1983 FIAT UNO chapter 13

Engine idles roughly
m mMixture too weak
m mAir leak in carburettor
m mAir leak at inlet manifold to cylinder head, or inlet manifold to
carburettor
m mCarburettor incorrectly adjusted
m mOther fuel system fault (see Chapter 3)
m mLow tension leads on coil loose
m mLow tension lead to distributor loose
m mDirty, incorrectly set, or pitted contact breaker points
m mTracking across inside of distributor cover
m mFaulty coil
m mIgnition leads loose
m mSpark plugs fouled or incorrectly gapped.
m mIgnition timing incorrect
m mOther ignition fault (see Chapter 4)
m mIncorrect valve clearances
m mWidely differing cylinder compressions
m mLow battery voltage (charging fault)
m mBattery leads loose on terminals
m mBattery earth strap loose on body attachment point
m mEngine earth lead loose
Pre-ignition (pinking) during acceleration
m
mIncorrect grade of fuel being used
m mIgnition timing over-advanced
m mOther ignition fault (see Chapter 4)
m mEngine overheated
m mExcessive carbon build-up
m mFuel system fault (see Chapter 3)
m mValve timing incorrect (after rebuild)
m mMixture too weak
Engine runs on after switching off
m
mIdle speed too high
m mIncorrect type of spark plug
m mOverheating
m mExcessive carbon build-up
m mOther emission control fault (see Chapter 3)
Oil being lost due to leaks
m
mLeaking oil filter gasket
m mLeaking rocker cover gasket
m mLeaking timing gear cover gasket
m mLeaking sump gasket
m mLoose sump plug
Low oil pressure (verify accuracy of sender before
dismantling engine!)
m mOil level low
m mEngine overheating
m mIncorrect grade of oil in use
m mOil filter clogged or bypass valve stuck
m mPressure relief valve stuck or defective
m mOil pick-up strainer clogged or loose
m mMain or big-end bearings worn
m mOil pump worn or mountings loose
Excessive oil consumption
m
mOverfilling
m mLeaking gaskets or drain plug washer
m mValve stem oil seals worn, damaged or missing after rebuild
m mValve stems and/or guides worn
m mPiston rings and/or bores worn
m mPiston oil return holes clogged
Oil contaminated with water
m
mExcessive cold running
m mLeaking head gasket
m mCracked block or head
Oil contaminated with fuel
m
mExcessive use of choke
m mWorn piston rings and/or bores
Unusual mechanical noises
m
mUnintentional mechanical contact (eg fan blade)
m mWorn drivebelt
m mWorn valvegear (tapping noises from top of engine) or incorrect
clearance
m mPeripheral component fault (generator, coolant pump)
m mWorn big-end bearings (regular heavy knocking, perhaps less under
load)
m mWorn main bearings (rumbling and knocking, perhaps worsening
under load)
m mSmall-end bushes or gudgeon pins worn (light metallic tapping)
m mPiston slap (most noticeable when engine cold)
m mWorn timing chain and gears (rattling from front of engine)
m mWorn crankshaft (knocking, rumbling and vibration)
1•36 All engines

2
System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “No loss” with radiator and integral expansion tank. Electric cooling
fan, belt-driven coolant pump, thermostat on cylinder head
General
Radiator fan cuts in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 to 94ºC (194 to 201ºF)
Radiator fan switches off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 to 89ºC (185 to 192ºF)
Thermostat opens:
903 cc engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 to 89ºC (185 to 192ºF)
1116 cc and 1301 cc engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 to 87ºC (181 to 188.6ºF)
Fully open:
903 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100ºC (212ºF)
1116 cc and 1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95ºC (203ºF)
Expansion tank pressure cap rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.78 bar (11 lbf/in2)
Coolant
Capacity:
903 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 litre (8.1 pint)
1116 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.0 litre (10.6 pint)
1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 litre (10.9 pint)
Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ethylene glycol based antifreeze
Torque wrench settingsNm lbf ft
Temperature sender switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Coolant pump mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 25
Alternator adjuster and mountings nuts . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Chapter 2 Cooling and heating systems
For modifications, and information applicable to later models, see Supplement at end of manual
Coolant mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Coolant pump - removal, overhaul and refitting . . . . . . . . . . . . . . . . 9
Cooling system - draining, flushing and refilling . . . . . . . . . . . . . . . . 2
Cooling system sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Description and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Drivebelt - tensioning and renewal . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Fault finding - cooling and heating . . . . . . . . . . . . See end of ChapterHeater - dismantling, overhaul and reassembly . . . . . . . . . . . . . . . . 13
Heater unit - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Heating and ventilation system - description . . . . . . . . . . . . . . . . . . 11
Radiator - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Radiator fan thermostatic switch - removal, checking and refitting . 5
Radiator fan - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . 6
Thermostat - removal, testing and refitting . . . . . . . . . . . . . . . . . . . . 4
2•1
Specifications Contents
1 Description and
maintenance
1
1The cooling system consists of a
front-mounted radiator with built-in expansion
tank, a coolant pump (belt-driven from the
crankshaft pulley) and a thermostatically-
controlled electric cooling fan.
