check engine FIAT TEMPRA 1988 Service And Owner's Manual

J Job 22. Check/clean/gap spark plugs. Q Job 23. Change spark plugs.
GENERAL. On all Tipo and Tempra petrol engines the spark

plugs
face forwards, allowing easy working access.
Carefully remove the
spark plug caps, being
careful to pull only on

the cap and
not the HT
lead. If you can't be

sure
to remember which

HT lead
belongs to
which spark plug,
number them from one

end
of the engine to the
other.
22B. If the electrodes of the
plugs look rounded and worn,

replace
the plugs. See page

154
for details of 'Reading
Your Spark Plugs. Nip' the

cap
tight with pliers, so that it
can't come loose.
Spark plugs 'tire' and lose efficiency over a period of time,
even if they look okay. See Job 22 for information on their
removal and replacement. Use good quality Champion or FIAT
plugs of the correct specification.
• Job 24. Check/dean HT leads and distributor
cap.
See SAFETY FIRST! at the start of this section and
Chapter 1, Safety First!
IMPORTANT NOTE: On latest models, there is no conven-
tional distributor and, for those cars, none of the
following should be attempted. Illustration to Job 28C
illustrates the type which should NOT be worked on
except for wiping off the outer surface, with the engine
not running.
Remove each plug lead from the spark plugs, pulling only on
the plug caps, not on the HT cables. Also, remove the large HT
lead from the coil and take off the distributor cap, either by
popping off its spring retainers if the distributor is on the side
of the engine (front of engine bay
-
see illustration 25A) or by
undoing the two retaining screws.
24A. On later
cars (Digiplex
ignition -
distributor
mounted
horizontally on
end of cylinder
head) unclip and
remove the
22A. Unscrew the plug

using
the correct type of
spark plug socket. Take

care
to keep the
spanner strictly in line
with the plug so as not to
crack the electrode.

22C.
it
is
essential

that the
plug is

gapped
correctly.

See Chapter 3,
Facts
and Figures.

Use a
feeler blade

of the
correct
thickness, sliding it

between
the
electrodes. It should

be a firm
sliding fit.

Use a
gapping tool

or
carefully wielded pliers to bend the curved electrode

towards
or away from the centre electrode. Take GREAT CARE

not to
damage the insulator near the tip of the plug.
H INSIDE INFORMATION: The spark plugs screw into
aluminium, which is easily damaged if the spark plugs do

not
engage their threads properly. Screw in the plugs by
hand initially
-
by, say, two or three turns
-
before using
the plug spanner. A light smear of copper grease on the

plug
threads will enable them to turn more freely and

also
make them easier to remove next time. Finally,
don't over-tighten the plugs
-
firm hand-pressure on the
spanner is sufficient. D
IMPORTANT NOTE: DO NOT
spray water dispellant or
apply lubricant to any part
of an electronic ignition
distributor. (It's okay to
clean the cap, as described,
however.)
shroud. Clean the
cap and cables of
either type with a clean rag, applying a little aerosol water-
dispellant spray to help shift oil and grime.
24B. Check each of the HT posts (a) inside the cap for burning
or damage, and the central carbon brush (b) to ensure that it's
not worn down and that the
spring loading is okay. Clean
the dust cover (c) and rotor
arm, and check the tip (d) for
burning.

• Job 25. Check ignition timing.
_ FACT FILE: IGNITION SYSTEM TYPES
Two different types of electronic ignition
systems have been fitted to the petrol
engines covered by this manual.
The earlier Breakerless Inductive Discharge System can
be adjusted. Its distributor is fitted as shown in illus-
tration 25A.
The later, Digiplex 2 system, has an integrated ignition
and fuel injection control system and any checks and
adjustments will need to be carried out by your FIAT
dealership with the appropriate diagnostic equipment.
See Job 28.
MAGNETI MARELLI BREAKERLESS INDUCTIVE
DISCHARGE IGNITION SYSTEM
CHECK VACUUM AND MECHANICAL ADVANCE SYSTEMS
25A. This is the
location of the break-
erless electronic
ignition components in
the car. The distributor
(1) is fitted to the front
of the block while the
ignition coil
(2)
is
alongside the battery.
25B. This type of distributor can be
identified by the electronic ignition
control module (a) and the vacuum
advance unit (b), not fitted to other
ignition types.
• the engine must be at
ature.
• the idle speed/mixture/CO adjustments must be correct

