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Troubleshooting

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  Preface Based on the model GW491Q (4Y) carburetor petrol engine, the GW491QE petrol engine produced by our company is of one petrol engine able to electrically inject fuel at multiple points, and is developed from electrical control components made by Delphi company, USA, and Shanghai United Electronic Company.
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  Model GW491QE petrol engine Service Manual Engine service &maintenance data ………………United Electronic engine management system …………..EF.1 Delphi engine management system ………………EF.2 Engine body ……………………..EM.1 Cylinder head ……………………..EM.2 Valve mechanism ……………………EM.3 Cooling system ……………………. Lubrication system ……………………
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  GI-1 Engine service /Maintenance data Page Key technical parameters for model GW491QE petrol engine……. Specification &adjustment parameters for key components ……Technical data for maintenance…………..Tightening torque for fastening elements…………Troubleshooting……………….. Engine service /maintenance data…………..
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  GI-2 Engine service /maintenance data-Key technical parameters for Model GW491QE petrol engine Key technical parameters for Model GW491QE petrol engine S.N. Item Specification and parameters Model Model GW491QE Four-cylinder, inline, water-cooled, overhead valve，4-stroke Pattern petrol engine Fuel supply pattern Electronic controlled jet injection by group at multiple points Measurement method for air intake Velocity &density type…
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  GI-3 Engine service /maintenance data-key technical parameters for Model GW491QE petrol engine S .N . I tem S pecification and parameters M ax . oil temperature C onsumpti on rate of oil 2 g/kw·h F uel consumption ratio of machine oil C ooling method U se forced water circulation for cooling purpose.
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  Engine service /maintenance data- specification /adjustment parameters / maintenance technical data GI-4 data for key componeats S pecification /adj ustment par ameter s for k ey components S .N . Item Specification and parameters S park plug F6R T C D ecelerating type when under an electromagnetic Starter motor control…
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  Engine service /maintenance data- specification/adjustment parameters /maintenance technical GI-5 data for key components Name Test items Standard value Use limit Inner diameter of rocker hole 18.5 +0.013 R ocker and axis -0.018 Diameter of rocker shaft 18.5 for valve -0.033 Gap between rocker and rocker shaft 0.018~0.046 0.08…
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  GI-6 Engineservice/maintenancedata-maintenancetechnicaldata Unit mm Name Test items Standard value Use limit A xial clearance 0.02~0.22 0.30 T hickness of thrust washer 2.450~2.490 Increased by 0.125 2.575~2.615 Increased by 0.250 2.700~2.740 Main journal diameter -0.015 Clearance of main journal diameter 0.021~0.053 0.10 C rankshaft journal diameter of connection rod…
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  Engineservice/maintenancedata-tighteningtorqueforfasteningelements GI-7 4.Ignition system Name Test items Standard value Use limit Model F6RT C Spark plug Clearance 1.0~1.2 mm High-tension wiring R esistance 16k /m 5.Starting system Name Test items Standard value Use limit R ated voltage Output power Zero-load characteristics size of >90A current specified when it’s 11.5V…
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  Engine service /maintenance data-Tightening torque for fastening elements GI-8 Frequently tightened spare parts Water pump cylinder body B ox of timing chain chamber cylinder block B olt B earing cover of connection rod connection rod B earing cover of crankshaft cylinder block Crankshaft belt pulley crankshaft Flywheel crankshaft Oil bottom oil pan cylinder block…
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  Engine service /maintenance data-Troubleshooting GI-9 Tightening torque screw pitch Hexagonal Grade diameter mm Hexagonal-headed flange bolt bolt N m 1.25 1.25 1.25 1.25 1.25 1.25 Common failures and troubleshooting 1.E ngine not start or start with difficulty C ause of failure Methods of elimination 1.
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  Engine service /maintenance data-Troubleshooting GI-10 3.engine is slack. C ause of failure Methods of elimination 1 E ngine is under a bad compression condition. Valve is leaking air. A brade the valve. Hydraulic retaining column not Check or change or wash the hydraulic tappet working well.
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  Engine service /maintenance data-Troubleshooting GI-11 5.Unstable idle-speed for engine C ause of failure Methods of elimination 1 With air leakage T he intake manifold pipe is leaking air. 1 Check the intake manifold pipe and gasket. 2 Failure in ignition system 2 A rticle 2 of “engine not start or start with difficulty ”.
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  GI-12 Engine service /maintenance data-Troubleshooting E ngine service /maintenance data-T roubleshooting L arge consumption of machine oil Cause of failure M ethods of elimination 1 L eakage of machine oil T he oil-discharge bolt on bottom oil pan T ighten the oil-discharge bolt. is loose.
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  Engine service /maintenance data- engine service /maintenance data GI-13 11.Pressure of machine oil is too low C ause of failure Methods of elimination 1 The leakage of machine oil R efer to article 1 in “Too much machine oil 2 Much insufficient machine oil or the density consumption”;…
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  GI-14 Engine service /maintenance data- engine service /maintenance data Tools used to dismantle and change the piston pins Main body Spring sleeve A guiding rod A guiding rod B Tools used to change the oil seal before the crankshaft Tools used to change the oil seal after the co-axis.
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  Engine service /maintenance data- engine service /maintenance data GI-15 Clutch guiding tools Tools used to dismantle guide bearing from crankshaft Tools used to dismantle guide bearing from crankshaft Tools used to align with clutch film spring 2.SSM special repair data Name of material Product No.
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  EF.1-1 United Electronic engine management system Page Description of system………………..Precautions to the maintenance of electric-injection system………. Analysis of the function /principal /failure for system parts &components ….. General troubleshooting and steps to engine …………… Criterion to flashing code /mounting torque of components within M1.5.4 system..Description of the diagnosis function on M7.9.7 system failure……..
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  EF.1-2 Description of system Model GW491QE petrol engine adopts BOSCH Motronic1.5.4 and Motronic7.9.7 engine management system for electric-injection: As for the exhaust, the former is in compliance with European Class-II standard, and the latter is in compliance with European Class-III standard.
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  UASE Electronic Control Engine Management System -System Introduction EF.1-3 (g) Exhaust control function (h) Heating function of catalytic converter Carbon-canister control Idle-speed control (k) Limped back home Speed sensing through an incremental system Additional function (a) Theft-detector function (b) Connection between torque and exterior system eg. transmission mechanism, or vehicle dynamic control (c) Control over several types of engine parts and components (d) Provide a matching interface across EOL-programming tool and maintenance tools.
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  UAES Electronic Control Engine Management System-Notes for Electronic Injection EF.1-4 System Service Precautions to the maintenance of electric-injection system cases)
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  UAES Electronic Control Engine Management System-Notes for Electronic Injection EF.1-5 System Service 6. Precautions to the replacement with new ECU: (a)Prior to the change of ECU, remove the negative electrode line from accumulator jar. (b)Check whether the power supply and the overlapped steel on ECU wiring harness are under a normal condition. (c)As for the first engine starting process after new ECU has been installed, do not start the engine immediately, instead, open the ignition switch before wait for ten seconds to restart the engine, Following a successful starting process, perform a ECU self-learning as per following sequence:…
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  United Electronic engine management system-Analysis of function /principal / EF.1-6 failure for system parts &components Analysis of function /principal /failure for system parts &components 1. System circuit diagram and the definition of ECU Pins (a)United Electronic M1.5.4 system circuit diagram…
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  United Electronic engine management system-Analysis of function /principal / EF.1-7 failure for system parts &components…
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  United Electronic engine management system-Analysis of function /principal / EF.1-8 failure for system parts &components (b)Definition of ECU pins within Motronic 1.5.4 system S.N. Description of function Type S.N. Description of function Type Ignition coil(pin 2) Output Signal of oxygen sensor(pin 4) Input Pin A on step motor, or Power ground…
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  United Electronic engine management system-Analysis of function /principal / EF.1-9 failure for system parts &components c Definition of E CU pins within Motronic 7.9.7 system C onnection point Type C onnection point Type A ir-conditioner Heating point Output I nput of oxygen sensor temperature sensor Ignition coil 2…
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  United Electronic engine management system-Analysis of function /principal / EF.1-10 failure for system parts &components 2. Air inlet pressure /temperature sensor DS-S-TF (a) Function: this sensor is used to measure the absolute-pressure / temperature of inlet manifold, and to provide information concerning engine load and air-inlet temperature.
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  United Electronic engine management system-Analysis of function /principal / EF.1-11 failure for system parts &components (h)Technical &characteristic parameter Limit data Measurement Value Unit Min. Typical Max. Tolerable supply voltage Tolerable pressure Tolerable storage +130 ℃ temperature Performance data Measurement Value Unit Min.
