Exhaust pipe FIAT PUNTO 1998 176 / 1.G User Guide

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
10.10 Tighten the flywheel bolt to the specified torque However, it may be possible lo have it surface*ground; seek (he advice of a Rat dealer or engine reconditioning specialist, 5 If Ihe ring gear is badly worn or has missing teeth, the flywheel must be renewed. Automatic transmission models 6 Check the driveplate for signs of damage and renew it if necessary. If the ring gear is badly worn or has missing teeth, the driveplate must be renewed.
Refitting 7 Clean the mating surfaces of the flywheel/ drivoplate and crankshoft. Remove any remaining locking compound from the threads of the crankshaft holes, using the correct-size tap. if available.
ft a suitable tap fs not . # | available, cut two slots down jHlNTI
toe
threads of ono of the old bolts with a hacksaw, and use the bolt to remove the locking compound from the throads.
8 If the new retaining bolts are not supplied with their threads already pre-coated, apply a suitable thread-locking compound to the threads of each bolt. 9 Offer up the fiywhee'/drlveplate lo the crankshaft, using the alignment marks made during removal, and fit the new retaining bolts (together with the spacer plate on manual transmission models), 10 Lock the flywheel/dnveplate using Ihe method employed on dismantling, and tighten
the retaining bolts to the specified torque (see illustration), 11 Refit the clutch on manual transmission models as described in Chapter 6. 12 Relit the transmission as described In Chapter 7A or 78.
11 Engine mountings • inspection and renewal
inspection 1 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see Jacking and vehicle support). 2 Check Ihe mounting rubbers to see if they are cracked, hardened or separated from the metal at any point; renew the mounting if any such damage or deterioration is evident. 3 Check that all the mounting's fasteners are securely tightened; use a torque wrench to check II possible. 4 Using a large screwdriver or a crowbar, check for wear In the mounting by carefuliy levering against It to check for free play. Where this is not possible enlist the
aid
of
an
assistant to move the engina/transmission back
and
forth, or from s»de to side, while you watch the mounting. While some free play rs to bo expected even from new components, excessive wear
should
be obvious. If excessive free play is found, check first that the fasteners are correctly secured, then renew any worn components as described below.
Renewal Right-hand mounting 5 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see Jacking and vehicle support). 8 Place a trolley jack beneath the right-hand side of Ihe engine, with a block of wood on the jack head. Raise the jack until it is supporting the weight of the engine. 7 Unscrew the nut securing the engine bracket to the mounting. 8 Lower the engine slightly then unboll the mounting from the body. 9 Locate the new mounting on the body, insert the bolts and tighten to the specified torque.
10 Raise tne engine and locate the bracket on the mounting. Refit tho nut and tighten lo the specified torque. 11 Remove the trolley jack and lower the vehicle to the ground. Left-hand mounting 12 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see Jacking and vehicle support) 13 Place a trolley |sck beneath the transmission, with a block of wood on the jack head. Raise the jack until it is supporting tne weight of the engine/transmission. 14 Unscrew Ihe bolts securing the left-hand mounting to tho body. 15 Unscrew the nut securing ihe mounting to the transmission bracket and recover the washers. 16 Lower the transmission sufficiently to remove the mounting from the transmission bracket. 17 Locate the new mounting In the trans-mission bracket and refit the nut and washers. Tighten the nut to the specified torque. 18 Raise the engine and refit the mounting-to-body bolts. Tighten the bolts to the specified torque. 19 Remove the Irolloy jack and lower the vehicle lo the ground. Rear mounting 20 Firmly apply the handbrake, then Jack up the front of the car and support It securely on axle stands (see Jacking and vehicle support). 21 Working beneath Ihe vehicle, unscrew Ihe bolts secunng the rear engine mounting to the underbody. 22 Temporarily support the weight of the engine/transmission using a trolley jack. 23 Unbolt the rear mounting assembly from Ihe transmission and withdraw from under the vehicle. 24 Unscrew the bolt and separate Ihe bracket from tlve mounting. 28 Fitting the new mounting Is a reversal of the removal procedure.
12 Sump -removal and refitting
12.2 Removing the flywheel housing cover plate 12.4 Removing the sump
Removal 1 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see Jacking and vehicle support). Drain the engine oil as described in Chapter 1 A. 2 Unbolt and remove the cover plate from the lower pari of the llywheel housing (see illustration). 3 Refer to Chapter 4D and unbolt the exhaust Iront pipe from Ihe manifold. Undo Ihe support bracket fastenings and lower the front pipe clear of the sump. 4 Unscrew the sump securing screws and nuts and pull the sump downwards to remove it (see Illustration). The joint sealant will

DOHC (16-valve) petrol engine in-car repair procedures 2B*11
camshaft cover plate... 25 Locate the cam follower retaining tools in position and refit the cylinder head extension
as
described In Section 8.

