check engine FIAT UNO 1983 Service Service Manual

important that the following precautions are
observed.
3Never start the engine if the battery leads
are loose.
4Do not stop the engine by pulling off a
battery lead.
5Remove the control unit if ambient
temperature (paint drying oven) is above 80ºC
(176ºF).
6Never connect or disconnect the multi-plug
at the control unit unless the ignition is
switched off.
7Disconnect the battery negative lead before
carrying out electric body welding.10 Digiplex (electronic) ignition
- checks and adjustments
3
1Without special equipment, any work on the
system components should be restricted to
the following.
Engine speed sensor
2The gap between the sensor and the teeth
of the flywheel should be between 0.25 and
1.3 mm (0.0099 to 0.0512 in). Any
deviation will be due to mechanical damage to
the sensor, no adjustment being possible.
TDC sensor
3The gap between the sensor and one of the
TDC reference marks on the crankshaft pulley
should be between 0.4 and 1.0 mm (0.016 to
0.039 in).
4Any deviation will be due to the sensor
plate becoming loose. To reposition it will
necessitate setting No. 1 piston at TDC which
can only be carried out accurately by your
dealer using special tools.
Supply circuit and continuity of
coil primary winding
5Connect a test lamp between contacts 11
and 9 of the multi-plug having first pulled it
from the control unit.
6Switch on the ignition, the test lamp should
come on. If it does not, either the connection
at the positive pole of the control unit or the
coil primary winding is open.
Control unit earth
7Connect a test lamp between contacts 8
and 9 of the multi-plug having first pulled it
from the control unit. Switch on the ignition,
the test lamp should come on. If it does not,
improve the earth connection.
11 Spark plugs
1
1The correct functioning of the spark plugs is
vital for the correct running and efficiency of the
engine. It is essential that the plugs fitted are
appropriate for the engine, and the suitable type
is specified at the beginning of this chapter. If
Ignition system 4•7
Fig. 4.9 Digiplex control unit (Sec 9)
1 Vacuum hose connector
2 Multi-plug socket
1 Control unit
2 Distributor
3 Ignition coil4 TDC sensor
5 Wiring connector plug6 Engine speed sensor
7 Wiring connector plug
Fig. 4.8 Location of Digiplex ignition system components (Sec 9)
Fig. 4.13 Test lamp connected between
terminals 8 and 9 of control unit multi-plug
(Sec 10)Fig. 4.12 Test lamp connected between
terminals 11 and 9 of control unit
multi-plug (Sec 10)
Fig. 4.11 TDC sensor gap (Sec 10)
Fig. 4.10 Engine speed sensor gap
(Sec 10)
4

this type is used and the engine is in good
condition, the spark plugs should not need
attention between scheduled replacement
intervals. Spark plug cleaning is rarely
necessary and should not be attempted unless
specialised equipment is available as damage
can easily be caused to the firing ends.
2At the specified intervals, the plugs should
be renewed. The condition of the spark plug
will also tell much about the overall condition
of the engine.
3If the insulator nose of the spark plug is
clean and white, with no deposits, this is
indicative of a weak mixture, or too hot a plug.
(A hot plug transfers heat away from the
electrode slowly - a cold plug transfers it away
quickly.)
4If the tip of the insulator nose is covered
with sooty black deposits, then this is
indicative that the mixture is too rich. Should
the plug be black and oily, then it is likely that
the engine is fairly worn, as well as the mixture
being too rich.
5The spark plug gap is of considerable
importance, as, if it is too large or too small
the size of the spark and its efficiency will be
seriously impaired. The spark plug gap should
be set to the gap shown in the Specifications
for the best results.
6To set it, measure the gap with a feeler
gauge, and then bend open, or close, the
outer plug electrode until the correct gap is
achieved. The centre electrode should never
be bent as this may crack the insulation and
cause plug failure, if nothing worse.
7When fitting new plugs, check that the plug
seats in the cylinder head are quite clean.
Refit the leads from the distributor in the
correct firing order, which is 1-3-4-2; No 1cylinder being the one nearest the flywheel
housing (903 cc) or timing belt (1116 or
1301 cc). The distributor cap is marked with
the HT lead numbers to avoid any confusion.
Simply connect the correctly numbered lead
to its respective spark plug terminal (photo).
12 Ignition switch-
removal and refitting
1
1Access to the steering column lock/ignition
switch is obtained after removing the steering
wheel and column shrouds (Chapter 10) and
the column switch unit (Chapter 9).
2In the interest of safety, disconnect the
battery negative lead and the ignition switch
wiring plug (photo).
3Insert the ignition key and turn to the STOP
position (photo).
4Pull the two leads from the switch.
5Turn the ignition key to MAR.
6Using a screwdriver depress the retaining
tabs (1) (Fig. 4.16) and release the ignition
switch.