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  United Electronic engine management system-Analysis of function /principal / EF.1-12 failure for system parts &components (h) Technical &characteristic parameter Limit data M easurement Value U nit M echanic rotation angle between two extreme positions D egree Available electrical rotating angle between two extreme positions D egree A llowable current on sliding contact arm Storage temperature…
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  United Electronic engine management system-Analysis of function /principal / EF.1-13 failure for system parts &components ( i ) Technical &characteristic parameter Limit data Measurement Value Unit Min. Typical Max. Working temperature Performance data M easur em ent V al ue U ni t S ensi ti v i ty o f new sens or agai nst a m V /g…
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  United Electronic engine management system-Analysis of function /principal / EF.1-14 failure for system parts &components Performance data R esistance value k Temperature S.N. Tolerance of temperature Tolerance of temperature Min. Max. Min. Max. 6. Oxygen sensor LSH (a)Function£ºto measure the oxygen content in exhausted gas from engine, and to determine a sufficient or insufficient combustion of petrol and air.
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  Value Measurement Unit Min. Typical Max. ℃ Storage temperature +100 ℃ End of ceramic pipe ≤570 ℃ Hexagonal headed shell Working temperature Cable grommet and ≤250 ℃ connection cable ≤230 ℃ Connection plug Allowable Max. Exhausted gas ℃ temperature when heating on the end of ceramic pipe element is connected the ℃…
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  Performance data After a Measurement 250-hour bench test Temperature of 350℃ 850℃ 350℃ 850℃ exhausted gas based on performance data Voltage mV of 840±70 710±70 840±80 710±70 sensing element whenλ=0.91(co=1%) Voltage mV of 20±50 50±30 20±50 40±40 sensing element whenλ=1.10 ≤1.0 ≤1.0 ≤1.5…
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  Electrical data of sensor Measurement Value Unit The resistance between At room temperature, MΩ and under a power cut to heating element the heating element of new sensor and the When exhausted gas is at temperature 350℃ MΩ connector When exhausted gas is at temperature 850℃ KΩ…
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  United Electronic engine management system-Analysis of function /principal / EF.1-17 failure for system parts &components 7. Rotating speed sensor DG (a)Function: When the induction type of rotating speed sensor is working with pulse disc, relevant information concerning engine rotating-speed and the upper stop point of crankshaft will be provided to the ignition system (without ignition distributor).
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  United Electronic engine management system-Analysis of function /principal / EF.1-18 failure for system parts &components Limit data Value Unit Measurement Min. M in. Typical Coil zone +150 Transition zone B lended blended L ead-wire zone +120 Tolerable Storage temperature temperature for PUR A mbient temperature when not starting +120…
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  United Electronic engine management system-Analysis of function /principal / EF.1-19 failure for system parts &components 8. Phase sensor PG a)Function:The sensor is applicable to the case that the ignition system (without ignition distributor) is working with rotating speed sensor, and may provide ECU with information concerning the phase of crankshaft, which is usable to identify the upper compression stop point inside cyinder 1 from the the upper exhaust stop point.
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  United Electronic engine management system-Analysis of function /principal / EF.1-20 failure for system parts &components 9. Idle-speed adjustor EWD3 M 1.5.4 (a)Function: to provide a bypass air duct for idle-speed, control the bypass air capacity by changing the cross-section area of channel, and effect a closed- loop control over the rotating-speed while engine is running at idle-speed.
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  United Electronic engine management system-Analysis of function /principal / EF.1-21 failure for system parts &components cup shaped component cover touch plate stator assembly spring washer bobbin o ring lead-wire of electromagnet compressive spring rotor sleeve front bearing connector dust cap rear bearing shaft pin ball bearing…
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  United Electronic engine management system-Analysis of function /principal / EF.1-22 failure for system parts &components (h) Technical &characteristic parameter£º Limit data M easurement V alue U nit M in. T ypical M ax . W ork ing temperature M ax . contacting times of T imes chok e plug on step motor w ith the seat Characteristic data…
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  United Electronic engine management system-Analysis of function /principal / EF.1-23 failure for system parts &components (g)Technical &characteristic parameter Limit data V alue M easurement U nit M in. T y pical M ax . S torage temperature w hen w ith original pack age A llow able temperature of injector inside vehicle +140…
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  United Electronic engine management system-Analysis of function /principal / EF.1-24 failure for system parts &components (f)Precautions to maintenance -Based on the demand of engine, the electrical fuel pump may have various flow capacities; During maintenance, Part No. of fuel pump to be re-installed shall be consistent to the original one as fuel pumps looking alike and able to be installed might be inappropriate;…
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  United Electronic engine management system-Analysis of function /principal / EF.1-25 failure for system parts &components (g)Technical &characteristic parameter Limit data M easurement V alue U nit M in. T y pical M ax . L eak age of flow at pressure diff erenc e 80k pa /min A llow able c onstant-w ork ing temperature A llow able M ax .
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  United Electronic engine management system-Analysis of function /principal / EF.1-26 failure for system parts &components (g) Technical &characteristic parameter Limit data M easurement V alue U nit M in. T ypical M ax . W ork ing voltage O ne-minute over voltage M in.
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  United Electronic engine management system-Analysis of function /principal / EF.1-27 failure for system parts &components Performance data Value Measurement Unit Min. Typical Max. Nominal voltage R esistance Value Primary windings 20 25 Secondary windings Inductance value Primary windings 20 25 Secondary windings L oad 50pF Formed voltage…
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  United Electronic engine management system-Analysis of function /principal / EF.1-28 failure for system parts &components Precautions to maintenance -Do not dismantle the ECU casually during maintenance. -Prior to dismantle of ECU, have the head of accumulator jar being removed for at least five minutes. -Store the ECU securely after it is dismantled;…
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  United Electronic engine management system-Analysis of function /principal / EF.1-29 failure for system parts &components ( f ) Technical &characteristic parameter Limit data V alue M easurement U nit M in. T y pic al M ax . U nder a normal operation A cc umulator v oltage W ith li mi ted f unction L i mit value &…
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-30 to engine General troubleshooting and steps to engine General troubleshooting and steps to M1.5.4 system 1. When starting, the engine is not rotating or rotating slowly. Check S.N. Operation steps Follow-up steps result Next step.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-31 to engine Check S.N. Operation steps Follow-up steps result Change the fuel, and perform a hot starting process again to see whether the Ended. starting is successful. Change the ECU Check whether the fuel pipe has been bent or blocked, and whether the Next step.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-32 to engine Check Operation steps Follow-up steps result Pull out the plug of idle-speed actuator from wiring harness before the engine Next step. cooling temperature reaches 35 ℃ , then observe whether the engine Repair or change the rotating-speed has been decreased.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-33 to engine Check S.N. Operation steps Follow-up steps result Next step. Check whether the fuel pressure is below 250kpa. Close the fuel manometer valve, and re-connect the ignition switch to have oil Next step.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-34 to engine Check S.N. Operation steps Follow-up steps result Next step. Check whether the oil injector is able to inject oil after it has been washed. Change the oil injector Change the fuel Check whether fuel contains water or has deteriorated.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-35 to engine 7．The idle-speed is unstable after the vehicle heating process is ended. Check S.N. Operation steps Follow-up steps result Clear displayed Place ignition switch to the ON” position. A fault diagnosis instrument may be failure away.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-36 to engine 8．Unstable idle-speed or even flameout when under load eg. air-conditioner, etc. Check S.N. Operation steps Follow-up steps result Place ignition switch to the ON” position. A fault diagnosis instrument may be Clear the displayed failure used to check whether there’s any record of failure information.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-37 to engine Check S.N. Operation steps Follow-up steps result Check whether the resistance value of high-voltage line for each cylinder is Next step. under a normal condition (about 16KΩ/m, specific data as given in the chapter Change it.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-38 to engine Check whether the inlet-air pressure is within 35kpa and 65kpa while engine is Next step. running at idle-speed. Check and repair it. Have the engine running at idle-speed, and do not connect the Pin 51 of ECU Next step.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-39 to engine Check S.N. Operation steps Follow-up steps result After the connection of ignition switch, connect a commutator between ECU Next step. and wiring harness, and check whether respective voltage on Pin 53 (the signal Repair change output end for throttle position sensor), Pin 30 (ground end), and Pin 12 (used…
