1997 FIAT PUNTO Fuel system
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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
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Fuel system - diesel models 4C*3
8.5 Dial gauge (1), mounting bracket (2) and setting rod (3) In position on the injection pump (Lucas)
so that Its tip Is In contact with the bracket linkage (see Illustration). Position the dial gauge so that its plunger is at the mid-point of its travel and zero the gauge. 6 Rotate the crankshaft slowly in the correct direction of rotation (clockwise) until the crankshaft is positioned at TDC on No 1 piston with ell the sprocket timing marks aligned. 7 Check the reading on the dial gauge which should correspond to the value marked on the pump (there is a tolerance of * 0.04 mm). The timing value may be marked on a plastic disc attached to the front of the pump, or alternatively on a tag attached to Ihe pump control lever (see illustrations). 8 If adjustment is necessary, slacken the front pump mounting nuts/bolt and the raar mounting bolt, then slowly rotate tne pump body until the point is found where the specified reading is obtained on the dial gauge (access to the lower front bolt is gained through the hole in the injection pump sprocket). When the pump Is correctly positioned, tighten both its front mounting nuta/bolt and the rear bolt to their specified torque settings. 9 Withdraw the timing probe slightly, so that it
8.7a Pump timing value (x) marked on plastic diso (Lucas)
15 If the procedure is being carried out as part of the pump refilling sequence, proceed as described in Section 5. 16 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. 17 Start the engine, and check for any leakage at the fuel unions. To enable the engine to start it may be necessary to loosen tho injector union nuts while turning the engine on the starter motor in order to purge trapped air. 18 Check and If necessary adjust the Idle speed as described In Chapter 1B.
9 Fuel Injectors -testing, removal and refitting Sk ^
A
Warning: Exercise extreme caution when working on the fuel injectors. Never expose the hands or any part of the body to Injector spray, as the high working pressure can cause the fuel to pen ot rate the skin, with possibly fatal results. You are strongly advised to have any work which involves testing the injectors under pressure carried out by a dealer or fuel Injection specie list.
Testing 1 Injectors do deteriorate with prolonged uso, and it is reasonable to expect them to need reconditioning or renewal after 60 000 miles
8.7b Pump timing values marked on label (1) and tag (2) (Lucas)
(100 000 km) or so. Accurate testing, overhaul and calibration of the Injectors must be left to a specialist. A defective injector which Is causing knocking or smoking can be located without dismantling as follows. 2 Run the engine at a fast idle. Slacken each Injector union In turn, placing rag around the union to catch spilt fuel, and being careful not to exposa the skin to any spray. When tho union on the defective Injector is slackened, the knocking or smoking will stop.
Removal 3 Remove ihe air Inlet ducting from tho front part of the onglne. 4 Carefully clean around the Injectors and injector pipe union nuts. 5 Pull the leak-off pipes from the injectors (see illustration). 6 Unscrow the union nuts securing Ihe injector pipes to the fuel Injection pump. Counterhold the unions on the pump when unscrewing the nuts. Cover open unions lo keep dirt out, using small plastic bags, or fingers cut from discarded (but clean!) rubber gloves. 7 Unscrew the union nuts and disconnect the pipes from the ln|ectors, If necessary, the Injector pipes may be completely removed-Note carefully the locations of the pipe clamps, for use when refitting. Cover tho onds ot (he injectors, to prevent dirt ingress. 8 Unscrew the injectors using a deep socket or box spanner, and remove Ihem from the cylinder head (see Illustration). 9 Recover the tire seal washers from the cy-linder head and discard them (see illustration).
9.5 Disconnecting the Injector leak-off pipes 9.8 Removing an injector
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Fuel system - diesel models
4C*3
9.9 Removing the fire seal washor 9.13 Tightening an injector with a torque wrench
Refitting 10 Obtain new fire seal washers. 11 Take care not to drop the Injectors, or tfow the needles at their tips to become damaged. The injectors are prectsion-mado to Ine knits, and must not be handled roughly. In particular, never mount them in a bench vice. 12 Commence refitting by inserting the fire
seal
washers {convex face uppermost}. 13 Insert the injectors and tighten them to the specified torque (see illustration). 14 Refit the injector pipes and tighten the union nuts. Make sure the pipe clamps are in Iteir previously-noted positions. If the clamps
are
wrongly positioned or missing, problems may be expenenced with pipes breaking or splitting,
15 Reconnect the leak-off pipes. 16 Refit the air ducting. 17 Start the engine, and check for any leakage at the fuel unions. To enable the engine to start it may be necessary to loosen the Injector union nuts while turning the engine on the starter motor in order to purge trapped air.