7Set the switch cam (2) so that the notches
(3) are in alignment.
8Insert the switch into the steering lock and
engage the retaining tabs.
9Turn the ignition key to STOP and connect
the two leads.
10Reconnect the battery and refit the
steering wheel, switch and shrouds.
11Removal and refitting of the steeringcolumn lock is described in Chapter 10.
Note: The ignition key is removable when set
to the STOP position and all electrical circuits
will be off. If the interlock button is pressed,
the key can be turned to the PARK position in
order that the parking lamps can be left on
and the steering lock engaged, but the key
can be withdrawn.
4•8 Ignition system
Fig. 4.16 Typical ignition switch (Sec 12)
1 Retaining tabs 3 Alignment notches
2 Switch cam 4 Locating projection12.3 Ignition key positions
1 AVV (Start) 3 Stop (Lock)
2 Park (Parking lights on) 4 MAR (Ignition)12.2 Ignition switch and lock
11.7 Distributor cap HT lead markingsFig. 4.15 Spark plug connections on
1116 cc and 1301 cc engines (Sec 11)
Fig. 4.14 Spark plug connections on
903 cc engine (Sec 11)
It’s often difficult to insert spark plugs
into their holes without cross-threading
them. To avoid this possibility, fit a
short piece of rubber hose over the end
of the spark plug. The flexible hose
acts as a universal joint, to help align
the plug with the plug hole. Should the
plug begin to cross-thread, the hose
will slip on the spark plug, preventing
thread damage.

20By connecting a pressurised container to
the master cylinder fluid reservoir, bleeding is
then carried out by simply opening each bleed
screw in turn and allowing the fluid to run out,
rather like turning on a tap, until no air is
visible in the expelled fluid.
21By using this method, the large reserve of
hydraulic fluid provides a safeguard against
air being drawn into the master cylinder
during bleeding which often occurs if the fluid
level in the reservoir is not maintained.
22Pressure bleeding is particularly effective
when bleeding “difficult” systems or when
bleeding the complete system at time of
routine fluid renewal.
All methods
23When bleeding is completed, check and
top up the fluid level in the master cylinder
reservoir.
24Check the feel of the brake pedal. If it
feels at all spongy, air must still be present in
the system and further bleeding is indicated.
Failure to bleed satisfactorily after a
reasonable period of the bleeding operation,
may be due to worn master cylinder seals.
25Discard brake fluid which has been
expelled. lt is almost certain to be
contaminated with moisture, air and dirt
making it unsuitable for further use. Clean
fluid should always be stored in an airtight
container as it absorbs moisture readily
(hygroscopic) which lowers its boiling point
and could affect braking performance under
severe conditions.
13 Vacuum servo unit-
description
A vacuum servo unit is fitted into the brake
hydraulic circuit on 55 and 70 models in series
with the master cylinder, to provide assistance
to the driver when the brake pedal is
depressed. This reduces the effort required by
the driver to operate the brakes under all
braking conditions.
The unit operates by vacuum obtained from
the induction manifold and comprises basically
a booster diaphragm and non-return valve. The
servo unit and hydraulic master cylinder are
connected together so that the servo unit
piston rod acts as the master cylinder pushrod.
The driver’s braking effort is transmitted
through another pushrod to the servo unit
piston and its built-in control system. The servo
unit piston does not fit tightly into the cylinder,
but has a strong diaphragm to keep its edges
in constant contact with the cylinder wall, so
assuring an air tight seal between the two
parts. The forward chamber is held under
vacuum conditions created in the inlet manifold
of the engine and, during periods when the
brake pedal is not in use, the controls open a
passage to the rear chamber so placing it
under vacuum conditions as well. When the
brake pedal is depressed, the vacuum passageto the rear chamber is cut off and the chamber
opened to atmospheric pressure. The
consequent rush of air pushes the servo piston
forward in the vacuum chamber and operates
the main pushrod to the master cylinder.
The controls are designed so that
assistance is given under all conditions and,
when the brakes are not required, vacuum in
the rear chamber is established when the
brake pedal is released. All air from the
atmosphere entering the rear chamber is
passed through a small air filter.
Under normal operating conditions, the
vacuum servo unit is very reliable and does
not require overhaul except at very high
mileages. In this case, it is far better to obtain
a service exchange unit, rather than repair the
original unit.
It is emphasised that the servo unit assists
in reducing the braking effort required at the
foot pedal and in the event of its failure, the
hydraulic braking system is in no way affected
except that the need for higher pressures will
be noticed.
14 Vacuum servo unit-
servicing and testing
1Regularly, check that the vacuum hose
which runs between the servo unit and the
inlet manifold is in good condition and is a
tight fit at both ends.
2If broken or badly clogged, renew the air
filter which is located around the brake pedal
push rod. Access to this is obtained by
disconnecting the pushrod from the
cross-shaft or pedal arm, withdrawing the
pushrod, dust excluding boot and end cap.
