Chapter 4 Part B: Fuel system - single-point fuel injection engines

Transcription

1 4B 1 Chapter 4 Part B: Fuel system - single-point fuel injection engines Contents Air cleaner assembly - removal and refitting Air cleaner element renewal see Chapter 1 Fuel filter renewal see Chapter 1 Fuel gauge sender unit - removal and refitting Fuel injection system - testing and adjustment Fuel injection systems - general information Fuel pump - removal and refitting Fuel system - depressurisation Fuel tank - removal and refitting General fuel system checks see Chapter 1 Degrees of difficulty Easy, suitable for novice with little experience 1 Specifications Fairly easy, suitable for beginner with some experience General System type System application: TU1M/Z, TU3M/Z and TU3FM/L engines Bosch Mono-Jetronic A2.2 XU5M2/Z engines MMFD Mono-point G5 TU1M/L, XU5M3/Z and XU5M3/L engines MMFD Mono-point G6 Fuel system data Idling speed* ± 50 rpm Idle mixture CO content* Less than 1.0 % *Not adjustable, controlled by ECU - data given for reference purposes only Recommended fuel Minimum octane rating (see text Section 8) Fairly difficult, suitable for competent DIY mechanic General information and precautions Inlet manifold - removal and refitting MMFD Mono-point G5 and G6 system components - removal.... and refitting Mono-Jetronic A2.2 system components - removal and refitting Throttle cable - removal, refitting and adjustment Underbody and fuel/brake line check see Chapter 1 Underbonnet check for fluid leaks and hose condition..see Chapter 1 Unleaded petrol - general information and usage Difficult, suitable for experienced DIY mechanic Rear-mounted fuel tank, electric fuel pump, single-point fuel injection system 4 95 RON unleaded. Leaded fuel must not be used Very difficult, suitable for expert DIY or professional 5 4B 1 General information and precautions General information The fuel system consists of a fuel tank (which is mounted under the rear of the car, with an electric fuel pump immersed in it), a fuel filter, fuel feed and return lines, and the throttle body assembly (which incorporates the single fuel injector and the fuel pressure regulator). In addition, there is an Electronic Control Unit (ECU) and various sensors, electrical components and related wiring. The air cleaner contains a disposable paper filter element, and incorporates a flap valve air temperature control system. This allows cold air from the outside of the car and warm air from around the exhaust manifold to enter the air cleaner in the correct proportions. Refer to Section 9 for further information on the operation of each fuel injection system. Precautions Warning: Petrol is extremely flammable - great care must be taken when working on any part of the fuel system. Do not smoke or allow any naked flames or uncovered light bulbs near the work area. Note that gas powered domestic appliances with pilot flames, such as heaters, boilers and tumble dryers, also present a fire hazard - bear this in mind if you are working in an area where such appliances are present. Always keep a suitable fire extinguisher close to the work area and familiarise yourself with its operation before starting work. Wear eye protection when working on fuel systems and wash off any fuel spilt on bare skin immediately with soap and water. Note that fuel vapour is just as dangerous as liquid fuel; a vessel that has just been emptied of liquid fuel will still contain vapour and can be potentially explosive. Petrol is a highly dangerous and volatile liquid, and the precautions necessary when handling it cannot be overstressed. Many of the operations described in this Chapter involve the disconnection of fuel lines, which may cause an amount of fuel spillage. Before commencing work, refer to the above Warning and the information in Safety first at the beginning of this manual. When working with fuel system components, pay particular attention to cleanliness - dirt entering the fuel system may cause blockages which will lead to poor running. Note: Residual pressure will remain in the fuel lines long after the vehicle was last used. When disconnecting any fuel line, first depressurise the fuel system as described in Section 4.

