1998 FIAT PUNTO specifications

4A*2 Fuel system -
single-point
petrol Injection models
6.13b ... and tho EVAP purge valve hose
14 Undo the two bolls securing the plastic nlet manifold upper section to the lower section. Release the spark plug HT lead from Ihe location groove in the manifold upper section, then lift the upper section, complete with throttle body, off the engine (see illustrations). Recover the O-nngs from the manifold ports. 16 Unscrew the two bolts securing the fuel rail assembly to the Inlet manifold lower section, inen carefully pull the injectors from ttie inlet manifold (see Illustration). Remove
tt>e
assembly from the engine and remove the injector lower O-ring seals. t& The injectors can be removed individually from the fuel rail by disconnecting the wiring connector, extracting the relevant metal clip
ano
easing the injector out of the rail. Remove themjector upper O-ring seals. 17 Check the electrical resistance of the tractor using a multimeter and compare it with the Specifications. Note: If a faulty Rector fc suspected, before condemning Wie
Rector,
it is worth trying the effect of one of m
proprietary
injector-cleaning treatments. Refitting
15 Refit the injectors and fuel rail by following tie removal procedure, In reverse, noting the Mowing points:
4} Re/few
the Injector O-ring seals, and
smear
them with a little Vaseline before assembling. Take care when fitting the
injectors
to the fuel rail and do not press
them
in further than required to fit the
retaining
clip otherwise the O-ring
seal may
be damaged.
6.14a Undo the inlet manifold upper section retaining bolts ... b) Ensure that the injector retaining clips are securely seated. c) Renew the sealing O-nngs fitted between the manifold upper and lower sections if in any doubt about their condition. d) Make sure the fuel supply and return hoses are correctly fitted as noted on removal. e) Check that all vacuum and electrical connections are remade correctly and securely. f) On completion check the fuel rail and injectors tor fuel leaks.
Fuel pressure regulator
Removal 19 Remove the resonator, air cleaner and inlet air ducts as described In Section 2. 20 Depressurise the fuel system as described In Section 9. 21 Disconnect the vacuum hose from the port on the side of the regulator. 22 Extract the retaining clip and pull the pressure regulator out of the fuel rail. 23 Remove the O-ring seal. Refitting 24 Refit the fuel pressure regulator by following the removal procedure in reverse, noting the following points: a) Renew the O-ring
seaJ
and smear it with a little Vaseline before assembling. b) When fitting the retaining clip, use a suitable socket or metal tube to press in the three anchorage points at the same time. c) Refit the vacuum hose securely.
Idle control stepper motor 25 The idle control stepper motor is an Integral part of the throttle body and cannot be individually renewed.
Throttle potentiometer 26 The throttle potentiometer Is an integral part of the throttle body and cannot be individually renewed.
Intake air temperature/pressure sensor
Removal
6.14b ... and lift off the manifold upper section and throttle body 28 Disconnect the sensor wiring connector, located on the right-hand side of the Inlet manifold upper section. 29 Undo the two screws and remove the sensor from the manifold. Refitting 30 Refitting is a reversal of the removal procedure. Coolant temperature sensor 31 Refer to Chapter 4A.
Crankshaft TDC sensor 32 Refer to Chapter 4A.
Electronic control unit (ECU)
Removal Note: 77?e engine management system has a learning capability which allows the ECU to store details of the engine's running characteristics in Its memory. This memory will be erased by the disconnection of the battery cables, with the result that the engine may idle roughly, or lack performance for a while, until the engine's characteristics are re-learnt. 33 The ECU (electronic control unit) is located on the right-hand inner wing panel. 34 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual). 35 Undo the mounting bracket nuts and withdraw the unit from the inner wing (see Illustration). 36 Disconnect the ECU wiring connector, then remove the unit from the engine compartment.
6.15 Fuel rail securing bolts (arrowed) 27 Remove the resonator, air cleaner and inlet air duct as described in Section 2. 6.35 Undo the mounting bracket nuts and withdraw the ECU from the inner wing