3If the new filter is cut diagonally from its
centre hole, future renewal can be carried out
without the need for disconnection of the
pushrod.
4If the efficiency of the servo unit is suspect,
it can be checked out in the following way.
5Run the engine, then switch off the ignition.
Depress the footbrake pedal; the distinctive
in-rush of air into the servo should be clearly
heard. It should be possible to repeat this
operation several times before the vacuum in
the system is exhausted.
6Start the engine and have an assistant
apply the footbrake pedal and hold it down.
Disconnect the vacuuum hose from the servo.
There should not be any in-rush of air into the
servo through the connecting stub. lf there is,
the servo diaphragm is probably faulty. During
this test, expect the engine to idle roughly,
unless the open end of the hose to the inlet
manifold is plugged. Reconnect the hose.
7With the engine off, depress the brake
pedal fully. Start the engine with the brake
pedal still depressed; the pedal should be felt
to go down fractionally.
8If the results of these tests are not
satisfactory, remove the unit and fit a new one
as described in the next Section.
15 Vacuum servo unit-
removal and refitting
3
1Syphon as much fluid as possible out of the
master cylinder reservolr.
2Disconnect electrical leads from the
terminals in the reservoir cap then uncouple
the rigid pipelines from the master cylinder
body. Be prepared to catch leaking fluid and
plug the open ends of the pipelines.
3The master cylinder can be unbolted now
from the servo unit, or detached later when
the complete assembly is withdrawn.
4Working inside the car, disconnect the
servo pushrod from the pedal then remove the
servo mounting nuts.
5Withdraw the servo assembly into the
engine compartment, then remove it to the
bench. lf the master cylinder is still attached,
cover the wings with protective sheeting, in
case brake fluid is spilled during removal.
6Refitting is a reversal of the removal
process, but adjust the pushrod clearance as
described in Section 9. On completion of
refitting, bleed the complete hydraulic system
as described in Section 12. Note: Where the
help of an assistant is available, the servo
pushrod need not be disconnected from the
pedal. The rod is a sliding fit in the servo and
the servo can be simply pulled off the rod.
Refitting without having disconnected the rod
from the pedal can be difficult unless the help
of an assistant is available.
16 Handbrake- adjustment
1
Adjustment is normally automatic, by the
movement of the rear brake shoes on their
automatic adjusters.
However, owing to cable stretch,
supplementary adjustment is occasionally
required at the control lever adjuster nut. The
need for this adjustment is usually indicated
by excessive movement of the control lever
when fully applied.
1The rear brakes should be fully applied
when the handbrake control lever has been
pulled over four or five notches.
2If adjustment is required, release the
8•8 Braking system
16.2 Handbrake adjuster nuts

1 General description
The electrical system is of 12 volt negative
earth type and employs a belt-driven
alternator and a pre-engaged type starter
motor.
The models in the range are all adequately
equipped with electrical accessories, while SX
versions also have power windows and
centralised door locking plus a check control
system (Section 34).
2 Battery- inspection, charging,
removal and refitting
2
1The battery is of maintenance-free type and
under normal circumstances, no topping up
will be required, but regularly check that the
electrolyte level is between the minimum and
maximum lines on the translucent battery
casing.
2If the electrolyte level does drop below theminimum line, suspect a leak in the battery
casing or that the alternator is overcharging. If
the latter is the case, rectify the alternator fault
and then prise out the two rectangular plugs
from the top of the battery and top up with
distilled or purified water.
3Always keep the battery terminals clean
and smear them with petroleum jelly to
prevent corrosion.
4The battery will normally be kept fully
charged by the alternator, but it is possible for
the battery to become discharged if the daily
mileage is very low with much use being
made of the starter and electrical accessories.
5When the battery begins to deteriorate with
age it may also require a boost from a mains
charger.
6Disconnect both battery leads before
connecting the mains charger. 7To remove the battery from the car, first
disconnect the leads from the battery
terminals (earth first) and then unscrew the
securing clamp from the casing projection at
the base of the casing (photo).
8Lift the battery from its mounting platform.
Refitting is a reversal of removal. Reconnect
the earth cable last.
