switch FIAT PUNTO 1995 176 / 1.G Owner's Manual

3*1
Chapter 3
Cooling, heating and ventilation systems
Contents
Air conditioning system - general Information and precautions .... 9 Mr conditioning system components * removal and refitting 10 Antifreeze mixture See Chapter 1A or 1B Auxiliary drivebell(s) check and renewal See Chapter 1A or IB Coolant level check See Weekly checks Coolant pump - removal, Inspection and refitting 7 Coolant renewal See Chapter 1A or 1B
Degrees of difficulty
Cooling fan switch - testing, removal and refitting 6 Cooling system hoses • disconnection and renewal 2 Electric cooling fan(s) - testing, removal and refitting 5 General information and precautions 1 Heater/ventilation components • removal and refitting 8 Radiator - removal, inspection and refitting 3 Thermostat - removal, testing and refitting 4

Easy,
suitable foe JS^, novice
with
little experience ^
Fairly
easy,
sutable for beginner witti
some experience
^
Faiilydifltctit,
suitable
for competent
DIY mechanic
^

Difficult,
sutable for & experienced DIY « mechanic ^
VerydMlcult, ^
suitable
for
expert DIY
« or professional
Specifications
General Expansion tank relief valve opening pressure 0.96 bar Coolant pump Impeller-to-casing clearance: Diesel engine models 0.53 to 1.37 mm Petrol engine models 0.4 to 0.9 mm
Thermostat Diesel engine models: Opening temperature: Starts to open 78 to 82*0 Fully open 88°C Maximum valve travel (approximate) 7.5 mm Petrol engine models: Opening temperature: 1108 cc and 1242 cc (8-valve) engines: Starts to open 85 to 89°C Fully open 100°C 1242 cc (16-valve) engines: Starts to open 81 to 85°C Fully open 103°C Maximum valve lift (approximate) 7.5 mm
Electric cooling fan Petrol engine models with single speed fan: Cut-in temperature 90to94°C Cut-out temperature B5 to 89°C Diesel engine models with twin speed fan: Cut-In temperature: Primary fan 86 to 90® C Secondary fan 90 to 94°C Cut-out temperature: Primary fan 81to85°C Secondary fan 85 to 89°C
Torque wrench settings Nm tbfft Coolant pump pulley securing bolts (diesel engine models) 23 17 Coolant pump securing bolts: Diesel engine models 23 17 Petrol engine models 8 6 Coolant pump securing nuts (petrol engine models) 10 7

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

A


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.

A


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.

A


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
3.4b On diesel engine models, disconnect the expansion tank coolant hose from the radiator 3.5 Unscrew the bolts securing the radiator to the uppor body panel
3.8 Disengage the lower mountings studs from the onglne compartment lower crossmember
4.6a Removing the thermostat housing (petrol engine) 4.6b Thermostat housing location - Ignition distributor removed for clarity (petrol engine) ? Withdraw the mounting brackets (where applicable), and recover the upper mounting rubbers. 8 Carefully tilt the radiator back towards the engine, then disengage the lower mountings studs from the crossmember and lift the radiator from the engine compartment (see illustration). Recover the lower mounting rubbers if they are loose. Inspect/on 9II the radiator has been removed due to suspected blockage, it may be flushed out as descnbed in Chapter lAor 10. Clean dirt and debris from the radiator fins, using an air line fn which case, wear eye protection) or a soft Brush. Be careful, as the fins are sharp, and
can
also be easily damaged. ID If necessary, a radiator specialist can perform a flow test on the radiator, to establish whether an internal blockage exists. 11 A leaking radiator must be referred to a specialist for permanent repair. Do not attempt to weld or solder a leaking radiator, as damage to the plastic components may result. Note: In
an emergency,
minor
leaks
from the radiator can often be cured by using a suitable radiator seat'ng compound, in accordance with its manu-
facturer's
instructions, with the radiator in situ. 12 If the radiator is to be sent for repair or is
to
be renewed, remove all hoses (and where
applicable, the cooling fan switch). 13 Inspect Ihe radiator mounting rubbers, and renew them if necessary. Refitting 14 Refitting is a reversal of removal, bearing in mind the following points: a) Ensure that the radiator lower lugs engage correctly with the lower mounting rubbers. b) On completion, refill the cooling system as described in Chapter 1A or IB.
Thermostat - Jk removal, testing and refitting #
General 1 The thermostat housing Is bolted to the left hand end of the cylinder head. The thermostat itself cannot be separated from the housing and can only be renewed as part of a complete assembly.
Removal 2 Drain the cooling system as described in Chapter 1A or 1B. 3 On diesel engine models, unbolt the wiring harness/fuel hose support bracket from the housing. On 1242 cc (16-valve) petrol engine
models, remove the air cleaner and inlet ducts as descnbed in Chapter 4B. 4 Slacken the clipfs) and detach the coolant hose(s) from the thermostai housing, Make a careful note of their orientation to aid refitting. 5 Where applicable, disconnect the wiring plug from the cooling fan switch and coolant temperature sensor, which are threaded into the thermostat cover. 6 Unscrew the securing bolts, and remove the thermostat housing from the cylinder head (see illustrations). If it sticks, tap it gently first on one side and then the other to free it - do not lever between the mating faces. Recover the remains of the old c,
4.6c Removing the thermostat housing (diesel engine)