2 4B 2 Fuel system - single-point fuel injection engines 2 Air cleaner assembly - removal and refitting 1 Refer to the procedures in Chapter 4A, Section 2, substituting throttle body for all references to the carburettor. 3 Throttle cable - removal, refitting and adjustment 2 Removal and refitting 1 Refer to Chapter 4A, Section 3 substituting throttle body for all references to the carburettor. Adjust the cable as described below. Adjustment 2 Remove the spring clip from the adjustment ferrule then, ensuring that the throttle cam is fully against its stop, gently pull the cable out of its grommet until all free play is removed from the inner cable. 3 With the cable held in this position, ensure that the flat washer is pressed securely against the grommet, then fit the spring clip to the third ferrule groove visible in front of the rubber grommet and washer (see illustration). This will leave a fair amount of freeplay in the inner cable which is necessary to ensure correct operation of the idle speed control motor. 4 Have an assistant depress the accelerator pedal and check that the throttle cam opens fully and returns smoothly to its stop. 4 Fuel system - depressurisation 1 before proceeding. Warning: The following procedure will merely relieve the pressure in the fuel system - remember that fuel will still be present in the system components, and take precautions accordingly before disconnecting any of them. 1 The fuel system referred to in this Section is defined as the tank-mounted fuel pump, the fuel filter, the fuel injector and the pressure regulator in the injector housing, and the metal pipes and flexible hoses of the fuel lines between these components. All these contain fuel which will be under pressure while the engine is running, and/or while the ignition is switched on. The pressure will remain for some time after the ignition has been switched off, and it must be relieved in a controlled fashion when any of these components are disturbed for servicing work. 2 Disconnect the battery negative lead. 3.3 Adjust the throttle cable as described in text 3 If possible, place a suitable container beneath the connection or 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 to avoid a sudden release of pressure, and position the rag around the connection, to catch any fuel spray which may be expelled. Once the pressure is released, disconnect the fuel line. Plug the pipe ends, to minimise fuel loss and prevent the entry of dirt into the fuel system. 5 Fuel pump - removal and refitting 3 Note: Observe the precautions in Section 1 before working on any component in the fuel system. Removal 1 Disconnect the battery negative lead. 2 Raise the rear seat cushion. 3 Prise up the right-hand plastic cover from the floor then disconnect the wiring, and the fuel supply and return pipes, noting their location (see illustration). 4 Unscrew the retaining screws and lift the fuel pump housing from the fuel tank. Note that in some cases, the hole in the floor may not be aligned with the pump, in which case the fuel tank may need to be lowered for access (refer to Section 7 for details). 5 Release the filter from the bottom of the housing, then the collar (see illustration). 5.3 Fuel pump locations and connections 6 Disconnect the wiring and release the fuel pump from the upper collar. Refitting 7 Refitting is a reversal of removal, but fit new collars and make sure that the wiring terminals are positioned away from the pump terminals. Always fit a new gasket between the pump housing and fuel tank. 6 Fuel gauge sender unit - removal and refitting 3 Refer to Part A, Section 6. 7 Fuel tank - removal and refitting 3 Refer to Part A, Section 7, noting that it will be necessary to depressurise the fuel system as the feed and return hoses are disconnected from the fuel pump (see Section 5). It will also be necessary to disconnect the wiring connector from the fuel pump before lowering the tank out of position. 5.5 Fuel pump components 1 Bleed tube 2 Bracket 3 Collar 4 Collar 5 Fuel pump 6 Filter

3 Fuel system - single-point fuel injection engines 4B 3 8 Unleaded petrol - general information and usage 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 Peugeot dealer. If travelling abroad, consult one of the motoring organisations (or a similar authority) for advice on the fuel available. All Peugeot 205 single-point fuel injection models are designed to run on fuel with a minimum octane rating of 95 (RON). All models are equipped with catalytic converters, and therefore must be run on unleaded fuel only. Under no circumstances should leaded fuel be used, as this may damage the catalytic converter. Super unleaded petrol (97/98 RON) can also be used in all models if wished, though there is no advantage in doing so. 9 