2In order to assist rapid warm-up, athermostat is located in a housing at the
left-hand end of the cylinder head. The hose
connections to the thermostat housing vary
according to model.
3The heater is supplied with coolant from the
engine and incorporates a matrix and blower
with the necessary controls.
4The throttle valve plate block of the
carburettor is coolant-heated as a means of
improving fuel atomisation.
5Maintenance is minimal as in theory no
coolant should ever be lost from theexpansion tank. Regularly check that the
coolant level is between 50.0 and 70.0 mm
(1.97 and 2.8 in) above the MIN mark on the
tank with the engine cold. The need for
regular topping up will indicate a leak
somewhere in the system. If one cannot be
found suspect an internal leak in the engine
although this is usually confirmed by a rise in
the engine oil level and water on the dipstick
(photo). Any topping-up should be done using
an antifreeze mixture (see Section 3), not plain
water.
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

3
System type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rear mounted fuel tank, mechanically-operated fuel pump,
downdraught carburettor
Air cleaner element
903 cc (45) and 1116 cc (55) engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion W121
1116 cc (60) and 1299/1301 cc (70) engines . . . . . . . . . . . . . . . . . . . . . Champion W136
Fuel tank
Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.0 litre (9.25 gal)
Octane rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leaded 97 RON minimum (see Supplement for use of unleaded petrol)
Fuel filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion L101
Carburettor - calibration (dimensions in mm)
Weber 32 ICEV 50/250/1
Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 903 cc engine
Venturi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Auxiliary venturi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5
Main jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.12
Air bleed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.70
Emulsion tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F89
Idle jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.47
Air idle jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.60
Pump jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40
Pump outlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40
Superfeed jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.80
Superfeed mixture jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.50
Fuel inlet needle valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.50
Anti-syphon device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.00
Idle mixture adjustment hole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.50
Float setting (fuel level) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5 to 11.0
Float setting (travel/stroke) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45.0
Fast idle (throttle valve gap) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.75 to 0.80
Accelerator pump delivery (ten strokes) . . . . . . . . . . . . . . . . . . . . . . . . . 4.0 to 5.5 cc
Chapter 3 Fuel system
For modifications, and information applicable to later models, see Supplement at end of manual
Accelerator cable - adjustment and renewal . . . . . . . . . . . . . . . . . . 17
Air cleaner - servicing, removal and refitting . . . . . . . . . . . . . . . . . . . 2
Carburettor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Carburettor idle speed and mixture - adjustment . . . . . . . . . . . . . . . 7
Carburettor (Solex C32 DISA 12) - servicing and adjustment . . . . . . 13
Carburettor (Solex C30 - 32 CIC/1) - servicing and adjustment . . . . 15
Carburettor (Solex C32 DISA 11) - servicing and adjustment . . . . . . 10
Carburettor (Weber 30/32 DMTR 90/250) - servicing and
adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Carburettor (Weber 32 ICEV 50/250/1) - servicing and adjustment . . 9
Carburettor (Weber 32 ICEV 51/250) - servicing and adjustment . . . 12Carburettors (Weber 32 ICEE/250 and Solex C32 DISA 14) -
description and adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Carburettors - general . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Choke control cable - removal and refitting . . . . . . . . . . . . . . . . . . . 18
