1983 FIAT UNO run flat

Roadside Repairs0•7
Connect one end of the red jump lead to
the positive (+) terminal of the flat
batteryConnect the other end of the red lead to
the positive (+) terminal of the booster
battery.Connect one end of the black jump lead
to the negative (-) terminal of the
booster battery
Connect the other end of the black
jump lead to a bolt or bracket on the
engine block, well away from the
battery, on the vehicle to be started.
–
+
+
–
123
4
Make sure that the jump leads will not
come into contact with the fan, drive-
belts or other moving parts of the
engine.5
Start the engine using the booster
battery, then with the engine running at
idle speed, disconnect the jump leads in
the reverse order of connection.6
Jump starting will get you out
of trouble, but you must correct
whatever made the battery go
flat in the first place. There are
three possibilities:
1The battery has been drained by
repeated attempts to start, or by
leaving the lights on.
2The charging system is not working
properly (alternator drivebelt slack
or broken, alternator wiring fault or
alternator itself faulty).
3The battery itself is at fault
(electrolyte low, or battery worn out).
Booster battery (jump) starting
When jump-starting a car using a
booster battery, observe the following
precautions:
4Before connecting the booster
battery, make sure that the ignition is
switched off.
4Ensure that all electrical equipment
(lights, heater, wipers, etc) is
switched off.4Make sure that the booster battery is
the same voltage as the discharged
one in the vehicle.
4If the battery is being jump-started
from the battery in another vehicle,
the two vehcles MUST NOT TOUCH
each other.
4Make sure that the transmission is in
neutral (or PARK, in the case of
automatic transmission).
Jump starting

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

Fault FindingREF•9
REF
Introduction
The vehicle owner who does his or her own
maintenance according to the recommended
schedules should not have to use this section
of the manual very often. Modern component
reliability is such that, provided those items
subject to wear or deterioration are inspected
or renewed at the specified intervals, sudden
failure is comparatively rare. Faults do not
usually just happen as a result of sudden
failure, but develop over a period of time.
Major mechanical failures in particular are
usually preceded by characteristic symptoms
over hundreds or even thousands of miles.
Those components which do occasionally fail
without warning are often small and easily
carried in the vehicle.
With any fault finding, the first step is to
decide where to begin investigations.
Sometimes this is obvious, but on other
occasions a little detective work will be
necessary. The owner who makes half a
dozen haphazard adjustments or
replacements may be successful in curing a
fault (or its symptoms), but he will be none the
wiser if the fault recurs and he may well have
spent more time and money than was
necessary. A calm and logical approach will
be found to be more satisfactory in the long
run. Always take into account any warning
signs or abnormalities that may have been
noticed in the period preceding the fault –
power loss, high or low gauge readings,
unusual noises or smells, etc – and remember
that failure of components such as fuses or
spark plugs may only be pointers to some
underlying fault.
The pages which follow here are intended
to help in cases of failure to start or
breakdown on the road. There is also a Fault
Diagnosis Section at the end of each Chapter
which should be consulted if the preliminary
checks prove unfruitful. Whatever the fault,
certain basic principles apply. These are as
follows:Verify the fault. This is simply a matter of
being sure that you know what the symptoms
are before starting work. This is particularly
important if you are investigating a fault for
someone else who may not have described it
very accurately.
Don’t overlook the obvious. For example,
if the vehicle won’t start, is there petrol in the
tank? (Don’t take anyone else’s word on this
particular point, and don’t trust the fuel gauge
either!) If an electrical fault is indicated, look
for loose or broken wires before digging out
the test gear.
Cure the disease, not the symptom.
Substituting a flat battery with a fully charged
one will get you off the hard shoulder, but if
the underlying cause is not attended to,the
new battery will go the same way. Similarly,
changing oil-fouled spark plugs for a new set
will get you moving again, but remember that
the reason for the fouling (if it wasn’t simply an
incorrect grade of plug) will have to be
established and corrected.
Don’t take anything for granted.
Particularly, don’t forget that a ‘new’
component may itself be defective (especially
if it’s been rattling round in the boot for
months), and don’t leave components out of a
fault diagnosis sequence just because they
are new or recently fitted. When you do finally
diagnose a difficult fault, you’ll probably
realise that all the evidence was there from
the start.
Electrical faults
Electrical faults can be more puzzling than
straightforward mechanical failures, but they
are no less susceptible to logical analysis if
the basic principles of operation are
understood. Vehicle electrical wiring exists in
extremely unfavourable conditions – heat,
vibration and chemical attack and the first
things to look for are loose or corroded
connections and broken or chafed wires,especially where the wires pass through holes
in the bodywork or are subject to vibration.
All metal-bodied vehicles in current
production have one pole of the battery
‘earthed’, ie connected to the vehicle
bodywork, and in nearly all modern vehicles it
is the negative (–) terminal. The various
electrical components – motors, bulb holders,
etc – are also connected to earth, either by
means of a lead or directly by their mountings.
Electric current flows through the component
and then back to the battery via the
bodywork. If the component mounting is
loose or corroded, or if a good path back to
the battery is not available, the circuit will be
incomplete and malfunction will result. The
engine and/or gearbox are also earthed by
means of flexible metal straps to the body or
subframe; if these straps are loose or missing,
starter motor, generator and ignition trouble
may result.
Assuming the earth return to be
satisfactory, electrical faults will be due either
to component malfunction or to defects in the
current supply. Individual components are
dealt with in Chapter 9. If supply wires are
broken or cracked internally this results in an
open-circuit, and the easiest way to check for
this is to bypass the suspect wire temporarily
with a length of wire having a crocodile clip or
suitable connector at each end. Alternatively,
a 12V test lamp can be used to verify the
presence of supply voltage at various points
along the wire and the break can be thus
isolated.
If a bare portion of a live wire touches the
bodywork or other earthed metal part, the
electricity will take the low-resistance path
thus formed back to the battery: this is known
as a short-circuit. Hopefully a short-circuit will
blow a fuse, but otherwise it may cause
burning of the insulation (and possibly further
short-circuits) or even a fire. This is why it is
inadvisable to bypass persistently blowing
fuses with silver foil or wire.

