1983 FIAT UNO light

35Clean the mating faces of the thermostat
cover and cylinder head, and use a new
gasket when refitting the cover.
36Refill the cooling system as described
earlier in this Section.
Coolant pump -
removal and refittingÁ
Note: A new coolant pump gasket must be
used on refitting. If the pump is found to be
worn it must be renewed as a complete unit as
dismantling and repair is not possible.
37Disconnect the battery negative lead.
38Drain the cooling system as described
earlier in this Section.
39Remove the coolant/alternator drivebelt
as described in the next sub-Section.
40Unscrew the four coolant pump securing
bolts, noting that two of the bolts also secure
the alternator adjuster bracket, and withdraw
the pump from the housing (photo). Recover
the gasket.
41Refitting is a reversal of removal, bearing
in mind the following points.
42Use a new gasket between the pump and
the housing.
43Refit and tension the coolant
pump/alternator drivebelt as described in the
next sub-Section.
44On completion, refill the cooling system
as described earlier in this Section.
Coolant pump/alternator
drivebelt - checking,
renewal and tensioning
Á
45At the intervals specified in Section 3 or
“Routine maintenance” at the beginning of
this manual (as applicable), the drivebelt
should be checked and if necessary
re-tensioned.
46Access to the drivebelt is made from the
underside of the car on the right-hand side.
Loosen off the front right-hand roadwheel
retaining bolts, then raise and support the car
on axle stands at the front. Remove the front
roadwheel on the right-hand side.
47Remove the underwing shield from the
right-hand wheel arch by drifting the
compression pins out from the retaining
clips. Prise free the clips and remove the
shield.
48Additional, though somewhat restricted,
access can be obtained from above by
removing the air cleaner unit on the non-Turbo
ie-engine (photo).
49Check the full length of the drivebelt for
cracks and deterioration. It will be necessary
to turn the engine in order to check the
portions of the drivebelt in contact with the
pulleys. If a drivebelt is unserviceable, renew it
as follows (photo).
50Loosen the alternator mounting and
adjuster nuts and bolts and pivot the
alternator towards the cylinder block.51Slip the drivebelt from the alternator,
coolant pump and crankshaft pulleys.
52Fit the new drivebelt around the pulleys,
then lever the alternator away from the
cylinder block until the specified belt tension
is achieved. Lever the alternator using a
wooden or plastic lever at the pulley end to
prevent damage. It is helpful to partially
tighten the adjuster nut before tensioning the
drivebelt (photo).
53When the specified tension has been
achieved, tighten the mounting and adjuster
nuts and bolts (photo).
PART D: HEATER UNIT- LATER
MODELS
Heater unit -
removal and refitting
Á
1The heater unit is removed complete with
the facia/control panel. Commence by
draining the cooling system as described
previously in this Section.
2Disconnect the battery negative lead.
3Refer to Section 15 of this Chapter for
details and remove the ashtray/cigar lighter
and the auxiliary control panel.
4Undo the upper screw retaining the heater
unit to the facia (see Fig. 13.31).
5Remove the radio from the central facia.
6Undo the retaining screw on each side at
the front of the gear lever console. Prise free
13•58 Supplement: Revisions and information on later models
Fig. 13.31 Removing the heater unit-to-
facia upper retaining screw (Sec 8D)8C.53 Tightening the alternator adjuster
nut8C.52 Fitting a new coolant
pump/alternator drivebelt around the
pulleys
8C.49 Alternator/water pump drivebelt and
tensioner viewed from the right-hand
wheel arch8C.48 Top side view of water pump,
alternator and drivebelt8C.40 Coolant pump/alternator bracket
bolt removal

