1983 FIAT UNO fuel filter location

Throttle position switch
(potentiometer)
90This is located on the left side of the
throttle valve housing (photo).
91Disconnect the wiring plug, unscrew the
two fixing screws and withdraw the switch.
Fuel filter
92Unscrew the fuel line banjo unions from
the filter, which is located in the right-hand
rear corner of the engine compartment. Be
prepared for some loss of pressurised fuel,
and mop it up with rags.
Fuel pump
93The fuel pump can be removed from its
location beside the fuel tank afterdisconnecting the fuel hoses and wiring plug,
and then releasing the mounting clamp.
Refitting all components
94Refitting of all components is a reversal of
removal, but observe the following points.
95Use new seals and gaskets as applicable,
noting that three rubber seals are used on
each fuel injector and insulator (photos).
96Adjust the throttle position switch as
described in paragraph 46 of this Section.
97When refitting a new fuel filter, make sure
that the arrow marked on it is in the direction
of the fuel flow.
98Apply gasket cement to the threads of the
coolant temperature sensor.
Throttle control linkage -
general
99This is of the cable and rod type. Adjust the
cable by means of the end fitting and nut, to give
the slightest play in the cable when the plastic
socket is engaged with the ball on the link rod
which runs across the camshaft cover (photos).
100Keep the cross-shaft pivots and return
springs lubricated.
Fuel tank - general
101The fuel tank is of metal construction, but
note the plastic anti-blow-back compartment
between the filler cap and the tank. This is
accessible from under the right-hand wheel
arch (photo).
13•72 Supplement: Revisions and information on later models
9C.99B Throttle cable (secondary section)
and cross-shaft9C.99A Throttle cable and end fitting
(primary section)9C.95D Inlet pipe stub gasket
9C.95C Fuel injector insulator seal9C.95B Fuel injector small seal9C.95A Fuel injector large seal
9C.90 Throttle position switch (wiring plug
arrowed)9C.88B Supplementary air valve (arrowed)9C.88A Disconnecting the supplementary
air valve hose from the inlet manifold

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)

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)

31Unscrew and remove the two
turbocharger mounting bracket bolts.
32Referring to Fig. 13.67, loosen off the
retaining clip and detach the air hose from the
heat exchanger and the oil return pipe from
the turbocharger (to sump).
33Working from above, undo the
turbocharger mounting bracket bolts.
34Unscrew and remove the coolant
pipe-to-pump retaining bolts. The
turbocharger can now be removed from above
by withdrawing it together with the exhaust
manifold from the engine compartment.
35Locate and support the exhaust manifold
in a vice. Fit protector clamps to the jaws of the
vice to avoid possible damage to the manifold.
36Note the orientation and fitted position of
the turbocharger mounting bracket, then
unscrew the retaining nuts and detach the
bracket.
37Undo the retaining nuts, separate andremove the exhaust manifold from the
turbocharger.
38The turbocharger and wastegate valve are
not repairable and must therefore be renewed
as a complete unit. This being the case,
remove the following ancillary items from the
turbocharger unit before renewing it.
a) Loosen off the retaining clip and remove
the air outlet hose from turbocharger.
b) Undo the two retaining bolts and remove
the oil return hose union.
c) Unscrew the union and bolt and coolant
inlet pipe.
d) Undo the retaining nuts and remove the
turbocharger-to-exhaust manifold
connector.
39Where applicable, always use new
gaskets and ensure that the mating faces are
clean before refitting the ancillary components
to the turbocharger.Intercooler -
removal and refitting Á
40The intercooler is mounted behind the
left-hand side of the front bumper/spoiler (photo).
41Disconnect the air ducts from the intercooler.
42Unscrew the mounting bolts and lift the
intercooler from the car.
43Refitting is a reversal of removal (photo).
Injector cooling fan -
removal and refitting Á
44This unit is located on the left-hand side at
the front of the car. It can be accessed for
removal from above, in the engine compartment.
45Detach and remove the air intake duct
from the air cleaner unit to the ECU/airflow
meter.
46Disconnect and remove the air duct from
the air blower unit.
47Undo the air blower retaining nuts, withdraw
the unit and detach its wiring connector.
13•84 Supplement: Revisions and information on later models
9F.43 Intercooler mounting bolt (arrowed)
on 1301 cc engine9F.40 Intercooler location (1301 cc engine)Fig. 13.69 Turbocharger coolant pipe-to-
pump bolt location (arrowed) (Sec 9F)
Fig. 13.68 Turbocharger mounting bracket
bolts removal (Sec 9F)Fig. 13.67 Disconnect the heat exchanger
air hose and the oil return pipe
(turbocharger-to-sump) (Sec 9F)Fig. 13.66 Turbocharger mounting bracket
bolts (arrowed) (Sec 9F)
Fault finding - fuel injection system
Difficult starting from cold
m mFuel pump fault
m mBlocked fuel pipe or filter
m mSupplementary air valve fault
m mCoolant temperature sensor fault
Excessive fuel consumption
m
mIncorrect mixture setting
m mDirty air cleaner element
m mCoolant temperature sensor fault
m mAirflow sensor fault
Difficult to start when hot
m
mChoked air cleaner element
m mFuel pump fault
Uneven idling
m
mIncorrect mixture setting
m mIntake system air leak
m mThrottle position switch out of adjustment
m mLoose ECU connector