10
Cylinder head - &
removal and
refitting S
Removal Note; The cylinder head bolts are of special
sekned
design and a Fiat tool should be
obtained
to unscrew them. A Ton key will not
JSt however
in practise It was found that a dose-httlng Alien key could be used as an itemative. 1 Drain the cooling system as described in Chapter 1A. 2 Remove the cylinder head extension as oescAbed
m
Section 8. 3 Disconnect the radiator hose from the thermostat housing on the left-hand end of
Ihe
cylinder head. 4 Disconnect the heater hose from the outlet
at the
rear of the cylinder head. 5 Disconnect the coolant temperature sensor md temperature gauge sensor wiring plugs
torn
the left-hand end of the cylinder head. 9 Undo the engine oil dipstick tube bracket retaining bolt and the two bolts securing the wing harness support clips to the inlet marriold lower section. 7 Undo Ihe retaining nuts and separate the ixhaust system front pipe from the exhaust manifold flange.
8
Check that nothing remains attached to the cinder head likely to impede removal. It Is assumed that the head will be removed complete with exhaust manifold and inlet manifold lower section. 9 Unscrew the cylinder head bolts half a turn K
e
time in the reverse order to that shown in (lustration 10.20a. When the bolts are free. «mwe them from their locations.. Id Lift the cylinder head from the block. If it is stuck tight rock the head to break the joint by mans of the manifolds. On no account drive
levers
into the gasket Joint, nor attempt to tap tf« head sideways, as it is located on positioning dowels. 11 Remove and discard the cylinder head gasket.
JK'
l^. 9.22b ... then apply RTV gasket sealant to the cover plate contact face 12 Refer to Chapter 20 for cylinder head dismantling and inspection procedures. Preparation for refitting 13 The mating faces of the cylinder head and cylinder block must be perfectly dean before refitting the head. Use a hard plastic or wooden scraper to remove all traces of gasket and carbon; also clean the piston crowns, Take particular care when cleaning the piston crowns as the soft aluminium alloy is easily damaged. Make sure that the carbon is not allowed to enter the oil and water passages -this Is particularly important for the lubncahon system, as carbon could block the oil supply to the engine's components. Using adhesive tape and paper, seal the water, oil and bolt holes in the cylinder block. To prevent carbon entering the gap between the pistons and bores, smear a little grease In the gap. After cleaning each piston, use a small brush to remove all traces of grease and carbon from the gap. then wipe away the remainder with a clean rag. Clean all the pistons in the same way. 14 Check the mating surfaces of the cylinder block and the cylinder head for nicks, deep scratches and other damage. If slight, they may be removed carefully with a file, but If excessive, machining may be the only alternative to renewal. If warpage of the cylinder head gasket surface Is suspected, use a straight-edge to check it for distortion. Refer to Part 0 of this Chapter if necessary. 15 Check the condition of the cylinder head bolts, and particularly their threads, whenever they are removed. Wash the bolts In a suitable
sequence
9.24 Lubricate the cam followers and place them in position in their respective bores solvent, and wipe them dry. Check each bolt for any sign of visible wear or damage, renewing them if necessary.
Refitting 18 Before refitting the assembled cylinder head, make sure that the head and block mating surfaces are perfectly clean, and that the bolt holes in the cylinder block have been mopped out to clear any oil, 17 The now gasket should not be removed from its nylon cover until required for use. Fit Ihe gasket dry, and make sure that the mating surfaces on the head and block are perfectly clean. 18 Place the gasket on the cylinder block so that the word ALTO can be read from above. 19 Lower the cylinder head onto the block so that it locates on the positioning dowel. 20 The cylinder head bolt threads must be clean and lightly lubricated. Screw the bolts in finger-tight then working progressively and in the sequence shown, lighten all the cylinder head bolts to the Stage 1 torquo setting given In the Specifications, using a torque wrench and a suitable socket. With all the bolts tightened to their Stage 1 setting, working again in the specified sequence, first angle-tighten the bolts through the specified Stage 2 angle, then again through the Stage 3 angle, using a socket and extension bar. It Is recommended that an angle-measuring gauge Is used during this stage ot tightening, to ensure accuracy (see Illustrations). 21 Reconnect the exhaust system front pipe to the manifold using a new flange gasket.
10.20b Tighten the cylinder head bolts to the Stago 1 torque setting ...