Description and maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Economy meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Fault finding - fuel system . . . . . . . . . . . . . . . . . . . See end of Chapter
Fuel level transmitter - removal and refitting . . . . . . . . . . . . . . . . . . . 4
Fuel pump - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Fuel tank - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Manifolds and exhaust system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3•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

Engine idle speed
At normal operating temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 to 850 rev/min
CO percentage at idle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 maximum
Torque wrench settingsNm lbf ft
Exhaust manifold nuts (903 cc) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
Exhaust and intake manifold nuts (1116 cc, 1301 cc) . . . . . . . . . . . . . . 28 20
Fuel pump nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 20
Carburettor mounting nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 18
3•4 Fuel system
2.11B Air cleaner mounting bracket and
pipe clip2.11A Air cleaner mounting studs (1116 cc)2.9 Crankcase vent hose at air cleaner
1 Description and
maintenance
1
1The fuel system consists of a rear-mounted
fuel tank, a mechanically-operated fuel pump
and a carburettor and air cleaner.
2On all engines except the 1301 cc a single
venturi downdraught carburettor is fitted. On
the 1301 cc version, a dual barrel carburettor
is fitted.
3Maintenance consists of periodically
checking the condition and security of the fuel
hoses to the pump and carburettor. The fuel
pump cannot be cleaned or repaired and in
the event of a fault developing, the pump
must be renewed.
4On ES versions, an electronic fuel cut-out
device is fitted which reduces fuel
consumption on overrun, see Chapter 9,
Section 33.
2 Air cleaner- servicing,
removal and refitting
1
1The air cleaner air intake draws air either
from the front of the car or from the outside of
the exhaust manifold according to ambient
temperature (photo).
2At an ambient temperature of 13ºC (55ºF)
and above, the SUN symbol should align with
the intake spout arrow head. Remove the
cover nuts and turn the cover.
3At an ambient temperature lower than this,
move the air cleaner cover until the
SNOWFLAKE symbol aligns with the intake
spout arrow head.
4At the intervals specified in “Routine
Maintenance” renew the air cleaner filter
element.
5To do this, remove the cover nuts and take
off the cover (photo).6Take out the filter element and discard it.
Wipe out the air cleaner casing (photo).
7Locate the new element and refit the cover
aligning the appropriate symbols.903 cc engine
8To remove the air cleaner from the 903 cc
engine, unscrew the nuts and take off the
cover. Lift out the filter element.
9Unbolt the air cleaner casing from the
carburettor flange and from the bracket on the
rocker cover. Disconnect the vent hose
(photo).
10Disconnect the warm and cool air intake
hoses from their collecting points and lift the
air cleaner from the engine.
1116 cc and 1301 cc engines
11Removing the air cleaner from the 1116 cc
engine is similar to that described for the
903 cc engine, but having a cylinder head
support bracket (photos).
2.6 Removing air cleaner element
2.5 Air cleaner cover2.1 Air cleaner hot air intake

pump jet and give ten full strokes of the
throttle lever, pausing between each stroke to
allow fuel to finish dripping.
8The total volume of fuel collected should be
between 2.5 and 4.5 cc. Adjust the nut on the
pump control and if necessary to increase or
decrease the volume of fuel ejected.
Fast idle adjustment
9With the choke valve plate fully closed, the
throttle valve plate should be open to give a
dimension (X) (Fig. 3.18) of between 0.90 and
1.0 mm (0.035 to 0.039 in). Use a twist drill of
suitable diameter to measure the gap. If
necessary, adjust by means of the screw and
locknut.
Anti-flooding device
10Close the choke valve plate by means of
the control lever. At the same time, push the
lean out valve rod towards the valve.
11There should be a gap (X) (Fig. 3.19)
between the edge of the choke valve plateand the carburettor throat of between 4.75
and 5.25 mm (0.187 to 0.207 in). Adjust if
necessary by means of the screw and locknut
on the lean out valve.