4C»1
Chapter 4 PartC:
Fuel system - diesel models
Contents
Accelerator cable • removal, refitting and adjustment 3 Air cleaner and inlet system • removal and refitting 2
AJr
cleaner filter element - renewal See Chapter IB Fuet filter renewal See Chapter 1B Fuel gauge sender unit • removal and refitting 10 Fuel injection pump • removal and refitting 5 Fuel injectors - testing, removal and refitting 9
Fuel
system • priming and bleeding 4
Fuel
tank - removal and refitting 11 General Information and precautions 1
Idle speed - checking and adjustment See Chapter 1B Injection timing • checking methods 6 injection timing {Bosch fuel Injection pump) • checking and adjustment 7 Injection timing (Lucas fuel Injection pump) - checking and adjustment 8 Inlet manifold - removal and refitting 12 Turbocharger - description and precautions 13 Turbocharger - examination and renovation 15 Turbocharger - removal and refitting 14
Degrees of difficulty

Easy,
suitable for novice
with Ittle
p experience sS^
Fairly easy, suitable (or beginner with some experience
Fairly tfifficuit, suitable
for
competent ^
DIY
mechanic

Difficult, suitable
for ^ experienced DIY jR mechanic ^
Very difficult, ^ sutable for expert
DIY
S or professional ^
Specifications
General System type
Firing order
Injection pump (Bosch VE) Direction of rotation Static timing: Engine position Pump timing measurement Maximum engine speed
Injection pump (Lucas/CAV FT08) Direction of rotation Static timing: Engine position Pump timing measurement Maximum engine speed
injectors Type Opening pressure: Bosch Lucas: New After running in
RPM sensor Sensor-to-flywheel ring gear teeth gap — Winding resistance
Rear-mounted fuel tank, distributor fuel injection pump with integral transfer pump. Indirect Injection, Turbocharger on TDS, TD and TDSX models 1-3-4-2 (No
1
at timing belt end of engine)
Clockwise, viewed from sprocket end
No
1
piston at TDC 0.93 ± 0.05 mm 5200 to 5300 rpm
Clockwise, viewed from sprocket end
No 1 piston at TDC 0° ± 1° TDC (Note: Value shown on pump - see text} 5150150 rpm
Pintle
150 to 158 bar
124 to
131
bar 116lo123 bar
0.25 to 1.3 mm 680* 100 ohms

