1994 FIAT PUNTO relay

2C*2 Diesel engine in-car repair procedures
Refitting 6 Locate a new gasket on the cylinder head and make sure tt Is correctly seated. 7 Lower the cover onto the gasket making sure the gasket Is not displaced, 8 Insert the mounting bolts and tighten them securely In a progressive sequence. Position Ihe support brackets as noted during removal. 9 Clip ihe coolant hoses in position then refil the air ducting.
7 Camshaft oil seal -renewal
8 Crankshaft oil seals -renswal I
9 Cylinder head -
removal
and refitting
1 Remove the timing belt and camshaft sprocket as descnbed in Sections 4 and 5. 2 Using a suitable hooked instrument, remove tho oil seal from the cylinder head taking care nol to damage the surface of the camshafl. Alternatively drill a small hole In tho oil seal and Insert a self-topping screw - the seal can then be removed by pulling on the screw with a pair of pliers. 3 Clean the seating In the cylinder head and tho end of the camshaft To prevent damage to the new oil seal as It is being fitted, wrap some adhesive tape around the end ol the camshaft and lightJy oil it. 4 Dip tho new ail s«al In oil then locate it over Ihe camshaft making sure that the sealing lips are facing inwards. 5 Using a suitable tubular drift, drive the oil seal squarely into the cylinder h*ad. Remove the adhesive tap© 6 Refit the camshaft sprocket and timing belt with reference to Sections 6 and 4.
Front (right-hand side) oil seal t The front oil seal is located in the oil pump casing on the front of the crankshaft. Remove the timing belt as described in Section 4 and the crankshaft sprocket as described in Section 5, 2 Using a suitable hooked instrument, remove the oil seal from the oil pump casing taking care not to damage the surface of the crankshaft. Alternatively drill a small hole In the oil soal and insert a self-tapping screw - the seal can then be removed by pulling on the screw with a pair of pliers. 3 Clean the seating in the oH pump and the surface of the crankshaft. To prevent damage to the new off seal as It Is being fitted, wrap some adhesive tape around the end of tha crankshaft and lightly oil it. 4 Oip the new oii seal In oil then otter it up to the oil pump casing making sure that the sealing Hps are facing inwards,
8.Ba Rear oil soal and housing
5 Using a suitable tubular drift, driva the oil sea! squarely into the casing. Remove the adhesive tape. 6 Refit the crankshaft sprocket and timing belt with reference to Sections 5 and 4.
Rear (left-hand side) oil seal Note: The following paragraphs describe renewal of the rear oil seal leaving the housing In position. The alternative mathod is to remove the housing and renew the oil seel on the bench, however there is then the possibility of damaging the sump gasket. Refer to Chapter 2D for details of removing the mar oil sea! housing. 7 Ramove the flywheel as described in Section 10. 8 Using a suitable hooked Instrument. remove 1he oil seat from the roar oil seal housing taking care not to damage Ihe surface of Ihe crankshaft. Alternatively dnll a small hole In the o» seal and insert a self-tapping screw - the seal can ihan be removed by pulling on the screw with a pair of pliers (see Illustrations), 9 Clean the seating in the housing and the surface of the crankshaft. Check the crankshaft for burrs which may damage the oil seal tip of tno new saal, and It necessary use a Una file to removothem. 10 Dip the new soal in clean engine oil and carefully tocato it over tho crankshafl rear Range making sure that
H
the correct way round. 11 Progressively tap the oH seal into the housing keepfng it square to prevent distortion. A block of wood is useful for this purpose. 12 Refit the flywheel with reference to Section 10.
I
5.8b Using a self-tapping screw and pliers to remove the rear oil seal
Removal Note: The cylinder head bolts are of special splined design and a Fiat tool should be obtained to unscrew them. A Torn key will
not
fit however In practise It was found that a close-fitting Allen key could bo used as an alternative. 1 Disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual), 2 Remove tha battery as described In Chapter 5A. 3 Refer to Chapter IB and carry out the following: o) Drain the engine oil, b) Drain the cooling system. 4 Remove the timing belt as described in Section 4. 5 Unbolt and remova the relay guard and bracket from the left-hand side of the engine. 6 Unbolt and remove the battery mounting tray and disconnect the wiring and lines from the modulator valva and relays. 7 Remove the air eleanar assembly and air duct with reference lo Chapter 4C. 8 Loosen the clip and disconnect the vacuum hosa from the vacuum pump on the left-hand end of the cylinder head. 9 Loosen Ihe clips and disconnect the radiator top hose from the cylinder head outlet. Also disconnect the heater inlet hose from the thermostat housing, 10 Loosen the clips and disconnect the expansion tank and heater outlet hoses. 11 Identify all wiring connectors then disconnect them from the cylinder head, 12 Unscrew the expansion tank mounting screws, then disconnect tha expansion tank hoses at their connections to the engine. Remove the expansion tank from tha engine compartment. 13 Release tha clip and disconnect ihe crankcase breather from the left-hand rear of the cylinder head. 14 Unbolt the power steering pump uppar cover bracket then unscrew the pivot ana adjustment bolts while leaving ihe tMd lioses still attached. Release the drivebelt (if still In place) then tie the pump to the bulkhead. 15 Loosen tha clips and disconnect Ihe short coolant hose from the cylinder head outlet to the coolant pump (soe illustration). 18 At the rear of the engine, unbolt and disconnect the oil delivery pipe from the turbocharger (where applicable) and crankcase (see Illustrations). 17 Disconnect the return hose from tha thermostat housing to the coolant pump (see Illustration), 18 Unbolt the metal coolant return pipe and pull it out from the coolant pump inlet elbow (see Illustrations).
expert22 flna http://rutracker.org