11 Carburettors (Weber 32 ICEE/
250 and Solex C32 DISA 14)-
description and adjustment
4
1One of these carburettors is used on
903 cc ES engines. They are very similar to
the Weber 32 ICEV 50/250 and Solex
C32 DISA 11 already described in this
Chapter except that a fuel cut-out solenoid
valve is fitted in association with the Digiplex
ignition system (see Chapters 4 and 9).
2The solenoid valve cuts off the supply of
fuel to the carburettor whenever the
accelerator pedal is released during overrun
conditions.
3A fuel cut-out device control unit receives
information regarding engine speed from the
static ignition control unit.
4A throttle butterfly switch relays informationthat the accelerator pedal is in the released
state.
5At certain minimum idle speeds during
deceleration, the fuel cut-out solenoid valve is
re-energised so that engine idling is
maintained without the tendency to cut out.
6The Solex type control unit varies the fuel
cut-out point according to the deceleration
value.Fault testing
7Should a fault develop, connect a test lamp
between the fuel cut-out solenoid switch and
a good earth.
8Connect a reliable tachometer to the engine
in accordance with the maker’s instructions.
9Start the engine and raise its speed to
between 3000 and 4000 rev/min, then fully
release the accelerator pedal.
10The test lamp should only go out during
the period when the accelerator pedal is
released. Should the test lamp remain on all
the time, or never come on, check the throttle
switch earth and the solenoid switch
connections.
11Disconnect the multi-plug from the control
unit. Switch on the ignition and check that a
test lamp connected between contact 7 of the
multi-plug and earth will illuminate. If it does
not, there is an open circuit from connection
15/54 of the fuel cut-off switch.
12Switch off the ignition and check for
continuity between contact 3 of the multiplug
and earth. An ohmmeter will be required for
this test.
13If there is no continuity (ohmmeter shows
infinity), check all the system earth
connections. Also check that the wiring plug
under the control unit is properly connected.
14Finally, check the engine speed signal. To
do this, a tachometer must be connected to
the single socket under the control unit within
the engine compartment.
15If the tachometer registers correctly then
this confirms that the electronic ignition
Fuel system 3•9
Fig. 3.18 Fast idle adjustment diagram (Solex C32 DISA 11)
(Sec 10)
X = 0.90 to 1.0 mm (0.035 to 0.039 in)Fig. 3.19 Anti-flooding device adjustment diagram
(Solex C32 DISA 11) (Sec 10)
X = 4.75 to 5.25 mm (0.187 to 0.207 in)
Fig. 3.21 Sectional view of fuel cut-off
switch (Solex C32 DISA 14) (Sec 11)
Fig. 3.20 Moving lean out valve rod
(Solex C32 DISA 11) (Sec 10)
X = 4.75 to 5.25 mm (0.187 to 0.207 in)
3

Anti-flooding device (automatic)
10Pull the choke control fully out and hold the
control lever, on the anti-flooding device,
depressed. There should be a gap (Y)
(Fig. 3.27) between the edge of the choke valve
plate and the carburettor wall of between 3.75
and 4.25 mm (0.15 and 0.17 in). If adjustment is
required, turn the adjuster screw provided.
15 Carburettor
(Solex C30-32 (CIC/1)-
servicing and adjustment
4
1The carburettor top cover with float may be
removed without the need to withdraw the
carburettor from the manifold.
2The other adjustments described in this
Section will require removal of the carburettor.
3Extract the top cover fixing screws and lift
away the top cover with float.
4Refer to Section 9 paragraphs 4 and 5 for
details of removal of the fuel inlet needle
valve.
Float adjustment
5Invert the carburettor cover so that theweight of the floats depresses the ball of the
needle valve.
6Measure the distance between the float and
the surface of the cover gasket. This should
be between 6.5 and 7.5 mm (0.26 and 0.30 in).
If adjustment is required, change the
thickness of the needle valve washer or
carefully bend the float arm.
Accelerator pump
7Refer to Section 10, paragraphs 6 and 7.