Fuel system - diesel models
4C*3

7.4 Unscrew the access screw from the 7.5 Dial gauge and adapter (Bosch) rear of the Injection pump (Bosch)
7 Injection timing ^ (Bosch fuel injection pump) -checking and adjustment ^
Caution: Some of the Injection pump uttlngs and access plugs may be sealed ty the manufacturers at the factory, using
paint
or locking wire and lead seals. Do not
disturb
the seals If the vehicle is still within the warranty period, otherwise the warranty will be invalidated. Also do not attempt the timing procedure unless
accurate
Instrumentation Is available. Note: To check the injection pump timing a special
timing
probe and mounting bracket is required. Without access to this piece of
tquipment.
injection pump timing should be intrusted to a Fiat dealer or other suitably
eqwpped
specialist. 1
H
the Injection timing is being checked with ffie pump in position on the engine, rather rian as part ot the pump refitting procedure, disconnect the battery negative terminal (refer to
Disconnecting
the battery in the Reference S«ction of this manual), and remove the air rtel ducting from the front of the engine. 2 Unscrew the union nuts and disconnect the injector pipes from the Injection pump and injectors. Counterhold the unions on the pump, while unscrewing the pipe-to-pump irion
nuts.
Remove the pipes as a set. Cover open unions to keep dirt out, using small plastic bags, or fingers cut from discarded
ibut clean!)
rubber gloves. 3 Referring to Chapter 2C, set the engine at
TDC on
cylinder No 1. 4 Unscrew the access screw, situated In the centre of the four injector pipe unions, from the rear of the Injection pump (see illustration). As the screw Is removed, position a suitable container beneath the
pump
to catch any escaping fuel, Mop up any tpilt fuel with a clean cloth. 5 Screw the adapter into the rear of the pump
and
mount the dial gauge in ihe adapter (see •ustration). If access to the special Fiat *Japter cannot be gained, they can be purchased from most good motor factors. Position the dial gauge so that its plunger is at
Ifce
mid-point of its travel and securely tighten Ite adapter locknut. 6 Slowly rotate the crankshaft first back then towards whilst observing the dial gauge, to ctotermlne when the Injection pump piston is
a',
the bottom of Its travel (BDC), When the pston Is correctly positioned, zero the dial
7 Rotate the crankshaft slowly in the correct direction until the TDC timing marks are tfjned on both the crankshaft, camshaft and rjecbon pump sprockets.
6
The reading obtained on the dial gauge should be equal to the specified pump timing measurement given in the Specifications at ew start of this Chapter, If adjustment is necessary, slacken the fronl and rear pump mounting nuts/bolts and slowly rotate the
pump body until the point is found where the specified reading Is obtained. When the pump is correctly posilioned, tighten both its front and rear mounting nuts and bolts securely. 9 Rotate the crankshaft through one and three quarter rotations in the normal direction of rotation. Find the injection pump piston BDC as described in paragraph 6 and zero the dial gauge. 10 Rotate the crankshaft slowly in the correct direction of rotation until the TDC marks are aligned. Recheck the timing measurement. 11 If adjustment is necessary, slacken the pump mounting nuts and bolts and repeat the operations In paragraphs 8 to 10. 12 When the pump timing Is correctly set, unscrew the adapter and remove the dial gauge. 13 Refit the screw and sealing washer to the pump and tighten it securely. 14 If the procedure is being carried out as part of the pump refitting sequence, proceed as described in Section 5, 15 If the procedure is being carried out with the pump fitted to the engine, refit the injector pipes tightening their union nuts to the specified torque setting. Reconnect the battery and refit the air inlet ducting. 16 Start the engine, and check for any leakage at the luel unions. To enable the engine to start it may be necessary to loosen the injector union nuts while turning tho engine on the starter motor in order to purge trapped air. 17 Check and if necessary adjust the idle speed as described in Chapter 1B.
8.4 Removing the injection pump timing inspection plug (Lucas)
8 injection timing ^ (Lucas fuel injection pump) - ^ checking
and
adjustment ^
Caution: Some of the injection pump settings and access plugs may be sealed by the manufacturers at the factory, using paint or locking wire and lead seo/s. Do not disturb the seals if the vehicle Is still within the warranty period, otherwise tho warranty will be Invalidated. Also do not affempf the timing procedure unless accurate instrumentation is available.
Note: To check the Injection pump timing a speciai timing probe and mounting bracket Is required. Without access to this piece of equipment, injection pump timing should be entrusted to a Fiat dealer or other suitably equipped specialist. 1 If the injection timing is being checked with the pump tn position on the engine, rather than as part of the pump refitting procedure, disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual), and remove the air inlet ducting from the front of the engine. 2 Unscrew the union nuts and disconnect the injector pipes from the Injection pump and In-jectors. Counterhold the unions on the pump, while unscrewing the pipe-to-pump union nuts. Remove the pipes as a set. Cover open unions to keep dirt out. using smalt plastic bags, or fingers cut from discarded (but clean!) rubber gloves. 3 Referring to Chapter 2C, set the engine at TDC on cylinder No 1, then turn the crank-shaft backwards (anti-clockwise) approx-imately a quarter of a turn. 4 Unscrew the access plug from the guide on the top of the pump body and recover the sealing washer (soe Illustration). Insert the special liming probe Into the guide, making sure it Ib correctly seated against the guide seating washer surface. Note: The timing probe must be seated against the guide sealing washer surface and not the upper lip of the guide for the measurement to be accurate. 5 Mount the bracket on the pump guide (using adapter tool) and securely mount the dial gauge {dial test indicator) In the bracket
expert22 fl/i* http://rutracker.org

4D«1
Chapter 4 Part D:
Exhaust and emission control systems
Contents
Catalytic converter - general Information and precautions 7 Crankcase emission system • general information 3 Evaporative loss emission control system • information and component renewal 2
Degrees of difficulty
Exhaust manifold - removal and refitting 5 Exhaust system - general information and component renewal .... 6 General information 1 Lambda oxygen sensor - removal and refitting 4

