1983 FIAT UNO engine oil

Supplement: Revisions and information on later models 13•87
13
10.35 Ignition ECU on rear bulkhead
(1301 cc Turbo ie engine)
Fig. 13.76 Microplex ignition system components on the 1372 cc Turbo ie engine (Sec 10)
Fig. 13.75 Microplex ignition system components on the 1301 cc Turbo ie engine (Sec 10)
1 ECU
2 Safety pressure switch
3 Ignition unit and coil4 Distributor
5 Anti-knock sensorS1 TDC sensor
S2 Engine speed sensor
1 Battery
2 Ignition switch
3 Ignition coil with
control unit
4 ECU
5 Distributor
6 Anti-knock sensor
7 Air pressure
switch
8 Engine speed
sensor
9 TDC sensor
10 Tachometer 10.34 Anti-knock sensor

13•88 Supplement: Revisions and information on later models
Fig. 13.73 Wiring diagram of the Microplex ignition system on the 1301 cc Turbo ie
engine (Sec 10)Fig. 13.74 Wiring diagram of the Microplex ignition system on the 1372 cc Turbo ie
engine (Sec 10)1 ECU
2 Safety pressure switch
3 Ignition unit with coil
4 Distributor
5 Anti-knock sensor
6 Vacuum/pressure pick-up in engine inlet
manifold
7 Socket for diagnostic equipment8 Tachometer
9 Spark plugs
10 Switch to earth (to retard advance
curve if necessary)
11 Turbocharger operation warning light
12 Anti-theft relay (where fitted)
13 Hidden anti-theft switch (where fitted)1 ECU
2 Pipe (pressure/vacuum
in inlet manifold to
control unit)
3 Spark plug
4 Distributor
5 Ignition coil (with
control unit)6 Tachometer
7 Ignition switch
8 Connector
9 TDC sensor
10 Engine speed
11 Anti-knock sensor
12 Air pressure safety
switch13 Speedometer signal
for electronic injection
14 Connector
15 Diagnostic socket
a Crankshaft pulley
b Flywheel

Ignition unit
36This comprises four elements (photo).
a) Power module - receives the ignition
advance command and controls the
conduction angle of the primary current
and energy stored in the coil.
b) Dissipater plate - eliminates the heat
which is generated by the high volume of
current.
c) Ignition coil with low primary resistance.
d) Distributor - a means of distributing high
tension to the spark plugs. The rotor is
driven in an anti-clockwise direction
(viewed from transmission) by a dog on
the end of the camshaft.
37The system incorporates a safety
pressure switch, which cuts out the ignition if
the turbocharging pressure exceeds a value
of between 0.84 and 0.93 bars (12.2 and
13.5 lbf/in
2) above atmospheric pressure.
Distributor (Microplex) -
removal and refitting#
38Remove the distributor cap and place it to
one side, complete with spark plug leads
(photo).
39Turn the crankshaft by means of the
pulley nut, or by raising and turning a front
wheel with top gear engaged, until No. 4
piston is on its firing stroke. This will be
indicated when the contact end of the rotorarm is aligned with the mark on the distributor
body rim, and the lug on the crankshaft pulley
is aligned with the timing pointer on the
engine. The right-hand underwing shield will
have to be removed in order to see the marks
(photo).
40Unscrew the distributor fixing nuts and
withdraw the distributor.
41When fitting the distributor, the offset
drive dog will automatically locate the
distributor rotor in its correct position, but the
distributor body may require rotating in order
to align the rim mark with the rotor. The
elongated slots for the fixing studs are to
permit initial alignment, not for subsequent
adjustment, as advance angle alterations are
carried out automatically by the system ECU
(photos).
42Tighten the nuts and refit the cap with
leads.
43Unless a stroboscope and a vacuum
pressure gauge are available, it will not be
possible to check the advance values with the
engine running. Where these instruments are
available, connect the vacuum gauge to the
inlet manifold, and the stroboscope in
accordance with the equipment manufac-
turer’s instructions. Refer to Fig. 13.79
according to the inlet manifold vacuum
pressure indicated.
Microplex ignition system
components - testing ª
44An ohmmeter and a voltmeter will be
required for these tests.
45Remove the multipin plug from the ECU.