the trim cover, undo the retaining screw at the
rear of the console. Prise free and release the
gear lever gaiter and lift clear the central
console.
7Undo the retaining screws and remove the
steering column upper and lower shroud.
8Detach and remove the lower facia trim on
the side of the central facia.
9Referring to Fig. 13.32, unscrew and
remove the four heater facia to main facia
retaining screws from the points indicated.
10Undo the two retaining nuts securing the
heater to the body on the driver’s side.
11Undo the retaining screws and remove
the pipe shield from the side of the heater
unit, then disconnect the coolant supply and
return hoses from the heater. As the hoses are
detached, be prepared to catch any remainingcoolant as it flows from the hoses and heater
connections.
12Undo the remaining two heater unit
securing nuts and withdraw the heater unit
from the car. As the unit is removed, detach
the wiring and position the hoses with their
ends pointing upwards to avoid further
coolant spillage.
13Refit in the reverse order of removal.
Ensure that the hoses are securely
reconnected. Top up the cooling system on
completion.
Heater unit - dismantling
and reassemblyÁ
14Remove the heater unit as described
previously.
15Pull free the heater/fresh air and blower
control knobs (photo).
16Undo the two retaining screws and
withdraw the control panel from the facia.
Detach the wiring connectors from the panel
illumination lights and remove the panel.17Unscrew the retaining bolts and remove
the centre panel from the heater unit.
18Undo the retaining screws and remove
the control lever mounting.
19Loosen off the grub screws and detach
the cables from the control levers.
20Undo the retaining screws and remove
the control valve.
21Undo the two retaining screws and
withdraw the heater matrix from the heater
housing.
22To separate the casing halves, drill out the
pop rivet securing the mounting bracket,
release the retaining clips and unscrew the
securing bolts.
23Reassemble in the reverse order of
dismantling. Check that the control cables are
correctly adjusted and that the controls
operate in a satisfactory manner before
refitting the heater unit to the car.
Supplement: Revisions and information on later models 13•59
8D.15 Pull free the heater/fresh air and
blower control knobs
Fig. 13.33 Heater pipe shield securing
screw positions on later models (Sec 8D)
Fig. 13.32 Heater unit facia to main facia
retaining screw locations (arrowed)
(Sec 8D)
Fig. 13.34 Heater unit components on later models (Sec 8D)
1 Coolant inlet tap 2 Centre panel 3 Side casings 4 Heater matrix 5 Blower fan
13

15Release the clamp screw and pinch-bolt,
and disconnect the choke cable.
16Slacken the throttle cable by releasing the
locknut and turning the adjuster sleeve, then
slip the cable nipple out of the notch in the
throttle spindle quadrant.
17Disconnect the lead from the idle cut-off
solenoid valve.
18Unscrew the two long mounting bolts and
lift the carburettor from the inlet manifold
(photo).
19Refitting is a reversal of removal, but
observe the following points (photo).
a) Use a new flange gasket at each side of
the insulator block.
b) Check that the choke cable is fitted so
that full choke can be obtained but the
choke is fully off when the choke control
lever is pushed right in.
c) Adjust the throttle cable so that there is
just a slight amount of slackness when the
accelerator pedal is released, but when
fully depressed, full throttle can be
obtained (throttle valve plate quadrant up
against its stop).
Carburettor (Weber 32
TLF) - overhaul¢
20It is rare for a carburettor to require
complete overhaul and if the unit has seen
considerable service and wear is detected in
the throttle valve spindle bushes, it is
recommended that a new or rebuilt carburet-
tor is obtained.21Normally, the following operations are all
that will be required to keep the carburettor
working perfectly. The unit need not be
removed from the manifold unless the throttle
block is to be detached; simply remove the air
cleaner.
22Periodically, unscrew the large hexagonal
plug adjacent to the fuel inlet pipe, extract the
filter and clean it. Refit the filter and plug
(photo).
23Obtain a repair kit for your carburettor
which will contain all the necessary
replacement gaskets and seals. Extract the top
cover and choke diaphragm assembly fixing
screws, remove the small plastic cover and
push out the bush, then lift the top cover from
the carburettor. Discard the gasket (photos).24Mop out fuel and sediment from the float
chamber.
25The various jets and calibrated bleeds can
then be removed and cleared by blowing
them through with air from a tyre pump. Do
not attempt to clear them by probing with
wire, as this will ruin the calibration.
26Check the tightness of the fuel inlet
needle valve. If necessary, remove the float
and its pivot pin so that a close-fitting ring
spanner can be used on the valve body. Take
care to support the pivot pin pedestals as the
pin is tapped out - they are brittle. The throttle
valve plate block can be removed after
extracting the screws (photos).
27As reassembly progresses, carry out the
following checks and adjustments.
Supplement: Revisions and information on later models 13•63
9B.22 Fuel filter removal from the Weber
32 TLF carburettor9B.19 Carburettor insulator block9B.18 Removing the Weber 32 TLF
carburettor by gripping air cleaner
mounting bracket
9B.26B Fuel inlet valve needle removal
from the Weber 32 TLF carburettor9B.26A Floats and pivot pin arrangement
on the Weber 32 TLF carburettor
9B.23B Disconnecting the choke linkage
on the Weber 32 TLF carburettor9B.23A Choke linkage cover removal from
the Weber 32 TLF carburettor
9B.23C Underside view of the cover on the
Weber 32 TLF carburettor
13