Easy, suitable
tor novice with fittie ^
1 experience
Fairly easy, suitable for beginner with ^ some experience ^
Fairiy dfficult, lb suitable for competent ^ DIY mechanic ^
Difficult, suitable for experienced DIY ^ mechanic
Very difficult, ^ suitable far expert DIY or professional
Specifications
Torque wrench settings Exhaust down pipe to manifold Exhaust manifold Exhaust system mounting Exhaust to catalytic converter: M8 M10x1.25
Nm Ibfft 24 18 24 18 27 20
24 18 40 30 53 39
1 General information
Emission control systems All petrol engine models use unleaded petrol and are controlled by engine management systems that are 'tuned' to give the best compromise between driveability. luel consumption and exhaust emission production. In addition, a number of systems are fitted that help to minimise other harmful emissions: a crankcase emission-control system (petrol models only) that reduces the release of pollutants from the crankcase, an evaporative loss emission control system (petrol models only) to reduce the release of hydrocarbons from the fuel tank, a catalytic converter (petrol and diesel models) to reduce exhaust gas pollutants, and an Exhaust Gas Recirculation (EGR) system (turbo diesel models only) to reduce exhaust emissions. Crankcase emission control To reduce the emission of unburned hydrocarbons from the crankcase Into the atmosphere, the engine is sealed and the blow-by gases and oil vapour are drawn from inside the crankcase, through a flame trap.
into the inlet tract to be burned by the engine during normal combustion. Under conditions of high manifold depression (idling, deceleration) the gases will by sucked positively out of the crankcase. Under conditions of low manifold depression (acceleration, full-throttle running) ihe gases are forced out of the crankcase by the (relatively) higher crankcase pressure: if the engine is worn, the raised crankcase pressure (due to increased blow-by) will cause some of the flow to return under all manifold conditions. Exhaust emission control -petrol models To minimise the amount of pollutants which escape Into the atmosphere, a catalytic converter is fitted In the exhaust system. The fuel system is of the closed-loop type, in which a Lambda (or oxygen) sensor In the exhaust system provides the engine management system ECU with constant feedback, enabling the ECU to adjust the air/fuel mixture to optimise combustion. The Lambda sensor has a heating element built-in that Is controlled by the ECU through the Lambda sensor relay to quickly bring the sensor's tip to Its optimum operating temperature. The sensor's tip Is sensitive to oxygen and relays a voltage signal to the ECU
that varies according on the amount of oxygen In the exhaust gas. If the inlet air/fuel mixture is too rich, the exhaust gases are low in oxygen so the sensor sends a low-voltage signal, the voltage rising as the mixture weakens and the amount of oxygen rises In the exhaust gases. Peak conversion efficiency of all major pollutants occurs if the inlet air/fuel mixture Is maintained at the chemlcally-con*ect ratio for the complete combustion of petrol of 14.7 parts (by weight) of air to
1
part of fuel (the stoichiometric ratio). The sensor output voltage alters in a large step at this point, the ECU using the signal change as a reference point and correcting the Inlet air/fuel mixture accordingly by altering the fuel Injector pulse width. Exhaust emission control -diesel models An oxidation catalyst is fitted in the exhaust system of all diesel engine models. This has the effect of removing a large proportion of the gaseous hydrocarbons, carbon monoxide and particulates present in the exhaust gas. An Exhaust Gas Recirculation (EGR) system Is fitted to all turbo diesel engine models. This reduces the level of nitrogen oxides produced during combustion by Introducing a proportion of the exhaust gas back into the inlet manifold, under certain engine operating