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-40 to engine Check S.N. Operation steps Follow-up steps result Connect the fuel manometer valve. And have the Pin 30 of fuel pump relay Next step. short-circuit connected with the Pin 87, and check whether the fuel pressure is within 250kpa and 300kpa while the fuel pump is working.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-41 to engine General troubleshooting and steps to engine within M7.9.7 system 1．During startup process, the engine is not rotating or rotating slowly. Check S.N. Operation steps Follow-up steps result A multimeter may be used to check and measure whether the voltage between Next step.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-42 to engine Check S.N. Operation steps Follow-up steps result Check the fuel condition, and observe whether the symptom is caused by the Change the fuel filling with petrol. Next step. Open the ignition switch to check whether respective power supply to Pin 12, Next step.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-43 to engine Check S.N. Operation steps Follow-up steps result Check and repair relevant Pull out the plug from the cooling-fluid temperature sensor, and start the loops or change the engine; Observe whether the starting of engine proves to be a success. sensor.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-44 to engine 7．Despite of a normal starting, the idle-speed during vehicle heating process is unstable. Check S.N. Operation steps Follow-up steps result Check and repair the air Check the air filter for blockage, and the air inlet passage for air leakage. inlet system.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-45 to engine eg ： 9. Despite of a normal starting process, the idle-speed when under partial load air-conditioner is unstable or even flameout. Check S.N. Operation steps Follow-up steps result After a removal of idle-speed adjustor, check whether any carbon deposit is Wash relevant parts and produced on the throttle valve unit and the idle-speed adjustor, or inside the…
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-46 to engine Check S.N. Operation steps Follow-up steps result Next step. Check whether the inlet-air pressure sensor, throttle position sensor, and its Check and repair relevant loops are under a normal condition. loops or change the sensor.
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  United Electronic engine management system-Genaral troubes hooting and steps EF.1-47 to engine 13. The acceleration is slack and with inferior performance. Check S.N. Operation steps Follow-up steps result Check and repair the air Check for following failures: slide of clutch, low pressure inside tire, dragging inlet system.
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  Criterion to flashing codes and the mounting torque of parts &components within EF.1-48 M1.5.4 system Criterion to flashing codes and the mounting torque of parts &components within M1.5.4 system 1．List of flashing codes within M1.5.4 system Fault Type of S.N. Name of failure information Flashing code indicator…
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  Criterion to flashing codes and the mounting torque of parts &components within EF.1-49 M1.5.4 system 2 Steps to read flashing fault codes: (a)Connect the engine ignition switch rather than to start the engine. (b)Connect the diagnosis plug-7# on line K ECU-55# or OBD to ground, and the connection time is longer than 2.5 seconds.
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  EF.1-50 Description of the diagnosis function on M7.9.7 system failure Description of the diagnosis function on M7.9.7 system failure 1. Record of failure information The electronic control unit is uninterruptedly checking the sensor, actuator, relevant loops, fault indicator lamp, accumulator voltage, or even itself;…
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  Description of the diagnosis function on M7.9.7 system failure EF.1-51 4. Four types of failure Failure B_mxdfpMax. indicates the signal goes beyond the upper limit of normal scope; Failure B_mndfpMin. indicates the signal goes beyond the lower limit of normal scope; Failure B_sidfpsignal indicates some failure without signal.
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  EF.1-52 M7.9.7 system service &diagnosis flow process based on fault code M7.9.7 system service &diagnosis flow process based on fault code 1.List of fault codes within M7.9.7 system S.N. Fault code Description Grade of failure P0107 The signal voltage in the loop of inlet-air pressure sensor is too low. Class31 P0108 The signal voltage in the loop of inlet-air pressure sensor is too high.
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  M7.9.7 system service &diagnosis flow process based on fault code EF.1-53 2.M7.9.7 system service &diagnosis flow process based on fault code Fault code：P0107“the signal voltage in the loop of inlet-air pressure sensor is too low” Check S.N. Operation steps Follow-up steps result Connect with the diagnosis instrument, and place the ignition switch to the ON”position.
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  EF.1-54 M7.9.7 system service &diagnosis flow process based on fault code Fault code：P0113 The temperature indicated by inlet-air temperature sensor is too high” Check S.N. Operation steps Follow-up steps result Connect with the diagnosis instrument, and place the ignition switch to the ON”position. Next step.
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  M7.9.7 system service &diagnosis flow process based on fault code EF.1-55 Fault code：P0122 The signal voltage in the loop of throttle position sensor is too low.” Check S.N. Operation steps Follow-up steps result Connect with the diagnosis instrument, and place the ignition switch to the ON”position. Next step.
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  EF.1-56 M7.9.7 system service &diagnosis flow process based on fault code Fault code：P0132 the signal voltage in the loop of upstream sensor is too high” Note: The diagnosis flow process below is applicable to cases excluding that P0135 is not produced simultaneously; if P0135 is produced simultaneously, you need to settle the failure with P0135 first before performing a check and repair as per the flow process below.
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  M7.9.7 system service &diagnosis flow process based on fault code EF.1-57 The self-adaptive value for a closed-loop control of air /fuel ratio is beyond the upper limit. ” Fault code：P0171 Note: The diagnosis flow process below is applicable to cases excluding that fault codes are produced simultaneously on inlet-air pressure sensor, carbon-canister control valve, oxygen sensor, etc.
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  EF.1-58 M7.9.7 system service &diagnosis flow process based on fault code Fault code：P0201 Failure with the loop of fuel injector inside cylinder 1” Check S.N. Operation steps Follow-up steps result Connect with the diagnosis instrument, and place the ignition switch to the Next step.
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  M7.9.7 system service &diagnosis flow process based on fault code EF.1-59 Fault code：P0203 Failure with the loop of fuel injector inside cylinder 4” Check S.N. Operation steps Follow-up steps result Connect with the diagnosis instrument, and place the ignition switch to the Next step.
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  EF.1-60 M7.9.7 system service &diagnosis flow process based on fault code Fault code：P0335 Failure with the signal of crankshaft position sensor.” Check S.N. Operation steps Follow-up steps result Connect with the diagnosis instrument, and place the ignition switch to the Next step.
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  M7.9.7 system service &diagnosis flow process based on fault code EF.1-61 Check S.N. Operation steps Follow-up steps result A multimeter may be used to verify whether the resistance between Pin 1 and Next step. Ω when at 20℃. Pin 2 of carbon-canister control valve is within 22-30 Change the control valve.
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  EF.1-62 M7.9.7 system service &diagnosis flow process based on fault code Check S.N. Operation steps Follow-up steps result Repair or change the wiring Check whether the loop on the power supply end of cooling-fan relay is a harness. broken loop or short circuit to ground. Continue to proceed until step 2.
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  M7.9.7 system service &diagnosis flow process based on fault code EF.1-63 Fault code：P0508 The voltage in the control loop of idle-speed adjustor is too low.” Check S.N. Operation steps Follow-up steps result Connect with the diagnosis instrument, and place the ignition switch to the Next step.
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  EF.1-64 M7.9.7 system service &diagnosis flow process based on fault code Check S.N. Operation steps Follow-up steps result Repair or change the wiring Check whether the resistance in the respective loop between Pin 87 of main harness. relay and Pin 44 /45 /63 of ECU is too large. Next step.
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  M7.9.7 system service &diagnosis flow process based on fault code EF.1-65 Check S.N. Operation steps Follow-up steps result Repair or change the wiring Check whether the loop between the control end (i.e. Pin 86 ) of harness. air-conditioner compressor relay and Pin 70 of ECU is a broken loop. Next step.
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  EF.1-66 M7.9.7 system service &diagnosis flow process based on fault code Fault code：P1530 “Failure with the loop of temperature sensor for air-conditioner evaporator” Check S.N. Operation steps Follow-up steps result Connect with a diagnosis instrument, and place the ignition switch to the Next step.
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  EF.2-1 Delphienginemanagementsystem Page Description of system………………EF.2-2 MT20U system control……………….EF.2-4 Determinationontheprincipal/utility/failureofkeysystemparts……EF.2-9 Methods for failure diagnosis /fault codetospareparts……..EF.2-23 Precautionstotheuse/service/troubleshootingofelectricalinjectionsystem…EF.2-26 Troubleshooting…………………EF.2-27…
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  Delphi engine management system-Description of system Description of system Model GW491QE petrol engine has been installed with Delphi ITMS-6 and MT20U engine management system for electric-injection: the exhaust from ITMS-6 is in compliance with European Class-II standard, and the exhaust from MT20U is in compliance with European Class- standard;…