-
see Job 35.
• Start the engine and run it at between 750 and 850 rpm.
• Point the timing light at the crankshaft pulley timing mark
and ensure that the mark lines up with the 10 degrees Before
Top Dead Centre (BTDC) mark on the timing belt cover.
• If the reading is 'out' stop the engine and slacken the clamp
nut on the distributor so that the distributor can just be turned
with firm hand pressure.
• Turn the distributor a very small amount, restart the engine
and check again.
• Repeat the procedure until, with the engine running, the
crankshaft pulley timing mark lines up with the 10 degree
BTDC mark. Then tighten the nut securing the distributor to
the engine block.
You can now check the vacuum advance system as follows:
• increase the engine speed to approximately 2,000 rpm and,
with the timing light pointed at the timing marks, make a
mental note of the position of the mark on the crankshaft
pulley in relation to the timing belt cover. If the position is no
further advanced than 10 degrees BTDC, the mechanical
advance system inside the distributor is probably seized.
• stop the engine, reconnect the vacuum advance pipe and
repeat the procedure.
• you should see a further amount of advance taking place
and if not, the diaphragm inside the vacuum advance
mechanism is probably punctured.
• if either or both of these faults have occurred, your engine
will run uneconomical^ and inefficiently and it may pay you to
fit a new distributor.
MAGNETI MARELLI DIGIPLEX 2 ELECTRONIC
IGNITION
25D. This is the layout of the Digiplex ignition system, viewed
from over the engine looking towards the left-side of the car.
The ignition coil (1) is adjacent to the battery. The electronic
control unit (2) is nearer to the engine bay sidewall. The
distributor (3) is mounted on the end of the cylinder head and
the rpm and Top Dead Centre (TDC) sensor (4) is located on
the crankshaft cover on the flywheel side.
IMPORTANT NOTE: Before
checking the ignition timing,
you must be certain that:
• the pipe from the distributor
vacuum unit is disconnected
from the distributor and plugged.
its normal operating temper-
instructions. The
timing light should
always be connected
to No.
1
spark plug
lead
-
the one nearest
the timing belt end of
the engine.
48
25C. To check the ignition timing, connect up a stroboscopic
lamp, either as shown on the inset or in accordance with the
manufacturer's

FACT FILE: DIGIPLEX DISTRIBUTOR
REMOVAL
25E. If the distributor has to be removed
for any reason, it is ESSENTIAL that the
PRECISE position of the rotor arm in
relation to the distributor body and the
position of the distributor body (2) in relation to the
cylinder head
-
via the spacer (1)
-
are clearly marked so
that they can be
replaced in
EXACTLY the
same position.
Note that the
locator
(arrowed) only
gives an approx-
imate, not a
precisely correct
location of the
spacer.
25F. D INSIDE
INFORMATION:

Use
touch-up
paint
and
let it
dry before
removing the
unit. D
SETTING THE RPM AND TDC SENSOR POSITION
25G. This job can not
be carried out without
the FIAT special tool
illustrated. The sensor
is correctly positioned
when the engine is
produced and to
prevent accidental
tampering, one of the
two bolts holding the
sensor in place is a
shear bolt and will have to be renewed if removed.
IMPORTANT NOTE: The slots in the distributor body are
NOT used to alter the advance setting, as on a conven-
tional distributor. This operation is carried out by the
position of the TDC sensor
-
see later.
CHECKING THE IGNITION ADVANCE can be carried out in an
approximate manner using the same method as described in