The total volume of fuel collected should be
between 7.5 and 9.5 cc. If the volume of fuel
is incorrect, release the locknut and turn the
adjuster screw on the pump lever then re-test
the volume ejected.
Fast idle
8Operate the choke control lever to close the
choke valve plate. The gap between the edge
of the primary throttle valve plate and the
venturi wall should be between 0.90 and
1.00 mm (0.035 and 0.039 in). If adjustment is
required, turn the nut on the fast idle rod.
Automatic anti-flooding device
9The vacuum system of the device can be
checked for leaks by applying a vacuum to
the drilling in the carburettor throttle valve
block. If vacuum cannot be maintained, renew
the diaphragm.
Choke valve plate automatic
opening
10Move the choke control lever to fully close
the choke valve plate and then press the lean
out valve rod. There should now be a gap (X)
(Fig. 3.32) between the edge of the choke
valve plate and the wall of the carburettor
throat of between 4.75 and 5.25 mm (0.187
and 0.207 in).
11Where adjustment is required, release the
locknut and turn the screw on the lean out
valve.
16 Economy meter
1This device is fitted to ES (energy saving)
models. It is essentially a vacuum gauge to
advise the driver with regard to economical
throttle opening related to engine and road
speed. The point of change to a higher gear
can also be deduced from this gauge. The
latter facility is provided by an LED (light
emitting diode).
2Fault testing of the system is described in
Chapter 9.
Fuel system 3•11
Fig. 3.29 Adjusting accelerator pump
stroke (Solex C30-32 CIC/1) (Sec 15)Fig. 3.28 Float setting diagram
(Solex C30-32 CIC/1) (Sec 14)
A = 6.7 to 7.5 mm (0.26 to 0.30 in)
Fig. 3.32 Choke valve plate setting
(Solex C30-32 CIC/1) (Sec 15)
X = 4.75 to 5.25 mm (0.187 to 0.207 in)Fig. 3.30 Fast idle screw on
Solex C30-32 CIC/1 (Sec 15)
A Choke control lever C Lean out valve
B Fast idle adjustmentFig. 3.31 Vacuum drilling for automatic
anti-flooding device (Solex C30-32 CIC/1)
(Sec 15)
3
Fig. 3.27 Anti-flooding device (automatic)
adjustment diagram
(Weber 30/32 DMTR 90/250) (Sec 14)
Y = 3.75 to 4.25 mm (0.148 to 0.167 in)

4
System type
Except ES engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Battery, coil mechanical breaker distributor
ES engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Marelli Digiplex electronic with breakerless distributor
Firing order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 3 - 4 - 2 (No. 1 cylinder at crankshaft pulley end)
Mechanical breaker distributor
Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Marelli or Ducellier
Contact breaker points gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.37 to 0.43 mm (0.015 to 0.017 in)
Condenser capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 to 0.25 µF
Dwell angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 to 58º
Rotor rotational direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clockwise
Ignition timing (dynamic)
903 cc engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5º BTDC at idle
1116 and 1301 cc engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10º BTDC at idle
Centrifugal advance:
903 cc engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Between 30 and 34º max
1116 and 1301 cc engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Between 22 and 24º max
Vacuum advance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Between 10 and 14º max
Ignition coil
Primary winding resistance at 20ºC (68ºF) . . . . . . . . . . . . . . . . . . . . . . . Between 2.6 and 3.3 ohms depending upon make of coil
Secondary winding resistance at 20ºC (68ºF) . . . . . . . . . . . . . . . . . . . . Between 6745 and 12 000 ohms depending upon make of coil
Marelli Digiplex electronic ignition
Rotor arm resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000 ohms
Advance range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Between 6 to 10º and 47 to 51º
Engine speed sensor
Resistance on flywheel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612 to 748 ohms
Sensor to flywheel tooth gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.25 to 1.3 mm (0.0099 to 0.0512 in)
TDC sensor
Resistance on pulley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612 to 748 ohms
Sensor to pulley tooth gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.4 to 1.0 mm (0.016 to 0.039 in)
Ignition coil
Primary winding resistance at 20ºC (68ºF) . . . . . . . . . . . . . . . . . . . . . . . 0.310 to 0.378 ohms
Secondary winding resistance at 20ºC (68ºF) . . . . . . . . . . . . . . . . . . . . 3330 to 4070 ohms
Chapter 4 Ignition system
For modifications and information applicable to later models, see Supplement at end of manual
Condenser (capacitor) - removal, testing and refitting . . . . . . . . . . . 5
Digiplex (electronic) - ignition checks and adjustments . . . . . . . . . . 10
Digiplex (electronic) ignition - location of components and
precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Distributor - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Distributor (mechanical breaker type) - overhaul . . . . . . . . . . . . . . . 7
Dwell angle - checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Fault finding - ignition system . . . . . . . . . . . . . . . . See end of Chapter
General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Ignition coil - (mechanical breaker ignition) . . . . . . . . . . . . . . . . . . . . 8
Ignition switch - removal and refitting . . . . . . . . . . . . . . . . . . . . . . . . 12
Ignition timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Mechanical contact breaker - points servicing . . . . . . . . . . . . . . . . . 2
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4•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

Note the washers above and below the
contact assembly (photos).