Diesel engine in-car repair procedures
2C*11

9.15 Short coolant hose from the cylinder head outlet to the coolant pump 19 Where applicable, unscrew the bolts retaining the bracket to the turbocharger and thecrankcase (see illustration). 20 Unscrew the nut and slide the timing belt tensioner off Its stud.
9,17 Disconnecting the return hose from the thermostat housing
9.18a Metal coolant rotum pipe mounting bolt
injection pump
9.16a Disconnecting the oil delivery pipe from the turbocharger 21 Release the fuel supply and return hoses from the supports on the cylinder head. 22 Unscrew the union bolt and disconnect the fuel supply hose from the filter on the bulkhead. 23 Loosen the clip and disconnect the fuel return hose from the injection pump. 24 Unscrew Ihe union nuts while holding insert fiats, and disconnect the fuel supply lines from the Injectors and injection pump (soo illustration). Cover tho apertures to prevent dust entry. 25 Disconnect the glow plug supply wiring from the terminal on No 4 glow plug heater on the front left-hand side of the engine. 26 Disconnect the wiring from the maximum coolant temperature connector on the front of the engine. 27 Disconnect the fuel return line from No 1 Injector.
9.18b Removing the metal coolant return pipe from the coolant pump
9.31a Bolts securing the inner timing cover to the cyllndor head
9.16b Oil delivery pipe location on the crankcase 28 Unscrew the nuts securing the exhaust front pipe to the exhaust manifold. Where necessary, use a screwdriver to bend back the lock tabs. Lower the front pipe and recover the gasket. 29 Where applicable, remove the clip and disconnect the oil return hose from the turbocharger to the sump. 30 Remove the camshaft sprocket as described in Section 5. 31 Unscrew the bolts securing the timing belt inner cover to the cylinder head and injection pump bracket, then remove the inner cover (see illustrations). 32 Unbolt and remove the camshaft cover and recover the gasket. Note the location of the support brackets. 33 Unscrew and remove the bolts and washers located on the front of the cylinder head, alongside the injectors (see illustration),
9.19 Unbolt the bracket retaining the turbocharger and manifold to the crankcase
9.31b Removing the bolts securing the Inner timing cover to the injection pump/oll Alter bracket