3*2 Cooling, heating and ventilation systems
Testing 7 A rough test of the thermostat may be made by suspending it with a piece of siring in a container full of water. Heat tho water to bring it to the boii and observe the movement of the vaive shaft through the inlet port (see illustrations). 6 The thermostat valve must be fully open, by the time the water boils. If not, renew the complete IhermOstat/housIng assembly. 9 If a thermometer is available, the precise opening temperature of the thermostat may be determined; compare with the figures given in the Specifications. The opening temperature Is also marked on the thermostat housing. 10 Note that a thermostat which falls to close completely as ihe water cools must also be renewed.
Refitting 11 Ensure that the cylinder head and thermostat housing mating surfaces are
completely clean and free from ail traces of Ihe old gasket material. 12 Lay a new gasket In position on the cylinder head, then fit the thermostat housing and Insert retaining bolts, tightening them securely.
Caution: Do not over-tlghten tho retaining bolts, as tho alloy casting could easily be damaged 13 Where applicable, transfer the cooling fan switch and coolant temperature sensor to the new housing. 14 Refit the coolant hose(s) to the ports on the thermostat housing and lighten the clips securely. 15 Where applicable, refit the harness/hose support bracket to the thermostat housing and tighten the bolts securely. Also refit the air cleaner and Inlet ducts as described in Chapter 4B 15 Refill the cooling system as described in Chapter 1A or 1B.
5 Electric cooling fan(s) -testing, removal and refitting ^
Testing 1 Detailed fault diagnosis should be camw out by a Rat dealer using dedicated tesl equipment, but basic diagnosis can be car&c out as follows. 2 If the fan does not appear to work, run if* engine until normal operating temperature s reached, Ihen allow It to idle. The fan shouldcti In within a few minutes (before lite temperalure gauge needle enters the red section), il nol. switch off the engine and disconnect tfie cooling fan motor wiring connector. 3 The motor can be tested by disconnecting it from the wiring loom, and connecting a 12? volt supply directly to It. The motor should operate - if not. the motor, or the motor wiring. Is faulty.
frotf heater from cylinder head mdotor
4.7b Thermostat operation in the fully closed position (diesel engine)
from neoier Irom cylinder head radiator
4.7c Thermostat operation in the fully open position (diesel engine)