2D*10 Engine removal and overhaul procedures
4.36a Relay guard mounting nuts 4.36b Battery tray and mounting bolts 4.36c Disconnect the engine wiring harness located above the transmission .
4.36d ... the inner wiring plug ...
sure that the dnveshaft is positioned to clear Ihe lower suspension arm when the engine is removed. 34 Disconnect the left-hand driveahaft using the same procedure
4.41 Engine wiring harness connections to the battery positive cable
4.36e ... and the outer wiring plug
35 Remove the exhaust front downpipe witfl reference to Chapter 4D. Diesel engines 36 Unbolt and remove the roiay guard then disconnect the wiring as applicable and unbolt the battery tray (see Illustrations). 37 Disconnect tho gear selector cable from the transmission by removing the retaining plate and prising the socket end off Ihe ball on the lever. Use a pair of pliors to pull out the plate. Tie the cable to the bulkhead (see illustration). 38 Unscrew the nut and disconnect the gear selector rod from the ievor on the top of the transmission, 39 Remove the air cleaner and air inlet duct by unscrewing the two bolls securing the duct to the valve cover and loosening the clip securing the duct to the air cleaner. Refer to Chapter 4C if necessary.
4.37 Tie tho gear selector cable to the bulkhead
40 Disconnect the vacuum pipe from the vacuum pump on the left-hand side of the cylinder head and disconnect the wiring plug located over the transmission, 41 Unscrew ihe nuts and disconnect the engine wiring harness from the battery positive cable (see illustration) 42 At the fuel filter unscrew the union bolt and disconnect the fuei delivery hose lor the injection pump. Use polythene and an elastic band to cover the end of the hose (see illustrations). 43 At the fuel injection pump unscrew the clip and disconnect thie fuel return hose (see illustration). 44 Disconnect the radiator top hose from the thermostat housing on tho left-hand side of the cylinder head, and also disconnect the healer hose at Ihe engine (see illustrations). 45 Disconnect the heater return hose and expansion tank hose from the elbow on the
4.42a Unscrew the union bolt and disconnect the fuel delivery hose from the fuel filter 4.42b Cover the end of the hose to prevent dust entry 4.43 Disconnecting the fuel return hose from the fuel injection pump