Fuel injection systems - general information Bosch Mono-Jetronic A2.2 system The Mono-Jetronic A2.2 system is a single-point fuel injection system incorporating a catalytic converter in the exhaust system. The fuel pump, located in the fuel tank, pumps the fuel through a filter to the single fuel injector. The electronic control unit (ECU), which is triggered by the ignition circuit, sends impulses to the injector, which sprays fuel upstream of the throttle valve. A constant fuel pressure is maintained by a fuel pressure regulator, which returns excess fuel to the fuel tank. The ECU also receives information from various sensors to determine engine temperature, speed and load, and the quality of air entering the engine. The sensors inform the ECU of throttle position, inlet air temperature, coolant temperature, and exhaust gas oxygen content. Engine speed and crankshaft position information is provided by the ignition circuit. All the information supplied to the ECU is computed and compared with pre-set values stored in the ECU memory, to determine the required period of injection. The injector operates four times per engine cycle, and the injector opening duration is varied to control the quantity of fuel delivered. The ECU constantly varies the fuel mixture and engine idle speed to provide optimum engine efficiency under all operating conditions, and to reduce exhaust gas emissions. The mixture strength is accurately controlled to maintain it within the operating limits of the catalytic converter. MMFD Mono-point G5 and G6 systems The Mono-point G5 and G6 systems are single-point fuel injection systems also incorporating a catalytic converter in the exhaust system. The only difference between the two systems is that the idle speed is controlled via a control valve on the G5 system, and via a control motor on the G6 system. The system operation is as described above for the Mono-Jetronic system and is under the overall control of an electronic control until (ECU), which also controls the ignition system. 10 Fuel injection system - testing and adjustment 3 Testing 1 If a fault appears in the fuel injection system, first ensure that all the system wiring connectors are securely connected and free of corrosion. Ensure that the fault is not due to poor maintenance; ie, check that the air cleaner filter element is clean, the spark plugs are in good condition and correctly gapped, the valve clearances are correctly adjusted, the cylinder compression pressures are correct, the ignition timing is correct (where adjustable), and that the engine breather hoses are clear and undamaged, referring to Chapters 1, 2 and 5 for further information. 2 If these checks fail to reveal the cause of the problem, the vehicle should be taken to a suitably-equipped Peugeot 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 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 also carries a risk of damaging the ECU. Adjustment 3 Experienced home mechanics with a considerable amount of skill and equipment (including a tachometer and an accurately 11.1 Fuel injector wiring clip (A), and fuel pressure regulator securing screws (B) - Mono-Jetronic A2.2 system calibrated exhaust gas analyser) may be able to check the exhaust CO level and the idle speed. However, if these are found to be in need of adjustment, the car must be taken to a suitably-equipped Peugeot dealer for further testing. 4 On both single-point fuel injection systems, no adjustment of the CO level and idle speed is possible, these being under the complete control of the ECU. Should the idle speed or exhaust gas CO level be incorrect, then a fault is likely to be present in the fuel injection system. 11 Mono-Jetronic A2.2 system components - removal and 3 refitting Note: Check the availability of individual components with your Peugeot dealer before dismantling. Fuel pressure regulator before proceeding. 1 The fuel pressure regulator (consisting of a valve operated by a spring-loaded diaphragm and a metal cover) is secured by four screws to the top of the throttle body (see illustration). Although the unit can be dismantled for cleaning, if required (once the air inlet trunking and the fuel injector wiring clip have been removed for access), it should not be disturbed unless absolutely necessary. 2 Note that the regulator assembly is only available as part of the complete throttle body assembly; no individual components can be renewed separately. 3 If the regulator cover is removed, note its orientation on the throttle body before removal, to ensure correct Fuel injector before proceeding. If a faulty injector is suspected, before condemning the injector, it is worth trying the effect of one of the proprietary injector-cleaning treatments. 4 Disconnect the battery negative lead. 5 Remove the air inlet trunking from the top of the throttle body. 6 Remove the Torx screws securing the injector wiring connector to the top of the throttle body, then carefully lift off the connector (see illustrations). 7 Withdraw the injector (see illustration). Recover and discard the injector sealing rings. 8 Refitting is the reverse of the removal procedure, noting the following points. a) Always renew both sealing rings: apply a smear of grease to each ring, to ease injector b) Ensure that the injector is refitted so that its connector pins align with the connector when the connector is correctly located on the top of the throttle body. 4B