25C.
However, you must make sure that the following steps

are
taken:
•
the
vacuum pipe between the electronic control unit and

the
inlet manifold must remain connected and be in good
condition
-
neither blocked nor split.
•
the
engine must be at its normal operating temperature.
•
the
idle speed/mixture/CO adjustments must be correct
-

see Job 35.
•
with
the engine idling at between 800 and 900 rpm, the

mark on
the crankshaft pulley should be at approximately 12
degrees BTDC.
IMPORTANT NOTE: The only marks are for 0, 4 and 10
degrees BTDC, so you will have to make a guess at the
correct position for 12 degrees.
FACT FILE: TIMING MARKS
y-; • It appears that some earlier engines
H. j may be fitted with different types of
J timing marks. There might be a metal
pointer fitted to the timing belt cover.
Other engines may have their timing marks in the
flywheel housing, so that you need to take out a rectan-
gular rubber bung and look out for the fixed timing
mark on the flywheel housing and the timing settings

on
the flywheel itself.
• It always helps to paint all of the timing marks with
white paint or typists' correction fluid so that they are
easier to see when the timing light is operating.
1. Line up the mark on the crankshaft pulley with the 0
degrees (TDC) mark on the timing belt cover. See 25C.
2. Without moving the crankshaft from this position, undo the
screws holding the rpm and TDC sensor to the sensor carrier
plate. Fit the tool no. 1895898000 in place of the sensor.
Check that the flywheel pin or lug (3) must fit in the groove of
the tool and the bolts must tighten easily. If not, carry out the
following procedure:
3. Slacken the bolts securing the carrier plate behind the
sensor.
4. Move the plate so that the tool slips freely into the sensor's
hole and the bolts tighten easily.
5. Tighten the bolts holding the sensor carrier plate in place.
6. Remove the tool and refit the sensor.
ON BOTH TYPES: As the distributor is turned (clockwise to
advance, anti-clockwise to retard), the timing mark on the
flywheel will be seen to move relative to the pointers. Move
the distributor so the timing marks are aligned correctly, and
retighten the clamp nut or bolts.
• Job 26. Check/adjust drive belt/s.
26A. Depending on
your Tipo or Tempra
model, access to the
alternator belt and
adjustment fixings will
probably be possible
from the engine bay.
V-BELTS ONLY
Check the belt, and if there is any sign of cracking, 'polishing',
fraying or severe wear on the inner face, replace it. The belt
should deflect by about 10 mm when firm thumb pressure is
applied to the belt between the pulleys in the direction of the
arrow. Too little tension and the belt might slip; too much,
and belt and bearing wear will increase.

26B. If adjustment is
necessary, slacken the
tensioning nut (A) and
the alternator pivot (B),
on all models. (These
are two typical
layouts.)
Use a length of wood
to pivot the alternator
away from the engine
block but take great
care not to damage the
alternator casing.
Tighten the nuts/bolts
when the tension is correct.
RIBBED BELTS ONLY
If your vehicle is fitted with a ribbed belt, pivot the alternator
as described above and tighten it when you can just twist the
belt by 1/4 turn in the middle of its longest run.
IMPORTANT NOTE:
• Belt tension should only be adjusted when the engine
is cold.
• After adjustment, run the engine for 15 to 30 seconds,
to allow the belt to bed-in, then check again.
• Experience mechanics claim that belts often go slack
when the engine heats up, producing belt squeal.
• If this happens on your vehicle, adjust the belt again
when the engine is hot. Wear industrial leather gloves
and long-sleeved overalls and take very great care not to
burn yourself on the hot engine or exhaust.
If there is an auxiliary unit, such as an air conditioning pump,
driven by a separate drive belt, examine and adjust it as
described here.
Q Job 27. Check electric fan operation.
Drive the car until it is at normal operating temperature. Park
outdoors and, with the gearbox in neutral (or 'P' in the case of
an automatic) leave the engine running. At just above normal
temperature the electric cooling fan should come on, and
then go off again when the temperature drops. Refer to your
temperature gauge, if fitted. If the fan doesn't behave, check
the thermo-switch on the radiator, along with all connections
and wires in its circuit with the fan motor. See Job 13 and
Chapter
6,
Repairs and Replacements.
• Job 28. Run diagnostic ignition/injection test.
DIAGNOSTIC TEST
28A. Have your FIAT dealer
carry out a diagnostic test,
plugging his tester into the
diagnostic socket tucked away
at the front of the passenger-
side footwell.
EMISSIONS TESTS
Vehicles fitted with the Mono-Jetronic fuel injection system
are not fitted with adjustment screws. The system is self-
regulating. However, specified annual checks carried out with
an exhaust gas analyser will provide essential information on
the condition of the injection/ignition system, the catalytic
converter and the engine itself.
28B. The checks are carried out twice: once with the test
sensor at least 300 mm into the end section of the exhaust
pipe (a). (If the shape of the end section of the exhaust pipe is
such that the sensor cannot be completely introduced, a
special extension pipe must be added ensuring that the joint
with the car's tail-pipe is sealed.); the second after undoing
the cap or nut on the exhaust pipe upstream of the catalytic
converter (b).
The following table shows the test limits for carbon monoxide,
unburned hydrocarbons (in parts per million) and carbon
dioxide:
CO (%) HC (p.p.m.) C02(%)
Upstream of the catalyzer (a) 0,4 -h 1 500/600* >12
Downstream of the catalyzer (b)
=£
0,35 =s 90 >13
* FIAT's figures vary.
IMPORTANT NOTE: The engine must be at its normal
operating temperature and normal tick-over speed.
• if the percentage concentration of CO upstream of the
catalytic converter is not within the limits in the table,
check:
• the Lambda sensor
-
see Job 37.
• air penetration around the Lambda sensor housing.
• faults in the ignition or injection systems. (First try
renewing the spark plugs, distributor cap and HT leads.)
If, at the same time, the concentration of hydrocarbons
is not less than 500/600 parts per million (FIAT'S figures
vary), check:
• the ignition timing (see Job 25).
• the valve clearances (see Job 9).
• the valve gear timing (see Job 12).
• the engine compression. (You will need to remove the
spark plugs, fit a compresson tester to each plug
aperture in turn and crank the engine. See the FACT FILE
on page 51.)