Fuses
Circuit protected Fuse rating (A)
1 Stop lamps, direction indicator lamps, instrument panel warning
lamps, tachometer economy gauge, check control system . . . . . . 10
2 Windscreen wiper and washer, rear screen wiper/washer, check
system panel illumination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3 Left front parking, right rear tail lamp, cigar lighter illumination,
heater control and clock, digital clock illumination . . . . . . . . . . . . . 7.5
4 Right front parking lamp and left rear tail lamp, instrument panel
illumination and rear number plate lamp . . . . . . . . . . . . . . . . . . . . . 7.5
5 Left-hand dipped headlamp, rear foglamps . . . . . . . . . . . . . . . . . . 10
6 Right-hand dipped headlamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Left-hand headlamp (main beam) . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8 Right-hand headlamp (main beam) . . . . . . . . . . . . . . . . . . . . . . . . . 10
9 Engine cooling fan and horn (Comfort) . . . . . . . . . . . . . . . . . . . . . . 25
10 Heater booster fan, digital clock map reading lamp . . . . . . . . . . . . 20
11 Heated tailgate glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
12 Courtesy lamps, cigar lighter, radio power feed, disc pad
sensors, economy gauge (ES models) . . . . . . . . . . . . . . . . . . . . . . 10
13 Hazard warning lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
14 Spare (Comfort), Horn (Super) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
BulbsWattage
Headlamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40/45 or Halogen H4 60/55
Front parking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Side repeater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Tail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Reversing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Rear foglamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Direction indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Rear number plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Courtesy lamp (roof) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Courtesy lamp (pillar) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Warning and indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wedge base
Torque wrench settingsNm lbf ft
Alternator mounting and adjustment nuts . . . . . . . . . . . . . . . . . . . . . . . 50 87
Starter motor bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 35
9•2 Electrical system
2.7 Battery clamp
If battery terminal corrosion
has occurred, it may be
neutralised by applying
sodium bicarbonate or
household ammonia.

ease the holder out of the alternator. Inspect
the brushes and if worn below the specified
minimum length, they must be renewed.
7Disconnect the brush leads by unsoldering
or carefully cutting them.
8When soldering the new brush leads, do
not allow solder to run down them or their
flexibility will be ruined.
9When inspecting or renewing brushes,
check the surface of the slip rings. Clean them
with solvent or if they are very discoloured,
use very fine glasspaper.
6 Voltage regulator
1This is of integral type and is part of the
brushholder assembly.
2No provision is made for adjustment or
overhaul.
7 Starter motor-
description and testing
2
1The starter motor may be one of two
different makes. Both are of pre-engaged
type.
2This type of starter motor incorporates a
solenoid mounted on top of the starter motor
body. When the ignition switch is operated,
the solenoid moves the starter drive pinion,
through the medium of the shift lever, into
engagement with the flywheel starter ring
gear. As the solenoid reaches the end of its
stroke, and with the pinion by now partially
engaged with the flywheel ring gear, the main
fixed and moving contacts close and engage
the starter motor to rotate the engine.
3This pre-engagement of the starter drive
does much to reduce the wear on the flywheel
ring gear associated with inertia type starter
motors.
4If the starter fails, some fault-finding can be
done with it still on the car. Check the ignition
warning light comes on, and does not go out
when the starter is switched on. If it goes out,
the fault is probably in the battery. If it stays
bright, get an assistant to work the switch,whilst listening to the starter. Listen to find out
if the solenoid clicks into position. If it does
not, pull off the solenoid wire, and check it
with a test bulb. If the wire is live when the key
is turned, but the solenoid does not move,
take off the starter and remove it to the bench
for overhaul.
8 Starter motor-
removal and refitting
1
1Disconnect the battery negative lead.
2Disconnect the lead from the starter motor
(photo).
3Unscrew the fixing bolts and withdraw the
starter motor, downwards on 1116 cc and
1301 cc models (photo).
4Refitting is a reversal of the removal
procedure.
9 Starter motor- overhaul
3
1As with the alternator, the operations
should normally be limited to renewal of the
brushes. If the unit has covered a high
mileage it will usually be more economical to
purchase a new or factory-reconditioned one
rather than renew several components of the
original unit.
2Owing to the possibility that a fault can
develop in the starter motor solenoid or drive
assembly, full dismantling procedures are
given later in this Section.
Brush - renewal
3Slide off the cover band.
4Using a hooked piece of wire, pull up the
springs so that the brushes can be withdrawn
and their lengths checked for wear. If they
have worn below the specified minimum
length, renew them by extracting the brush
lead connecting screws (photo).
Solenoid
5Disconnect the field connecting wire from
the solenoid.
6Unscrew the bolts which hold the solenoid
to the end-frame.
7Unscrew the yoke tie-rod nuts.
9•4 Electrical system
9.4 Starter motor brush partly withdrawn
8.2 Starter motor connections8.3 Removing starter motor
Fig. 9.2 Exploded view of typical starter motor (Sec 9)
1 Armature
2 Drive pinion/clutch3 Drive end bracket
4 Shift lever5 Solenoid
6 Brush endplate7 Brush
8 Field windings
Gripping the brush leads with
a pair of pliers to act as a
heat sink will prevent heat
transfer to the internal
components of the alternator.

3The centralised door locking system can
operate independently of the key.
4To gain access to the lock solenoid and
linkage, remove the front door trim panel as
described in Chapter 12.
