1983 FIAT UNO checking oil

Idle speed and mixture
adjustment¢
29Before carrying out any adjustments, the
engine must be at operating temperature, the
fan having cut in at second speed and then
switched off.
30Release the locknut and turn the main idle
speed screw in the throttle valve housing until
the engine idles at the specified speed. This
should be all that is necessary to obtain the
correct idle speed, as the throttle valve plate
base setting is set during production.
However, if wear has taken place, or incorrect
adjustment has been carried out previously,
proceed in the following way.
31Disconnect the intake duct from the
throttle valve housing. Release the locknut on
the base (small) adjusting screw, and turn thescrew until there is a clearance between the
lower edge of the throttle valve plate and the
throat wall of between 0.05 and 0.1 mm
(photos).
32With the engine still at operating
temperature, start the engine, and having
released the locknut, turn the main (large) idle
speed screw fully clockwise to close the
bypass passage.
33Now turn the base (small) screw until the
engine idles at between 700 and 800 rpm.
Tighten the locknut.
34Finally, turn the main (large) adjusting
screw to give an idle speed of between 800
and 900 rpm.
35It is unlikely that the mixture will require
alteration, but if it does, connect an exhaust
gas analyser to the car in accordance with the
equipment manufacturer’s instructions.
36With the engine at operating temperature,
prise out the tamperproof cap, and turn the
mixture screw, which is located in the airflow
meter, until the CO level is as given in the
Specifications. Turning the screw clockwise
richens the mixture, turning it anti-clockwise
weakens the mixture. Use a close-fitting Allen
key for the adjustment (photo).
Fuel injection system -
electrical testsª
37When carrying out checks to trace a fault
in the system, an ohmmeter should be used
for the following tests.
38Disconnect the multipin connector from
the ECU, and also the one from the system
control relay, and apply the probes of the
ohmmeter in accordance with the following
sequence to check for continuity in thecables. The component wiring plug will of
course be disconnected for the test.
ECU connector Component connector
plug terminal plug terminal
1 1 of ignition coil
2 2 of throttle position
switch
3 3 of throttle position
switch
4 50 of ignition switch
5 Earth
5 5 of airflow meter
7 7 of airflow meter
8 8 of airflow meter
9 9 of airflow meter
9 9 of throttle position
switch
9 18 of supplementary air
valve
9 87 main relay socket
10 10 of coolant temperature
sensor
12 Injector terminals
13 Earth
System control Component connector
relay connector plug terminal
plug terminal
1 1 of ignition coil
15 15 of ignition switch
30 Battery positive
31 Earth
50 50 of ignition switch
87 Injector terminals
87 18 of throttle position
switch
87 9 of ECU multipin socket
87b Fuel pump (fused)
13•68 Supplement: Revisions and information on later models
Fig. 13.42 ECU and component connector plug terminals - 1301 cc Turbo ie engine (Sec 9C)
For colour code see main wiring diagrams
9C.31C Checking throttle valve plate
opening with a feeler blade
9C.36 Using an Allen key to adjust the
mixture (CO level)
9C.31B Idle speed base setting screw (1)
and main adjustment screw (2)9C.31A Disconnecting the throttle valve
housing intake duct9C.27B Removing the air cleaner element

final drive unit. The inboard end of each
driveshaft locates in the differential. All helical
gear clusters are in constant mesh, with the
fifth gear assembly located on an intermediate
plate mounted on the rear end of the gearbox.
Gear engagement is made by sliding
synchromesh hubs. Gearchanges are made
via a central floor-mounted gear lever.
MaintenanceÁ
2Maintenance is limited to periodically
checking the oil level, topping up as required,
renewing the oil, and visually inspecting the
transmission for oil leaks. The most likely
source of an oil leak will be from the driveshaft
seals.
Oil level - checkingÁ
3For improved access, jack up the vehicle
and support it on axle stands. Note that the
vehicle must be level in order to carry out this
check.
4If the transmission is hot due to the car
having been driven recently, allow it to cool
before making the check; oil foams when hot
and can produce a false level reading. Wipe
the area around the filler plug then unscrew
and remove the plug from its location in the
front of the casing. The oil should be level with
the base of the filler plug hole.