3*2 Cooling, heating and ventilation systems
1 General information and precautions
Genera/ Information The engine cooling/cabin heating system is ol pressurised type, comprising a coolant pump driven by the camshaft timing belt (petrol engine models) or auxiliary drlvebelt (diesel engine models), a crossllow radiator, a coolant expansion tank, an electric cooling fan, a thermostat, heater matrix, and all associated hoses and switches. The system functions as follows: Ihe coolant pump circulates cold water around the cylinder block and head passages, and through the Inlet manifold, heater matrix and throttle body to the thermostat housing. When the engine Is cold, the thermostat remains closed and prevents coolant from circulating through the radiator. When the coolant reaches a predetermined temperature, the thermostat opens, and the coolant passes through the top hose to the radiator. As the coolant circulates through the radiator, it is cooled by the in-rush of air when the car is in forward motion. The airllow is supplemented by the action of the electric cooling fan. when necessary, As the temperature of the coolant in the radiator drops, it flows to the bottom of the radiator by convection, and passes out through the bottom hose to the coolant pump - the cycle is then repeatod, When the engine is at normal operating temperature, the coolant expands, and some of It is displaced into the expansion tank. Coolant collects In the tank, and ts returned to Ihe radiator when the system cools. On petrol engine models, the expansion tank is integrated into the side of the radiator. On diesel engine models, and certain petrol engine models with air conditioning, the tank is a separate unit, mounted on the right hand side of the engine compartment. On turbo diesel engine models, the coolant is also passed through a supplementary engine oil cooler, to assist In controlling the engine lubricant temperature. Tho electric cooling fan mounted in front of the radiator is controlled by a thermostatic switch. At a predetermined coolant temperature, the swilch/sensor actuates the tan lo provide additional airflow through the radiator, The switch cuts the electrical supply to the Ion when the coolant temperature has dropped below a preset threshold (see Specifications).
Precautions

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Warning: Do not attempt to remove the expansion tank pressure cap, or to disturb any part of the cooling system, whlio the engine is hot, as then is a high risk of scalding, tf the expansion tank pressure cap must be removed before the
engine and radiator have fulty cooled (even though this is not recommended?, the pressure in the cooling system must first be relieved. Cover the cap with a thick layer of cloth, to avoid scalding, and slowly unscrew the pressuro cap until a hissing sound Is heard. When the hissing stops, indicating that the pressure has reduced, slowly unscrew the pressure cap until it can be removed; If more hissing sounds are heard, wait until they have stopped before unscrewing the cap completely. At all times, keep your face well away from the pressure cap opening, and protect your hands.

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Warning: Do not allow antifreeze to come into contact with your skin, or with the painted surfaces of the vehicle. Rinse off spills immediately, with plenty of water. Never leave antifreeze lying around in an open container, or In a puddle In the driveway or on the garage floor. Children and pets are attracted by its sweet smell, but antifreeze can be fatal tf ingested.