5Disconnect the battery negative lead.
6Disconnect the electrical wiring plugs from
the solenoid within the door cavity.
7Disconnect the solenoid from the lock lever
by removing the clip.
8Unscrew the two bolts which secure the
solenoid to the door and remove it.
9Renew the solenoid or switch as necessary.
10Refitting is a reversal of removal.
11Refer to Section 10 for details of system
fuses and relays.
33 Economy gauge
(Econometer)
2
1This device is fitted to ES (energy saving)
models and indicates to the driver the fuel
consumption (in litres per 100 km) coupled
with a needle which moves over coloured
sections of a dial to make the driver aware
that his method of driving is either conducive
to high or low fuel consumption. Refer to
Chapter 3, Section 16.
2The device is essentially a vacuum gauge
which also incorporates a warning lamp to
indicate to the driver when a change of gear is
required.
3A fuel cut-out valve (see Chapter 3, Sec-
tion 11) is used in conjunction with the
economy gauge so that when the accelerator
pedal is released during a pre-determined
engine speed range, fuel supply to the engine
is stopped, but resumes when the engine
speed falls below the specified range.
LED (light emitter diode)
4The gearchange indicator will only light up
at engine speeds in excess of 2000 rev/min
for vacuum pressures up to 600 mm Hg in 1st,
2nd and 3rd speed gears and for vacuum
pressures up to 676 mm Hg in 4th speedgear. The light will not come on if 5th speed
gear is engaged or if the coolant temperature
is below 55ºC.
5There is a two second delay in the light
coming on to prevent it operating during rapid
acceleration in a low gear.
6If the LED light comes on during
deceleration it should be ignored.
Fault finding
7A faulty economy gauge should be checked
in the following way.
8Refer to Section 21 and remove the
instrument panel.
9Disconnect the economy gauge L
connector and then connect a test lamp
between the BN cable contact and earth. If
the lamp comes on then the gauge supply
circuit is not open. If the lamp does not come
on, check all connections in the supply cable
which comes from the interconnecting unit of
the electrical system, also Fuse No 12.
10Now connect a voltmeter between the
white cable and earth. Check the voltage with
the engine not running, but the ignition
switched on. It should be between 0.7 and
0.9 volt. If the reading varies considerably
from that specified, check the connections
between the economy gauge and the fuel
cut-out device control unit. If the fault cannot
be rectified, renew the ignition control unit
(Digiplex system, see Chapter 4).
11Now check the closed throttle valve plate
switch by connecting a voltmeter between the
brown and BN cables of the L connector. With
the valve plate open, there should be no
reading, but with it open, voltage should be
indicated.
12Failure to conform as described will be
due to a faulty earth in the switch or a faulty
fuel cut-out device control unit.
13A further test of the throttle valve plate
switch may be carried out by disconnecting
the multi-plug from the fuel cut-out device
control unit.
14Connect a test lamp to contact 4 (positive
battery terminal). The lamp should come on,
when the engine is idling or the accelerator
released. If it does not, renew the throttle
valve plate switch.15Connect a tachometer to the brown/white
cable contact in the L connector and record
the engine speed with the engine running. If
no reading is obtained, renew the Digiplex
ignition control unit which must be faulty.
34 Check control (warning
module) system
2
1This is fitted into the instrument panel of
certain models to provide a means of
checking the operation of many electrical
circuits and other systems in the interest of
safety. Sensors are used where appropriate.
2The following components are not
monitored by the system, but have separate
warning lamps:
Handbrake “on”
Choke in use
Low engine oil pressure
Battery charge indicator
3The multi-functional electronic device
automatically checks the following functions
whether the engine is running or not:
Coolant level
Disc pad wear
Door closure
Engine oil level
Front parking lamps
Rear foglamps
Stop lamps
4The check information is stored by the
system monitor until the engine is started
when the display panel then indicates the
situation by means of the LEDs (light emitter
diodes) and the general lamp.
5If all functions are in order, the green panel
lamp will come on when the ignition key is
turned and will go out after two to three
seconds.
6If some functions are not in order, then the
red panel lamp will come on also the
appropriate LED.