Engine speed sensor
46Insert the probes of an ohmmeter
between terminals 3 and 16 of the multipin
connector; 618 to 748 ohms (1301 cc) or
578 to 782 ohms (1372 cc) should be
indicated.
47If necessary, carry out a check of the gap
between the sensor and flywheel teeth as
described in Chapter 4, Section 10.
Supplement: Revisions and information on later models 13•89
10.39 Crankshaft pulley timing marks
(arrowed)10.38 Removing the distributor cap10.36 Ignition coil (1) and power module (2)
on 1301 cc Turbo ie engine
Fig. 13.78 Rotor aligned with distributor
body rim mark - Microplex ignition system
(Sec 10)
10.41A Distributor body showing elongated
slots in the mounting lugs
Fig. 13.77 Crankshaft pulley timing mark
aligned with timing pointer - Microplex
ignition system (Sec 10)
1 TDC sensor10.41B Distributor drive dog
13

TDC sensor
48Insert the probes of the ohmmeter
between terminals 1 and 2 of the multipin
connector; 618 to 748 ohms (1301 cc) or 578
to 782 ohms (1372 cc) should be indicated.
49If necessary, carry out a check of the gap
between the sensor and the crankshaft pulley,
as described in Chapter 4, Section 10.
ECU supply
50Switch on the ignition, and then insert the
probes of a voltmeter between terminals 13
and 11 of the multipin connector. Battery
voltage should be indicated. If not, check the
battery earth, ignition switch or intermediate
connector plug for security.
Power module supply (1301 cc)
51Pull the multipin plug from the powermodule, and connect the probes of a
voltmeter between terminal 4 of the connector
and earth. If the reading is less than battery
voltage, check the security of all connections
between the ignition switch and terminal + 15
of the ignition coil.
52Reconnect the multipin connector to the
ECU, but have the one from the power
module disconnected, and then switch on the
ignition.
53Connect the voltmeter between terminals
4 and 2 of the power module multipin
connector. If the indicated voltage is less than
battery voltage, check the security of all
connections between the ignition switch and
terminal + 15 of the ignition coil, and the
battery earth. If all are satisfactory, check for
continuity between terminals 11 and 12. If
continuity is broken, renew the ECU.
Power module (1372 cc)
54Proceed as described in paragraph 53.
Anti-knock sensor
55If “pinking” occurs, or loss of power is
noticed, test the sensor by substitution of a
new one.
Ignition coil
56Disconnect the leads from terminals 1
and 15 on the coil before testing.
57Using the ohmmeter, check the resistance
of the primary winding. This should be
between 0.31 and 0.37 ohms (1301 cc) or
0.40 to 0.49 ohms (1372 cc), at an ambient
temperature of 20ºC (68ºF).
58The secondary winding resistance should
be between 3330 and 4070 ohms (1301 cc) or
4320 to 5280 ohms (1372 cc), at an ambient
temperature of 20ºC (68ºF).
Distributor
59Check the resistance of the rotor arm,
which should be between 800 and
1200 ohms.
60Where all the foregoing tests have proved
satisfactory, then any problem must be due to
a fault in either the power module or the ECU.
These components can only be checked by
the substitution of a new unit - power module
first, then the ECU.
Safety pressure switch
61The device protects the engine from
excessive turbocharging pressure, cutting off
the ignition by earthing the Microplex ECU.
Testing is not possible without a special
pressure pump, so the easiest way to check a
suspected fault is to fit a new unit.
Digiplex 2 ignition system -
description
62This system operates in a similar manner
to that of the earlier type described in Chap-
ter 4, but the circuit layout differs to suit the
Mono Jetronic fuel injection system. In
operation, the main difference is that the
Digiplex 2 system has a greater number of
13•90 Supplement: Revisions and information on later models
Fig. 13.81 Microplex ignition system
control unit connection (Sec 10)
For colour code, see main wiring diagramsFig. 13.80 Microplex ignition system ECU multipin connector (Sec 10)
For colour code, see main wiring diagrams
Fig. 13.79 Ignition advance curves - Microplex ignition system on the 1301 cc Turbo ie
(Sec 10)

advance points than the earlier system.
Comparison of Fig. 13.82 with Fig. 4.2
illustrates the difference in layout. Note that
the distributor is mounted on the rear end of
the cylinder head and is driven by the
camshaft.