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  EF.2-3 Delphi engine management system-Description of system The basic structure of MT20U system is as shown in the figure below: 12V accumulator jar power supply 12V ignition-switch power supply system ignition ignition coil A system power-supply ground wire power-supply systemcontrol ignition coil B ignition &oil-injection ground management…
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  EF.2-4 Delphi engine management system-MT20U system control -Evaporating /exhaust /pollution control. — Waste-gas exhaust control; post-processing by a three-way catalytic converter; and closed-loop fuel control by signal from oxygen sensor. -Protection function offered by three-way catalytic converter; -When the electronic theft-prevention system has not received a correct password from the key, the computer control system will not make fuel-injection or ignition, which prevents the engine from starting.
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  Delphi engine management system-MT20U system control EF.2-5 The desired idle speed is determined by various elements: When the engine water temperature is lower, system will give a greater desired idle speed 1200r/min to accelerate the warming of vehicle; For engine using mechanical fan£¬when the temperature of engine coolant is much higher, system will give a greater idle speed 1300r/min as well to increase air inflow amount inside the cooling water tank.
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  EF.2-6 Delphi engine management systm-MT20U system control 6. Accelerating /decelerating /fuel cut &overflow control Whenever the engine rotating speed is greater than the set highest rotating speed, system will cut off fuel suppy, protect the engine by stopping its rotating speed from rising unlimitedly, and prevent vehicle from flying And system will immediately resume the fuel supply when the rotating speed returns to a level lower than Max.
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  Delphi engine management systm-MT20U system control EF.2-7 accumulator high-speedfanforengine dual-speed fan for engine low-speed fan for engine 11. Mileage accumulation function control The mileage accumulation function of MT20U is specially designed for mileage statistics within after-sale warranty period, an d will not supercede the existing vehicle speed meter or odometer.
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  EF.2-8 Delphi engine management systm-MT20U system control 13. Whole-vehicle exhaust control ¡¤Whole-vehicle exhaust control means to precisely adjust the initial rating data of open-loop fuel within the vehicle traveling scope allowed by exhaust laws and regulations, using a closed-loop control. In such way, the exhaust characteristics of vehicle may be optimized.
• Page 94
  Delphi engine management systm-Determination on the EF.2-9 principal /utility /failure of key system parts Determination on the principal /utility /failure of key system parts . System power supply and wire-harness FUSE 4 B AT T FUSE4 B AT T ignition FUSE 3 B AT T IGN FUSE3…
• Page 95
  Delphi engine management systm-Determination on the EF.2-10 principal /utility /failure of key system parts (e)Engine control-module fail mode:The failure of generator voltage-adjustor will burn and damage the computer. When the computer is changed, measure first the supply voltage at idle speed and ensure it’s less than 15 volts. When the engine rotating speed has been increased to a value greater than 2,000 revolutions,the supply voltage shall be less than 15 volts.
• Page 96
  Delphi engine management systm-Determination on the EF.2-11 principal /utility /failure of key system parts 3. Absolute-pressure sensor for inlet manifold (MAP (ITMS-6) (a)Function &principal The absolute-pressure sensor for inlet manifold (MAP) is used to measure the pressue of inlet manifold, and ECU may use this signal to determined the air amount inside engine and the load of engine.
• Page 97
  Delphi engine management systm-Determination on the EF.2-12 principal /utility /failure of key system parts 5. Manifold pressure /temperature sensor M A P/M AT (a)Function &principal T he pressure sensor for inlet manifold shall be installed together with the inlet temperature sensor for an easy use and installation. And the function of the integrated unit is thesame as that of each separated unit.
• Page 98
  Delphi engine management systm-Determination on the EF.2-13 principal /utility /failure of key system parts 7. Coolant temperature sensor (CTS) (a)Function &principal -The coolant temperature sensor is used to check the working temperature of engine Depending on various temperatures, ECM will provide the engine with an optimum control scheme.
• Page 99
  Delphi engine management systm Determination on the EF.2-14 principal /utility /failure of key system parts 9. Camshaft position sensor (CAM)(MT20U) (a)Function &principal -Tnearby the camshaft, and works with signal wheel on camshaft. The may measure the digital voltage signal via its sensor so as to determine the cylinder on which engine is working, and to perform an one-to-one control;…
• Page 100
  Delphi engine management systm Determination on the EF.2-15 principal /utility /failure of key system parts (c)Characteristics of product Output signal (b)Failure determination Frequency Output signal Importantnote:Either of following determinationsmay beconcluded 5kHz (17~37)mV/g based on that the whole vehicle, its wire-harness, and other system 8kHz 5kHz parts &components are normal in function.Failure diagnosed by the…
• Page 101
  Delphi engine management systm-Determination on the EF.2-16 principal /utility /failure of key system parts 14. Idle speed control valve (a)Function &principal: The function of idle-speed control valve is to control theflow area of bypass air duct on throttle valve, adjust the air inlet amount inside engine, and control the engine idle speed.
• Page 102
  Delphi engine management systm-Determination on the EF.2-17 principal /utility /failure of key system parts (c)Characteristics of product -R ange A n opening degree within 7% 93% — Working voltage (5 0.1)V -T hrottle valve close 12% of reference voltage -T hrottle full opened 83% 93% E C U -A B impedance -Working temperature (-40 150)
• Page 103
  Delphi engine management systm-Determination on the EF.2-18 principal /utility /failure of key system parts 17. Spark plug and high-tension wiring (a)Spark plug -The function of spark plug is to ignite inflammable gas inside engine cyliner; -The spark plug used shall be of resistor type so as to protect the driver of ignition coil, and to reduce radio interference wave released during ignition;…
• Page 104
  Delphi engine management systm-Determination on the EF.2-19 principal /utility /failure of key system parts fuel supply system fuel rail as- fuel pump line sembly assembly injec fuel pressure fuel fuel level fuel fuel inlet fuel filter fuel trail returnpipe -tor adjustor pump sensor…
• Page 105
  Delphi engine management systm-Determination on the EF.2-20 principal /utility /failure of key system parts 21. Fuel-rail assembly work schematic diagram for fuel-rail assembly Function &principal fuel return fuel inlet — Fuel-rail is composed of fuel guide pipe, pressure stabilization fuel-pressure adjustor chamber, pressure adjustor, injector, and some components used for fixing purpose;…
• Page 106
  Delphi engine management systm-Determination on the EF.2-21 principal /utility /failure of key system parts 23. I nj ector (a)Function &principal: -The injection nozzle structure is an electromagnetic switch unit. The coil pulled out from two electrodes will connect with ECM and power supply respectively via engine wire-harness;…
• Page 107
  Delphi engine management systm-Determination on the EF.2-22 principal /utility /failure of key system parts 25. Carbon-canister wash solenoid valve (a)Function &principal -The petrol evaporation amount from carbon-canister into inlet manifold may be controlled by ECM via carbon-canister wash &control solenoid valve; The occupation ratio between ECM output pulse square wave and air amount shows a linear correlation.
• Page 108
  Delphi engine management systm-Determination on the EF.2-23 principal /utility /failure of key system parts The oxidation reaction of HC and CO made by catalytic converter will keep an optimum status when the air /fuel ratio is greater than 14.5, while the deoxidation reaction of No x will keep an optimum status when the air /fuel ratio is less than 14.8.
• Page 109
  EF.2-24 Methods for failure diagnosis /fault code to spare parts Digit 0 will flash for ten times, other digits will correspond to their literal flashing times accordingly; (e)After failure is cleared away, a Fault Diagnosis Instrument shall be used to clear away fault code to avoid any influence on the determination of next maintenance.
• Page 110
  EF.2-25 Methods for failure diagnosis /fault code to spare parts (b) Fault code checklist for MT20U fault code reader Fault Fault Fault Description of failure Description of failure Description of failure code code code The pressure of inlet manifold too K nock sensor has no The voltage of accumulator is too high.
• Page 111
  Precautions to the use /service /troubleshooting of electrical injection system EF.2-26 9. Key points to failure elimination when fault indicator light is lighting (a)A Fault Diagnosis Instrument may be used to read out fault code and to find out its appropriate content ; (b)Most failures displayed and indicated by fault code are caused by loop failure or bad connection of plug connectors;…
• Page 112
  Precautions to the use /service /troubleshooting of electrical injection system EF.2-27 (c)The leadin of spark plug shall not be pulled out when checking whether the ignition system is working, as the injection nozzle is still working, and some petrol spraying out yet not being used will be combusting rapidly inside three-way catalytic converter and causedamages;…
• Page 113
  Precautions to the use /service /troubleshooting of electrical injection system EF.2-28 (g)Reversed logic thinking method -Think in a reversed way what symptom might be against a certain failure with component; -Accumulate and make a conclusion from symptoms which are produced when components are damaged or fail to help quickly find out the failure point.
• Page 114
  Precautions to the use /service /troubleshooting of electrical injection system EF.2-29 1) Engine fault indicator light 2) Display of fault code None 3) Coolant temperature (80 ~ 94) 4) Accumulator jar voltage (13.5 ~ 14.5) V 5) Absolute-pressure sensor for inlet manifold 20 kPa ~ atmospheric pressure 6) Work range of throttle position sensor (0 ~ 99.6)%…