Sensors - checking
7If a fault signal occurs which is
subsequently found to be incorrect, first
check the wiring connections between the
9•12 Electrical system
Fig. 9.15 Check system control panel (Sec 34)
A Parking lamps
B Coolant levelC Engine oil level
D Door closureE Brake fluid level
F Disc pad wearFig. 9.14 Location of control units (Sec 33)
A Digiplex ignition system control unit
B Fuel cut-out valve control unit

9•14 Electrical system
Fault finding - electrical system
No voltage at starter motor
m mBattery discharged
m mBattery defective internally
m mBattery terminals loose or earth lead not securely attached to body
m mLoose or broken connections in starter motor circuit
m mStarter motor switch or solenoid faulty
Voltage at starter motor - faulty motor
m
mStarter brushes badly worn, sticking, or brush wires loose
m mCommutator dirty, worn or burnt
m mStarter motor armature faulty
m mField coils earthed
Starter motor noisy or rough in engagement
m
mPinion or flywheel gear teeth broken or worn
m mStarter drive main spring broken
m mStarter motor retaining bolts loose
Alternator not charging*
m
mDrivebelt loose and slipping, or broken
m mBrushes worn, sticking, broken or dirty
m mBrush springs weak or broken
* If all appears to be well but the alternator is still not charging, take the
car to an automobile electrician for checking of the alternator
Ignition light fails to go out, battery runs flat in a
few days
m mDrivebelt loose and slipping, or broken
m mAlternator faulty
Battery will not hold charge for more than a few
days
m mBattery defective internally
m mElectrolyte level too low or electrolyte too weak due to leakage
m mPlate separators no longer fully effective
m mBattery plates severely sulphated
m mDrivebelt slipping
m mBattery terminal connections loose or corroded
m mAlternator not charging properly
m mShort in lighting circuit causing continual battery drain
Fuel gauge gives no reading
m
mFuel tank empty!
m mElectric cable between tank sender unit and gauge earthed or loose
m mFuel gauge case not earthed
m mFuel gauge supply cable interrupted
m mFuel gauge unit broken
Fuel gauge registers full all the time
m
mElectric cable between tank unit and gauge broken or disconnected
Horn operates all the time
m
mHorn push either earthed or stuck down
m mHorn cable to horn push earthed
Horn fails to operate
m
mBlown fuse
m mCable or cable connection loose, broken or disconnected
m mHorn has an internal fault
Horn emits intermittent or unsatisfactory noise
m
mCable connections loose
m mHorn incorrectly adjusted
Lights do not come on
m
mIf engine not running, battery discharged
m mLight bulb filament burnt out or bulbs broken
m mWire connections loose, disconnected or broken
m mLight switch shorting or otherwise faulty
Lights come on but fade out
m
mIf engine not running, battery discharged
Lights give very poor illumination
m
mLamp glasses dirty
m mReflector tarnished or dirty
m mLamps badly out of adjustment
m mIncorrect bulb with too low wattage fitted
m mExisting bulbs old and badly discoloured
m mElectrical wiring too thin not allowing full current to pass
Lights work erratically, flashing on and off,
especially over bumps
m mBattery terminals or earth connections loose
m mLights not earthing properly
m mContacts in light switch faulty
Wiper motor fails to work
m
mBlown fuse
m mWire connections loose, disconnected or broken
m mBrushes badly worn
m mArmature worn or faulty
m mField coils faulty
Wiper motor works very slowly and takes
excessive current
m mCommutator dirty, greasy or burnt
m mDrive spindle binding or damaged
m mArmature bearings dry or unaligned
m mArmature badly worn or faulty
Wiper motor works slowly and takes little current
m
mBrushes badly worn
m mCommutator dirty, greasy or burnt
m mArmature badly worn or faulty
Wiper motor works but wiper blade remains static
m
mDrive spindle damaged or worn
m mWiper motor gearbox parts badly worn

balljoint from the hub carrier using a suitable
“splitter” tool. If such a tool is not available,
support the base of the brake disc and drive
the balljoint taper pin downwards, but screw
on the nut to protect the threads.
4Remove the hub carrier.
5Refitting is a reversal of removal, use a new
driveshaft nut and tighten all nuts and bolts to
the specified torque. Stake the driveshaft nut
after tightening.
6 Track control arm-
removal and refitting
3
1Raise the front of the car and support it
securely.
2Unless a special tool is available to press
the track control arm balljoint from the hub
carrier, the driveshaft will have to be
disconnected as described in Chapter 7,
Section 2, paragraphs 1 to 8 to provide more
space to enable the balljoint taper pin to be
driven from the hub carrier. This should now
be done as described in the preceding
Section (photo).
3Unbolt the inboard end of the track control
arm. This is retained by a pivot bolt and a
clamp (photo).
4As previously explained, a worn balljoint or
flexible pivot bushes will necessitate renewal
of the track control arm complete. Note that itmay, however, be possible to obtain a
replacement balljoint through a motor factor.
5Refitting is a reversal of removal. Tighten all
nuts and bolts to the specified torque. Use a
new driveshaft nut and stake it into the
driveshaft groove after tightening.
7 Front crossmember-
removal and refitting
3
1Raise the front of the car, support securely
with axle stands placed under the
side-members or sill jacking points.
2Remove the front roadwheels.
3Unscrew the nuts from the tie-rod end
balljoint taper pins and then using a balljoint
“splitter” tool disconnect the balljoints from
the steering arms on the hub carrier.