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Warning: If the engine is hot, the electric cooling fan may start rotating even if the engine and ignition are switched off. Be careful to keep your hands, hair, and any loose clothing well clear when working In the engine compartment.
2 Cooling system hoses - f&> disconnection and renewal ^
1 The number, routing and pattern of hoses will vary according to model, but the same basic procedure applies. Before commencing work, make sure that the new hoses are to hand, along wilh new hose clips if needed, it is good practice to renew the hose clips at the same time as the hoses. 2 Drain the cooling system, as described in Chapter 1A or 18, saving the coolant if it is fit for re-use. Apply a little penetrating oil onto the hose clips if they are corroded. 3 Release the hose clips from the hose concerned. Three types of clip are used; worm-drive. spring and 'sardine-can'. The worm-drive clip is released by turning its screw anti-clockwise. The spring clip Is released by squeezing Its tags together with pliers, at the same time working the cbp away from the hose stub. The sardine-can clips are not re-usable, and are best cut off with snips or side cutters. 4 Unclip any wires, cables or other hoses which may be attached to the hose being removed. Make notes for reference when reassembling If necessary. 5 Release the hose from its stubs with a twisting motion. Be careful not to damage the stubs on deltcate components such as the radiator, or thermostat housings. If the hose Is stuck fast, the best course is often to cut it off using a sharp knife, but again be careful not to damage the stubs.
6 Before fitting the new hose, smear the stubs with washing-up liquid or a suitable rubber lubricant to aid fitting. Do not use oil or grease, which may attack the rubber. 7 Fit the hose clips over the ends of the hose, then fit the hose over its stubs. Work the hose Into position. When satisfied, locate and tighten the hose dips. 6 Refill the cooling system as described In Chapter 1A or 1B. Run the engine, and chock that there are no leaks. 9 Recheck the tightness of Ihe hose clips on any new hoses after a few hundred miles. 10 Top-up the coolant level if necessary.
3 Radiator -
removal,
inspection and refitting
Removal Note: If leakage is the reason for removing
the
radiator, bear In mind that minor leaks can often be cured using proprietary radiator sealing compound, with the radiator in situ. 1 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual). On diesel engine models, unbolt the relay bracket from the side of the battery tray. 2 Drain the cooling system as described In Chapter 1A or 1B. 3 On 1242 cc (16-valve) petrol engine models, remove the air cleaner and Inlet ducts as desenbed In Chapter 4B, 4 Slacken the clips and disconnect Ihe (op and bottom coolant hoses from the radiator. In addition on diesel engine models, and petrol engine models with a remotely-sited expansion tank, disconnect the expansion tank coolant hose from the right hand side ol the radiator (see Illustrations), 5 Unscrew the fixings and lift the plastic trim panel from above the front bumper Unscrew the bolt(s) securing tho radiator to the upper body panel (see Illustration). Note that the radiator and cooling fan assembly share the same upper mounting bolt. 6 Unbolt the cooling fan(e) and shroud assembly from Ihe rear ot the radiator, as described in Section 5.
3.4a Slacken the clip and disconnect the radiator bottom hose

3*2 Cooling, heating and ventilation systems
4 If the motor operates when tested as described, (he fault must lie In the engine wring harness or the temperature sensor. The temperature sensor/switch can be tested as described in Section 6. Any further fault Diagnosis should be referred to a suitably-equipped Fiat dealer - do not attempt to test
Ihe
electronic control unit.
Removal 5 Disconnect the battery negative terminal (refer to D/scon oecf/ng the battery in the Reference Section of this manual). 6 On diesel engine models, unbolt the relay bracket from the side of the battery tray to improve access. On 1242 cc {16-valve) petrol engine models, remove the air cleaner and
inset
ducts as described in Chapter 4B. 1 Disconnect the motor wiring connectorfs). 8 Unbolt the shroud from the rear of the ratiator. then lift out the cooling fan assembly. Refitting 9 Refitting is a reversal of removal
6 Cooling fan switch -testing, removal and refitting ^
Testing 1 The switch is threaded into the lower left
nand
comer of the radiator. 2 The switch can be tested by removing it,
and
checking that the switching action occurs
at
the correct temperature {heat the sensor in a container of water, and monitor the temperature with a thermometer). 3 There should be no continuity between the switch terminals, until Ihe specified cooling fan cut-In temperature Is reached, when continuity (and zero resistance) should exist between the terminals.
Removal 4 Disconnect the battery negative terminal refer to Disconnecting the battery in the Reference Section of this manual). 5 Allow the engine to cool completely, then drain the cooling system as described in Chapter 1Aor 1B. 6 Disconnect the wiring plug from the sensor.
bolts...
7 Carefully unscrew the sensor and. whore applicable, recover the sealing ring. Refitting 8 If the sensor was originally fitted using sealing compound, clean the sensor threads thoroughly, and coat them with fresh sealing compound. 9 If the sensor was originally fitted using a sealing ring, use a new sealing ring on refitting. 10 Refitting is a reversal of removal, but refill the cooling system as described in Chapter 1A or 18. 11 On completion, start the engine and run it until it reaches normal operating temperature. Continue to run the engine until the cooling fan cuts in and out correctly.
7 Coolant pump • & removal, inspection 5 and refitting
Removal
Petrol engine models 1 Disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual). 2 Drain the cooling system and remove the auxiliary drivebett(s) as described In Chapter 1 A. 3 Remove the timing belt as described In Chapter 2A or 28. 4 Unscrew the securing bolts/nuts, and withdraw the coolant pump (see illustrations).
7.9b ... and lift off the pulley (diesel engine)
(petrol engine) If the pump Is stuck, tap it gently using a soft-faced mallet - do not lever between the pump and cylinder block mating faces.
Diesel engine models 5 Disconnect the battery negative terminal (refer to D/s connecting the battery in the Reference Section of this manual). 6 Drain the cooling system as described in Chapter 1B. 7 Remove the auxiliary drivebelt(s) as descnbed In Chapter 1B. 6 On models fitted with power steenng, refer to Chapter 10 and remove the power steering pump from its mountings; this can be achieved without disconnecting the power steering fluid hoses from the pump. Tie the pump away from the work area, taking care to avoid kinking the fluid hoses. 9 Unscrew the securing bolts, and remove the coolant pump pulley. It will be necessary to counterhold the pulley In order to unscrew the bolts, and this is most easily achieved by wrapping an old drivebelt tightly around the pulley to act in a similar manner to a strap 3 wrench. Alternatively, a stout screwdriver can be braced between two of the pulley bolts while the third is slackened (see illustrations). 10 Disconnect ihe bypass hoses from the coolant pump outlet stubs. 11 Unscrew the securing bolts, and withdraw the coolant pump assembly. Note that the pump must be detached from the transfer pipe than runs behind the cylinder block to the thermostat housing (see illustration). The pipe is a push fit in the port on the rear of the coolant pump
7.11 Removing the coolant pump assembly (diesel engine)