• Page 115
  Delphi engine management system-troubleshooting and common failure EF.2-30 Attached figure III and IV are Electric-Control Schematic diagram for MT20U SystemAttached figure V, V I , VII, and VIII are Typical Failure Diagnosis Flow Diagram. (b) Slack accelerating — Check oil amount and the fuel filter inside oil tank — Check the air exhaust system for blockage eg.
• Page 116
  Delphi engine management system-troubleshooting and common failure EF.2-31 A ttached figure I electronic ignition timing 3 Note: J1-Cxx and J1-Dxx are white plug terminals electronic ignition timing A J2-Axx and J2-Bxx are red plug terminals high-voltage electronic ignition timing B coil driver spark plug idle valve drive A(high)
• Page 117
  EF.2-32 Delphi engine management system-troubleshooting and common failure A ttached figure II fuse4 battery fuse4 battery battery ignitionfuse3 fuse3 ignition switch fuse2 ignition fuse2 ignition switch ignition fuse1 fuse1 power ground engine fault power ground battery indicatorlight injection nozzle (low)A injection nozzle (low)B 58gear signal (high) 58-gear ring…
• Page 118
  Delphi engine management system-troubleshooting and common failure EF.2-33 A ttached figure III fuel pump accumulator yellow purple &black pink &brown red &yellow main relay green &red black &blue red &yellow black &yellow fuel pump relay black &green black &green red &blue brown &blue purple &red blue &red…
• Page 120
  Delphi engine management system-troubleshooting and common failure EF.2-35 attached figure V…
• Page 121
  EF.2-36 Delphi engine management system-troubleshooting and common failure Attached figure VI…
• Page 122
  EF.2-37 Delphi engine management system-troubleshooting and common failure A ttached figure VII…
• Page 123
  Delphi engine management system-troubleshooting and common failure EF.2-38 A ttached figure VIII…
• Page 124
  EM.1-1 Enginebody Page Disassemblyfigureofenginebody ……………EM.1-2 Preparations before and key points to the disassembly of engine body….EM.1-3 Disassemblyofenginebody …………….EM.1-4 Inspectiononenginebody ……………….EM.1-9 Inspectiononcamshaftcomponents …………..EM.1-10 Disassemblyofpistonandconnection-rodcomponents ……..EM.1-12 Inspectiononpistonandconnection-rodcomponents ……..EM.1-13 Assembly of piston and connection-rod components………..EM.1-18 Installation of engine body………………EM.1-20 Assembly of engine body……………….EM.1-22…
• Page 125
  EM.1-2 Disassembly figure of engine body Disassembly figure of engine body piston ring piston timing chainwheel chamber cover connection-rod connection-rod timing chain and chainwheel bearing bush timing chainwheel chamber sealing gasket rear oil-seal cover sealing gasket sealing gasket crankshaft pulley crankshaft crankshaft main bearing crankshaft thrust washer…
• Page 126
  Preparations before and key points to the disassembly of engine body EM.1-3 Preparations before and key points to the disassembly of engine body 1. Preparations before the disassembly of engine body ( a ) -Removal of flywheel. -The flywheel may be removed by unscrewing six bolts. (b)Removal of rear end cover plate The rear end cover plate may be removed by unscrewing two bolts.
• Page 127
  EM.1-4 Preparations before and key points to the disassembly of engine body 2. Key points to the disassembly of engine body (a)As oil dish is sealed by joint strip and sealing gum, S S T shall be inserted to a place between the engine body and the crankcase oil tray to thoroughly cut off the sealing material after the fixing bolts have been unscrewed.
• Page 128
  Preparations before and key points to the disassembly of engine body EM.1-5 (c) A plastic hammer may be used to remove the connection-rod cover by gently striking against the connection-rod bolt. Remark Have the lower bearing bush retained inside the connection-rod cover.
• Page 129
  EM.1-6 Preparations before and key points to the disassembly of engine body 491QE connection-rod bearing bush hole and connection-rod neck-journal mm H ole diameter D iameter of M ax . abrasion S .N connection-rod C learance connection-rod cl earance neck -journal bearing bush −…
• Page 130
  Preparations before and key points to the disassembly of engine body EM.1-7 5. Measure the oil clearance of main neck-journa r adial cl ear ance (a) A twelve-edge socket spanner may be used to unscrew and remove bolts on main bearing cover progressively in three steps in accordance with numeric sequence indicated in the figure.
• Page 131
  EM.1-8 Preparations before and key points to the disassembly of engine body (k)Plastic feeler gauge shall be scraped thoroughly away from the main-bearing bush and the main neck-journal. Remark If a standard bearing bush is to be used replace with a bearing bush having the same mark as that made on the engine body at a place close to cylinder hole and on the contacting surface between the cylinder and the cylinder cover .
• Page 132
  Preparations before and key points to the disassembly of engine body EM.1-9 (d)Remove the camshaft. Inspection on engine body 1. W ash the engine body. A spacer scraper may be used to clear all spacer materials away from the surface of the engine body.
• Page 133
  EM.1-10 (c)Thedifferenceofvaluesmeasuredfrompushingdirectionandaxialdirection respectively shall be less than the limit of roundness. Limit of roundness 0.02 mm Inspection on camshaft components 1. Check the tension degree of timing chain When a 98N force is applied to pull the timing chain at a position as indicated in the figure, a spring balance may be used to measure Max.
• Page 134
  Preparations before and key points to the disassembly of engine body EM.1-11 (b) Check the abrasion situation of plunger piston on chain tensioner. If a vernier caliper is used to measure Min. thickness on the head of plunger piston, it shall not be less than 12.5mm. If the actual of thickness is less than Min.
• Page 135
  Preparations before and key points to the disassembly of engine body EM.1-12 6. Check the axial clearance of camshaft The thrust collar, and the timing chainwheel shall be installed onto the camshaft; and fixing bolts shall be tightened to the specified tightening moment.
• Page 136
  Preparations before and key points to the disassembly of engine body EM.1-13 Remark Piston and piston pin are mating members; And the installation of piston, piston pin, piston ring, connection-rod, and bearing bush shall be subject to a correct sequence. Inspection on piston and connection-rod components 1.
• Page 137
  EM.1-14 Preparations before and key points to the disassembly of engine body (c)The measured value of diameter for piston shall be reduced by that for the engine body. Standard piston clearance (0.065 0.085)mm Oper ation limit: 0.085 mm If the actual piston clearance is greater than Max. value, all pistons for four cylinders must be changed, and /or four cylinders must be re-bored.
• Page 138
  Preparations before and key points to the disassembly of engine body EM.1-15 -Check the torsional deformation Max. torsional deformation 0.15 mm/100 mm T he connection-rod component shall be changed if the actual torsional deformation is greater than Max. value. R emark I f the connection-rod needs to be changed, the No. for connection-rod bearing bush shall be the same that fornewconnection-rod bearing cover (b)Check the connection-rod bolt using following method:…
• Page 139
  EM.1-16 Preparations before and key points to the disassembly of engine body 6. Change of lining on small end of the connection-rod (a)Remove lining from small end of the connection-rod Using SST, lining may be removed from the small end of connection-rod. SST 09207-76010 (b)Installation of new lining Using SST, lining may be re-installed into the small end of connectionrod.
• Page 140
  Preparations before and key points to the disassembly of engine body EM.1-17 (b)Inspection on main neck-journal and the connection-rod neck-journal A micrometer may be used to measure the diameter of main neck-journal and that of the connection-rod neck-journal. Diameter of main neck-journal (57.985 58.000)mm Diameter of the connection-r od neck -j our nal (47.985 48.000) Measure the roundness and cylindrictiy of neck-journal as indicated in…
• Page 141
  EM.1-18 Preparations before and key points to the disassembly of engine body (b)MP multi-purpose grease may be applied to the lip of new oil-seal. (c)New oil-seal will be installed using SST. SST 09223-56010 Remark The oil-seal shall not be installed to an inclined shape. 9.
• Page 142
  Preparations before and key points to the disassembly of engine body EM.1-19 (d)Pressed installation of piston pin — Set the pressure of a hydraulic machine to 6Mpa. When the piston is placed to the clamping fixture (used for pressed installation) on a universal single- columnhydraulicmachine,takeouttheconnection-rodcomponentssequentially from oven, and the piston pin from the liquid nitrogen pot;…
• Page 143
  EM.1-20 Preparations before and key points to the disassembly of engine body (e)To avoid confusion, one end of bush covers (having been installed with connection-rod bush) , plus relevant nuts, shall be installed onto the connection-rod unit. General precautions during the assembly (a)A ll parts to be installed must be washed thoroughly;…
• Page 144
  Preparations before and key points to the disassembly of engine body EM.1-21 5. Tighten bolts on crankshaft Bolts on the main bearing cover shall be tightened progressively in three steps as indicated in the figure. Tightening moment ( 80 3) N 6.
• Page 145
  EM.1-22 Preparations before and key points to the disassembly of engine body 10. Screw up nuts on the bearing cover of connection-rod. Nuts shall be tightened progressively in two or three steps using a torque spanner. Tightening moment ( 50 2) N 11.
• Page 146
  Preparations before and key points to the disassembly of engine body EM.1-23 5. Installation of flywheel When flywheel has been installed to a place behind the crankshaft, manually rotate the flywheel to make it facing exactly the assembly mark made on the rear end surface of crankshaft, then six flywheel bolts will be used to fix the flywheel onto the rear end of crankshaft: the bolts shall be subject to a pre- tightening made by a pneumatic wrench, and a re-tightening diagonally to the…
• Page 147
  EM.1-24 Assembly of engine body 7. Installation of oil dish component oil dish, namely the cr ank case oil tr ay (a)Check the oil dish to assure its internal cleanness: E xisting sealing materials The oil-seal is 3mm wide must be cleared away from the oil dish, and it’ s unallowable for oil to drop onto the installation interconnection surface.

