1998 FIAT PUNTO fuel cap

2C*2 Diesel engine in-car repair procedures
4.4a Unbolt the engine oil dipstick tube...
3 Cylinder compression test
Note: A compression tester specifically designed for diesef engines must be used for this test. 1 When engine performance Is down, or if misfiring occurs, a compression test can provide diagnostic clues as to the engine's condition, If the lest is performed regularly, it can give warning of trouble before any other symptoms become apparent. 2 A compression tester specifically Intended for diesel engines must be used, because of the higher pressures involved. The Ie6ter is connected to an adapler which screws Into the glow plug or injector hole. It is unlikely to be worthwhile buying such a tester for occasional use. but it may be possible to borrow or hire one • if not. have the test performed by a garage. 3 Unless specific instructions to the contrary are supplied with the tester, observe the following points: 9) The battery must bo in a good state of charge, the air titter must be clean, end the engine should be at normal operating temperature. b) AH the in/actors or glow plugs should be removed before starting the lest. If removing the injectors, also remove the flame shield washers, otherwise they may be blown out. c) The stop solenoid must be disconnected.
4.4b ... and remove it from the rubber grommet in the oil pump housing
fo prevent the engine from running or fuel from being discharged. 4 There is no need to hold the accelerator pedal down during the test, because the diesel engine air inlet is not throttled. 5 The cause of poor compression Is less easy to establish on a diesel engine than on a petrol one. The effect of introducing oil into the cylinders (wet testing) Is not conclusive, because there is a risk that the oil will sit in the recess on the piston crown, instead of passing to the rings. However the following can be used as a rough guide to diagnosis. 6 All cylinders should produce very similar pressures; a difference of more than 5 bars between any two cylinders Indicates the existence of a fault. Note that the compression should build up quickly In a healthy engine; low compression on the first stroke, followed by gradually-increasing pressure on successive strokes, indicates worn piston rings. A low compression reading on the first stroke, which does not build up during successive strokes, indicates leaking valves or a blown head gasket (a cracked hoad could also be the cause). 7 A low reading from two adjacent cylinders Is almost certainly due to the head gasket having blown between them: the presence of coolant In the engine oil will confirm this,
Leakdown test 8 A leakdown test measures the rate at which compressed air fed into the cylinder Is lost. It is an alternative to a compression test, and in many ways it is better, since the escaping air provides easy identification of where pressure loss is occurring (piston rings, valves or head gasket). 9 The equipment needed for leakdown testing is unlikely to be available to the home mechanic. If poor compression Is suspected, have the test performed by a suitably-equipped garage.
4 Timing belt and covers -removal
and
refitting
Note: Fiat specify the use of a spec/a/ timing belt tension measuring tool to correctly set the timing belt tension. If access to this equipment cannot be obtained, an approximate setting can be achieved using the method described below. If the method described is used, the tension must be checked using the special tool at the earliest possible opportunity. Do not drive the vehicle over large distances, or use high engine speeds, until the belt fens/on rs known to be correct. Refer to a Fiat dealer for advice.
General Information 1 The function of the timing belt is to drive the camshaft and fuel injection pump. Should the belt slip or break in service, the valve timing will be disturbed and piston-to-valve contact
will occur, resulting In serious engine damage. 2 The timing bolt should be renewed at the specified intervals (see Chapter 1B), or earlier If It is contaminated with oil. or If It is at al noisy In operation (a scraping noise due to uneven wear),
Removal 3 Set the engine at TDC on No 1 cylinder
as
described in Section 2. 4 Unbolt and remove tho engine oil dipstick tube and remove It from the rubber gromme! in the oil pump housing (see illustrations), 5 Before removing the timing belt check rts tension by turning the belt through 90" with finger and thumb midway between u* injection pump and camshaft sprockets. This will give you an Idea of the tension to apply when refitting, assuming the tension is already correct. Also note the position of the tensions pulley as a reference mark. 6 Release tho nut on the timing bea tensioner, move the tensioner pulley away from the belt and retlghten the nut to hold the pulley in the retracted position. 7 If the timing belt is to be re-used, use white paint or chalk to mark the direction of rotation on the belt (if markings do not already exist), then slip the belt off the camshaft, crankshaft and injection pump sprockets, and the idler and tensioner pulleys. Caution: If the belt appears to be In good condition and can be re-used, it fs essential that It Is refitted the same
wsy
round, otherwise accelerated wear will result, leading fo premature failure. 8 Check the timing belt carefully for any signs of uneven wear, splitting, or oil contamination. Pay particular attention to the roots of the teeth. Renew it if there is the slightest doutt about its condition. If the engine is undergoing an overhaul, renew the belt as a matter of course, regardless of its apparent conditio*. The cost of a new belt Is nothing compa/ed with the cost of repairs, should the belt freak in service. If signs of oil contamination art found, trace the source of the oil leak and rectify It. Wash down the engine timing baft area and all related components, to remove
sd
traces of oil.
Refitting 9 Before refitting, thoroughly clean the tknmg belt sprockets. Check that the tensioner and idler pulleys rotate freely, without any sign ol roughness. If necessary, renew them as described in Section 5. 10 Ensure that the crankshaft, camshaft and injection pump sprockets are still at their TDC positions as described In Section 2. 11 Engage the timing belt with the crankshaft sprocket, then locate it around the idler pufiey and onto the Injection pump sprocket making sure that it is kept taught. Continue to locate! around the camshaft sprocket and finally around Ihe tensioner pulley (see Illustration) Ensure the belt teeth seat correctly on Ihe sprockets.