4A*2 Fuel system - single-point petrol Injection models
1 General information and precautions
General information The iAW Weber-Marelli single point Injection (SPI) system is a self-contained engine management system, which controls both the fuel Injection and Ignition (see Illustration), This Chapter deals with the fuel Injection system components only - refer to Chapter 5B for details ol the ignition system components. The fuel Injection system comprises a fuel tank, an electric fuel pump, a fuel filter, fuel supply and return lines, a throttle body with an integral electronic fuel Injector, and an Electronic Control Unit (ECU) together with its associated sensors, actuators and wiring. The fuel pump delivers a constant supply of fuel through a cartridge fitter to the throttle body, and the fuel pressure regulator (integral with the throttle body) maintains a constant fuel pressure at the fuel injector and returns excess fuel to the tank via the return line. This
constant flow system also helps to reduce fuel temperature and prevents vaporisation. Tne fuel injeclor Is opened and closed by an Electronic Control Unit (ECU), which calculates the injection timing and duration according to engine speed, throttle position and rate of opening, Inlet air temperature, coolant temperature and exhaust gas oxygen content information, received from sensors mounted on the engine. inlet air is drawn Into the engine through the air cleaner, which contains a renewable paper filter element. The inlet air temperature is regulated by a vacuum operated valve mounted in the air ducting, which blends air at ambient temperature with hot air, drawn from over the exhaust manifold. Idle speed is controlled by a stepper motor located on the side of the throttle body. Cold starling enrichment is controlled by the ECU using the coolant temperature and inlet air temperature parameters to increase the injector opening duration. The exhaust gas oxygen content is constantly monitored by the ECU via the Lambda (oxygen) sensor, which is mounted in
me exhaust downpipe. The ECU then uses this Information to modify the Injection timing and duration to maintain the optimum air/fuel ratio. An exhaust catalyst Is fitted to all SPI models. The ECU also controls the operation of the activated charcoal filter evaporative loss system • refer to Chapter 4D for further details. It should be noted that fault diagnosis of the I IAW Weber-Marelli system is only possible with dedicated electronic test equipment. Problems with the system should therefore be I referred to a Flat dealer for assessment. Once i the fault has been Identified, the I removal/refitting procedures detailed in the following Sections can then be followed.
Precautions |