• Page 148: Cylinder Head

  EM.2-1 Cylinder head page Disassembly figures for cylinder head………..EM.2-2 Dismantle of cylinder head…………EM.2-3 Disassemblyofcylinderhead …………EM.2-4 Cleanup/inspectiononeachsparepart ……..EM.2-5 Assembly of cylinder head…………EM.2-12 Installation of cylinder head…………EM.2-15…

• Page 149
  Disassembly figures for cylinder head EM.2-2 To prevent the cylinder gasket from leaking air or water, the tightening torque of bolts on cylinder head shall be checked using a torque wrench before new vehicles travel for 500 or1000 kilometers, and will be 90N.m for ten M12 bolts, or 20N.m for three M8 bolts.
• Page 150
  Dismantle of cylinder head EM.2-3 Dismantle of cylinder head 1. Dismantle of high-tension damping wiring andignition coil components (a)High-tension damping wiring shall be removed. (b)Ignition coil components shall be removed. 2. Dismantle of wiring harness and the fuel distributor assembly (a)Wiring harness must be removed.

• Page 151: Disassembly Of Cylinder Head

  Disassembly of cylinder head EM.2-4 5. Dismantle of cylinder head The cylinder head may be removed by unscrewing the bolts and nuts on cylinder head. 6. Dismantle of rocker-shaft Subject to the numbering sequence indicated in the figure, bolts and nuts on rocker-shaft may be removed progressively in three steps.

• Page 152
  Cleanup /inspection on each spare part EM.2-5 3. Dismantle of the rocker-shaft assembly Based on the numbering sequence indicated in the figure, bolts and nuts on rocker shaft maybe unscrewed progressively in two or three steps to prevent the rocker-shaft from bending or prevent bolts from damage. 4.
• Page 153
  Cleanup /inspection on each spare part EM.2-6 4. Clean the valve guide All valve guides may be cleaned using brush and solvent. 5. Clean the cylinder head The cylinder head maybe cleaned using soft brush and solvent. Note Do not wash the cylinder head with br ush inside a hot container , or it will be ser iously damaged.
• Page 154
  Cleanup /inspection on each spare part EM.2-7 9. Inspection on the abrasion degree of valve rod and guide. (a)An amesdial may be used to measure the inner diameter of guide. Standard inner diameter (8.01-8.03) mm (b)A micrometer may be used to measure the external diameter of valve rod.
• Page 155
  Cleanup /inspection on each spare part EM.2-8 (d)Selection of new valve guide If the diameter of installation hole for valve guide on cylinder head is greater than 13.027mm, the installation hole needs a re-boring to ensure the diameter is within (13.050 13.077) mm, and the external diameter for 0.05mm valve guide (an increased size for repair purpose) will be applicable.
• Page 156
  Cleanup /inspection on each spare part EM.2-9 (e)Check whether the valve rod has been abraded too much on endsurface. If it does occur, a grinding machine may be used to repair the end surface, or the valve shall be changed. Note Do not mak e an over-abr asion to avoid thewhole length of valve is less than M in.
• Page 157
  Cleanup /inspection on each spare part EM.2-10 (d)The valve and the valve seat may be manually abraded using carborundum. (e)Following a manual abrasion, the valve and the valve seat shall be cleaned. 13. Check the valve spring (a)A steel square will be used to check theperpendicularity of valve spring.
• Page 158
  Cleanup /inspection on each spare part EM.2-11 (b)Measure the clearance between rocker and rocker-shaft Standard value (0.018 0.046)mm M ax. value 0.08 mm R ocker and rocker-shaft shall be changed if the clearance is greater than Max. value. (c) Check whether the direction on the rear end of air valve rocker-shaft is correct.
• Page 159
  Assembly of cylinder head EM.2-12 When hydraulic tappet is submerged in light oil, push the plunger piston for several times to discharge air insidethe hydraulic tappet. SST 09276-71010 -During a settlement test aimed at an inspection on the hydraulic tappet, a sealing settlement tester may be used to apply a 196N force onto the plunger piston.
• Page 160
  Assembly of cylinder head EM.2-13 2. Matching air inlet valve with air exhaust valve After the bottom surface of cylinder head has been put level on work bench and is facing upward, air inlet &exhaust valves will be installed onto the cylinder head as per the sequence “exhaust-inlet-inlet-exhaust- exhaust-inlet-inlet-exhaust”, and could be inserted into the valve guides smoothly after installation without any loose.
• Page 161
  EM.2-14 Assembly of cylinder head (f)To have the locker clamp of valve well connected with the spring seat and the valve rod, a copper hammer may be used to strike gently against the tail end of each valve rod. 6. Installation of spark plug component (a)R espective sealing gasket shall be installed onto the spark plug sheath, and the level end of sealing ring must be connected with the flanged surface of socket.
• Page 162
  Reinstallation /restoration of cylinder head EM.2-15 Reinstallation /restoration of cylinder head 1. Installation of cylinder gasket Cylinder gasket will be installed onto the device plane, and be fixed using positioning pin. 2. Installation of cylinder head The cylinder head component may be installed onto the cylinder gasket on device unit, be positioned by two positioning pin sleeves, and befixed using ten M12 cylinder-cover bolts plus three M8 cylinder-cover bolt with cylinder-cover bolts &washers .
• Page 163
  Reinstallation /restoration of cylinder head EM.2-16 5. Installation of inlet &outlet manifold (a)Install air-inlet manifold components onto eight stud boltson the left side of cylinder head, and have the positioning pinfacing exactly to its installation hole. (b)Install the lower part of air inlet /exhaust manifold onto eight stud bolts on the left side of cylinder head, followed by a fixing using relevant components like nut, washer, etc.
• Page 164
  Reinstallation /restoration of cylinder head EM.2-17 7. Installation of wiring harness on engine (a)Using fixing clips, the rear end of wiring harness may be fixed to the rear end surface of cylinder head, and one M8 20 bolt with flat washer and standard spring washer is usable to fix a manifold supporting frame.

• Page 165: Valve Mechanism

  EM.3-1 Valve mechanism Page Disassembly diagram for valve mechanism……..EM.3-2 Disassembly of timing chain/camshaft………..EM.3-3 Inspection &repair for timing chain/camshaft components…..EM.3-5 Replacement of front oil seal on crankshaft……..EM.3-8 Installation of timing chain/camshaft……….EM.3-9…