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

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

13•88 Supplement: Revisions and information on later models
Fig. 13.73 Wiring diagram of the Microplex ignition system on the 1301 cc Turbo ie
engine (Sec 10)Fig. 13.74 Wiring diagram of the Microplex ignition system on the 1372 cc Turbo ie
engine (Sec 10)1 ECU
2 Safety pressure switch
3 Ignition unit with coil
4 Distributor
5 Anti-knock sensor
6 Vacuum/pressure pick-up in engine inlet
manifold
7 Socket for diagnostic equipment8 Tachometer
9 Spark plugs
10 Switch to earth (to retard advance
curve if necessary)
11 Turbocharger operation warning light
12 Anti-theft relay (where fitted)
13 Hidden anti-theft switch (where fitted)1 ECU
2 Pipe (pressure/vacuum
in inlet manifold to
control unit)
3 Spark plug
4 Distributor
5 Ignition coil (with
control unit)6 Tachometer
7 Ignition switch
8 Connector
9 TDC sensor
10 Engine speed
11 Anti-knock sensor
12 Air pressure safety
switch13 Speedometer signal
for electronic injection
14 Connector
15 Diagnostic socket
a Crankshaft pulley
b Flywheel

require maintenance other than general
inspection for wear in the linkage joints. If
excessive wear is found in any of the joints, they
can be individually detached and renewed.
13Access to the control rods is eased by
detaching and lowering the exhaust system
from the exhaust manifold.
14If a new adjustable control rod is to be
fitted, remove the original rod as a unit, but do
not alter its adjustment for length. The new
rod can then (if required) be set to the same
length as the original in order to maintain the
original setting. Do so by loosening off the
locknut and turning the balljoint as required;
ensure that the angle of the joint is correct
before tightening the locknut.
15Access to the gear lever/main connecting
rod joint from above is made by prising back
the gear lever gaiter from the centre console.
Access from underneath can be made by
raising and supporting the car on axle stands.
Working from the underside of the lever, undo
the retaining nuts and remove the inspection
plate from the floor (photos).
16Any adjustment to the gear linkage should
be entrusted to a FIAT dealer.
Transmission -
removal and refitting#
17The transmission can be removed
together with the engine and then separated
as described in Section 7, or on its own (as
described below), leaving the engine in
position in the car. Before starting to remove
the transmission, it should be noted that
suitable equipment will be required to support
the engine during this procedure.
18Disconnect the battery negative lead.
19Remove the bonnet as described in
Chapter 12.
20Refer to Section 11 in this Chapter for
details and detach the clutch operating
cylinder together with its mounting bracket
from the top of the transmission, but do not
disconnect the hydraulic fluid hose from the
cylinder connection. Leave the cylinder
attached to the bracket. Tie the cylinder and
bracket up to support them out of the way.
21Reaching down between the transmission
and the bulkhead, unscrew the knurled
retaining nut and withdraw the speedometer
cable from the transmission.
22Remove the front roadwheel trims, then
loosen off the front wheel retaining bolts.
Raise the vehicle and support it on axle
stands at a suitable height to allow working
underneath and eventual transmission
removal from under the front end.
23Drain the transmission oil as described
previously in this Section.
24Disconnect and remove the starter motor
(photos).
25Detach the reversing light switch lead
connector.
26Undo the retaining bolt and detach the
earth lead from the rear end of the
transmission (see photo 7C.33). Refit the bolt
once the lead has been disconnected.
13•96 Supplement: Revisions and information on later models
12B.15B Access cover to gear lever lower
connection to rod on the 1372 cc engine
Fig. 13.92 Exploded view of the gear selector and control road assembly components
fitted to 1372 cc models (Sec 12)
12B.15A Gear lever connection to the main
connecting rod on the 1372 cc engine
Fig. 13.91 Exploded view of the gear selector lever, rod and linkage components on
1372 cc models (Sec 12)