63When working on the Digiplex 2 ignition
system or associated components, the
precautionary notes outlined in Section 9 of
Chapter 4 must be adhered to.
64As with the earlier system, test
procedures possible on the Digiplex 2 system
are restricted due to the need for specialised
testing equipment. The following checks are
possible, however, using a conventional test
meter.
Ignition coil check
65To check the resistance of the coil’s
primary windings, connect the probes of an
ohmmeter between the positive terminal and
the negative terminal as shown in Fig. 13.83,
and check that the resistance reading at 18 to
28ºC is 0.45 ohms ± 10% (photo).66To check the resistance of the coil’s
secondary windings, connect the probes of an
ohmmeter between the positive terminal and
the HT lead terminal as shown in Fig. 13.84.
Check that the resistance reading at 18 to
28ºC (64 to 82ºF) is 4800 ohms ± 10%.
Ignition timing check
67Refer to paragraph 2 in this Section.
Engine speed and TDC sensor check
68To check the resistance between the
sensor and the ECU, detach the wiring
connector (photo). Connect the probes of an
ohmmeter to the connector terminals and
check that the resistance reading is between
600 and 760 ohms at 20ºC (68ºF). If the
reading is not as specified, the sensor must
be renewed.
69The gap between the sensor and the pins
on the rear face of the flywheel must be
between 0.2 and 0.8 mm. Any deviation
outside of this clearance will be due to
mechanical damage to the sensor andnecessitates its renewal. The sensor is
accurately positioned during manufacture and
secured with tamperproof screws; it does not
require any adjustment during servicing. If it is
necessary to renew the sensor, a special gap
setting tool is required and the task is
therefore best entrusted to a FIAT dealer.
Supplement: Revisions and information on later models 13•91
Fig. 13.82 Digiplex 2 ignition system wiring circuits and components (Sec 10)
10.68 ECU location on the 1372 cc ie
engine10.65 Ignition coil and connections on the
1372 cc ie engineFig. 13.84 Test connections for ignition
coil secondary windings check - Digiplex 2
ignition system (Sec 10)
Fig. 13.83 Test connections for ignition
coil primary windings check - Digiplex 2
ignition system (Sec 10)
13
1 Connection point (lines connected to
the intake manifold)
2 ECU
3 Ignition coil
4 Distributor
5 Engine flywheel (with
five pins)
6 On/off switch (if fitted)
for advance reduction
7 On/off switch 2 (if fitted)
for curves
8 Battery
9 Spark plugs
10 Tachometer
11 Diagnostic socket
12 Engine speed and TDC sensor
13 To check actuator idle speed
14 To terminal no. 1 of injection control unit
(rpm signal)

11 Clutch
Clutch pedal - adjustment
(cable clutch)
Á
1The method of adjusting the clutch has
been revised.
2Fully depress the clutch pedal two or three
times.
3Using a suitable measuring stick placed in
contact with the floor panel (carpet peeled
back), measure dimension “X” in Fig. 13.87.
This dimension must be taken between the
centre of the pedal pad and the floor, first withthe pedal in the fully depressed position, and
then in the fully released position.
4The dimension measured should fall within
the range quoted in the Specifications for this
Supplement.
5Any adjustment which may be required
should be carried out by slackening the
locknut on the cable at the release lever (on
top of the gearbox) and turning the adjusting
nut. Tighten the locknut on completion.
Hydraulic clutch - description
6Some later models are fitted with an
hydraulically operated clutch in place of the
cable operated type. The main components of
the system are a master cylinder, with
separate hydraulic fluid reservoir, and the
operating cylinder. The master cylinder is
Distributor (Digiplex Z) -
removal and refitting#
70Proceed as described in paragraphs 14
to 21. When refitting the distributor, ensure that
the engine is still set at the TDC position. Engage
the rotor arm into position on the shaft so that its
lug engages in the slot in the top end of the drive
spindle. Align the rotor arm with the reference
slot on the edge of the distributor housing as
shown in Fig. 13.85, then fit the distributor into
position and secure with the retaining nuts
(photo). As previously mentioned, the fine timing
is made automatically through the ECU.
Spark plugs and HT leads -
general
71Copper-cored spark plugs are now fitted
to all models. The recommended types are
given in the Specifications Section of this
Supplement.72The HT lead connection sequence to the
distributor cap on the 999 and 1108 cc
engines is shown in Fig. 13.86. That for the
1301 cc Turbo ie is as shown (photo).