• Page 166
  EM.3-2 Valve mechanism Disassembly figure for valve mechanism Disassembly figure for valve mechanism sealingring valve-box cover rocker shaft assembly push rod tappet camshaft thrust disk vibrationabsorber tensioner cam chainwheel timing chain cover cam chainwheel bolt timing chain crankshaft chainwheel crankshaft sealing ring pulley bolt front oil seal of crankshaft…
• Page 167
  Valve mechanism Disassembly of timing chain/camshaft EM.3-3 Disassembly of timing chain/camshaft Preparation for disassembly (a)Dismantle of driving belt. (b)Dismantle of fan &water pump pulley. (c)Dismantle of rocker arm shaft assembly and push rod. 1. Removal of valve tappet Eight tappets will be removed using a steel wire or magnet. Note A lways k eep tappets in an upr ight ar r ay as per a cor r ect sequence.
• Page 168
  Valve mechanism Disassembly of timing chain/camshaft EM.3-4 3. Removal the cover of timing chainwheel chamber The cover of chain wheel cham ber may be removed by unscrewing eleven bolts on the cover of chainwheel chamber using a torque spanner. 4. Inspection on the tension degree of timing chain Subject to a removal of crankshaft front belt /timing chain cover, the tension degree of timing chain may be checked in accordance with Max.
• Page 169
  Valve mechanism Inspection &repair for timing chain/camshaft components EM.3-5 7. Removal of shock absorber Two bolts plus the shock absorber may be dismantled. 8. Removal of thrust disk and camshaft (a)Two bolts plus the thrust disk may be dismantled. (b)Take out the camshaft carefully. Note Do not damage the camshaft bear ing.
• Page 170
  Valve mechanism Inspection &repair for timing chain/camshaft components EM.3-6 (d)Have the thrust disk and the camshaft chainwheel installed on camshaft. (e)The fixing bolts for camshaft chainwheel need to be installed and tightened. Tightening torque 90 N (f)Axial clearance between the thrust disk and the camshaft may be measured using a feeler gage.
• Page 171
  Valve mechanism Inspection &repair for timing chain/camshaft components EM.3-7 4. Change the chain tensioner column when necessary. (a)Side plate may be removed using gasket scraper and hammer. Note: do not bend the plate. (b)Dismantle the chain tensioner column and spring. (c) Machine oil for engine may be filled to the chain tensioner unit, or to the sliding surface of column.
• Page 172
  Valve mechanism Replacement of front oil seal on crankshaft EM.3-8 6. Inspection on valve tappet Measure the diameter of tappet using a micrometer. Diameter of tappet (21.387 21.404)mm If actual diameter does not conform to relevant stipulations, oil clearance needs to be checked. 7.
• Page 173
  Valve mechanism Installation of timing chain/camshaft EM.3-9 (b)Strike new oil seal into place using SST and hammer until the surface of oil seal reaches The same height as the edge of timing chain cover. SST 09223-22010 (c)MP multi-purpose grease shall be applied to the jaw of oil seal. Method II (a)Dismantle the oil seal using SST.
• Page 174
  Valve mechanism Installation of timing chain/camshaft EM.3-10 2. Installation of shock absorber The shock absorber may be fixed using two bolts. Tightening torque 18.5 N 3. Installation of timing chain and chainwheel (a)The set key of crankshaft chainwheel must be installedupward. setting of camshaft (b)Have the set key on camshaft chainwheel matching well with the mark made on the thrust disk.
• Page 175
  Valve mechanism Installation of timing chain/camshaft EM.3-11 (e)Have the crankshaft pulley installed on crankshaft. (f)A thin layer of engine oil will be applied to the top /screwed parts of camshaft chainwheel bolts. (g)The camshaft chainwheel bolts may be installed using SST and tightened as well SST 09213-70010 and 09330-00021 Tightening torque…
• Page 176
  Valve mechanism Installation of timing chain/camshaft EM.3-12 7. Installation of valve tappet One small part of steel wire or magnet may be used to insert the valve tappet into the tappet hole carefully. Installation at a later stage (a)Installation of the assembly for push rod and rocker shaft; (b)Installation of water-pump pulley and fan;…

• Page 177: Cooling System

  CO-1 Cooling system Composition &characteristics of cooling system……CO-2 Inspection /change of coolant for engine……..CO-2 Cooling water pump…………..CO-3 Thermostat……………….CO-5 Radiator………………CO-6…

• Page 178
  Cooling system-Composition &characteristics of cooling system, Inspection /change of CO-2 coolant for engine Composition &characteristics of cooling system The cooling system provided for engine is used to emit an appropriate amount of heat produced by each part and component of engine in a timely and forcible manner, so that engine may work continuously under a best temperature condition.
• Page 179
  Cooling system Cooling water pump CO-3 (b)The coolant must be changed if it’s too dirty. (c)The coolant used shall be of quality ethylene glycolbase coolant antifreeze liquid . (d)Capacity 7.9L 3. Change of engine coolant (a)Dismantle the radiator, or the outlet cover of water tank. (b)Have the coolant discharged from the radiator and the exhaust valve of engine.
• Page 180
  Cooling system Cooling water pump CO-4 Disassembly of Cooling water pump 1. Discharge the coolant. 2. Dismantle the transmission-belt. 3. Dismantle the fan, and the cooling water-pump pulley. After removing four nuts on the belt pulley seat used to fix the silicone- oil clutch, dismantle the fan, the assemblyof silicone-oil clutch, and the water pump pulley respectively.
• Page 181
  Cooling system Thermostat CO-5 2. Installation of cooling water pump pulley and fan Using four nuts, the water pump pulley, and the assembly of silicone-oil clutch and fan may be installed. 3. Check if there’s any leakage after starting the engine. Thermostat Dismantle of thermostat 1.Discharge the coolant.
• Page 182
  CO-6 Cooling system radiator (b)Using two nuts, the inlet of water tank may be installed. Tightening torque 12 N m 2. Connect the outlet hose of radiator to the inlet of water tank. 3. Refill with coolant. 4. Check whether there’s any leakage after starting engine.

• Page 183: Lubrication System

  LU-1 Lubrication system Page Composition /function of lubrication system……..LU-2 Inspection on machine-oil pressure……….,.LU-2 Change of engine oil /oil filter …………LU-3 Oil pump………………LU-4…

• Page 184
  Lubrilation system-Composition /function of lubrication system¡¢Inspection on machine-oil LU-2 pressure Composition /function of lubrication system Model 491QE petrol engine adopts a compound lubrication the combination of pressure lubrication and splash lubrication ; And the lubrication system mainly consists of oil filter, oil pump, oil cooler, pressure- limiting valve, etc.
• Page 185
  LU-3 Lubrilation system-Change of engine oil / filter 3. dismantle he machine-oil pressure switch or sensor; manometer 4. Install the oil manometer. 5. Start the engine. Start the engine, and increase the temperature to a normal working temperature. 6. Check the oil pressure Machine-oil pressure >49 kPa when at idle speed ±…
• Page 186
  LU-4 Oil pump Oil pump Part drawing for oil pump oil pump body oil pump cover bolt safety valve machine-oil filter screen driving rotor o ring spring safety valve plug use by two driving vehicles driven rotor oil pump cover machine-oil filter screen use by four driving vehicles The one with mark * refer to spare part which has been used and can not be re-used…

• Page 187: Disassembly Of Oil Pump

  Oil pump LU-5 Disassembly of oil pump 1. Check whether oil pump is working normally. (a)Have the filter screen submerged in oil using a screwdriver,and rotate the shaft of oil pump in a clockwise direction, and machine-oil is supposed to discharge from the oil outlet. (b)Rotate the shaft of oil pump in a similar way stated above when the machine-oil outlet has been blocked by finger, and the shaft of oil pump shall be difficult to rotate.

• Page 188
  LU-6 Oil pump (b)Check the end clearance of rotor unit A gauge may be used to measure the clearance as indicated in the drawing. ( 0 . 0 3 — 0 . 0 7 )mm Standard clearance (0.03-0.07) mm M ax. clear ance 0.15 mm T he rotor shall be changed if the actual clearance exceeds Max.
• Page 189
  Oil pump LU-7 2. Installation of machine-oil filter screen (a)New O ring must be installed on the position where the machine-oil filter screen is located. (b)The pump cover may be fixed with filter screen securely by an installation and tightening of two bolts. Tightening torque 17.5N (c)Filter screen may be fixed with the device unit securely by an installation and tightening of two bolts.
• Page 190
  IG-1 Ignition system…
• Page 191
  Ignition system-preventive measures, Circuit diagram /vehicle inspection of ignition system Preventive measures Great Wall automotives are driven by petrol engine, which works after the mixture of petrol and air has been ignited by the high-voltage electric spark produced by one set of ignition system installed inside the engine. And the ignition system has such function as to transform the low-voltage provided by battery into a high-voltage current able to ignite the inflammable gas mixture inside engine cylinder;…
• Page 192
  IG-3 Ignition system- Circuit diagram /vehicle inspection of ignition system Vehicle inspection Spark plug test check the form of spark plug 1. Remove the high-tension wiring from spark plug 2. Remove the spark plug 3. Spark plug needs to be installed on each high-tension wiring 4.
• Page 193
  IG-4 Ignition system- Inspection on high-tension wiring, inspection on spark plug Inspection on high-tension wiring 1. Remove the high-tension wiring. Hold the rubber cover with hand, removing the high tension wiring from the spark plug carefully. Note Dragging, pulling or bending the hightension wiring might cause some damages on internal conductors.