5A»1
Chapters Part A:
Starting and charging systems
Contents
Alternator - brush holder/regulator module renewal 6 Alternator/charging system • testing in vehicle 4 Alternator • removal and refitting 5 Auxiliary drivebelt • removal, refitting and adjustment See Chapter 1A or 1B Battery • condition check See Weekly Checks Battery • removal and refitting 3
Battery - testing and charging 2 Electrical fault finding • general Information See Chapter 12 General Information and precautions 1 Starter motor • removal and refitting 8 Starter motor - testing and overhaul 9 Starting system - testing 7
Degrees of difficulty
Easy, suitable for & novice with Tittle jg experience ^
Fairly easy, suitable ^ for beginner with some experience 3J
Fairly tfifftait, J^ sutable for competent ^ DIYmechanic ^
Difficult, suitable for ^ experienced D!Y mechanic ^
Verydtfficult, jk stitable far expert DfY X or professional ^
Specifications
General System type 12 volt, negative earth
Starter motor Type: Petrol engines Magneti-Marelli pre-engaged Diesel engines Bosch pre-engaged with reduction gear Output: 5A Petrol engines 0.8 kW (1108 cc) or 0.9 kW (1242 cc) Diesel engines 1.7 kW
Battery Capacity: Petrol engines 32 to 50 amp/hr Diesel engines 60 amp/hr Charge condition: Poor 12.5 volts Normal 12.6 volts Good 12.7 volts
Alternator Type Magneti-Marelli Output 65 to 85 amp
Torque wrench settings Nm ibt ft Alternator 60 44 Battery tray 29 21 Oil pressure switch: Petrol engine 32 24 Diesel engine 37 27