10 Fuel gauge sender unit -removal and refitting
Refer to Chapter 4A, hov/ever note that the unit does not Incorporate a pump (see illustrations).
11 Fuel tank -removal and refitting
Refer to Chapter 4A, however note that in addition a safety valve with an anti-roll device is fitted in the top of the tank with a ventilation pipe to the front of the tank. The fuel gauge sender unit does not Incorporate a pump as this unit is located In the injection pump.
12 Inlet manifold - ^ removal and refitting %
Note: The Inlet and exhaust manifolds are both located on the rear of the engine and share the same securing bolts and gasket. Although the following procedure describes removal of the Inlet manifold separately it may be necessary to remove the exhaust manifold as well In order to renew the gasket.
Removal 1 Remove the air cleaner and ducting as described in Section 2. 2 Unbolt and remove the relay guard and bracket from the left-hand side of the engine. 3 On turbo models disconnect the air duct from the inlet manifold elbow. If necessary the elbow can be unbolted from the manifold and the sealing ring removed. 4 Unscrew the nuts securing the inlet manifold to the cylinder head noting the position of the support bracket. Note lhat some of the nuts also secure the exhaust manifold. Withdraw the inlet manifold from the studs (see illustrations), 5 Examine the gasket. If It is damaged it will be necessary to remove the exhaust manifold in order to renew it.
Refitting 6 Refitting Is a reversal of removal, but tighten all nuts and bolts lo the specified torque.
12.4c Removing the Inlet manifold
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Fuel system - diesel models 4C*3
14.6 Nuts securing the exhaust downpipe to the exhaust manifold 14.8 Disconnecting the oil return pipe from tho turbocharger
13 Turbocharger -description and precautions
Description A turbocharger 1$ fitted to TDS, TD and SX models. It increases engine efficiency by raising the pressure In the inlet manifold above atmospheric pressure. Instead of the air simply being sucked Into the cylinders. It Is forced in. Additional fuel is supplied by the injection pump in proportion to the increased air inlet. Energy for the operation of the turbocharger comes from the exhaust gas. The gas flows through a specially-shaped housing (the turbine housing) and In so doing, spins the turbine wheel. The turbine wheel is attached lo a shaft, at the end of which is another vaned wheel known as the compressor wheel, The compressor wheel spins in Its own housing, snd compresses the inlet air on the way to the inlet manifold. Boost pressure (the pressure in the Inlet manifold) is limited by a wastegate, which diverts Ihe exhaust gas away from the turbine wheel In response to a pressure-sensitive actuator. A pressure-operaled switch operates a warning light on the instrument panel in the event of excessive boost pressure developing. The turbo shaft is pressure-lubricated by an oil feed pipe from the main oil gallery The shaft floats on a cushion of oil. A drain pipo returns the oil to the sump.
Precautions The turbocharger operates at extremely high speeds and temperatures. Certain precautions must be observed, to avoid premature failure of the turbo, or injury to the operator. Do not operate the turbo with any of its parts exposed, or with any of ils hoses removed. Foreign objects falling onto the rotating vanes could cause excessive
damage, and (if ejected) personal injury. Do not race the engine immediately after start-up, especially if it Is cold. Give the oil a few seconds lo circulate. Always allow the engine to return to idle speed before switching il off - do not blip the throttle and switch off, as this will leave the turbo spinning without lubrication. Allow the engine to idle lor several minutes before switching off after a high-speed run. Observe the recommended intervals for oil and filter changing, and use a reputable oil of the specified quality. Neglect of oil changing, or use of Inferior oil, can cause carbon formation on the turbo shaft, leading to subsequent failure.
14 Turbocharger -removal and refitting
8 Disconnect the oil return pipe from the turbocharger (see Illustration). 9 Unscrew the bolt securing the mounting bracket to the cyfindar block. 10 Unscrew the mounting nuts and withdraw the turbocharger from the studs in Ihe exhaust manifold. Recover the gasket. II It Is to be refitted, store the turbocharger carefully, and plug its openings to prevent dirt ingress.