13•92 Supplement: Revisions and information on later models
Fig. 13.87 Clutch pedal adjustment
diagram - cable clutch (Sec 11)
For dimension “X” , refer to Specifications
Fig. 13.86 HT lead connections on distributor cap of the 999 and 1108 cc engines (Sec 10)
Fig. 13.85 Rotor arm must align with
slot (1) in distributor housing when refitting
distributor - Digiplex 2 ignition system
(Sec 10)
10.72 HT lead connecting sequence on the
1301 cc Turbo ie engine10.70 Ignition distributor and HT lead
connections on the 1372 cc ie engine
Fault finding - Microplex ignition system
Starter motor turns but engine will not start
m mExcessive TDC sensor gap
m mEngine speed or TDC sensors short-circuited
m mFaulty ECU
m mECU multipin contacts corroded
m mDefective ignition coil
m mDefective ignition switch
m mECU terminal 8 cable faulty
Engine firing on three cylinders
m
mFaulty spark plug
m mDistributor cap cracked
m mFaulty HT cable
Loss of power, excessive fuel consumption
m
mTDC sensor incorrectly located
m mFault in ECU advance angle facility

25Unscrew the union nut and detach the
hydraulic fluid line from the operating cylinder
(photo).
26Undo the cylinder/mounting bracket
retaining bolts and lift clear the cylinder
together with the bracket (photo). Release the
retaining clip and separate the cylinder from
the bracket.
27To dismantle the cylinder, prise free and
pull back the dust boot, withdrawing it
together with the operating rod.
28Invert the cylinder and shake free the
piston and seal assembly. If it is stuck inside
the cylinder, remove the bleed screw then
apply moderate air pressure (from a foot
pump) into the bleed port and catch the
cylinder in a clean cloth as it is ejected.
29Remove the seals noting their orientation.
Clean all components in methylated spirits or
new hydraulic fluid. If the cylinder is damaged,
scored or badly worn it must be renewed. The
seals must always be renewed once they are
removed.
30Assemble the new seals to the piston and
lubricate the cylinder, seals and piston
assembly with new hydraulic fluid (of the
specified type) before assembling them.
Ensure that the seals are fitted the correct
way round (as noted during removal).
31Renew the dust boot, fit and secure the
operating rod into position then refit the dust
boot over the cylinder. If removed, refit the
bleed screw.
32Reconnect the cylinder to the mounting
bracket and refit the combined assembly to
the vehicle in the reverse order of removal.
Ensure the hydraulic union is clean and take
care not to damage the threads as it is
reconnected.
33Remove the polythene seal from the
hydraulic reservoir filler neck, top up the fluid
level and bleed the system as described
below.
Clutch hydraulic system -
bleeding#
34The clutch hydraulic circuit is bled in
much the same manner to that described for a
brake circuit. Refer to Section 12 in Chapter 8
and proceed as described, but note that the
bleed screw for the clutch circuit is located inthe end of the operating cylinder (see
photo 11.25). The clutch hydraulic circuit
reservoir is mounted in the engine
compartment on the left-hand side near the
bulkhead and is separate from the master
cylinder. As the system is being bled, ensure
that the fluid level in the reservoir is
maintained between the MIN and MAX level
marks. Do not allow the fluid level to drop
below the MIN level mark otherwise air will
enter the system and greatly lengthen the
operation. Wipe clean any fluid spillage from
the paintwork or adjacent components as it
has a corrosive effect if left.
12 Transmission
PART A:
1301 CC TURBO IE ENGINE
Description
1The transmission is of five-speed type,
based on that used in the Fiat Strada 105 TC.
2For all practical purposes, the operations
described in Chapter 6 apply, but observe the
following differences.
Gearchange linkage -
removal and refitting Á
3This is of two-rod type.
4Remove the gaiter and disconnect the rodsat the gear lever end as described in Chap-
ter 6, Section 3.
5Disconnect the rods at the transmission
end by unscrewing the nuts and bolts which
connect the linkage rods to the selector rods
(photo).
6Extract the spring clip which retains the end
of the short link rod (photo).
Gearchange linkage
(Antiskid models) - general
7The gearchange linkage and internal
selector arrangement has been modified, as
shown in Fig. 13.89.