5If necessary, top up with oil of the specified
grade.
6On completion refit the filler plug, wipe
clean any oil spillage, then lower the car to the
ground.
Oil - renewalÁ
7The transmission oil should ideally be
drained when hot (directly after the vehicle
has been used). For improved access, jack up
the vehicle and support it on axle stands.
Note that the vehicle must be level to ensure a
correct level reading when topping up.
8Wipe clean the area around the filler plug on
the front face of the transmission casing, then
unscrew and remove the plug.
9Position a suitable container underneath
the drain plug (located at the left-hand end of
the transmission). Unscrew the plug and allow
the oil to drain into the container. Oil will start
to drain before the plug is fully withdrawn so
take precautions against scalding. Wait about
ten minutes to allow the oil to drain fully.
10When the oil has finished draining, clean
around the threads of the drain plug and its
location in the transmission casing, then refit
the plug and tighten it.
11Refill the transmission with the specified
quantity and grade of oil through the
filler/lever plug hole. With the vehicle level and
the transmission cold check the oil level as
described above, then refit and tighten the
plug. Lower the vehicle to complete.
Gearlever and linkages - general
12The component parts of the gearchange
and selector assemblies are shown in
Figs. 13.91 and 13.92. They do not normally
Supplement: Revisions and information on later models 13•95
Fig. 13.90 Exploded view of the transmission unit fitted to 1372 cc models (Sec 12)
13
Fig. 13.89 Gearchange control linkage on the 1301 cc Turbo ie model with Antiskid
(Sec 12)

REF•4MOT Test Checks
MExamine the handbrake mechanism,
checking for frayed or broken cables,
excessive corrosion, or wear or insecurity of
the linkage. Check that the mechanism works
on each relevant wheel, and releases fully,
without binding.
MIt is not possible to test brake efficiency
without special equipment, but a road test can
be carried out later to check that the vehicle
pulls up in a straight line.
Fuel and exhaust systems
MInspect the fuel tank (including the filler
cap), fuel pipes, hoses and unions. All
components must be secure and free from
leaks.
MExamine the exhaust system over its entire
length, checking for any damaged, broken or
missing mountings, security of the retaining
clamps and rust or corrosion.
Wheels and tyres
MExamine the sidewalls and tread area of
each tyre in turn. Check for cuts, tears, lumps,
bulges, separation of the tread, and exposure
of the ply or cord due to wear or damage.
Check that the tyre bead is correctly seated
on the wheel rim, that the valve is sound andproperly seated, and that the wheel is not
distorted or damaged.
MCheck that the tyres are of the correct size
for the vehicle, that they are of the same size
and type on each axle, and that the pressures
are correct.
MCheck the tyre tread depth. The legal
minimum at the time of writing is 1.6 mm over
at least three-quarters of the tread width.
Abnormal tread wear may indicate incorrect
front wheel alignment.
Body corrosion
MCheck the condition of the entire vehicle
structure for signs of corrosion in load-bearing
areas. (These include chassis box sections,
side sills, cross-members, pillars, and all
suspension, steering, braking system and
seat belt mountings and anchorages.) Any
corrosion which has seriously reduced the
thickness of a load-bearing area is likely to
cause the vehicle to fail. In this case
professional repairs are likely to be needed.
MDamage or corrosion which causes sharp
or otherwise dangerous edges to be exposed
will also cause the vehicle to fail.
Petrol models
MHave the engine at normal operating
temperature, and make sure that it is in good
tune (ignition system in good order, air filter
element clean, etc).
MBefore any measurements are carried out,
raise the engine speed to around 2500 rpm,
and hold it at this speed for 20 seconds. Allowthe engine speed to return to idle, and watch
for smoke emissions from the exhaust
tailpipe. If the idle speed is obviously much
too high, or if dense blue or clearly-visible
black smoke comes from the tailpipe for more
than 5 seconds, the vehicle will fail. As a rule
of thumb, blue smoke signifies oil being burnt
(engine wear) while black smoke signifies
unburnt fuel (dirty air cleaner element, or other
carburettor or fuel system fault).
