Chapter 4 Part C: Emissions control systems

Transcription

1 Chapter 4 Part C: Emissions control systems Contents Catalytic converter - general information and precautions Crankcase emissions control system - testing and renewal Exhaust emissions control system - testing and renewal Exhaust gas recirculation system - testing and renewal Fuel evaporation control system - testing and renewal General information and precautions Secondary air injection pump assembly (1.4 and 1.6 litre DOHC engines) - renewal Secondary air pipe and combination valve (1.4 and 1.6 litre DOHC engines) - renewal Secondary air switchover valve (1.4 and 1.6 litre DOHC engines) - renewal Degrees of difficulty Easy, suitable for novice with little experience Fairly easy, suitable for beginner with some experience Fairly difficult, suitable for competent DIY mechanic Difficult, suitable for experienced DIY mechanic Very difficult, suitable for expert DIY or professional Specifications Torque wrench settings EGR valve-to-inlet manifold bolts: All except 1.0 and 1.2 litre DOHC engines EGR valve housing-to-cylinder head bolts: 1.0 and 1.2 litre DOHC engines EGR pipe to EGR valve housing: 1.2 litre DOHC engine Carbon canister strap to bracket Carbon canister to wheelarch Heat shield to exhaust manifold Secondary air combination valve to air pipe Secondary air pipe support bracket Secondary air pipe to exhaust manifold: M6 bolts M8 bolts Secondary air pump to bracket Secondary air switch over valve Nm Ibfft

2 4C-2 Emissions control systems 1 General information and precautions All engines covered by this manual use unleaded petrol and also have various other features built into the fuel/exhaust system to help minimise harmful emissions. The systems are described in more detail in the following paragraphs. Crankcase emissions control system A crankcase ventilation system is fitted to all models, but the systems differ in detail according to model. Oil fumes and blow-by gases (combustion gases which have passed by the piston rings) are drawn from the crankcase into the area of the cylinder head above the camshaft(s) via a hose. From here, the gases are 'drawn into the inlet manifold/throttle body (as applicable) and/or the airbox on the throttle body, where they are mixed with fresh air/fuel mixture and burnt, reducing harmful exhaust emissions, Certain models may have a mesh filter inside the camshaft cover, which should be cleaned in paraffin if clogging is evident. Exhaust emissions control system To minimise the level of exhaust gas pollutants' released into the atmosphere, all models are fitted with a catalytic converter, located in the exhaust system. A 'closed-loop' system is used; an exhaust gas oxygen sensor, mounted in the exhaust manifold, provides a signal to the engine management electronic control unit, to enable it adjust the air/fuel mixture ratio within very fine limits. This enables the catalytic converter to operate at optimum efficiency at all times. The oxygen sensor senses the level of oxygen in the exhaust gas, which is proportional to the air/fuel mixture ratio. A rich mixture produces exhaust gases with a low oxygen content, the oxygen content rising as the mixture weakens. The catalyst operates at maximum efficiency when the air/fuel mixture ratio is at the chemically-correct ratio for the complete combustion of petrol (14.7 parts of air to 1 part of fuel). The output voltage produced by the oxygen sensor alters sharply when this ratio is achieved. The electronic control unit uses this information to maintain the air/fuel ratio very close to the optimum value under all engine operating conditions, by varying the amount of fuel injected. Fuel evaporation control system To minimise the escape into the atmosphere of un burnt hydrocarbons, a fuel evaporation control system is fitted to all models. The fuel tank filler cap is sealed, to prevent the release of fuel vapour into the atmosphere, and a charcoal canister is mounted under the front right-hand wheelarch, to collect the fuel vapours which would otherwise be released from the tank when the vehicle is parked. The vapours are stored in the canister until a vent valve is operated by manifold vacuum, or by the fuel system electronic control unit (depending on engine type). The vent valve releases the vapours into the engine inlet tract, where they are burnt during the normal combustion process. Exhaust gas recirculation system The exhaust gas recirculation system, fitted to all engines except the 1.4 litre SOHC engine with multi-point fuel injection (C 14 SE), is designed to recirculate small quantities. of exhaust gas into the inlet tract, and therefore into the combustion process. This process reduces the level of oxides of nitrogen present in the final exhaust gas which is released into the atmosphere. The volume of exhaust gas recirculated is controlled by the engine management electronic control unit, via a valve mounted on the inlet manifold. A tract in the cylinder head allows exhaust gas to pass from the exhaust side of the cylinder head to the exhaust gas recirculation valve in the inlet manifold. Secondary air injection system A secondary air injection system is fitted to the 1.4 and 1.6 litre DOHC Ecotec engines (X 14 XE and X 16 XE). It is also known as the Air Injection Reactor (AIR). An electric pump, mounted on the inner wheelarch, forces air into the exhaust manifold, during cold start and run conditions. This quickly increases the exhaust temperature, which enables the catalytic converter to rapidly reach its most effective operating temperature. 2 Crankcase emissions control system ;.. testing and renewal 1 If the system is thought to be faulty, first check that the hoses are unobstructed. Highmileage vehicles, particularly those regularly used for short journeys, are likely to develop a jelly-like deposit inside the crankcase emissions control system hoses. If excessive deposits are present, the relevant hose(s) should be removed and cleaned. 2 Periodically inspect the system hoses for security and damage, and renew them as necessary. Note that damaged or loose hoses can cause various engine running problems (erratic idle speed, stalling, etc) which can be difficult to trace. Component renewal 3 The crankcase breather tube can be unbolted from the cylinder block (remove the starter motor for access) after disconnecting the hose. Use a new gasket when refitting. 4 Certain models have a mesh filter inside the camshaft cover, which should be cleaned in paraffin if clogging is evident. For access to the filter, remove the camshaft cover as described in the relevant Part of Chapter 2. The filter can be removed from the camshaft cover for cleaning after unscrewing the securing screws. 3 Exhaust emissions control system - testing and renewal 1 The system can only be tested accurately using specialist Vauxhall/Opel diagnostic equipment. Any suspected faults should be referred to a Vauxhall/Opel dealer. Catalytic converter renewal 2 The catalytic converter is located in the exhaust system, and is an integral part of either the exhaust front section or the exhaust intermediate section. 3 Removal and refitting details for the exhaust system components are given in Chapters 4A and 4B. Oxygen sensor renewal 4 Renewal of the oxygen sensor is described in the relevant fuel system Section of Chapters 4A and 4B. Fuel evaporation control system - testing 'and renewal 1 If the system is thought to be faulty, disconnect the hoses from the charcoal canister and vent valve, and check that the hoses are clear by blowing through them. If necessary, clean or renew the hoses (see 2 If the vent valve or the charcoal canister itself are thought to be faulty, the only course of action available is renewal. 4.1 Disconnecting the fuel vapour vent hose from the fuel injection unit - X 12 SZ engine