4Unscrew the bolts which hold the inboard
track control arms to the body members, and
also withdraw the pivot bolt from the body
bracket.
5Support the weight of the engine/
transmission using a hoist or support bar
across the top of the engine compartment as
described in Chapter 6.
6Disconnect the lower (central) engine/
transmission flexible mounting from the floor
pan.
7Unscrew the steering rack mounting boltsand remove them. Leave the steering rack
hanging loose.
8Remove the front crossmember mounting
bolts and manoeuvre it from the car.
9Refitting is a reversal of removal. Tighten all
nuts and bolts to the specified torque wrench
settings and on completion, check the front
wheel alignment as described in Chapter 10.
8 Rear shock absorber-
removal and refitting
3
1Open the tailgate and remove the cover
from the shock absorber top mounting which
is located within the luggage area (photo).
2Hold the flats on the spindle with an
open-ended spanner and then unscrew the
self-locking nut.
3Working under the car, disconnect the
shock absorber lower mounting.
4Withdraw the unit from under the wing.
5The shock absorber can be tested as
described in Section 2.
6Refitting is a reversal of removal. Tighten
mounting nuts and bolts to the specified
torque.
9 Rear coil spring-
removal and refitting
3
1Raise the rear of the car and support it
securely on axle stands placed under the
side-members or sill jacking points.
2Remove the roadwheel.
3Place a jack under the brake drum and
support the suspension trailing arm.
4Disconnect the shock absorber lower
mounting and then lower the trailing arm jack
until the coil spring can be withdrawn.
5Refitting is a reversal of removal. If the
spring is being changed, make sure that it is
of the same colour code as the original and
that its lower coil is correctly located up
against its stop in the spring pan.
6Tighten the shock absorber lower mounting
bolt to the specified torque.
11•4 Suspension
8.1 Rear shock absorber upper mounting
coverFig. 11.7 Front crossmember bolts (Sec 7)Fig. 11.6 Steering rack mounting bolts
(Sec 7)
6.3 Track control arm inboard fixing6.2 Separating track control arm balljoint
from hub carrier

12
For dimensions, weights etc. refer to the Introductory Section of this Manual.
Chapter 12 Bodywork
For modifications, and information applicable to later models, see Supplement at end of manual
Bonnet - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Bonnet - lock and release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Centre console - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 21
Door - dismantling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Door - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Door trim panel - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 11
Facia panel - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Fixed side window (five-door) - removal and refitting . . . . . . . . . . . . 17
Front bumpers - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . 9
Front seat - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Front wing - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Grab handles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Maintenance - bodywork and underframe . . . . . . . . . . . . . . . . . . . . 2Maintenance - upholstery and carpets . . . . . . . . . . . . . . . . . . . . . . . 3
Major body damage - repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Minor body damage - repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Opening side window (three-door) - removal and refitting . . . . . . . . 18
Radiator grille - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 6
Rear bumpers - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 26
Rear seat - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Rear view mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Roof rack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Seat belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Sunroof - operation and maintenance . . . . . . . . . . . . . . . . . . . . . . . 28
Tailgate - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Tailgate glass - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 16
Windscreen glass - removal and refitting . . . . . . . . . . . . . . . . . . . . . 15
12•1
Specifications Contents
Easy,suitable for
novice with little
experienceFairly easy,suitable
for beginner with
some experienceFairly difficult,
suitable for competent
DIY mechanic
Difficult,suitable for
experienced DIY
mechanicVery difficult,
suitable for expert DIY
or professional
Degrees of difficulty
54321
1 General description
The Uno is an all steel, welded Hatchback
of unitary construction available in three- or
five-door versions.
Various levels of trim and equipment are
available depending upon model.
Factory fitted options include a sunroof,
central door locking and electrically-operated
front windows.
2 Maintenance-
bodywork and underframe
1
The general condition of a vehicle’s
bodywork is the one thing that significantly
affects its value. Maintenance is easy, but
needs to be regular. Neglect, particularly after
minor damage, can lead quickly to further
deterioration and costly repair bills. It is
important also to keep watch on those parts
of the vehicle not immediately visible, for
instance the underside, inside all the wheel
arches, and the lower part of the engine
compartment.The basic maintenance routine for the
bodywork is washing - preferably with a lot of
water, from a hose. This will remove all the
loose solids which may have stuck to the
vehicle. It is important to flush these off in
such a way as to prevent grit from scratching
the finish. The wheel arches and underframe
need washing in the same way, to remove any
accumulated mud, which will retain moisture
and tend to encourage rust. Paradoxically
enough, the best time to clean the underframe
and wheel arches is in wet weather, when the
mud is thoroughly wet and soft. In very wet
weather, the underframe is usually cleaned of
large accumulations automatically, and this is
a good time for inspection.