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
motor c) Ensure that all hoses are correctly reconnected and, where necessary, that their retaining clips are securely tightened. d) Adjust the accelerator cable as described In Section 4.
Fuel injector Note: If a faulty Injector Is suspected, before condemning the Injector, it is worth vying the effect of one of the proprietary Injector cleaning treatments. Removal 8 Remove the air cleaner and air duct as described In Section 2. 9 Disconnect the wiring then unscrew the mounting screws and remove Ihe Injector from the throttle body. Refitting 10 Refitting is a reversal of removal.
Fuel pressure regulator
Removal 11 Remove Ihe air cleaner and air duel as described In Section 2. 12 Using a marker pen. make alignment marks between the regulator cover end the throttle body, then undo the four retaining
screws. As the screws are loosened, place a rag over the cover to catch any fuel spray which may be released. 13 Lift off the cover, then remove the spring and withdraw the diaphragm, noting Its correct fitted orientation. Remove all traces of dirt, and examine the diaphragm for signs of splitting. If damage Is found, it will be necessary to renew the complete upper throttle body assembly. Refitting 14 Refitting is a reversal of removal ensuring that the diaphragm and cover are fitted the correct way round, and that the retaining screws are securely tightened,
Idle control stepper motor
Removal 15 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual), then remove the air cleaner and air duct as described in Section 2. 16 Using a crosshead screwdriver, unscrew the mounting screws and remove the stepper motor from the throttle body. Recover the gaskei (see illustration). 17 Clean the unit and check for damage and wear. Refitting 18 When refitting the unit use a new gasket and make sure that the plunger is inserted correctly using the following procedure. Insert the unit and refit the mounting screws loosely. Reconnect the wiring then switch on the ignition several times so that the unit centralises itself. Finally fully tighten the mounting screws to the specified torque. Note: The mounting screws are covered with a locking agent and must be renewed every time they are removed 19 Leave the battery negative terminal disconnected for about 20 minutes - the injection/ignition ECU will position the Idle control stepper motor correctly the first time the engine is started. Reconnect the battery negative terminal.
Throttle potentiometer
Removal 20 Remove the air cleaner and air duct as described in Section 2. 21 Disconnect the wiring from the throttle potentiometer. 22 Using an Allen key unscrew the mounting screws then withdraw the unit from the throttle body (see Illustration). Note: The mounting screws ere covered with a locking agent and must be renewed every time they are removed. Refitting 23 When refitting the unit make sure that the pin Is correctly engaged, and tighten the mounting screws to the specified torque. 24 If a Rat test Instrument is available, the
operation of the throttle potentiometer can be checked at this stage. Before connecting the wiring first turn Ihe ignition key to position MAR and wait a few seconds, then return the key to the STOP position, Reconnect the wiring and connect the test instrument. Turn the Ignition key to the MAR position and cancel the error that will appear. The throttle position Indicated should be between 0° and 4°. If greater than this, check thai the accelerator cable is correctly adjusted however If the correct reading cannot be obtained renew the unit.
Inlet air temperature sensor
Removal 25 Remove the throtlle body assembly as described earlier In this Section. 28 Extract the plastic pins and remove the press-fit cover from the top of the throttle body. 27 Invert the cover then unscrew the mounting screws and remove the Inlet air temperature sensor from the cover. Refitting 28 Refining Is a reversal of removal.
Manifold absolute pressure (MAP) sensor
Removal 29 The manifold absolute pressure sensor is located on the left-hand side of the bulkhead. 30 Unscrew the mounting screws and remove the sensor from the bulkhead, Disconnect the wiring and vacuum pipe. Refitting 31 Refitting is a reversal of removal, but check the condition of the vacuum pipe and renew it if necessary.
Coolant temperature sensor
Removal 32 The coolant temperature sensor Is located on the left-hand side of the inlet manifold. Drain the cooling system as described In Chapter 1A before removing it. 33 Disconnect the wiring. 34 Unscrew the sensor and remove It from the Inlet manifold. If using a socket take care not to damage Ihe wiring connector on the sensor. Refitting 35 Refitting Is a reversal of removal bui tighten Ihe sensor to the specified torque. Do not exceed the specified torque otherwise the unit may be damaged.
Crankshaft TDC sensor
Removal 36 The crankshaft TDC sensor Is located on the front side of the crankshaft pulley. Firmly apply the handbrake, then jack up the front of the car Bnd support It securely on axle stands (see Jacking end vehicle support). Remove 5.22 Throttle potentiometer mounting screws

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.