• Page 194: Starting System

  ST-1 Starting system Structure /circuit diagram of starter ……..ST-2 Disassembly of starter …………ST-3 Inspection on starter …………ST-4 Assembly of starter …………ST-7 Testing on starter…………..ST-9…

• Page 195
  ST-2 Starting system-Structure /circuit diagram of starter The exterior force of petrol engine comes from one starter, which receives power supply from the battery, and drives the engine to rotate. The starter is of one special DC electrical motor, which has following features during operation: with a large starting torque, a large staring current, and subject to an intermittent operation.
• Page 196
  ST-3 Starting system-Disassembly of starter Circuit diagram of starter as shown in the figure below: ignition switch f u s e terminal 30 terminal 50 battery starter Disassembly of starter 1. Dismantle thearmature assembly inside the excitation frame. (a)Remove nuts from the terminal of solenoid switch, and remove the lead-wire as well.
• Page 197
  ST-4 Starting system-Inspection on starter 3. Removal of steel ball A magnetic rod may be used to take steel ball out from the axle hole of clutch. magnetic rod 4. Removal of brush frame Two screws and end cover will be removed from the excitation frame. Using screwdriver, spring could be taken out from the brush holder, and the brush holer could be removed, followed by a removal of four brushes and brush holders.
• Page 198
  Starting system-Inspection on starter ST-5 Rectifier 1. Check whether the surface of rectifier has been contaminated or damaged by burning. If it does occur, sand paper (No.400) or lathe may be used for a repair or correction purpose. 2. Check the circumferential radial runout of rectifier Max.

• Page 199: Brush Holder

  ST-6 Starting system-Inspection on starter Brush Check the length of brush Standard length 13.5 mm Min. length 8.50 mm The brush frame, and the excitation frame must be changed if the length is less than Min. Value. Brush spring Check the load of brush spring using a Pull up balance. Standard spring load (17.56-23.64) N Note Read the load produced at the moment when the spring isleaving the brush while the brushs pring is being pulled up by a Pull-up balance;…

• Page 200
  Starting system-Assembly of starter ST-7 2. The bearing may be changed if necessary. (a)Use SST to remove the bearing (b)Use SST and press tool to press new front bearing. SST 09285-76010 (c)Use a press tool to press into rear bearing Solenoid switch terminal 50 1.
• Page 201
  ST-8 Starting system-Assembly of starter 2. Installation of brush holder (a)Put the brush holder on armature. (b)To connect armature with the holder, screw tap may be used to press the brush spring on the back. Beside, four brushes must be connected. Note: Check and verify that the positive lead-wire has not been connected with ground.
• Page 202
  Starting system-Testing on starter ST-9 (d)Using two screws, the starter shell and solenoid switch may be assembled together. 5. Installation of the excitation frame and the armature assembly (a)A new felt sealing-gasket needs to be installed on the armature. (b)Have the convexity of excitation frame aligned with the tangent plane of solenoid switch.
• Page 203
  ST-10 Starting system-Testing on starter 3. Check the return status of plunger piston After a removal of negative lead-wire from the switch unit, check whether small gear is able to go back to the inside. The solenoid switch assembly needs to be changed if small gear does not return to the inside.
• Page 204
  CH-1 Chargingdevice Page Structuredrawing/electricalschematicdiagramofgenerator…..CH-2 Inspectiononvehicle …………….CH-5 Disassembly of AC generator…………..CH-7 Inspection on AC generator…………..CH-9 Assembly of AC generator…………..CH-12…
• Page 205
  Structure drawing /electrical schematic diagram of generator CH-2 Structure drawing /electrical schematic diagram of generator 1. Brief description of working principle for generator That the stator coil of generator goes across the rotating magnetic field produced by the rotor makes the statorproduce a 3-phase AC current, which will be transformed into DC current by rectifier bridge for a power supply to electrical devices on vehicle.
• Page 206
  CH-3 Structure drawing /electrical schematic diagram of generator 3. Electrical schematic diagram of generator (a) Circuit schematic diagram for 90A internally-adjusted generator Electrical schematic diagram stator coil excitation coil I·C adjustor (b) Circuit schematic diagram for 90A externally-adjusted generator Electrical schematic diagram stator coil excitation coil I·C adjustor…
• Page 207
  CH-4 Structure drawing /electrical schematic diagram of generator (c) circuit schematic diagram for 65A internally-adjusted generator Electrical schematic diagram stator coil excitation coil I·C adjustor (d) circuit schematic diagram for 65A externally-adjusted generator Electrical schematic diagram stator coil excitation coil…
• Page 208
  Charge device-Inspection on vehicle CH-5 Inspection on vehicle 1. Check the specific gravity of accumulator (a)Check the specific gravity for each accumulator unit. Standard specific gravity when charged with full power at 20 (1.25~1.27)g/cm 2 upper liquid (b)Check the electrolyte amount for each accumulator unit. level In case of an insufficient electrolyte amount, fill with distilled or pure water.
• Page 209
  CH-6 Charge device-Inspection on vehicle N o t e -The so called new belt r efer s to belt having wor k ed for less than five minutes on the r otating engine. -T he so called used belt r efer s to belt having wor ked for five minutes or above on the r otating engine.
• Page 210
  Charge device-Inspection on vehicle CH-7 (b)Check the charging loop using following method When the engine is increased from idle speed to 2000r/min, check the read value on ammeter and voltmeter. standard current standar d voltage (13.9-15.1)V when at 25 (13.4-14.4)V when at 11.5 If the voltage value is greater than standard value IC adjustor needs to be changed.
• Page 211
  Disassembly of AC generator CH-8 Disassembly of AC generator 1. Dismantle the assembly of driving end shell and rotor from the stator. (a)Remove three through-screws. (b)When the end shell is prized up by a screwdriver, have it removed simultaneously with the rotor. Note: Don’t pry the wire of the coil.
• Page 212
  Inspection on AC generator CH-9 5. Removal of IC adjustor When the terminal of IC adjustor is gripped using nipper pliers,remove it by welding. 6. Removal of rectifier support When the terminal of IC adjustor is gripped using nipper pliers remove th e lead wireby welding.
• Page 213
  CH-10 Inspection on AC generator Stator 1. Check whether the stator is in an open circuit. Use an ohmmeter to check conduction between leading of the coil. Note I nter sectant lines must be welded well. T he stator needs to be changed if non-conduction exists. conduction 2.
• Page 214
  Inspection on AC generator CH-11 Rectifier 1. Check the positive rectifier rectifier terminal (a)Using ohmmeter, connect one end of the test head with the rectifier terminal, and connect the other end with the positive terminal. (b)Exchange the test joint, and repeat the above step. ohmmeter (c)Check its conduction or non-conduction covered in above two steps.
• Page 215
  Assembly ofACgenerator CH-12 4. Change the bearing when necessary. (a)Remove the bearing using SST. SST 09286-46011 (b)Use a press tool to press the new bearing. Assembly of AC generator 1. Install the rectifier support onto the stator. Clamp the rectifier terminal using nipper pliers, and weld the wiring terminal. Note: the heat shall be prevented from transmission to rectifier.
• Page 216
  Assembly ofACgenerator CH-13 (d)Put two terminal insulators onto the positive stud bolt of the rectifier frame. (e)Install the capacitor and the lead-wire grip. (f)Install four nuts. (g)Confirm that electrical wire has not been overlapped with the rectifier shell. lead-wire grip 4.
• Page 217
  Assembly ofACgenerator CH-14 6. Assembly of the driving end shell and rectifier end shell (a)Have the rotor exposed by bending the wiring head of rectifier. (b)Bending tools may be used to push the electrical-brush to the end, then one hard steel wire shall go through the manhole of rectifier end shell, and the electrical-brush will be put to place.
• Page 218
  CL-1 C l u t c h…
• Page 219
  CL-2 Clutch-Dismantle of clutch components, and inspection on clutch components Dismantle of clutch components Dismantle of clutch cover (a)Remove bearing, bearing sleeve, and release shifting fork from the transmission. (b)Bearing and bearing sleeve, will be pulled out at the same time after removing the stop clamp.
• Page 220
  Clutch- assembly of clutch components CL-3 (b)Use SST to install a new guide bearing. SST 09304-30012 5. Check whether the diaphragm spring has been abraded. Check the abraded depth and width of diaphragm spring using a vernier caliper. Limit value depth 0.6 mm width 5.0 mm The clutch pressure plate shall be changed when necessary.
• Page 221
  CL-4 Clutch- assembly of clutch components 3. Check the alignment on the top of diaphragm spring. The alignment on the top of diaphragm spring may be measured using an matchmark amesdial containing ball bearing.The alignment on the top of diaphragm spring may be adjusted using SST if the deviation is greater than the specified value.