28C. With very latest
'distributorless' system,
disconnect the multi-plug
from the base of the 'black
box'.
28D. With the two earlier
systems, disconnect the
multi-plug leading to the
distributor/control unit
from the ignition coil
behind the battery.
FACT FILE: CRANKING AN ENGINE
WITH ELECTRONIC IGNITION
Severe damage can be
caused to the ignition
system if the engine is
cranked with plugs/leads
removed
-
and a severe
electric shock can be
experienced.
PART E: FUEL AND EXHAUST
SAFETY FIRST!

Always
wear impervious gloves so that fuel cannot

come
in contact with your
skin.
It can induce cancer.
Q Job 29. Check fuel pipes for leaks.
Check the fuel lines from the fuel tank and into the engine
compartment, looking for signs of chafing, splits and perishing

of the
rubber and plastic parts. Ensure any worm-drive hose

clips used
on the connections are firm and secure.
Q Job 30. Change petrol air filter.
IMPORTANT NOTE: If the HC reading when measured at
the end of the exhaust pipe is outside of the recom-
mended limit while that measured upstream of the
catalytic converter is OK, the cat. is almost certainly
faulty. Have it double-checked by your dealer before
replacing it
-
an expensive component!
30C. Pull on the
tabs
-
and watch
that the springs
don't fall on the
floor as you release
the catches!
30D. Lower the
filter cover and lift
out the filter
element.
31B. If you want to
take the cover right
off, you will have to
unscrew the air
hose clamp
(arrowed). Remove
and replace the
filter element (A).
• Job 31.
Change diesel
air filter.
31A. Take out the
four screws
(arrowed) and lift
off the cover (B). 30B. ...and release