MAn exhaust gas analyser capable of
measuring carbon monoxide (CO) and
hydrocarbons (HC) is now needed. If such an
instrument cannot be hired or borrowed, a
local garage may agree to perform the check
for a small fee.
CO emissions (mixture)
MAt the time of writing, the maximum CO
level at idle is 3.5% for vehicles first used after
August 1986 and 4.5% for older vehicles.
From January 1996 a much tighter limit
(around 0.5%) applies to catalyst-equipped
vehicles first used from August 1992. If the
CO level cannot be reduced far enough to
pass the test (and the fuel and ignition
systems are otherwise in good condition) then
the carburettor is badly worn, or there is some
problem in the fuel injection system or
catalytic converter (as applicable).
HC emissionsMWith the CO emissions within limits, HC
emissions must be no more than 1200 ppm
(parts per million). If the vehicle fails this test
at idle, it can be re-tested at around 2000 rpm;
if the HC level is then 1200 ppm or less, this
counts as a pass.
MExcessive HC emissions can be caused by
oil being burnt, but they are more likely to be
due to unburnt fuel.
Diesel models
MThe only emission test applicable to Diesel
engines is the measuring of exhaust smoke
density. The test involves accelerating the
engine several times to its maximum
unloaded speed.
Note: It is of the utmost importance that the
engine timing belt is in good condition before
the test is carried out.
M
Excessive smoke can be caused by a dirty
air cleaner element. Otherwise, professional
advice may be needed to find the cause.
4Checks carried out on
YOUR VEHICLE’S EXHAUST
EMISSION SYSTEM

REF•8General Repair Procedures
Whenever servicing, repair or overhaul work
is carried out on the car or its components,
observe the following procedures and
instructions. This will assist in carrying out the
operation efficiently and to a professional
standard of workmanship.
Joint mating faces and gaskets
When separating components at their
mating faces, never insert screwdrivers or
similar implements into the joint between the
faces in order to prise them apart. This can
cause severe damage which results in oil
leaks, coolant leaks, etc upon reassembly.
Separation is usually achieved by tapping
along the joint with a soft-faced hammer in
order to break the seal. However, note that
this method may not be suitable where
dowels are used for component location.
Where a gasket is used between the mating
faces of two components, a new one must be
fitted on reassembly; fit it dry unless otherwise
stated in the repair procedure. Make sure that
the mating faces are clean and dry, with all
traces of old gasket removed. When cleaning a
joint face, use a tool which is unlikely to score
or damage the face, and remove any burrs or
nicks with an oilstone or fine file.
Make sure that tapped holes are cleaned
with a pipe cleaner, and keep them free of
jointing compound, if this is being used,
unless specifically instructed otherwise.
Ensure that all orifices, channels or pipes
are clear, and blow through them, preferably
using compressed air.
Oil seals
Oil seals can be removed by levering them
out with a wide flat-bladed screwdriver or
similar implement. Alternatively, a number of
self-tapping screws may be screwed into the
seal, and these used as a purchase for pliers or
some similar device in order to pull the seal free.
Whenever an oil seal is removed from its
working location, either individually or as part
of an assembly, it should be renewed.
The very fine sealing lip of the seal is easily
damaged, and will not seal if the surface it
contacts is not completely clean and free from
scratches, nicks or grooves. If the original
sealing surface of the component cannot be
restored, and the manufacturer has not made
provision for slight relocation of the seal
relative to the sealing surface, the component
should be renewed.
Protect the lips of the seal from any surface
which may damage them in the course of
fitting. Use tape or a conical sleeve where
possible. Lubricate the seal lips with oil before
fitting and, on dual-lipped seals, fill the space
between the lips with grease.
Unless otherwise stated, oil seals must be
fitted with their sealing lips toward the
lubricant to be sealed.
Use a tubular drift or block of wood of the
appropriate size to install the seal and, if the
seal housing is shouldered, drive the seal
down to the shoulder. If the seal housing isunshouldered, the seal should be fitted with
its face flush with the housing top face (unless
otherwise instructed).