4 4B 4 Fuel system - single-point fuel injection engines 11.6a Remove the Torx screw b... and lift off the wiring connector 11.7 Withdrawing the fuel injector c) Before refitting the injector securing screw, apply a few drops of a suitable thread-locking compound to the threads. d) On completion, switch on the ignition and check carefully for signs of fuel leaks; if 11.11a Remove the sealing ring... any signs of leakage are detected the problem must be rectified before the engine is started. Inlet air temperature sensor 9 The sensor is located in the fuel injector wiring connector, and is available only as part of the connector assembly. To remove the connector assembly, proceed as follows. 10 Disconnect the battery negative lead. 11 Remove the air trunking from the top of the throttle body, then unscrew the three securing nuts, and remove the sealing ring. Recover the O-ring (see illustrations). 12 Release the securing clips, separate the two halves of the fuel injector wiring connector, then release the wiring from the clip on the top of the throttle body (see illustrations). 13 Remove the Torx screw securing the fuel injector wiring connector to the top of the throttle body, then carefully lift off the connector (see illustration). Idle speed control motor 14 Disconnect the battery negative lead. 15 Release the securing clip, and disconnect the wiring plug from the motor (see illustration). 16 Unscrew the securing screws, and withdraw the motor from the throttle body assembly (see illustration). 17 Refitting is the reverse of the removal procedure. Note that the motor will reset itself as soon as the engine is restarted. Throttle switch 18 The throttle switch is accurately matched on the throttle valve during manufacture - it is not adjustable and must not be disturbed b... and recover the O-ring 11.12a Separate the two halves of fuel injector wiring connector b... then release wiring from clip Intake air temperature sensor (arrowed) Disconnecting wiring plug from idle speed control motor (arrowed) Unscrewing an idle speed control motor securing screw

5 Fuel system - single-point fuel injection engines 4B a Disconnecting the wiring plug from the fuel injector b... and the throttle switch Vacuum hose connection to throttle body (arrowed) 19 Do not attempt to adjust the throttle switch setting or that of the stop screw on the throttle valve external linkage; if the accurately matched relationship between these components is lost, the components must be replaced. At the time of writing this means renewing the entire throttle body assembly. Throttle body before proceeding. 20 Disconnect the battery negative lead. 21 Remove the air inlet trunking from the top of the throttle body. 22 Disconnect the throttle cable (see Section 3). 23 Release the securing clips, and disconnect the wiring plugs from the fuel injector, the idle speed control motor, and the throttle switch (see illustrations). 24 Disconnect the fuel hoses from the unions on the throttle body (refer to Section 4). Plug the open ends of the hoses, to prevent dirt ingress and further fuel loss. Take note of the connections, and label them to ensure correct 25 Disconnect the vacuum hoses and pipes from the throttle body unions (see illustration). Label the hoses and pipes so that they can be correctly reconnected on 26 Remove the screws securing the throttle body to the inlet manifold, then withdraw the assembly (see illustration). Recover the gasket, and discard it. 27 If desired, the throttle body upper and lower sections may be separated by removing the securing screws. Note that a new gasket must be fitted on reassembly. As noted previously, do not disturb the throttle switch. The fuel inlet and return unions may be unscrewed from the throttle body, and the vacuum hose unions may be detached, but note that new sealing rings must be fitted on reassembly. 