the two
fasteners

(a) and the
two

spring clips
(b).
30A. Unscrew the

two
screws
(arrowed)...
51

• Job 32. Change petrol fuel filter. IMPORTANT NOTES:
• Wear plastic gloves and goggles and have a large rag
and a suitable fire extinguisher ready.
• Place a container beneath the filter to catch fuel
spillage.
• After fitting the new filter in place, refit the casing,
ensure no traces of fuel are left, reconnect the battery and
restart the engine.
• Check carefully to ensure there are no leaks before
refitting the cover.
• Job 33. Drain diesel fuel filter.
IMPORTANT NOTE: Some models are fitted with a water-
in-fuel sensor. Drain the filter when the warning light
comes on. Unplug the sensor from the base of the filter,
first.
FUEL INJECTION
MODELS
32A. The filter is under the
car, ahead of the fuel tank.
E3 INSIDE INFORMATION:
Remove the visible screws
holding the flexible
plastic cover in place.
You can now pull the
front down and out of
the way. E3
32B. Undo the clamp,
remove the outer
casing and renew the
special paper filter,
from your FIAT
dealership. There is
an arrow on the
casing to remind you
which way round it
must be fitted.
33. The fuel filter is
located in the rear of
the engine
compartment. Water
carried in the fuel
accumulates in the
bottom of the filter,
and should not be
allowed to build up.
To drain it position a receptacle under the filter, then unscrew
the knurled tap at the bottom of the filter by a couple of turns.
Do so at the recommended interval, or if the panel indicator
comes on. (See Chapter
2,
Getting to Know Your
Car.)
H INSIDE INFORMATION: Plastic fuel pipes become
brittle and snap. Extra care needed! E3
SAFETY FIRST!
• The high pressure pipework on a fuel injection
system can retain its pressure for days even after the
engine has been switched off.
• When you disconnect the pipework, a jet of fuel can
be emitted under very high pressure
-
strong enough
to penetrate the skin or damage the eyes.
• NEVER work on the fuel pipework when the engine
is running (except when bleeding Diesel injectors).
• ALWAYS place a rag over a union while it is being
undone until all the pressure has been let out of the
system.
• You are recommended to wear strong rubber gloves
and goggles when disconnecting the fuel injection
system's high pressure pipework. Always disconnect
VERY slowly, letting pressure out progressively.
• See Chapter 6, PART F: Job 8 for details of how to
depressurise the system.
• Disconnect the battery negative earth before
working on the fuel system.
• Work outdoors and away from sources of flame or
ignition.
• ALWAYS wear rubber gloves
-
don't let your
skin

come into contact with fuel.
IMPORTANT NOTE: All Tipo/Tempra diesel engines are
self-bleeding and there should be no need to bleed air
out of the system manually.
• Job 34. Change diesel fuel filter.
Drain the fuel filter. Unscrew the complete filter canister from
its head, in the same way that you would an engine oil filter.
First undip the sensor plug (if fitted) from the base of the unit.
^ 34A. If it is too tight to
^^ - unscrew by hand, use an oil
filter wrench on the lower,
flatted zone (C). Wipe the underside of the filter head,
fill the new filter
with fuel...
34B. ...lightly
lubricate its seal
with fuel, then
screw it onto the
filter head. Once it
is 'nipped up',
tighten it as far as
possible by hand,
without
'murdering' it
-
so
that you CAN
remove it next
time!

IMPORTANT NOTE: • All Tipo/Tempra diesel engines are
self-bleeding and there should be no need to bleed air
out of the system manually.
• If the engine does not eventually re-start, check all the
unions for the fuel inlet pipe and the other unions,
replacing the sealing washers if necessary, to eliminate
any air leaks.
Q Job 35. Check/adjust petrol engine idle and
emissions.
Setting the idle speed and mixture is not just a matter of

making
the car run smoothly and economically; it's also a
question of allowing it to run within the legal hydrocarbon
(HC), Nitrous Oxide (NO) and carbon monoxide (CO) emission
limits. If it
is
outside limits, the car will fail the annual test.
(However, a worn engine will fail even if the carburettor or
injection system is correctly set up.)
FACT FILE: ESSENTIAL
PREPARATIONS
• When tuning the engine you should
adjust the carburettor (when fitted) last
of all, as its settings will be affected by
the state of tune of the rest of the engine.
• Ignition dwell angle and timing must be correct, the
air
filter
should be clean, there should be no air leaks

on
the induction system, and all electrical components

and
the air conditioning (if fitted) should be switched
off.
• Get the engine to full operating temperature before
checking and adjusting.
• If
you
warm the engine on tick-over (instead of on a
journey), it won't be hot enough until you have heard
the electric cooling fan cut in twice.
Q INSIDE INFORMATION: These jobs require the use of a
tachometer (rev-counter) and an exhaust gas analyser to
achieve any degree of accuracy. If you don't own them -
and relatively inexpensive tools are now available
-
you

may
wish
to have the work carried out by your local FIAT
dealer. D

ROUGH
GUIDE: Within each section is a description of how
you
can
get the car running tolerably well without any

specialist
equipment, so that you can take it to your FIAT

dealership
for accurate (and MoT-able!) tuning.
35A. Check the float
level with the carburettor
in the position shown.
Distance (c) should be
30mm with gasket fitted.
Bend tab (2) to adjust
-