Screw threads and fastenings
Seized nuts, bolts and screws are quite a
common occurrence where corrosion has set
in, and the use of penetrating oil or releasing
fluid will often overcome this problem if the
offending item is soaked for a while before
attempting to release it. The use of an impact
driver may also provide a means of releasing
such stubborn fastening devices, when used
in conjunction with the appropriate
screwdriver bit or socket. If none of these
methods works, it may be necessary to resort
to the careful application of heat, or the use of
a hacksaw or nut splitter device.
Studs are usually removed by locking two
nuts together on the threaded part, and then
using a spanner on the lower nut to unscrew
the stud. Studs or bolts which have broken off
below the surface of the component in which
they are mounted can sometimes be removed
using a stud extractor. Always ensure that a
blind tapped hole is completely free from oil,
grease, water or other fluid before installing
the bolt or stud. Failure to do this could cause
the housing to crack due to the hydraulic
action of the bolt or stud as it is screwed in.
When tightening a castellated nut to accept
a split pin, tighten the nut to the specified
torque, where applicable, and then tighten
further to the next split pin hole. Never slacken
the nut to align the split pin hole, unless stated
in the repair procedure.
When checking or retightening a nut or bolt
to a specified torque setting, slacken the nut
or bolt by a quarter of a turn, and then
retighten to the specified setting. However,
this should not be attempted where angular
tightening has been used.
For some screw fastenings, notably
cylinder head bolts or nuts, torque wrench
settings are no longer specified for the latter
stages of tightening, “angle-tightening” being
called up instead. Typically, a fairly low torque
wrench setting will be applied to the
bolts/nuts in the correct sequence, followed
by one or more stages of tightening through
specified angles.
Locknuts, locktabs and washers
Any fastening which will rotate against a
component or housing during tightening
should always have a washer between it and
the relevant component or housing.
Spring or split washers should always be
renewed when they are used to lock a critical
component such as a big-end bearing
retaining bolt or nut. Locktabs which are
folded over to retain a nut or bolt should
always be renewed.
Self-locking nuts can be re-used in non-
critical areas, providing resistance can be felt
when the locking portion passes over the bolt
or stud thread. However, it should be noted
that self-locking stiffnuts tend to lose theireffectiveness after long periods of use, and
should then be renewed as a matter of course.
Split pins must always be replaced with
new ones of the correct size for the hole.
When thread-locking compound is found
on the threads of a fastener which is to be re-
used, it should be cleaned off with a wire
brush and solvent, and fresh compound
applied on reassembly.
Special tools
Some repair procedures in this manual
entail the use of special tools such as a press,
two or three-legged pullers, spring com-
pressors, etc. Wherever possible, suitable
readily-available alternatives to the manu-
facturer’s special tools are described, and are
shown in use. In some instances, where no
alternative is possible, it has been necessary
to resort to the use of a manufacturer’s tool,
and this has been done for reasons of safety
as well as the efficient completion of the repair
operation. Unless you are highly-skilled and
have a thorough understanding of the
procedures described, never attempt to
bypass the use of any special tool when the
procedure described specifies its use. Not
only is there a very great risk of personal
injury, but expensive damage could be
caused to the components involved.
Environmental considerations
When disposing of used engine oil, brake
fluid, antifreeze, etc, give due consideration to
any detrimental environmental effects. Do not,
for instance, pour any of the above liquids
down drains into the general sewage system,
or onto the ground to soak away. Many local
council refuse tips provide a facility for waste
oil disposal, as do some garages. If none of
these facilities are available, consult your local
Environmental Health Department, or the
National Rivers Authority, for further advice.
With the universal tightening-up of legis-
lation regarding the emission of environmen-
tally-harmful substances from motor vehicles,
most vehicles have tamperproof devices fitted
to the main adjustment points of the fuel
system. These devices are primarily designed
to prevent unqualified persons from adjusting
the fuel/air mixture, with the chance of a
consequent increase in toxic emissions. If
such devices are found during servicing or
overhaul, they should, wherever possible, be
renewed or refitted in accordance with the
manufacturer’s requirements or current
legislation.
Note: It is
antisocial and
illegal to dump
oil down the
drain. To find
the location of
your local oil
recycling
bank, call this
number free.

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!