28 Refitting is the reverse of the removal procedure, noting the following points. a) Renew all gaskets and seals, and use suitable thread-locking compound where applicable. b) Check the throttle cable operation and adjustment (Section 3). c) Ensure that all vacuum hoses and pipes are correctly reconnected, as noted before removal. d) Ensure that the fuel hoses are correctly reconnected. The direction of fuel flow is indicated by arrows cast into the throttle body next to each union. e) On completion, switch on the ignition, and check for signs of fuel leaks from all disturbed unions. If any signs of leakage are detected, the problem must be rectified before the engine is started. Coolant temperature sensor Refer to Chapter 3, Section 7. Electronic control unit (ECU) 29 The ECU is located behind the facia, to the right of the steering column. 30 Disconnect the battery negative lead. 31 For improved access, remove the driver s side lower facia panel. The panel is secured by four screws, and a single bolt. 32 Remove the nuts securing the ECU bracket to the facia, then lower the assembly. Withdraw the ECU from the bracket (see illustration). 33 Release the securing clip, or remove the securing screws, as applicable, and disconnect the wiring plug (see illustration). 34 Refitting is a reversal of removal, but ensure that the wiring plug is securely reconnected, and where applicable, ensure that the ECU locates correctly in the bracket. Fuel injection system fuses and relays 35 The relays are generally mounted on the left-hand side of the engine compartment bulkhead. The relays may be mounted on individual brackets, or on later models, in a plastic box. 36 Most of the fuses are located in the main fusebox inside the car, although on certain models, additional fuses may be located in a small fusebox mounted at the front left-hand corner of the engine compartment. 37 The number and type of fuses and relays fitted will depend on engine type and exact vehicle specification. 4B Throttle body securing screws (arrowed) Removing the ECU from its bracket. Note securing lug (arrowed) Disconnecting the ECU wiring plug

6 4B 6 Fuel system - single-point fuel injection engines 12.1 Fuel pressure regulator (A) and fuel injector wiring plug (B) 12.4 MMFD G6 fuel injection system throttle body assembly 12 MMFD Mono-point G5 and G6 system components - removal and refitting 3 Note: Check the availability of individual components with your Peugeot dealer before dismantling. Fuel pressure regulator 1 Refer to Section 11, Paragraphs 1 to 3 noting the revised component arrangement (see illustration). Fuel injector before proceeding. If a faulty injector is suspected, before condemning the injector, it is worth trying the effect of one of the proprietary injector-cleaning treatments. Note that at the time of writing, the injector does not appear to be available separately from the throttle body upper section assembly. 2 Disconnect the battery negative lead. 3 Remove the air inlet trunking from the top of the throttle body. 4 Release the securing clip, and disconnect the injector wiring plug (see illustration). 5 Remove the Torx screw securing the injector retainer plate to the top of the throttle body (see illustration), lift off the retainer, then withdraw the injector. Recover and discard the injector sealing rings (check to ensure that new sealing rings can be obtained before discarding the old ones). 6 Refitting is the reverse of the removal procedure, noting the following points. a) Always renew both sealing rings; apply a smear of grease to each, to ease injector b) Refit the injector so that its wiring terminals point towards the front of the vehicle, and locate the edge of the 1 Fuel injector wiring connector 2 Fuel pressure regulator retainer securely in the groove at the top of the injector. c) Before refitting the injector securing screw, apply a few drops of a suitable thread-locking compound to the threads. d) On completion, switch on the ignition, and check carefully for signs of fuel leaks; if any signs of leakage are detected, the problem must be rectified before the engine is started. Throttle switch 7 Disconnect the battery negative lead. 8 Disconnect the wiring plug, and disconnect the wiring plug from the switch. 9 Remove the two securing screws and withdraw the switch. 10 Refitting is a reversal of removal, noting the following points. a) Before refitting the switch, ensure that the throttle valve is fully closed. b) Ensure that the switch wiper engages correctly with the throttle shaft. Idle speed control valve (MMFD G5 system) 11 For improved access, remove the air cleaner trunking Fuel injector retaining plate securing screw (arrowed) 3 Idle speed control motor 4 Throttle switch 12 Disconnect the battery negative lead. 13 Release the securing clip, and disconnect the wiring plug from the valve. 14 Loosen the securing clamps, and disconnect the air hoses from the valve. Note the locations of the hoses to ensure correct 15 Remove the securing screws, and withdraw the valve. 