but the tab should
remain virtually perpen-
dicular. Do NOT adjust
items (1)or (3)1
35B. IDLE SPEED
ADJUSTMENT: Connect a
rev-counter according to
the maker's instructions,
and check the idle speed.
clockwise increases the
idle speed, anti-clockwise
reduces it. Set the idle
speed in accordance with
Chapter
3,
Facts and
Figures.
ROUGH GUIDE: Turn the screw until the engine is running at
the slowest speed at which it runs smoothly and evenly.
MIXTURE ADJUSTMENT: Check that the idle speed is correct
and make sure that the engine is at full operating temper-
ature. Connect an exhaust gas analyser as instructed by the
maker. If the CO reading is outside the range shown in
Chapter
3,
Facts and Figures, adjustment as follows:
Use a narrow-blade screwdriver and turn the screw (2)
clockwise to weaken (reduce) or anti-clockwise to richen
(increase) the reading.
ROUGH GUIDE: Turn the mixture screw inwards (clockwise).
As you do so, the tick-over speed will increase, until the point
comes where the engine starts to run 'lumpily'. Back off the
screw until the engine runs smoothly again, and then some
more until the speed just starts to drop. At this point, screw
the adjuster back in by a quarter-turn and you'll be
somewhere near the optimum setting for smooth running.
IMPORTANT NOTE: After setting the mixture adjustment,
re-check and, if necessary, re-adjust the idle speed.
CARBURETTOR MODELS ONLY
TAMPER PROOFING: All Tipo carburettors originally had a
tamper-proof seal placed over the mixture adjustment screw.

These
seals are to prevent anyone unauthorised from altering

the
mixture and exhaust emissions. In certain countries these

seals
must be retained by law.

If the
seal
is
a plastic cap placed over the adjuster screw, it can

be
broken
off with pliers. If it is a plug within the screw recess,

force
it out with a sharp object.
35C. This illustration
shows the correct
settings for the
choke fast idle
adjustment (manual
choke only) and the
automatic anti-
flooding device
adjustment. See
following page.

CHOKE (MANUAL) FAST IDLE ADJUSTMENT
Move the choke control lever by hand to the end of its travel
and hold it there. The main butterfly aperture (A) should now
be about 1.1 mm. If not, slacken the lock-nut (3), regulate the
adjustment screw (1), and retighten the lock-nut.
AUTOMATIC ANTI-FLOODING DEVICE ADJUSTMENT
With the choke control lever still at the end of its travel as
described in the previous paragraph, the strangler butterfly
aperture (B) should be between 3 and 3.5 mm. If not, regulate
the adjustment screw (2).
FUEL INJECTION MODELS
The idle speed and mixture settings are controlled by the
Electronic Control Unit (ECU) which is 'self-learning' and is
programmed to adjust itself to give the ideal settings under all
conditions. No manual adjustment is possible, nor provided
for. If there is a problem, see Job 29 You may need to take
your car to a FIAT dealer, with the appropriate diagnostic
equipment.
35D. At each service interval, the accelerator pivot (A).
35E. ...should be lubri-
cated with a dab of
TUTELA MRM2
grease.
The ACCELERATOR
LINKAGE must be
adjusted correctly if
the Mono-Jetronic
injection system is to operate smoothly and correctly.
• Disconnect the rod (1) from the lever (2). The pulley (3)
should now be against its closed stop.
• Check that the accelerator cable is not loose, but neither
should it be taut, and check that there is no free play in the
accelerator pedal.
• If necessary, adjust the accelerator cable by slackening the
lock-nut (B) and turning the adjuster nut (C) until the cable is
correctly tensioned. Then retighten the lock-nut.
Now reconnect the rod to the lever on the fuel injection unit
and let the engine warm up until the cooling fan has cut in at
least twice, then turn the engine off.
• With the accelerator pedal released check that the
clearance between the levers (2) and (4) is between 0.2 and
0.5 mm.
• If necessary, loosen the lockouts (5) and (6). Use a spanner
on the adjuster nut (7) to tighten or loosen the rod (1) until
the clearance is between 0.2 and 0.5 mm.
• Retighten the adjuster nuts (5) and (6).
• Finally, make sure that with the accelerator pedal
completely depressed, the butterfly in the fuel injection unit is
fully open.
• If not, the accelerator cable may be too taut or the
clearance between the levers (2) and (4) may be re-adjusted,
keeping them within the acceptable tolerances.
Q Job 36. Check emission control systems.
PETROL INJECTION MODELS ONLY
36A. On petrol-
injected Tipos and
Tempras, sophisti-
cated emission
control equipment is
fitted and must be
tested with a proper
emissions tester.
FACT FILE: EMISSION CONTROL
SYSTEM
36B. The main features of the system are:
• an Electronic Control Module Unit or (ECU) (1) -
the 'computer brain', which is programmed to alter the
car's fuel and ignition settings according to information
received from various sensors.
• a catalytic converter (2) in the exhaust system, to
convert CO and other gases to less harmful gases.
• a Lambda sensor (3) in the exhaust manifold or front
pipe (according to model) to detect the 'tune' of the
exhaust gases and give a signal to the ECU.
• a petrol evaporation control system, to cut down on
petrol vapour emissions from the fuel tank.
• part 4 is the 'upstream' emission test point. See Job
29.