Diesel engine in-car repair procedures 2C*11

r
<3^
9.46a The locating dowel in the cylinder block 43 It is possible for the ptston crowns to stnke and damage the valve heads, if the camshaft is rotated v/ith the timing belt removed and the crankshaft set to TDC. For this reason, the crankshaft must be set to a position other than TDC on No t cylinder before the cylinder head is refitted. Use a socket on the crankshaft pulley centre bolt to turn the crankshaft in its normal direction of rotation, until all four pistons are positioned Halfway down their bores, v/ith No 1 piston on lis upstroke - approximately 90° before TDC.
Refitting 44 If the manifolds are being refitted before refitting the cylinder head proceed as follows, otherwise fit the manifolds later when the head is refitted. Ensure thai the inlet and exhaust manifold mating surfaces are completely clean, then locale the new gasket on the studs. 45 Locate the inlet and exhaust manifolds together with the turbocharger, where applicable, on the studs. Refit the nuts and washers and tighten to the specified torque.
sequence
f^/f
9.52b Tighten the cylinder head bolts to the Stage 1 and Stage 2 settings using a torque wrench
on the block 46 Lay the new head gasket on the cylinder block engaging it with the locating dowel. The word ALTO must be uppermost (see illustrations). 47 As a means of locating Ihe cylinder head accurately, cut the heads from two of the old cylinder head bolts. Cut a slot, big enough for a screwdriver blade, in the end of each bolt. These can be used as alignment dowels to assist in cylinder head refitting, however If the head is being refitted without the manifolds it is not necessary to take this action. 48 With the help of an assistant, place the cylinder head assembly centrally on the cylinder block ensuring thai the locating dowels engage with Ihe holes in the cylinder head. Check that the head gasket Is correctly seatod before allowing the full weight of the cylinder head to rest on it. 49 Where necessary, unscrew the home-made alignment dowels, using a flat bladed screwdriver. 50 The oyllnder head bolt threads must be clean. Dip the bolts in engine oil. and allow them to drain for thirty minutes. 51 Carefully enter each bolt with washer into its relevant hole (do not drop them in) and screw in, by hand only, until finger-tight. 52 Working progressively and In the sequence shown, first tighten the cylinder head bolts to their Stage 1 torque setting, using a torque wrench and suitable socket (see illustrations). Go round again, in the sequence shown, and tighten the bolls to the Stage 2 torque setting. 53 Once all the bolts have been tightened to their Stage 2 setting, working again in the
bolts to the Stage 3 and Stage 4 settings
9.46c The word ALTO must be uppermost
given sequence, angle-tighten the bolts through the specified Stage 3 angle, using a socket and extension bar (see illustration). It Is recommended that an angle-measuring gauge is used during this stage of the tightening, to ensure accuracy. If a gauge is not available, use white paint to make alignment marks between the bolt head and cylinder head prior to tightening; the marks can then be used to check tho bolt has been rotated through the correct angle during tightening. Repeat for the Stage 4 setting. 54 Refit the cylinder head front retaining bolts and tighten lo the specified torque. 55 Refit the camshaft cover together with a new gasket and tighten the bolts progressively to the specified torque. 56 The remaining procedure is a reversal of the removal procedure noting the following points. a) Tighten all nut and bolts to the specified torque where given. b) When refitting the metal coolant pipe to the coolant pump, use a new O-ring (see illustration). cj Refit the timing belt with reference to Section 4. d) Use a new exhaust front pipe gasket. e) Refit the auxiliary dhvebeltfs) as described in Chapter 1B. f) Refer to Chapter 4C when refitting the
air
cleaner and air duct. g) Refill the cooling system and fill the engine with new oil with reference to Chapter 1B. 57 Refer to Chapter 20 when starting the engine for the first time.
9.56 Use a new O-ring on the coolant pipe before refitting it to the pump

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

2D*10 Engine removal and overhaul procedures
60 At the otl filter, unscrew the union nuts and disconnect the oil cooler lines/hoses then remove the oil cooler from the vehicle (see Illustration). Be prepared for some oil leakage. Note the fitted position of the hoses before disconnecting them so that they can be refitted correctly. 61 Disconnect the reversing light wiring from Ihe switch on the front of the transmission (see illustration) 82 Using an Allen key, unscrew the bolts securing the inner ends of the driveshafts to the flanges on the transmission. The right-hand driveshaft is disconnected from the Intermediate shaft flange on the rear of the engine. Recover the plates beneath the heads ol the driveshaft bolls (see illustrations). 63 Unscrew the bolts securing the front sv/lvel hub assemblies to the struts. Also
4.59c Removing the radiator from the vehicle
4.62a Use an Allen key to unscrew the inner driveshaft bolts
release the flexible brake hoses from the struts. 64 Move the swivel hub assemblies outwards and support the inner ends of the dnveshafts on axle stands (see Jacking and vehicle support). Take care not to strain the flexible brake hoses. 65 Remove the exhaust front pipe with reference to Chaptor 4D. If difficulty is expenenced in separating Ihe front pipe from the intermediate pipe, it may prove easier to remove the complete exhaust system. Ail models 66 Attach a suitable hoist to the engine and transmission lifting eyes (see illustration). The left-hand eye is located on the transmission and the right-hand one on the right-hand side of the engine, Take the weight of the engine/transmission.
4.60 Loosening the union nuts securing the oil cooler lines to the oil filter housing
4.62b Removing the driveshaft bolts and plates
67 Working boneath the vehicle, unscrew the bolts securing tne rear engine mounting to the underbody and transmission, and withdraw the mounting. 68 In the engine compartment, unscrew the bolts securing the right-hand engine mounting to the body and engine. For additional working room completely remove the mounting. 69 Unscrew the boils securing the left-hand engine/transmission mounting to the body. For additional working room completely remove Ihe mounting. 70 With the help of an assistant lower the engine/transmission from the engino compartment taking care not to damage the surrounding components (see illustration). Ideally lower the unit onto a low trolley so that it may be withdrawn from under the vehicle. Disconnect the hoist from ihe assembly.
4.61 Disconnecting the reversing light wiring
4.66 Attaching a hoist to tho ongine and transmission assembly