5A«2 Starting and charging systems
1 General information and precautions
General information The engine electrical system consists mainly of the charging and starting systems. Because of their engine-related functions, these components are covered separately from the body electrical devices such as the Ilght3, Instalments, etc (which are covered In Chapter 12). On petrol engine models refer to Part B for information on the ignition system, and on diesel models refer to Part C for information on the preheating system. The electncal system Is of 12-volt negative earth type. The battery fitted as original equipment is of maintenance* free (sealed for life} type and Is charged by the alternator, which is belt-driven from the crankshaft pulley. If a non-original battery is fitted It may be of standard or low maintenance type. The starter motor is of the pre-engaged type Incorporating an integral solenoid. On starting, the solenoid moves the drive pinion into engagement with the flywheel ring gear before the starter motor is energised. Once the engine has started, a one-way clutch prevents the motor armature being driven by the engine until the pinion disengages from the flywheel.
Precautions Further details of the various systems are given In the relevant Sections of this Chapter. While some repair procedures are given, the usual course of action is to renew the component concerned. The owner whose interest extends beyond mere component renewal should obtain a copy of the Automobile Electrical & Electronic Systems Manual, available from the publishers of this manual It Is necessary to take extra care when working on the electrical system to avoid damage to semiconductor devices (diodes and transistors), and to avoid the risk of personal injury. In addition to the precautions given in Safety first! at the beginning of this manual, observe the following when working on the system: Always remove rings, watches, etc before working on the electrical system. Even with the battery disconnected, capacitlve discharge could occur If a component's live terminal is earthed through a metal object. This could cause a shock or nasty bum. Do not reverse the battery connections. Components such as the alternator, electronic control units, or any other components having semi-conductor circuitry could be irreparably damaged. If the engine is being started using jump leads and a slave battery, connect the batteries positive-to-posibve and negative-to-
negative (see Jump starting). This also applies when connecting a battery charger but In this case both of the battery terminals should first be disconnected. Never disconnect the battery terminals, the alternator, any electrical wiring or any test Instalments when the engine Is running. Do not allow the engine to turn the alter-nator when the alternator Is not connected. Never test for alternator output by flashing the output lead to earth. Never use an ohmmeter ot the type Incorporating a hand-cranked generator for circuit or continuity testing. Always ensure that the battery negative lead is disconnected when working on the electrical system. Before using electric-arc welding equipment on the car, disconnect the battery, alternator and components such as the fuel Injection/ignition electronic control unit to protect them from the risk of damage. Several systems fitted to the vehicle require battery power to be available at all times, either to ensure their continued operation (such as the clock) or to maintain control unit memories or security codos which would be wiped if the battery were to be disconnected. To ensure that there are no unforeseen consequences of this action. Refer to Disconnecting the battery In the Reference Section of this manual for further Information.
2 Battery- % testing and charging
Standard and tow maintenance battery - testing 1 If the vehicle covers a small annual mileage, it is worthwhile checking the specific gravity of the electrolyte every three months to determine the state of charge of the battery. Use a hydrometer to make the check and compare the results with the following table, Note that the specific gravity readings assume an electrolyte temperature of 15*C (60'F); for every 10*C (18°f) below 158C (60aF) subtract 0.007, For every 108C (16'F) above 15"C (60'F) add 0.007. Ambient temperature Above 26"C Below 25DC Charged 1,210 to 1£30 1,270 to 1.290 70% charged 1.170to1.l90 1.230to1.250 Discharged 1.050toJ.070 1.110 to 1.130 2 If the battery condition is suspect, first check the specific gravity of electrolyte In each cell. A variation of 0.040 or more between any cells indicates loss of electrolyte or deterioration of the internal plates. 3 If the specific gravity variation is 0.040 or more, the battery should be renewed. If the cell variation Is satisfactory but the battery is discharged, it should be charged as described later in this Section.
Maintenance-free battery -testing 4 In cases where a sealed tor life maintenance-free battery is fitted, topplng-up and testing of the electrolyte in each cell Is not possible. The condition of the battery can therefore only be tested using a battery condition Indicator or a voltmeter. 5 Certain models may be fitted with a maintenance-free battery with a built-in charge condition Indicator. The indicator Is located in the top of the battery casing, and indicates the condition of the battery from its colour. If the Indicator shows green, then the battery is In a good state of charge. If the Indicator turns darker, eventually to black, then the battery requires charging, as described later in this Section. If Ihe indicator shows clear/yellow, then the electrolyte level in Ihe battery is too low to allow further use, and tho battery should be renewed. Do not attempt to charge, load or Jump start a battery when the indicator shows dear/yellow. 6 If testing the battery using a voltmeter, connect the voltmeter across the battery and compare the result with those given In the Specifications under 'charge condition'. The test is only accurate if the battery has not been subjected to any kind of charge for the previous six hours. If this is not the esse, switch on the headlights for 30 seconds, then wait four to five minutes baforo testing the battery after switching off the headlights. All other electrical circuits must be switched off, so check that the doors and tailgate are fully shut when making the test, 7 It the voltage reading Is less than 12.2 voHs, then the battery Is discharged, whilst a reading of 12.2 to 12.4 volts indicates 8 partially discharged condition. 6 If the battery Is to be charged, remove It from the vehicle (Section 3) and charge it as described later In this Section.
Standard and low maintenance battery - charging Note: The following is Intended as a guide only. Always refer to the manufacturer's recommendations (often printed on a label attached to the battery) before charging a battery. 9 Charge the battery at a rate of 3.5 to 4 amps and continue to charge the battery at this rate until no further rise In specific gravity Is noted over a four hour period. 10 Alternatively, a trickle charger charging at the rate of 1.5 amps can safely be used overnight. 11 Specially rapid boost charges which are claimed to restore the power of the battery in t to 2 hours are not recommended, as they can cause serious damage to the battery plates through overheating, 12 While charging the battery, note that the temperature of the electrolyte should never exceed 37.8*C(100°F),

5B*1
Chapters PartB:
Ignition system - petrol models
Contents
General information 1 Ignition system - testing 2 Ignriton HT coil - removal, testing and refitting 3 Ignition timing - checking and adjustment 4 Igrrtion system - check See Chapter 1A Spark plugs - renewal See Chapter 1A
Degrees of difficulty

Easy,
suitable for Falrty easy, sulabte Fafety difficult, suitable for competent Difficult, suitable for Very difficult, ^ novice with littie
1
for beginner with Fafety difficult, suitable for competent experienced DIY suitable for expert DIY or professional ^ expenence 1 some experience DIY mechanic mechanic *
suitable for expert DIY or professional ^
Specifications
General System type
firing order Ignition timing at Idle speed (non-adjustable, for reference onlyy. 6-valve engines: Single-point injection engine with manual transmission .... Single-point injection engine with automatic transmission.. Multi-point injection engine 16-valve engines
Ignition
coil winding resistance (at 20°C): Primary Secondary
Weber-Marelli static (distributorless), wasted spark Ignition system controlled by engine management ECU
1
-3-4-2 (No 1 cylinder at timing belt end of engine)
10® ± 3° BTDC 6° ± 3° STDC 13° ±3° BTDC 8° x 3° BTDC
0.495 to 0.605 ohms 6660 to 8140 Ohms