16 Refitting is a reversal of removal, noting that the arrows cast on the valve unions indicate the direction of airflow through the valve. Ensure that the hoses are securely refitted, to prevent air leaks. Idle speed control motor (MMFD G6 system) Note: At the time of writing, it was not clear whether the motor is available separately from the throttle body assembly. It is advisable to seek the advice of a Peugeot dealer before deciding on the course of action to be followed if the motor is thought to be faulty. 17 For improved access, remove the air inlet trunking. 18 Disconnect the battery negative lead. 19 Release the securing clip, and disconnect the wiring plug from the motor. 20 Remove the two securing screws, then withdraw the motor. Recover and discard the sealing ring (check to ensure that a new sealing ring can be obtained before discarding the old one). 21 Refitting is a reversal of removal bearing in mind the following points. a) Always fit a new sealing ring, greasing it lightly to ease installation. b) The control motor will be reset by the ECU as soon as the engine is restarted. c) Apply suitable thread-locking compound to the securing screw threads before

7 Fuel system - single-point fuel injection engines 4B 7 Inlet air temperature sensor 22 The sensor is screwed into the top of the inlet manifold. 23 Disconnect the battery negative lead. 24 Release the securing clip, and disconnect the wiring plug from the sensor. 25 Unscrew the sensor and withdraw it. 26 Refitting is a reversal of removal. Throttle body before proceeding. 27 Disconnect the battery negative lead. 28 Remove the air inlet trunking from the top of the throttle body. 29 Disconnect the throttle cable (see Section 3). 30 Release the securing clips, then disconnect the wiring plugs from the fuel injector (remove the rubber throttle body/trunking seals to release the wiring), throttle switch, and the idle speed control motor (MMFD G6 system only). 31 Disconnect the fuel hoses from the unions on the throttle body, labelling the hoses to ensure correct Plug the open ends of the hoses, to prevent dirt ingress and further loss of fuel. 32 Disconnect the vacuum pipes and hoses from the throttle body unions. Label the hoses so that they can be correctly reconnected. 33 Unscrew the studs securing the throttle body to the inlet manifold, and withdraw the assembly. Recover and discard the gasket. 34 If desired, the two halves of the throttle body (upper and lower) can be separated by removing the securing screws. Note that in this case, a new gasket must be used on reassembly. 35 Refitting is a reversal of removal, bearing in mind the following points. a) Renew all disturbed gaskets and seals, and use suitable thread locking compound where necessary. b) Check the throttle cable operation and adjustment (Section 3). c) Ensure that all vacuum hoses and pipes are correctly reconnected as noted before removal. d) When reconnecting the manifold absolute pressure sensor hose, ensure that it is routed so that it falls steadily from the sensor to the throttle body. This is necessary to prevent any fuel droplets from entering the sensor (no fuel vapour trap is fitted), allowing them to drain into the throttle body instead. e) Ensure that the fuel hoses are correctly reconnected, as noted before removal. f) On completion, switch on the ignition, and check carefully for signs of fuel leakage from all disturbed unions. If any signs of leakage are detected the problem must be rectified before the engine is started. Manifold absolute pressure sensor 36 Disconnect the battery negative lead. 37 Release the securing clip, and disconnect the wiring plug from the idle speed control motor (MMFD G6 systems only). 38 Slacken the clamp (if fitted), and disconnect the vacuum hose from the sensor. 39 Remove the securing screws and withdraw the sensor, complete with bracket, from the body front panel (or wing panel, as applicable). 40 Refitting is a reversal of removal, but note the following. When reconnecting the vacuum hose to the sensor ensure that the hose is routed so that it falls steadily from the sensor to the throttle body. This is necessary to prevent any fuel droplets from entering the sensor (no fuel vapour trap is fitted), allowing them to drain into the throttle body instead. Coolant temperature sensor Refer to Chapter 3, Section 7. Electronic control unit (ECU) Refer to Section 11, paragraphs 29 to 34. Fuel injection system fuses and relays Refer to Section 11, paragraphs 35 to Inlet manifold - removal and refitting 3 The procedure is essentially as described in Part A, Section 11, but remove the throttle body as described in Section 11 or 12 of this Part and ignore any references to carburettor. 4B

8 4B 8 Notes