2D*10 Engine removal and overhaul procedures
6.5s Prising out the feed stub of the camshaft lubricating pipe J) Flywheel (Chapter 2C). k) Clutch components (Chapter
6).
I) Cooling system components (Chapter
3).
Note: When removing trie external components from the engine, pay close attention to details that may be helpful or important during refitting. Note the fitted position of gaskets, seals, spacers, pins, washers, bolts, and other small components. 4 If you are obtaining a short engine (the engine cylinder block/crankcase, crankshaft, pistons and connecting rods, all fully assembled), then the cylinder head, sump, oil pump, timing belt (together with its tensloner and covers), coolant pump, thermostat housing, coolant outlet elbows, oil filter housing and where applicable oil cooler will also have to be removed. 5 If you are planning a full overhaul, the engine can be dismantled in the order given below: $) Ftywhaoi/drivoplate.
6.5d When removing the camshaft bearing caps, note the position of the (ong and short locating dowels
bearing/banjo union bolt b) Timing belt, sprockets, and tensioner. c) Inlet and exhaust manifolds. d) Cylinder head. e) Sump. f) Oil pump. g) Pistons and crankshaft.
6 Cylinder head - % dismantling, cleaning, inspection and reassembly ^
Note: Now and reconditioned cylinder heads are available from the manufacturer or engine overhaul specialists. Be aware that some specialist tools are required for the dismantling and inspection procedures, and new com-ponents may not be readily available. It may therefore be mors practical and economical for the home mechanic to purchase a reconditioned head, rather than dismantle, inspect and recondition the original head.
Dismantling Note: On 8-valve petrol engines and diesel engines, the camshaft and cam followers are /oca fed In the cylinder head assembly and the relevant dismantling and reassembly procedures are contained in this Section. On 1$-valve petrol engines, the camshafts and cam followers are /oca fed In a separate housing (cylinder head extension) which is bo/fed fo the top of the cylinder head. All procedures relating to the camshafts and cam followers on 16-valve engines are therefore contained in Chapter 2B. Proceed fo paragraph 15 for cylinder head dismantling
6.8a Unscrew and remove the bolts from the thermostat housing, noting the location of the bracket
6.5c Removing the camshaft lubricating pipe procedures on /6-vafve engines, and ignore any references to camshafts, cam followers and oil seals in the paragraphs that follow. 1 Remove the cylinder head as described in Part A. B or C of this Chapter (as applicable). 2 If not already done, remove the inlet and exhaust manifolds with reference to the relevant Part of Chapter 4. Also remove the spark plugs, glow plugs and injectors as applicable. 3 Remove the camshaft sprocket with reference to Chapter 2A or 2C. Petrol engines 4 Mark the positions of the camshaft bearing caps, numbering them from the timing end. 5 Unbolt and remove the lubrication pipe (prise the oil feed stub out with a screwdriver). Unscrew the remaining bolts and take off the bearing caps (see illustrations). 6 Lift the camshaft carefully from the cylinder head, checking lhat the valve clearance shims and cam followers are not withdrawn by the adhesion of the oil (see Illustration). 7 Remove the shims and cam followers, but keep them In their originally fitted order. Diesel engines 8 Unbolt the thermostat housing and gasket, and vacuum pump from the left-hand end of the cylinder head. Also if necessary unbolt the coolant cover and gasket from the right-hand end of the head. Note the location of brackets (see illustrations) 9 Using a soft metal drift, carefully lap out the left-hand side mount and recover the gasket (soe illustrations). 10 At tho timing bait end of the cylinder head.
6.8b Removing the thermostat housing ... 6.6 Removing the camshaft

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

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 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