ELECTRONIC CONTROL MODULE: The ECU is not an item
that requires any servicing. If you think it might be faulty, ask
your FIAT dealer or fuel injection specialist to check it for you.
This must be done by someone with the correct FIAT plug-in
diagnostic equipment and data.
CATALYTIC CONVERTER: The CAT is not serviceable. If it
fails, you will be told at the MoT test. Replacement is
expensive, so we recommend you obtain a second opinion
before replacing the 'cat'.
LAMBDA SENSOR: For information concerning the sensor,

see
Job
37.

I' sensor is a simple job (see
Chapter 6, Repairs and
Replacements, PART F: FUEL AND EXHAUST), but it
can only be tested by your FIAT dealer with the correct
equipment
• If the sensor is faulty, have it renewed by your
dealer.
• Lambda sensors are very delicate and easily
damaged. It is not likely that you would be able to
return one to the supplier if you fitted it yourself.
• Lambda sensors are only fitted to cars with a
catalytic converter.
• Job 38. Check/adjust diesel idle speed.
To accurately check and adjust the diesel's idle speed you
need a diesel-specific rev-counter. If you're happy with the idle
speed, leave well alone. But if you're convinced the idle is
incorrect, it's best to take the car to a FIAT dealer. If you wish
to adjust the speed yourself, get the engine to normal
operating temperature, and check there is some free play in
the accelerator cable before proceeding.
ADJUSTMENT
-
BOSCH PUMP
D INSIDE INFORMATION: If the canister is flooded with
petrol, it is probable that one of the purge valves or
purge valve floats is faulty. Get this investigated and
rectified by a FIAT dealer. If the engine cuts out and then
restarts after a while, it could be the breather hose
valve, fitted under the fuel filler neck. This one-way
valve allows air to enter the tank as the fuel level falls,
otherwise an air lock can prevent fuel reaching the
engine. To test the valve, take off the pipe clips, remove
the valve and test it as for the canister one-way valve,
above. It should allow air to pass into the tank, but not
the other way. H
Q Job 37. Check Lambda sensor.
PETROL INJECTION MODELS ONLY
For
a
description of how the sensor works, see Job 36, FACT
FILE: EMISSION CONTROL SYSTEM. It should be checked at
the recommended interval
-
the cost of checking and
replacing the sensor is far less than that of having to replace
the catalytic converter because it has been polluted due to a
sensor fault.
38A. Adjust the idle
speed, which
should be approxi-
mately 800 rpm, by
slackening the lock-
nut of the adjuster
screw (1) then
turning the screw
inwards to increase
the speed
-
or
outwards to
decrease. Retighten the lock-nut when the speed is correct.
ADJUSTMENT
-
LUCAS/ROTODIESEL/CAV PUMP
38B. Adjust the idle speed, which should be approximately
800 rpm, by slackening the lock-nut of the adjuster screw (A)
and turning the screw to give the desired speed. Retighten the
lock-nut, then rev the engine high and allow it to return to
idle. If it goes below idle speed (i.e. it threatens to stall, or
does stall), or if it decelerates too slowly, slacken the lock-nut
of the adjuster screw (B), adjust it and check the deceleration
again. Repeat as necessary to achieve comfortable deceler-
ation without stalling, then tighten the lock-nut.
36C. CHARCOAL
CANISTER: This unit is
located behind the car's
front panel, and does not
need regular servicing.
Check the canister one-
way valve (see Chapter

6,
Repairs and
Replacements, Part F,

FUEL
AND EXHAUST
for illustration) by discon-
necting it and trying to
blow through both ends.
You should only be able
to blow air towards the
canister, not away from
it. If the valve is faulty,
renew it, making sure
that it
is
fitted the right way round.