Final drive output shafts -
description and
oil seal renewal
#
8The output shafts on this transmission
incorporate a flange on the left-hand side, to
which a coupling flange on the driveshaft is
bolted. On the right-hand side, an
intermediate shaft (see Section 13) is splined
directly into the differential side gear.
9A leaking oil seal may be renewed on the
left-hand side of the final drive casing after
first disconnecting the driveshaft. Then using
two levers, prise out the flange/stub shaft
against the tension of its retaining circlip.
10Unbolt and remove the bearing cover.
When refitting the cover, make sure that the
O-ring is in good condition.
11To renew the oil seal on the right-hand
side, first remove the intermediate driveshaft,
and then prise the defective seal out of the
final drive housing using a suitable tool.
12Apply grease to the new seal lips before
refitting the intermediate shaft or the stub
shaft. Tighten all bolts to the specified torque.
PART B:
1372 CC IE AND 1372 CC
TURBO IE ENGINES
Description
1The transmission is of five-speed type,
based on that used in the FIAT Tipo. The
transmission is mounted in-line with the
engine and is located in the left-hand side of
the engine compartment. Drive from the
clutch is transferred through the input shaft
and the mainshaft to the integrally-located
13•94 Supplement: Revisions and information on later models
12A.6 Gearchange link rod spring clip
(arrowed) on the 1301 cc Turbo ie engine12A.5 Gearchange rod connections at
transmission (1301 cc Turbo ie engine)
11.26 Clutch operating lever (A) and
operating cylinder bracket-to-transmission
housing bolt (B)11.25 Clutch operating cylinder showing
hydraulic line connection and bleed nipple
(arrowed)

require maintenance other than general
inspection for wear in the linkage joints. If
excessive wear is found in any of the joints, they
can be individually detached and renewed.
13Access to the control rods is eased by
detaching and lowering the exhaust system
from the exhaust manifold.
14If a new adjustable control rod is to be
fitted, remove the original rod as a unit, but do
not alter its adjustment for length. The new
rod can then (if required) be set to the same
length as the original in order to maintain the
original setting. Do so by loosening off the
locknut and turning the balljoint as required;
ensure that the angle of the joint is correct
before tightening the locknut.
15Access to the gear lever/main connecting
rod joint from above is made by prising back
the gear lever gaiter from the centre console.
Access from underneath can be made by
raising and supporting the car on axle stands.
Working from the underside of the lever, undo
the retaining nuts and remove the inspection
plate from the floor (photos).
16Any adjustment to the gear linkage should
be entrusted to a FIAT dealer.
Transmission -
removal and refitting#
17The transmission can be removed
together with the engine and then separated
as described in Section 7, or on its own (as
described below), leaving the engine in
position in the car. Before starting to remove
the transmission, it should be noted that
suitable equipment will be required to support
the engine during this procedure.
18Disconnect the battery negative lead.
19Remove the bonnet as described in
Chapter 12.
20Refer to Section 11 in this Chapter for
details and detach the clutch operating
cylinder together with its mounting bracket
from the top of the transmission, but do not
disconnect the hydraulic fluid hose from the
cylinder connection. Leave the cylinder
attached to the bracket. Tie the cylinder and
bracket up to support them out of the way.
21Reaching down between the transmission
and the bulkhead, unscrew the knurled
retaining nut and withdraw the speedometer
cable from the transmission.
22Remove the front roadwheel trims, then
loosen off the front wheel retaining bolts.
Raise the vehicle and support it on axle
stands at a suitable height to allow working
underneath and eventual transmission
removal from under the front end.
23Drain the transmission oil as described
previously in this Section.
24Disconnect and remove the starter motor
(photos).
25Detach the reversing light switch lead
connector.
26Undo the retaining bolt and detach the
earth lead from the rear end of the
transmission (see photo 7C.33). Refit the bolt
once the lead has been disconnected.
13•96 Supplement: Revisions and information on later models
12B.15B Access cover to gear lever lower
connection to rod on the 1372 cc engine
Fig. 13.92 Exploded view of the gear selector and control road assembly components
fitted to 1372 cc models (Sec 12)
12B.15A Gear lever connection to the main
connecting rod on the 1372 cc engine
Fig. 13.91 Exploded view of the gear selector lever, rod and linkage components on
1372 cc models (Sec 12)