Ignition system - petrol models 5B®3
Chapter 1A tor further information. Also check tnat tha accelerator cable is correctly adjusted
as
described in the relevant part of Chapter 4. If the engine is running very roughly, check the compression pressures and the valve clearances as descnbed In the relevant parts of Chapters 1 and 2. 2
H
these checks fall to reveal the cause of the problem, the vehicle should be taken to a suitably equipped Fiat dealer for testing. A wiring block connector Is Incorporated in the engine management circuit Into which a special electronic diagnostic tester can be plugged. The tester will locate the fault quickly and simply alleviating the need to test all the system components Individually which is a time consuming operation that carries a high risk of damaging the ECU. 3 The only Ignition system checks which can
oe
earned out by the home mechanic are those cescribed in Chapter 1A, relating to the spark plugs, and the ignition coll test descnbed In this Chapter. If necessary, the system wiring and wiring connectors can oe checked as descnbed in Chapter 12, Section 2, ensuring that the ECU wiring connector(s) have first
been
disconnected.
3 Ignition HT coil - ^ removal, testing and refitting
Removal 1 On 6-valve engines, unscrew the boll and remove the plastic cover from the left-hand
end
of the cylinder head (see Illustration). On 15-valve engines, remove the air cleaner, resonator and Inlet air duct as described in Chapter 4B. 2 Identify the two HT leads for position then disconnect them from the coil HT terminals jsee illustration). 3 Disconnect the LT wiring plug.
4 Unscrew the mounting bolts and remove the relevant ignition coil from the end of the cylinder head,
Testing 5 Testing of the coil consists of using a multimeter set to its resistance function, to check the primary and secondary windings for continuity and resistance. Compare the results obtained to those given In the Specifications at the start of this Chapter. Note the resistance of the coil windings varies slightly according to the coil temperature; the results In the Specifications are approximate values for the coil at 20°C. 6 Check that there is no continuity between the HT lead terminals and the coil body/ mourning bracket. 7 Note that with the ignition switched on and the engine stationary, voltage will only be supplied to the ignition cotls for approx-imately 2 seconds. However, when tho engine is being cranked or running, voltage will be continually supplied. 8 If faulty, the coil should be renewed.
Refitting 9 Refitting ts a reversal of the removal procedure ensuring that the winng and HT leads are correctly reconnected (see illustration).
4 ignition timing • checking and adjustment
1 The Ignition timing is constantly being monitored and adjusted by the engine management ECU, and although it is possible to check the base ignition liming using a standard timing light It is not possible to adjust it. 2 For those wishing to check the ignition timing a stroboscope timing light will be required, and it will need to be the type which
3.1 Removing the ignition coll cover
can determine the amount of advance from the TDC markings on the crankshaft pulley or flywheel. It Is recommended that the timing mark is highlighted as follows. 3 Remove the plug from the top of the transmission then turn tho engine slowly (raise the front right-hand wheel and engage 4th gear) until the timing mark scribed on the edge of the flywheel appears in the aperture. Highlight the line with quick-drying white paint - typist's correction fluid is ideal. 4 Start the engine and run It to normal operating temperature, then stop it. 5 Connect the timing light to No 1 cylinder spark plug lead (No 1 cylinder Is at the timing belt end of the engine) as described in the timing light manufacturer's Instructions. 6 Start the engine, allowing it to idle at the specified speed (Chapter 1A), and point the timing light at the transmission housing aperture. Adjust the timing light until the TDC marks are aligned with each other and read off the amount of advance. 7 If the ignition timing is incorrect, the car should be taken to a Fiat dealer who will be able to check the system quickly using special diagnostic equipment. 8 After making the check stop the engine, disconnect the timing light and refit the plug to the transmission.
3.2 HT terminals (1) and LT wiring plugs (2) on the two ignition colls 3.9 Ignition colt connections