3 Emissions control systems 4C Charcoal canister bracket securing nut (1) and clamp bolt (2) Charcoal canister renewal 3 The charcoal canister is located under the front right-hand wheelarch. 4 Apply the hand brake, then jack up the front of the vehicle and support securely on axle stands (see Jacking and vehicle support). Remove the front right-hand roadwheel. 5 Remove the wheelarch liner (see Chapter 11) to expose the charcoal canister. 6 Remove the nut securing the canister bracket to the bracket on the body (see 7 Unscrew the canister clamp bolt, and withdraw the canister from the clamp bracket. 8 Loosen the hose clamps, and disconnect the hoses from the top of the canister, noting their locations to ensure correct refitting (see 9 Withdraw the canister from under the wheelarch. 10 Fit the new canister using a reversal of the removal procedure. Make sure that the hoses are correctly reconnected, as noted before removal. Ensure that the upper end of the canister clamp bracket locates in the cut-out in the body panel. Fuel tank vent valve renewal 1.0 and 1.2 litre DOHC engines 11 The valve is located at the left-hand end of the inlet manifold (see 12 Disconnect the battery negative terminal 13 Disconnect the upper and lower vent hoses, and the valve wiring plug. 4.8 Note the locations of the charcoal canister hoses 14 Detach the valve from the inlet manifold and remove it from the engine. 15 Refitting is a reversal of removal, ensuring that the hoses are reconnected securely. 1.2 and 1.4 litre SOHC engines 16 The valve is located at the timing belt end of the camshaft housing, at the rear. 17 Disconnect the battery negative terminal 18 For improved access, remove the breather hose connecting the airbox to the camshaft cover (see 19 Release the wiring harness from the brackets on the camshaft cover, and lift the harness clear of the fuel tank vent valve (see 20 Depress the retaining lugs, and slide the 4.18 Remove the breather hose Fuel tank vent valve (arrowed) - X 10 XE and X 12 XE engines val ve rearwards from its mounting bracket (see 21 Disconnect the valve wiring. plug, and the two hoses, noting their locations to ensure correct refitting (see 22 Withdraw the valve. 23 Refitting is a reversal of removal, ensuring that the hoses are recon nected correctly, as noted before removal. 1.4 and 1.6 litre DOHC engines 24 The valve is located on a bracket attached to the upper section of the inlet manifold. 25 Remove the oil filler cap and the plastic cover from the top of the camshaft cover. The plastic cover is secured by two screws. 26 Disconnect the battery negative terminal Reference Chapter), then disconnect the wiring plug from the valve (see and lift the wiring harness clear for access to the fuel tank vent valve (arrowed) - X 12 SZ and X 14 SZ engines 4.20 Slide the valve from its mounting bracket and disconnect the wiring and hoses - X 12 SZ and X 14 SZ engines 4.26 Disconnecting the wiring plug..