A


Warning: Many procedures in thH Chapter require the removal ot fuel lines and connections, which may result in fuel spillage. Before carrying | out any operation on Me fuel system, refer to the precautions given In Safety flrstt at the beginning ot this manual, and follow them Implicitly. Petrol Is a highly dangerous and volatile liquid, and the precautions
1.1 IAW Weber-Marelli single point Injection (SPI) system 1 Fuel
tank
2 Fuel pump 3 Fuel filter 4 Anii'reflux valve 5 Fuel pressure regulator 6 Injector
7 Air cleaner 8 Fuel vapour
trap
9 Idle stepper motor
10
Absolute pressure sensor J11njection/ignition ECU 12 Tnrottle position sensor
13 Engine coolant temperature sensor 14 Intake air temperature sensor 15 Inject'onfignitron dual
relay
16 Ignition coils 17 Rpm and TDC sensor
18 Spark plugs 79 Diagnostic socket 20 EVAP solenoid 21 Lambda/oxygen sensor 22 Rev counter 23 IAW failure warning light

Ihe right-hand front roadwheel and the protective plastic cover under the wheelarch. 37 Disconnect the sensor wiring plug on the front of the engine. 38 Detach the sensor from its mounting. Refitting 39 After refitting Ihe sensor use a feeler blade to check that the gap between sensor and the serrated part of the crankshaft pulley Is between 0.5 and 1.S mm. No adjustment is possible and if the gap is incorrect the sensor and pulley should be checked for possible damage.
Electronic control unit (ECU)
Removal Note: 77ie engine management system has a (earning capability which allows the ECU to store details of the engine's running
characteristics
in its memory,
This
memory
will
tie erased by the disconnection of the battery
cables,
with the resuit that the engine may idle
roughly,
or lack performance for a while, until
the
engine's characteristics are re-teamt. 40 The ECU {electronic control unit) is located on the right-hand Inner wing (see illustration). The 3-pin socket by the ECU is for connection of diagnostic test equipment. 41 Disconnect the battery negative terminal (refer to D/sconnecffng the battery in the Reference Section of this manual). 42 Disconnect the ECU wiring connector, then undo the retaining nuts and remove the unit from the bracket In the engine compartment. Refitting 43 Refitting Is a reversal of removal making sure that the wiring connector is securely reconnected. Inertia safety switch
Removal 44 The inertia safety switch is located by the left-hand side passenger seat. First pull back
the
carpet for access. 45 Disconnect the wiring then unbolt the switch. Refitting 48 Refitting is a reversal of removal.
Fuel injection system relays
Removal 47 The fuel injection system relay is located under a plastic cover on the bulkhead. The MAP sensor is also located under the same cover. 48 Two separate relays are incorporated in the single housing; the left-hand relay has a 5 amp fuse and the right-hand relay has a 25 amp fuse. The main purpose of the relays is to supply current to the fuel pump, ignition coils, oxygen sensor. Injectors and EVAP solenoid. The main relay is controlled by the ignition switch.
4A*2 Fuel system - single-point petrol Injection models
6 Fuel pump/fuel gauge sender unit -removal and refitting
Removal Note: Refer to the warning given in Section 1 before proceeding. 1 Disconnect the battery negative terminal (refer to Disconnecting the battery in the Reference Section of this manual). 2 Remove the rear seat as described in Chapter 11. Prise the fuel pump access cover out of the floor panel to gain access to the pump unit. 3 Disconnect the wiring connector. 4 Bearing in mind the warning given in Section t, disconnect the fuel supply and return lines from the pump unit by pressing the tabs (see illustration). Plug the ends of the lines or cover them with adhesive tape. 5 Using a suitable toot, unscrew the large ring nut and carefully withdraw the fuel pump/fuel tank sender unit assembly from the fuel tank, along with its sealing ring. 6 If necessary, the unit can be dismantled and the pump and sender unit separated. If this is the case, carefully note the correct
fitted positions of oil components while dismantling the unit, and use these notes on reassembly to ensure that all items are correctly fitted.
Refitting 7 Refitting is a reversal of the removal procedure using a new sealing ring. Prior to refitting the access cover, reconnect the battery, then start the engine and check the feed and return unions for signs of leakage.
5.40 ECU located on the right-hand inner wing 49 Remove the cover and pull the relay directly from its socket. Refitting 50 Refitting Is a reversal of removal.
7 Fuel tank -removal and refitting
6.4 Press the tabs Indicated to disconnect the fuel supply and return tines
Note: Refer to the warning given in Section 1 before proceeding.
Removal 1 Before removing the fuel tank, all fuel must be drained from the tank. Since a fuel tank drain plug is not provided, it is therefore preferable to carry out the removal operation when the tank is nearly empty. Before proceeding, disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual), and syphon or hand-pump the remaining fuel from the tank. 2 Remove the fuel pump/fuel gauge sender unit as described in Section 6. 3 Chock the front wheels, then jack up the rear of the vehicle and support on axle stands (see Jacking and vehicle support). 4 Loosen the clip and disconnect the filler pipe from the nght-hand side of the fuel tank. 5 Undo the tank flange and strap mounting bolts, then lower the tank out of position until It is possible to access the hose connections on top of the tank. 6 Loosen the clips and disconnect the EVAP purge hose and breather hose from the fuel tank. If necessary, the filler neck can be detached from the body. 7 Check that all hoses and wiring is disconnected, then remove the tank from underneath the vehicle. Refitting 8 Refitting is a reversal of the removal procedure, ensuring all hoses are correctly routed and securely reconnected.
8 Fuel injection system - ^ depressurisation
Note: Refer to the warning given In Section t before proceeding.