Periodically, except on vehicles with a wax-
based underbody protective coating, it is a
good idea to have the whole of the
underframe of the vehicle steam-cleaned,
engine compartment included, so that a
thorough inspection can be carried out to see
what minor repairs and renovations are
necessary. Steam-cleaning is available at
many garages, and is necessary for the
removal of the accumulation of oily grime,
which sometimes is allowed to become thick
in certain areas. If steam-cleaning facilities are
not available, there are some excellent grease
solvents available which can be brush-applied; the dirt can then be simply hosed off.
Note that these methods should not be used
on vehicles with wax-based underbody
protective coating, or the coating will be
removed. Such vehicles should be inspected
annually, preferably just prior to Winter, when
the underbody should be washed down, and
any damage to the wax coating repaired.
Ideally, a completely fresh coat should be
applied. It would also be worth considering
the use of such wax-based protection for
injection into door panels, sills, box sections,
etc, as an additional safeguard against rust
damage, where such protection is not
provided by the vehicle manufacturer.
After washing paintwork, wipe off with a
chamois leather to give an unspotted clear
finish. A coat of clear protective wax polish
will give added protection against chemical
pollutants in the air. If the paintwork sheen
has dulled or oxidised, use a cleaner/polisher
combination to restore the brilliance of the
shine. This requires a little effort, but such
dulling is usually caused because regular
washing has been neglected. Care needs to
be taken with metallic paintwork, as special
non-abrasive cleaner/polisher is required to
avoid damage to the finish. Always check that
the door and ventilator opening drain holes
and pipes are completely clear, so that water

13
Chapter 13 Supplement:
Revisions and information on later models
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Routine maintenance - all models from June 1991 . . . . . . . . . . . 3
Engine 903 and 1299/1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Sump pan sealing strips (903 cc engine) - modification
1299 cc engine - description
Rocker cover (903 cc engine) - removal
Cylinder head (903 cc engine) - refitting
Engine - 999 and 1108 cc (FIRE) . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Part A: General
Description
Part B: Operations possible with engine in car
Valve clearances - adjustment
Timing belt - renewal
Camshaft - removal and refitting
Cylinder head - removal and refitting
Sump pan - removal and refitting
Oil pump - removal, checking and refitting
Pistons/connecting rods - removal and refitting
Pistons/connecting rods - separation and piston ring renewal
Engine/transmission mountings - renewal
Part C: Engine removal and dismantling
Method of removal - general
Engine/transmission - removal and separation
Dismantling - general
Complete dismantling
Examination and renovation
Part D: Engine reassembly and refitting
Reassembly - general
Complete reassembly
Engine/transmission - reconnection and refitting
Initial start-up after major overhaul
Engine 1301 cc Turbo ie.................................................................. 6
Part A: General
Description
Lubrication system - description
Part B: Operations possible with engine in car
Camshaft and camshaft carrier - removal and refitting
Cylinder head - removal and refitting
Piston rings
Engine mountings - renewal
Timing belt - renewal
Oil pump drivegear cover plate
Engine oil cooler - removal and refittingPart C: Engine removal, dismantling, reassembly and refitting
Engine/transmission - removal and separation
Engine - dismantling and reassembly
Engine/transmission - reconnection and refitting
Initial start-up after major overhaul
Engine 1372 cc ie and 1372 cc Turbo ie......................................... 7
Part A: General
Description
Maintenance
Part B: Operations possible with the engine in car
Valve clearances - checking and adjustment
Timing belt, tensioner and sprockets - removal and refitting
Camshaft front oil seal - renewal
Camshaft, housing and followers - removal and refitting
Camshaft housing, camshaft and cam followers - dismantling,
inspection and reassembly
Cylinder head (1372 cc ie engine) - removal and refitting
Cylinder head (1372 cc Turbo ie engine) - removal and refitting
Cylinder head - inspection and renovation
Crankshaft front oil seal - removal and renewal
Crankshaft rear oil seal - removal and renewal
Flywheel - removal, inspection and refitting
Sump - removal and refitting
Oil pump - removal, checking and refitting
Pistons/connecting rods - removal and refitting
Pistons/connecting rods - examination and renovation
Engine/transmission mountings - renewal
Part C: Engine removal and dismantling
Method of removal - general
1372 cc ie engine/transmission - removal and separation
1372 cc Turbo ie engine/transmission - removal and separation
Engine dismantling - general
Auxiliary shaft - removal, inspection and refitting
Engine - complete dismantling
Crankshaft and main bearings - removal
Engine components - examination and renovation
Part D: Engine reassembly
Reassembly - general
Crankshaft and main bearings - refitting
Pistons and connecting rods - refitting
Oil pump - refitting
Sump - refitting
Flywheel - refitting
Auxiliary shaft - refitting
Cylinder head - refitting
Timing belt and covers - refitting
Engine/transmission - reconnection and refitting
Initial start-up after major overhaul
13•1
Contents