4 4C-4 Emissions control systems on the inlet manifold can be checked for condition and security, but any further testing should be referred to a Vauxhall/Opel dealer and the hoses from the fuel tank vent valve - X 14 XE and X 16 XE engines 27 Disconnect the hoses from the valve, noting their locations to ensure correct refitting (see 28 Withdraw the valve upwards from its bracket. 29 Refitting is a reversal of removal, ensuring that the hoses are reconnected securely. 5 Exhaust gas recirculation system - testing and renewal 1 The system can only be tested accurately using specialist Vauxhall/ Opel diagnostic equipment. The wiring to the solenoid valve Exhaust gas recirculation valve renewal Thoroughly clean the mating faces of the valve, cylinder head and EGR pipe flange, then refit the valve and pipe using new gaskets. 10 On completion, top-up the cooling system as described in Weekly checks. 1.0 and 1.2 litre DOHC engines 1.2 and 1.4 litre SOHC engines Note: A new EGR housing gasket and EGR pipe gasket must be used on refitting. 2 The valve is located at the left-hand end of the cylinder head. 3 Disconnect the battery negative terminal 4 Partially drain the cooling system as described in Chapter 1, then disconnect the coolant hose from the rear of the EGR valve housing (see 5 Disconnect the wiring plug from the top of the EGR valve and the wiring connector from the adjacent temperature gauge sender. 6 Move the wiring harness to one side for access to the EGR valve housing mounting bolts. 7 On 1.2 litre engines, undo the two bolts securing the EGR pipe to the side of the EGR valve housing (see 8 Undo the four bolts securing the EGR valve housing to the cylinder head and withdraw the housing assembly (see Recover the housing gasket and, where applicable, the EGR pipe-to-housing gasket. 9 Refitting is a reversal of removal. Note: A new gasket must be used on refitting. 11 The valve is located on top of the inlet manifold. 12 Remove the airbox from the top of the fuel injection unit, as described in Chapter 4B. 13 Disconnect the battery negative terminal Reference Chapter), then disconnect the wiring plug from the valve (see 14 Unscrew the two securing bolts, and withdraw the va lve from the inlet manifold (see Recover the gasket. 15 Check the valve vent holes for contamination, and clean if necessary (see 16 Refitting is a reversal of removal. Thoroughly clean the mating faces of the valve and manifold, then refit the valve using a new gasket. 1.4 and 1.6 litre DOHC engines 17 Depressurise the fuel system as described in Chapter 4B. 18 Disconnect the battery negative terminal if not already done (refer to Disconnecting the battery in the 5.4 EGR valve coolant hose (1), wiring plug (2) and coolant temperature sensor wiring connector (3) - X 10 XE and X 12 XE engines 5.7 EGR pipe-to-egr valve housing securing bolts (arrowed) - X 10 XE and X 12 XE engines 5.8 EGR valve housing securing bolts (arrowed) - X 10 XE and X 12 XE engines 5.13 Disconnecting the exhaust gas recirculation valve wiring plug - X 12 SZ and X 14 SZ engines 5.14 Exhaust gas recirculation valve securing bolts (arrowed) - X 12 SZ and X 14 SZ engines 5.15 Check the exhaust gas recirculation valve vent holes (arrowed) for contamination - X 12 SZ and X 14 SZ engines