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Warning; The following procedure will merely relievo the pressure in the fuel system • remember that fuel will still be present In the system components and take precautions accor-dingly before disconnecting any of them.

4A*2 Fuel system -
single-point
petrol Injection models
1 General information and precautions
General information The
LAW
Weber-Maretil multi-point Injection (MPI) system is a self-contained engine management system, which controls both the fuel injoction and Ignition (see Illustrations). This Chapter deals with the fuel Injection system components only - refer to Chapter 5B for details of the ignition system components. The fuel injection system comprises a fuel tank, an electric fuel pump, a fuel filter, fuel supply end return lines, a throttle body, a fuel rail with four electronic Injectors, and an Electronic Control Unit (ECU) together with its associated sensors, actuators and wiring. On pre-1998, 8-valve engines and all 16-valve engines, the fuel pump delivers a constant supply of fuel through a cartridge filter to the fuel rail, and the fuel pressure regulator (located on Ihe fuel rail) maintains a constant fuel pressure at the fuel Injectors and returns excess fuel to the tank via the return
line, This constant flow system also helps to reduce fuel temperature and prevents vaporisation. On later 8-valve engines, a returnless fuel system is used. With this arrangement, the fuel filter and fuel pressure regulator are an integral part of the fuel pump assembly located In the fuel tank. The regulator maintains a constant fuel pressure in the supply line lo the fuel rail and allows excess fuel to recirculate in the fuel tank, by means of a bypass channel, if the regulated fuel pressure is exceeded. As the fuel filler Is an integral part of the pump assembly, fuel filter renewal Is no longer necessary as part of the maintenance and servicing schedule. The fuel injectors are opened and closed by an Electronic Control Unit (ECU), which calculates the Injection timing and duration according to engine speed, throttle position and rate of opening, inlet air temperature, coolant temperature and exhaust gas oxygen content information, received from sensors mounted on the engine. The injectors are operated simultaneously (le not sequentially) and Inject half of the quantity of fuel required on each turn of the crankshaft. Inlet air Is drawn into the engine through
the air cleaner, which contains a renewable paper filter element. On 8-valve engines, the Inlet air temperature is regulated by a vacuum operated valve mounted in the air ducting, which blends air at ambient temperature with hot air, drawn Irom over the exhaust | manifold. Idle speed Is controlled by a stepper motor 1 located on the side of the throttle body. Cold storting enrichment is controlled by the ECU using the coolant temperature and Inlet air temperature parameters to Increase the Injector opening duration. The exhaust gas oxygen content it constantly monitored by the ECU via the Lambda/oxygen sensor, whioh Is mounted in the exhaust downpipe. The ECU then uses this Information to modify the Injection timing and duration to maintain the optimum air/fuel ratio. An exhaust catalyst is fitted to all models. The ECU also controls the operation of the activated charcoal filler evaporative loss system - refer to Chapter 4D for further details. It should be noted that fault diagnosis of the IAW Weber-Marelll system Is only possible with dedicated electronic test equipment.
1.1a IAW Weber-Marelii multt-point Injection (MPi) system (8-valve engines) f Fuel
tank
7 Air
cleaner
13 Coolant temperature sensor 19 Diagnostic socket 2 Fuel pump 8 Fuel vapour trvp 14 Intake air temperature 20
EVAP
solenoid 3 Filter (pre-1998 models) 9 Idle control stepper motor sensor 21 Lambda/oxygen sensor 4 Fuel
rail
10 Manifold absolute pressure 15 Duel
relay
22 Rev counter 5 Pressure regulator
(pre-1998
sensor 16 Ignition colls 23 IAW failure warning light models)
11 ECU
17 Rpm and TDC sensor 24 Anti-refhjx
valve
6 Injectors 12 Throttle position sensor 18 Spark piugs