Refitting 11 Refitting Is a reversal of removal, bearing in mind the fallowing points: a) if a new turbocharger Is being fitted, change the engine oil and filter. b) Tighten ail nuts and bolts to the specified torque. c) Before starting the engine, prime the turbo lubrication circuit by disconnecting the stop solenoid iead at the injection pump, and cranking the engine on the starter for three ten-second bursts.
Removal 1 Remove the battery as described in Chapter 5A. 2 Unbolt and remove the relay guard and bracket from the left-hand side of Ihe engine. 3 Remove the air cleaner and ducting as descnbed in Section 2. 4 Loosen the clips and remove the air outlet duct between tho turbocharger and inlet manifold. Also disconnect the air inlet duct from the turbocharger. 6 Appty the handbrake, then jack up tho front of the vohicle and support on axle stands (see Jacking and vehicle support). 6 Bend back the locking tabs (if fitted) and unscrew the nuts securing the exhaust downpipe lo the exhaust manifold (see Illustration). Disconnect the downpipe from the exhaust system (refer to Part 4D) end remove it from under the vehicle. Recover tne gasket. 7 Unscrew ihe union nut and disconnect the oil supply pipe from the turbocharger. Recover the copper ring and tape over the end of the pipe 10 prevent dust entry.
15 Turbocharger -examination and renovation l
1 With the turbocharger removed, inspect the housing for cracks or other visible damage. 2 Spin the turbine or the compressor wheel, to verify that the shaft is intact and to feel for excessive shake or roughness. Some play is normal, since in use, the shaft is floating on a film of oil. Check that the wheel vanes are undamaged. 3 The wastegate and actuator are Integral, and cannot be checked or renewed separately. Consul! a Flat dealer or other specialist If it is thought that testing or renewal is necessary. 4 If tho exhaust or induction passages are ail* contaminated, Ihe turbo shaft oil seals have probably failed. 6 No DIY repair of the turbo is possible. A new unit may be available on an exchange basis,
Page 144 of 225
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
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4D*2 Exhaust and emission control systems
2.2 Charcoal canister location behind tho right-hand headlight
conditions, via a plunger valve, The system is controlled electronically by means of an emissions system control unit. Evaporative emission control • petrol models To minimise the escape of unburned hydrocarbons Into the atmosphere, an evaporallve loss emission control system is fitted to petrol models, The fuel tank filler cap Is sealed and a charcoal canister is mounted underneath the right-hand headlamp to collect the petrol vapours released from the fuel contained In the fuel tank. It stores them until they can be drawn from the canister (under the control of the fuel Injection/ignition system ECU) via the purge valve into the Inlet tract, where they are then burned by the engine during normal combustion. To ensure thai the engine runs correctly when it is cold and/or idling and to protect the catalytic converter from the effects of an over-rich mixture, the purge control valve is not opened by the ECU until the engine has warmed up, and the engine is under load; the valve solenoid is then modulated on and off to allow the stored vapour to pass into the inlet tract.
Exhaust systems The exhaust system comprises the exhaust manifold, an exhaust downpipe, • catalytic convorter, an intermediate pipe with silencer, and a tailpipe with silencer, On turbo diesel models the turbocharger is fitted between ihe exhaust manifold and the downpipe.
5.5a On 16-valve engines, undo the bolts and remove the manifold heat shield...
2 Evaporative loss emission ^ control system - information and component renewal ^
Information 1 The evaporative loss omission control system consists of the control solenoid (or purge valve), the activated charcoal filter canister and a series of connecting vacuum hoses. 2 The control solenoid and charcoal canister are both mounted on the right-hand side of the engine compartment behind the headlight (see illustration).
Component renewal
Control solenoid 3 With the bonnet open, disconnect the hoses from the control solenoid on the top of the charcoal canister. 4 Disconnect the wiring and remove the solenoid. 5 Refitting is a reversal of removal. Charcoal canister 6 Remove Ihe control solenoid as desenbed previously. 7 Disconnect Ihe fuel tonk hose from the canister 8 Detach the mounting and remove the canister. 9 Refitting Is a reversal of removal. Multifunction valve 10 The multifunction valve >s mounted on top of the luel tank. Removal and refitting is similar to that described for the tank sender gauge/pump (refer to Chapter 4A or 4B).