A


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 The luel system referred to In this Section is defined as the tank-mounted fuel pump, the fuel litter, the throttle body and pressure regulator components, and the metal pipes and flexible hoses of the fuel lines between these components. All ihese contain fuel which will be under pressure while the engine Is running and/or while tha Ignition is switched on. The pressure will remain for some time after tho ignition has been switched off, and must be relieved before any of these components are disturbed (or servicing work. 2 Disconnect the battery negative terminal (refer to D/sconnecf/ngr the battery in the Reference Section of this manual), 3 Place a container beneath the relevant connection/union to be disconnected, and have a large rag ready to soak up any escaping fuel not being caught by the container. 4 Slowly loosen the connection or union nut (as applicable) to avoid a sudden release of pressure, and wrap tho rag around the connection to catch any fuel spray which may be expelled. Once the pressure is released, disconnect the fuel line, and Insert plugs to minimise fuel loss and prevent the entry of dirt Into the fuel system.
9 Inlet manifold -removal and refitting ^
Note: Refer to the warning given In Section 1 before proceeding.
Removal 1 Remove the throttle body assembly as described in Section 5. 2 Drain the cooling system as described in Chapter 1A. 3 Disconnect the winng connector from the coolanl temperature sensor (situated on the left-hand sidB of the manifold). 4 Undo the bolt securing the accelerator cable mounting bracket to the manifold, and position it clear of the manifold. 5 Slacken the retaining clip and disconnect tha coolant hose from the rear of the manifold. 6 Disconnect the brake vacuum hose. 7 Undo the seven manifold retaining nuts and
10.2 The diagnostic connector la located behind the ECU bolts, and remove (he manifold from the engine. Remove the gasket and discard It; a new one should be used on refitting.
Refitting 8 Refitting is a reverse of the removal procedure, noting the following points: a) Ensure that the manifold and cylinder head mating surfaces are clean and dry, and fit a nev/ manifold gasket. Refit the manifold and securely tighten Its retaining nuts. b) Ensure that all relevant hoses are reconnected fo their original positions and are securely held (where necessary) by the retaining clips. c) Refit the throttle body assembly with reference to Section S. d) On completion, refill the cooling system as described In Chapter 1A.
correctly adjusted, and that the engine breather hoses are clear and undamaged. 2 If 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 connector is situated behind the ECU (see Illustration). 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.
Adjustments 3 As mentioned above, the idle speed and mixture adjustment are all monitored and controlled by the ECU, and are not adjustable Experienced home mechanics with a considerable amount of skill and equipment (including a good-quality tachometer and a good-quality, carefully calibrated exhaust gas analyser) may be able to check the exhaust CO level and ihe idle speed. However, If thes* are found lo be in need of adjustment, the car must be taken to a suitably-equipped Flat dealer for testing using the special test equipment which is plugged into the diagnostic connector.
11 Unleaded petrol -general Information and usage
10 Fuel injection system - & testing and adjustment S
Testing 1 If a fault appears in the fuel injection system, first ensure that all the system winng connectors are securely connected and free of corrosion. Then ensure that the fault Is not due to poor maintenance; ie, check that the air cleanor fitter element is clean, the spark plugs are In good condition and correctly gapped, that tho valve clearances are
Note: The information given in this Chapter
is
correct at the time of writing. If updated Information is thought to be required, check with a Fiat dealer. If travelling abroad, consult one of the motonng organisations (or a similar authority) for advice on the fuel available. 1 All petrol models are fitted with a catalytic converter and must be run on unleaded fuel only - the fuel recommended by Flat is given In the Specifications of this Chapter. Under no circumstances should leaded fuei (UK 4-slar) be used, as this may damage the converter. 2 Super unleaded petrol (98 octane) can also be used in all models if wished, though there is no advantage in doing so.