2D*10 Engine removal and overhaul procedures
12.18 Angle-tightening the main bearing cap bolts (petrol engine)
12.Ida Application area for silicone Instant gasket on crankshaft rear oil seal housing (petrol engine) 12.19b Refitting the crankshaft rear oil seal housing (petrol engine)
19 Fit a new oil seal to the crankshaft rear oil seal housing. Apply grease to the seal lips. On 1108 cc petrol engines a conventional gasket Is not used at the oil seal retainer joint face, but a 3 mm diameter bead of RTV (Instant) silicone gasket must be applied as shown -allow at least one hour 1or the gasket to cure before oil contacts it. On all other engines a gasket Is fitted Securely tighten the housing bolts (see Illustrations). 20 Check that Ihe crankshaft rotates freely by turning It by hand. If resistance Is fell, re-check the running clearances, as described above. 21 Carry out a check of the crankshaft endfloat as described at the beginning of Section 8. If the thrust surfaces of the crankshaft have been checked and new thrust washers hove been fitted, then the endfioat should be within specification.
22 Refit the pistons and connecting rods as described in Section 7. 23 Refit the flywheeVdriveplate, and-vibration plate (16-valvo engines), oil pump and pick-up tube, and sump with reference to the relevant Sections of Parts A, B or C of this Chapter.
13 Engine -initial start-up after overhaul and reassembly
1 With the engine refitted In the vehicle, double-check the engine oil and coolant levels. Make a final check that everything has been reconnected, and that there are no tools or rags left In the engine compartment.
Petrol engine models 2 Remove the spark plugs, then disable the
ignition system by disconnecting the LT wiring plug to the ignition colls. 3 Turn the engine on the starter until Ihe oi pressure warning light goes out. Refit ihe spark plugs, and reconnect the LT wiring.
Diesel engine models 4 Disconnect tho wiring from the stop solenoid on the Injection pump, then turn the engine on the starter motor until the oil pressure warning light goes out. Reconnect ihe wire to the stop solenoid. 6 Fully depress the accelerator pedal, turn tho ignition key to its first position and wait tor HHJ preheating warning light to go out.
All models 6 Start the engine, noting that this may take i little longer than usual, due to the fuel system components having been disturbed.
12.19c On diesel engines use a screwdriver to prise out the rear oil seal 12.19d Locate the new oil soalln the housing (diosel engine)... 12.19e ... and use a block of wood to drive it in
12.19f On Diesel engines fit the gasket to the cylinder block ... 12.19g ... then locate the rear oli seal housing... 12.19h ... and Insert the bolts

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

Fuel system - diesel models
4C*3

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

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

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