3 Crankcase emission system - general information
The crankcase emission control system consists of a hose from the camshaft cover to the air cloanor with a branch to Ihe throttle body. The main hose Incorporates a flame trap and the Inlet to the throttle body incorporates a calibrated hole.
5.5b ... then remove the bracket
The system requires no attention other than to check at regular intervals that tho hoses are free of blockages and undamaged.
4 Lambda oxygen sensor -removal and refitting &
Note: 7?5e Lambda oxygen sensor is doiicata and will not work if it is dropped or knocked, it its power supply is disrupted, or if any cleaning materials are used on it.
Removal 1 The sensor Is threaded Into the exhaust front downpipe. Access if best gained Irom underneath the vehicle. Apply the handbrake then )ack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). 2 Disconnect the sensor wiring connector located on the front of the engine. 3 Working beneath the vehicle, unscrew the sensor, taking care to avoid damaging the sensor probe as it Is removed- Note: As a flying lead remains connected to the sensor after it has been disconnected, if the correct spanner is not available, a slotted socket
will
be required to remove the sensor.
Refitting A Apply a little anti-selze grease to (he sensor threads • avoid contaminating the probe tip. 5 Refit the sensor to the downpipe. tightening it to the correct torque. Reconnect the wiring. 6 Lower the vohicle to the ground.
5 Exhaust manifold - % removal and refitting jk
Petrol models
Removal 1 On 1242 cc (16-valve) engines, remove tho air cleaner and inlet system components as described in Chapter 48. 2 Firmly apply the handbrake, then jock up the front of the car and support It securely on axle stands (see Jacking and vehicle support). 3 Disconnect the oxygen sensor wiring or alternatively romovo Ihe sensor completely. 4 Unscrew the nuts and disconnect the exhaust downpipo from Ihe exhaust manifold flange. Recover the gasket. 5 On 1242 cc (16-valve) engines, undo the bolts and remove the manifold heat shield, then remove the bracket at the timing belt end of the manifold (seo Illustrations). 6 Unscrew the mounting nuts, remove the washers, and recover any additional brackets fitted over the studs, noting their locations. Withdraw the manifold from the studs on the cylinder head. 7 Recover the gaskets from Ihe studs.
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4D*3 Exhaust and emission control systems
Refitting 8 Refitting is a reversal of the removal pro-cedure but fit new gaskets. Tighten the nuts lo the specified torque.
Diesel models Note: On diesel models the inlet and exhaust
manifolds
are located on the rear of the engine
end
share the same securing nuts and gasket. Removal 8 Remove the inlet manifold as described In Part
C
of this Chapter. 10 Firmly apply the handbrake, then jack up lite front of tho car and support it securely on axle stands (see Jacking and vehicle support). 11 Straighten the tab washers (where fitted), then unscrew and remove the exhaust downpipe retaining nuts. Detach the downpipe from the manifold/turbocharger. Suitably support the downpipe. 12 Undo the manifold-to-cylinder head securing nuts and withdraw the manifold (see Illustration). 13 Separate the turbocharger from the manifold with reference to Chapter 4C. 14 Remove the gasket and clean the mating
(aces
of the manifold, cylinder head and down-pipe flange (see illustration). The gasket must
be
renewed when refitting the manifold, Refitting
15 Refitting is a reversal of the removal procedure but fit a new gasket. Tighten the retaining nuts to the specified torque and where necessary lock them by bending over
the
tocktabs.
6 Exhaust system - % general information and ^ component renewal
Genera/ Information 1 A three section exhaust system is fitted consisting of a twin-branch front downpipe, a catalytic converter, and a tailpipe with two silencers. The downpipe-to-manifold and downpipe-to-catalytic converter joints are both of flange and gasket type, whereas the remaining joint Is of the sleeve type secured
witn
a clamp ring (see illustration). 2 The system is suspended throughout its entire length by rubber mountings.