Engine fails to turn when starter
operated
m mFlat battery (recharge use jump leads or
push start)
m mBattery terminals loose or corroded
m mBattery earth to body defective
m mEngine earth strap loose or broken
m mStarter motor (or solenoid) wiring loose or
broken
m mIgnition/starter switch faulty
m mMajor mechanical failure (seizure)
m mStarter or solenoid internal fault (see
Chapter 12)
Starter motor turns engine slowly
m mPartially discharged battery (recharge, use
jump leads, or push start)
m mBattery terminals loose or corroded
m mBattery earth to body defective
m mEngine earth strap loose m mStarter motor (or solenoid) wiring loose
m mStarter motor internal fault (see Chapter 9)
Starter motor spins without
turning engine
m mFlywheel gear teeth damaged or worn
m mStarter motor mounting bolts loose
Engine turns normally but fails to
start
m mDamp or dirty HT leads and distributor cap
(crank engine and check for spark)
m mNo fuel in tank (check for delivery at
carburettor) m mExcessive choke (hot engine) or insufficient
choke (cold engine)
m mFouled or incorrectly gapped spark plugs
(remove, clean and regap)
m mOther ignition system fault (see Chapter 4)
m mOther fuel system fault (see Chapter 3)
m mPoor compression (see Chapter 1)
m mMajor mechanical failure (eg camshaft drive)
Engine fires but will not run
m
mInsufficient choke (cold engine)
m mAir leaks at carburettor or inlet manifold
m mFuel starvation (see Chapter 3)
m mIgnition fault (see Chapter 4)
Engine will not start
REF•10Fault Finding
Spares and tool kit
Most vehicles are supplied only with
sufficient tools for wheel changing; the
Maintenance and minor repairtool kit detailed
in Tools and working facilities,with the
addition of a hammer, is probably sufficient
for those repairs that most motorists would
consider attempting at the roadside. In
addition a few items which can be fitted
without too much trouble in the event of a
breakdown should be carried. Experience and
available space will modify the list below, but
the following may save having to call on
professional assistance:
m mSpark plugs, clean and correctly gapped
m mHT lead and plug cap – long enough to
reach the plug furthest from the distributor
m mDistributor rotor, condenser and contact
breaker points (where applicable)m mDrivebelt(s) — emergency type may
suffice
m mSpare fuses
m mSet of principal light bulbs
m mTin of radiator sealer and hose bandage
m mExhaust bandage
m mRoll of insulating tape
m mLength of soft iron wire
m mLength of electrical flex
m mTorch or inspection lamp (can double as
test lamp)
m mBattery jump leads
m mTow-rope
m mIgnition waterproofing aerosol
m mLitre of engine oil
m mSealed can of hydraulic fluid
m mEmergency windscreen
m mWormdrive clips
m mTube of filler pasteIf spare fuel is carried, a can designed for
the purpose should be used to minimise risks
of leakage and collision damage. A first aid kit
and a warning triangle, whilst not at present
compulsory in the UK, are obviously sensible
items to carry in addition to the above. When
touring abroad it may be advisable to carry
additional spares which, even if you cannot fit
them yourself, could save having to wait while
parts are obtained. The items below may be
worth considering:
m mClutch and throttle cables
m mCylinder head gasket
m mAlternator brushes
m mTyre valve core
One of the motoring organisations will be
able to advise on availability of fuel, etc, in
foreign countries.
A simple test lamp is useful for checking
electrical faultsCarrying a few spares may save you a long walk!