5 Emissions control systems 4C-S 5.27 Disconnecting the exhaust gas recirculation control module wiring plug - X 12 SZ engines 6.2 Loosen the clamp (arrowed) and remove the air duct hose from the secondary air injection pump - X 14 XE and X 16 XE engines 6.5 Secondary air injection pump mounting bracket nuts - X 14 XE and X 16 XE engines 19 Partially drain the cooling system as escribed in Chapter 1, then disconnect the coolant hoses and remove the cooling system expansion tank. 20 Unscrew the union nuts and disconnect e fuel feed line from the fuel rail, and the retum line from the fuel pressure regulator. 21 Undo the bolts securing the wiring trough and air inlet pipe from the inlet manifold lower section. Detach the air inlet hoses at the inlet pipe and push the pipe downwards slightly for access to the EGR valve. 22 Disconnect the wiring plug from the valve. 23 Unscrew the two securing bolts, and withdraw the valve from the inlet manifold. Recover the gasket. 24 Check the valve vent holes for contamination, and clean if necessary. 25 Refitting is a reversal of removal. Thoroughly clean the mating faces of the valve and manifold, then refit the valve using a new gasket. Top-up the cooling system as described in Weekly checks on completion. Exhaust gas recirculation control module renewal 1.2 litre SOHC engine 26 The module is located on a bracket mounted on the front left-hand wing panel. 27 Disconnect the battery negative erminal (refer to Disconnecting the battery in 7.1 Secondary air injection switchover valve (arrowed) - X 14 XE and X 16 XE engines the Reference Chapter), then disconnect the wiring plug from the module (see 28 Remove the two securing bolts, and withdraw the module from its mounting bracket. 29 Refitting is a reversal of removal. 6 Secondary air injection pump assembly (1.4 and 1.6 litre DOHC engines) - renewal 1 Disconnect the battery negative terminal 2 Loosen the hose clamp and remove the air duct hose from the pump, and unclip it from the support bracket (see 3 Disconnect the air pump wiring plug. 4 Detach the coolant hose from the air pump bracket and move the hose aside. 5 Undo the securing nuts and remove the pump and mounting bracket assembly from its location (see 6 Detach the air hose then undo the nuts and remove the air pump air cleaner from the pump bracket. 7 Check the pump air cleaner for damage. 8 Refitting is a reversal of removal. Ensure correct alignment of the components. 8.1 Disconnect the air duct and vacuum hose from the secondary air combination valve - X 14 XE and X 16 XE engines 7 Secondary air switchover valve (1.4 and 1.6 litre DOHC engines) - renewal The switchover valve is mounted on a bracket attached to the suspension strut tower on the left-hand side of the engine compartment (see 2 Disconnect the battery negative terminal 3 Disconnect wiring plug from the valve. 4 Mark the location of the vacuum hoses before removing them from the valve. 5 After disconnecting the hoses undo the two bolts, and remove the valve from its bracket. 6 Refitting is a reversal of removal. Ensure hoses are fitted correctly. 8 secondary air pipe and combi- nation valve (1.4 and 1.6 litre DOHC engines) - renewal Note: The gasket should be renewed when refitting the valve. 1 Release the retaining clip and disconnect the combination valve air duct and the vacuum hose (see 2 Unbolt the support bracket from the secondary air pipe and exhaust manifold. 3 Mark the location of the valve before removal. 4 Remove the valve from the secondary air pipe. 5 Remove the pipe support bracket by releasing its bolts. 6 Remove the heat shield that is secured by two bolts. 7 The air pipe can now be removed by releasing the two securing bolts. 8 Secure the pipe in the exhaust manifold, coating the bolts with Assembly Paste (Vauxhall PI N ). 9 Using a new gasket, refitting is a reversal of removal, tightening all bolts to the specified torque.

6 4C-6 Emissions control systems 9 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. a) DO NOT use leaded petrol in a car equipped with a catalytic converter - the lead will coat the precious metals, reducing 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. d) DO NOT push- or tow-start the car - this will soak the catalytic converter in unburned 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 dead 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 (like 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 the problem should disappear. k) The catalytic converter, used on a wellmaintained and well-driven car, should last for between and miles - if the converter is no longer effective it must be renewed.