Removal 3 Each exhaust section can be removed individually or, alternatively, the complete system can be removed as a unit. Where separation of the rear sleeve Joint is necessary, it may be more practical to remove
the
entire system rather than try and separate
the Joint
In position. 4 To remove the system or part of the system, first jack up the front of the vehicle and support on axle stands (see Jacking and nhlcle support), Alternatively position the
vehicle
over an inspection pit or on car ramps.
5.12 Removing the exhaust manifold (diesel engine) Downpipe 5 Support the catalytic converter using an axle stand or blocks of wood. Where applicable on petrol models, refer to Section 4 and remove the oxygen sensor from the exhaust downpipe. 6 Unscrew and remove the bolts securing the downpipe to tha catalytic converter, then separate the joint and recover the gasket. 7 Bend back the locktabs (where fitted) then unscrew the nuts securing the downpipe to the exhaust manifold/turbocharger. and lower the downpipe, Recover the gasket. Catalytic converter
8 Support the tailpipe section of the exhaust using an axle stand or blocks of wood. 9 Unscrew and remove the bolts securing the downpipe to the catalytic converter, then separate the joint and recover the gasket. 10 Unscrew the clamp bolt and separate the converter from the tailpipe section. 11 Release the mounting rubber and remove the converter from under the vehicle. Tailpipe and silencers 12 Support the catalytic converter using an axle stand or blocks of wood. 13 Unscrew the clamp bolt and separate the catalytic converter from the tailpipe section. 14 Release the tailpipe section from its mounting rubbers and remove from under the vehicle. Complete system 15 Disconnect the downpipe from the ex-haust manifold as described in paragraph 7.
6.1 Exhaust clamp ring securing the tailpipe to the front exhaust system
5.14 Removing the oxhaust manifold gasket (diesel engine) 16 With the aid of an assistant, free the system from all its mounting rubbers and manoeuvre it out from underneath the vehicle. Heatshield 17 The heatshield is secured to the underbody by bolts and Is easily removed once the exhaust system has been removed.
Refitting 18 Each section is refitted by a reverse of the removal sequence, noting the following points. a) Ensure that all traces of corrosion have been removed from the flanges and renew ail necessary gaskets. b) Inspect the rubber mountings for signs of damage or deterioru tion and renew
as
necessary. c) Before refitting the tailpipe joint, smear some exhaust system jointing paste to the joint mating surfaces to ensure an air-tight seal. Tighten the clamp bolt. d) Prior to fully tightening the rear joint damp, ensure that all rubber mountings are correctly /ocafed and that there is adequate clearance between the exhaust system and vehicle underbody.
7 Catalytic converter -general information and precautions
The catalytic converter is a reliable and simple device which needs no maintenance In itself, but there are some facts of which an owner should be aware if the converter is to function properly for its full service life.
Petrol models a) DO NOT use leaded petrot In a car equipped with a catalytic converter - Ihe lead will coat the precious metals, redudng their converting efficiency
and
will eventually destroy the converter. b) Always keep the ignition and fuel systems well-maintained in accordance with the manufacturer's schedule. c) If the engine develops a misfire, do not drive the car at all (or at least as little
as
possible) until the fault is cured.
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4D*4 Exhaust and emission control systems
d) DO NOT push- or tow-start the car - this will soak the catalytic converter
in
unbumed fuel, causing It to overheat when the engine does start. e) DO NOT switch off the ignition at high engine speeds. f) DO NOT use fuel or engine oil additives -these may contain substances harmful to the catalytic converter. g) DO NOT continue to use the car If
the
engine bums oil to the extent of leaving
a
visible trail of blue smoke.
h) Remember that the catalytic converter operates at very high temperatures. DO NOT, therefore, park the car in dry undergrowth, over long grass or piles of deed leaves after a long run. I) Remember that the catalytic converter is FRAGILE - do not strike it with tools during servicing work, j} In some cases a sulphurous smell
pike
that of rotten eggs) may be noticed from the exhaust. This Is common to many catalytic converter-equipped cars and
once the car has covered a few
thousand
miles tha problem should
disappear,
k)
The
catalytic converter, used on a
weW*
maintained and well-driven car, should las for between
SO
000 and
100
000
miles-If
the converter is no longer effective It
must
be renewed.
Diesel models Refer to the information given in parts i,
g, h
and I of the petrol models information given above.