• Job 39. Check/adjust diesel injection timing.
Although a check of the injection timing is scheduled as a
service item, there is no reason why the timing should have
altered if the pump mounting bolts are tight and the pump
has not been disturbed. Injection timing is best checked
dynamically by a FIAT dealer or diesel specialist using
specialised equipment. If you want to check the timing stati-
cally, and you have access to a dial gauge and the necessary
adaptor to fit it to the pump, proceed as follows:
39A. Slacken the injection
pump flange nuts
-
one can be
seen (A) in illustration 39B -
and rear support bracket lower
bolt. Make sure that the
manual cold start control lever
(at the dashboard, where fitted)
is fully off.
BOSCH PUMP ONLY
necessary Lucas dial gauge (A), the holder (B) and the probe
(C) threaded into position in place of the plastic cap, position
the engine crankshaft at Top Dead Centre. Ensure that the
dial gauge is fitted to its holder and the pump (D) with a pre-
loading of 10-15 mm, then zero it. Slowly turn the pump
body, turning the upper part away from engine block. Now,
slowly turn the engine crankshaft in the normal direction of
rotation until the dial gauge indicates the measurement you
read off the pump label (that's the correct timing point).
Tighten the pump nuts/bolt. Turn the crankshaft by two
complete revolutions in the normal direction of rotation, then
re-check the timing. If incorrect, repeat the timing procedure.
Remove the tool and refit the plastic plug. Adjust the idle
speed if necessary. See Job 38.
• Job 40. Check inlet and exhaust manifold
fixings.
Check that the inlet and exhaust manifold nuts and bolts are
tightened to the correct torque. See Chapter
3,
Facts and
Figures.
• Job 41. Check exhaust system.
Examine the silencer and exhaust pipes and joints for
corrosion and signs of leaking, indicated by a 'sooty' deposit
at the point of the leak.
41. Also check the condition of the rubber 'hangers' that hold
the system to the car. If any are missing or broken, the
exhaust system can fracture due to extra stresses. Stretch the
rubber, and look for cracks.
39B. Unscrew the plug (illus-
tration 39A, part B) at the rear
of the injection pump, and
screw in a Bosch pump dial
gauge and adaptor.
(The FIAT tool
number for this is no.
1865090000.) With
the tool fully screwed
in, turn the engine in
the opposite direction
to normal rotation
until the plunger
inside the pump
reaches its lowest
position
-
as indicated by gauge movement. In this position,
zero the gauge. Now turn the engine in normal direction until
engine piston No. 1 is at Top Dead Centre. The dial gauge
should read
1
mm if the timing is correct. If it isn't, gently turn
the injection pump housing relative to its mounting until the
correct measurement is shown on the gauge. Now lock up the
pump flange nuts and rear support bracket bolt. Remove the
tool and refit the blanking plug to the back of the pump.
Adjust the idle speed if necessary. See Job 38.
LUCAS/ROTODIESEL/CAV PUMP ONLY
39C. You will find a label
attached to the top of the
injection pump, quoting the
correct timing measurement in
millimetres. Slacken the pump
flange nuts (as in, illustration
39B, part A) and the rear
support bolt (as in, illustration
39A, part A). Remove the
plastic cap from the pump top.
Now turn the engine crankshaft
in the opposite direction to
normal rotation by about 20
degrees. Using either FIAT tool
No. 1865091000 or, with the
cos / * susPect a but
fl^^^Cf- ^^ its location isn't obvious,
start the engine and
pressurise the system by holding a piece of board
against the tailpipe.
• Under pressure, the leak should be more noisy and
obvious.
• Don't burn yourself on the exhaust!