Removal of the distributor on the 903,1116, 1299 and 1301 cc engines is as
described in Chapter 4, Section 6.
14On 999, 1108 and 1372 cc engines, mark
the position of the distributor clamp plate in
relation to the cylinder head surface.
15Unclip the distributor cap and move it to
one side with the HT leads attached.
16Disconnect the LT lead plug and, where
applicable, the vacuum hose (photo).
17Unscrew the distributor fixing nuts and
withdraw the unit.
18The distributor drive is by means of an
offset dog no special procedure is required to
refit it. Providing the dog engages in its slot
and the distributor body is turned to align the
marks made before removal, the timing will
automatically be correct.
19If a new distributor is being fitted (body
unmarked), set No. 4 piston at TDC (0º) by
turning the crankshaft pulley bolt until the
timing marks on the crankshaft pulley and
engine front cover are in alignment.
20Align the drive dog and fit the distributor
then turn the distributor body until the contact
end of the rotor is aligned with the arrow on
the distributor dust shield.
21Tighten the distributor clamp nuts. Refit the
cap and disconnected components and then
check ignition timing using a stroboscope.
Distributor (breakerless
type) - overhaul#
22It is recommended that a worn out or
faulty distributor is renewed. However,
individual components such as the cap, rotor,
reluctor, magnet/stator/baseplate assembly,
vacuum diaphragm unit, and drive gear or dog
are available separately.
Breakerless
ignition system
components - testing
ª
23A voltmeter and an ohmmeter will be
required for this work.
Primary circuit voltage
24Turn on the ignition, and using a voltmeter
check the voltage at the ignition coil LT
terminals. Any deviation from battery voltage
will indicate a faulty connection, or if these are
satisfactory, then the coil is unserviceable.
Magnetic impulse generator winding
25Remove the distributor and ECU and
disconnect their connecting leads.
26Connect an ohmmeter to the impulse
generator terminals and note the reading. The
resistance should be as given in the Specifi-
cations at the beginning of this Chapter.
27Now check between one of the impulse
generator terminals and the metal body of the
distributor. Infinity should be indicated on the
ohmmeter. If it is not, renew the impulse
generator carrier plate. Note: When carrying out
this test it is imperative that the connections are
remade as originally observed. Also ensure that
there is no possibility of the ECU supply (red)
cable and earth cable making contact in service.
Ignition coil winding resistance
28Check the resistance using an ohmmeter
between the coil LT terminals. Refer to the
Specifications for the expected coil resistance.
29Check the resistance between the LT lead
socket on the coil and each of the LT
terminals. Refer to the Specifications for the
expected coil resistance.
30The rotor arm resistance should be
approximately 5000 ohms.
Microplex ignition system -
description
31This system is fitted to the 1301 and
1372 cc Turbo ie models, and comprises the
following components.
Electro-magnetic sensors
32Two sensors are used to pick up engine
speed and TDC position directly from the
crankshaft.
Pressure and vacuum sensor
33This converts inlet manifold vacuum
pressure into an electrical signal for use by
the electronic control unit (ECU).
Anti-knock sensor
34This converts “pinking” detonations which
occur within the combustion chambers into
an electrical signal for use by the ECU (photo).
Electronic Control Unit (ECU)
35This computes the optimum ignition
advance angle from the sensor signals
received, and controls the action of the
ignition unit (photo).
13•86 Supplement: Revisions and information on later models
Fig. 13.72 Rotor aligned with arrow on
distributor dust shield - 999 and 1108 cc
engines (Sec 10)
1 ECU
2 Ignition coil
3 Distributor
4 Vacuum advance
unit5 Pick-up filter with
calibrated opening
for atmospheric
pressure
Fig. 13.71 Location of electronic ignition
components on early models with
breakerless ignition (Sec 10)
10.16 Distributor LT lead connecting plug