23Fit the new contact assembly by reversing
the removal operations.
24Although the points gap is normally set in
production, check it using feeler blades when
the plastic heel of the movable arm is on a
high point of the shaft cam. Adjust if
necessary by inserting an Allen key (3.0 mm)
into the socket-headed adjuster screw.
25Carry out the operations described in
paragraphs 14 to 17 in this Section.
3 Dwell angle- checking
3
The dwell angle is the number of degrees
through which the distributor cam turns
between the instants of closure and opening
of the contact breaker points.
1Connect a dwell meter in accordance with
the maker’s instruction. The type of meter that
operates with the engine running is to be
preferred; any variation in contact breaker
gap, caused by wear in the distributor shaft or
bushes, or the height of the distributor cam
peaks, is evened out when using this.
2The correct dwell angle is given in the
Specifications at the beginning of this
Chapter. If the angle is too large, increase the
contact points gap. If the angle is too small,
reduce the points gap. Only very slight
adjustments should be made to the gap
before re-checking.3On Ducellier distributors, adjustment of the
dwell angle can only be carried out by
switching off the ignition, removing the
distributor cap, rotor and spark shield and
adjusting the points gap.
4Re-check once the engine is running.
Adjustment may have to be carried out
several times to obtain the correct dwell
angle.
5On Marelli distributors, adjustment of the
points gap (dwell angle) is carried out with the
engine running by inserting a 3.0 mm Allen
key in the hole provided in the distributor
body.
6Always check and adjust the dwell angle
before timing the ignition as described in
Section 4.
4 Ignition timing
3
1Timing the ignition on engines with
mechanical breaker distributors is carried out
in the following way.
2Disconnect the vacuum hose from the
distributor diaphragm capsule (photo).
3Have the engine at normal operating
temperature and idling with a stroboscope
connected in accordance with the
manufacturer’s instructions.
4Point the stroboscope at the timing marks
on the flywheel and the index on the aperture
on the flywheel housing. The mark on the
flywheel should be opposite to the BTDC
mark on the index specified for your particular
engine. Alternatively, use the notch on the
crankshaft pulley and the marks on the timing
belt cover (photo), but this will necessitate
removal of the wheel arch shield.
5If the marks are not in alignment, release
the distributor clamp plate and turn the
distributor gently until they are (photo).
6Tighten the clamp plate nut, switch off the
ignition, reconnect the vacuum hose and
remove the stroboscope.
7If there is any difficulty in seeing the timing
marks clearly, highlight them by painting with
quick-drying white paint.
4•4 Ignition system
4.4 Ignition timing marks on belt coverFig. 4.5 Flywheel housing timing marks
(Sec 4)4.2 Distributor vacuum hose
Fig. 4.4 Adjusting Marelli type contact
breaker points gap (Sec 2)
Fig. 4.3 Marelli contact breaker (Sec 2)
2.22B Washers above contact breaker2.22A Marelli contact breaker E-clip