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

4A*2 Fuel system -
single-point
petrol Injection models
b) Ensure that the injector retaining clips are securely seated c) Make sure the fuel supply and return hoses are correctly fitted as noted on removal, d) Check that all vacuum and electrical connections are remade
correcily
and securely. e) On completion check the fuel rail and injectors for fuel leaks.
Fuel pressure regulator Note: On J998 models onward, the fuel pressure regulator is an integral pad of the fuel pump and cannot be renewed separately. The following procedure applies to pre-1998 models only. Removal 17 Remove the air cleaner and inlet air ducts as described In Section 2. 18 Oepressurise the fuel system as described in Section 9. 19 Disconnect the vacuum hose from the port on the side of the regulator. 20 Extract the retaining clip and pull the pressure regulator out of Ihe fuel rail. 21 Remove the O-ring seal. Refitting 22 Refit the fuel pressure regulator by following Ihe removal procedure in reverse, noting the following points: a) Renew the O'ting seal and smear it with a little Vaseline before assembling. b) When fitting the retaining clip, use a suitable socket or metal tube (o press In the three anchorage points at Ihe same time. c) Refit the vacuum hose securely.
Idle control stepper motor
23 Refer to Chapter 4A.
Throttle potentiometer 24 Refer to Chapter 4A,
Intake air temperature sensor 25 Refer to Chapter 4A.
Manifold absolute pressure (MAP) sensor 26 Reler to Chapter 4A.
6.12a Disconnect the wiring connectors for the fuel injector harness ...
6.3 Disconnect the wiring connectors from the throttle potentiometer and the idle control stepper motor
Coolant temperature sensor 27 Refer to Chapter 4A. Crankshaft TDC sensor 28 Refer to Chapter 4A. Electronic control unit (ECU)
29 Refer to Chopter 4A.
Inertia safety switch 30 Refer to Chapter 4A. Fuel injection system relays 31 Refer to Chapter 4A.
6 Engine management system ^ components
(1242
cc,16-vatve S engines) - removal and refitting ^
Note: Refer to the warning given in Section t before proceeding.
Throttle body assembly
Removal 1 Remove the resonator, air cleaner and inlet air duct as described in Section 2. 2 Free Ihe accelerator inner cab 6.12b ... and intake air temperature/pressure sensor
4 Slacken and remove the three bob j securing the throttle body assembly to ite inlet manifold. Ihen remove the assent?/ along with its insulating spacer. As the
throaii 1-
body is withdrawn, disconnect the vacuum hose from the underside of the unit. Refitting 5 Refitting is a reversal of the removal pi>: cedure, bearing in mind the following pants a) Examine the insulating spacer for signs d damage, and renew if necessary. b) Ensure the throttle body, inlet
manddd
and insulating spacer mating surfaces at -clean and dry. then fit the throttle
btxty
and spacer, and securely tighten the retaining bolts. c) Adjust Ute accelerator cable as desciter /nSecfw?4.
Fuel rail and injectors
Removal 6 Disconnect the battery negative termrul; (refer to Disconnecting the battery in ir*J Reference Section ol this manual), 7 Remove the resonator, air cleaner arid io«l 1 air duct as descnbed in Section 2. 8 Free the accelerator Inner cablc from l>*
1
throttle cam, remove the outer cable sprig. clip, then pull the outer cable out from
>H
mounting bracket rubber grommet, 9 From the side of the throttle bod/, | disconnect the wiring connectors from Ihs: throttle potentiometer and the idle cofttro^ stepper motor. 10 Oepressunse the fuel system si ' described in Section 9. ' 11 Loosen the clips or release tho quick-. release couplings and disconnect the fuel MdJ' and outlet hoses from the left-hand end oftfu fuel rail, below the throttle body. Note IM fitted positions ol the hoses to aid relirtirf i later. Undo the support bracket retaining bol and move the fuel hoses to one side. 12 Disconnect Ihe wiring connectors forth* fuel injector harness and the Intake an temperature/pressure sensor (m illustrations). 13 Disconnect the fuel pressure regulator-! vacuum hose and the EVAP purgo vaive h«* (see illustrations).
6.13a Disconnect the fuel pressure regulator vacuum hose...