4A*2 Fuel system -
single-point
petrol Injection models
1.1b IAW Weber-Marelli multi-point injection (MPI) system (16-valve engines) J Fuel
tank
2 Fuel pump 3 Multi-purpose
valve
4 Safety
valve
5 Anti-reflux
valve
6 F/fter 7 Battery 8
EVAP
solenoid
9 Dual
relay
10 Ignition switch 111nertia switch
12
Air conditioning compressor
13
Fuse 14 Throttle position sensor

1$
idle control stepper motor 17 Ignition coils 18 Sparkplugs 19 Fuel
rail
20 Pressure regulator 21 Injectors
15
Intake air temperature/pressure 22 Coolant temperature sensor sensor 23 Lambda/oxygen sensor
24 Rpm and TDC sensor 25 Engine immobiliser control unit 26 Catalytic converter 27 IAW failure warning light 28 EVAP canister 29 ECU 30 Diagnostic socket 31 Rev counter
Problems with the system should therefore be referred to a Fiat dealer for assessment. Once the fault has been Identified, the removal/ refitting procedures detailed in the following Sections can then be followed.
Precautions

A


Warning: Many procedures In this Chapter require the removal of fuel lines and connections, which may result In fuel spillage. Before carrying out any operation on the fuel system, refer to the precautions given In Safety flrstl at the beginning of this manual, and follow them implicitly. Petrol Is a highly dangerous and volatile liquid, and the precautions necessary when handling it cannot be overstressed. Note that residual pressure will remain in the fuel lines long after the vehicle was last used, When disconnecting tny fuel line, first depressurise the fuel system {see Section 9).
2 Air cleaner and inlet system Sk - removal
and
refitting ^
Removal
1242 cc (8-valve) engines 1 Remove the air cleaner element as described In Chapter 1A. 2 Disconnect the outer section from the hot air tube and the Inlet air duct and remove it from the engine compartment. 3 If necessary remove the inlet air duct. 4 Disconnect the large and small breather hoses from the inner section of the air cleaner, then unscrew the retaining nuts and lift the section from the throttle body. 5 Recover the sealing ring. Check the nng for condition and renew it it necessary. 6 Wipe clean the inner surfaces of both the Inner and outer sections of the air cleaner,
1242 cc (16-valve) engines 7 Release the hose clip and disconnect the inlet air duct from the resonator (see illustration).
2.7 Release the hose clip and disconnect the inlet air duct from the resonator