PETROL ENGINE TROUBLE DIAGNOSIS
Contents
1. PETROL ENGINE TROUBLE DIAGNOSIS Foreword The information in this Training Manual should not be interpreted as a basis for warranty or goodwill claims against Nissan Motor Co Australia Pty Ltd NMA unless so designated This Technical Training Manual is intended for use by NMA amp Nissan Dealership Technical Personnel It is not designed for the use by press or for customer distribution Before quoting any specifications be sure to check the relevant Service Manual and Technical Bulletins Right for alteration to data and specifications at any time is reserved Any such alterations will be advised by Nissan through Technical and Sales Bulletins 2009 Nissan Motor Company Australia Pty Ltd Inc Victoria Ref Technical Training Department NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 RETURN amp RETURNLESS FUEL SYSTEMS Fuel System Pressure Control Petrol Engine There are two types of fuel supply systems in common use on Petrol engines e Return Fuel Systems e Return less Fuel Systems It is important to understand the 2 different types of Petrol Engine fuel systems as the pressures will vary between the 2 and there will be slightly different testing procedures employed between these two systems Return Fuel Systems Since the introduction of electronic fuel injection systems until approx 2000 all Nissan EFI engines Injector Rail used Fuel Return2. Diagnosis Nissan Australia May 2009 ADR 81 01 FUEL CONSUMPTION TEST PROCEDURE FUEL CONSUMPTION Comparative fuel consumption Litres per 100 km THIS LABEL IS FITTED SO THAT THE CUSTOMER CAN COMPARE THE FUEL CONSUMPTION OF DIFFERENT VEHICLE MODELS IT DOES NOT SUGGEST THE ACTUAL FUEL CONSUMPTION OF THE VEHICLE ACTUAL FUEL CONSUMPTION OF THE ENGINE UNDER EVERYDAY DRIVING CONDITIONS IS TYPICALLY 15 34 HIGHER THAN THE FIGURE QUOTED ON THE LABEL The ADR 81 01 Test Cycle sourced directly from www greenhouse gov au fuelguide The test cycle simulates an 11 km trip with an average speed of 33 6 km h Approximately two thirds of the test time simulates urban stop go driving where the average speed is 18 8 km h with the final third of the test drive time being similar to driving on a highway with the vehicle driven to over 100 km h The vehicle used in the test exactly matches the vehicle as it appears in the new vehicle brochure I E NO ACCESSORIES ARE FITTED 25 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 EFFECTS ON PETROL ENGINE FUEL ECONOMY Increased purchasing cost of Fuel Rising fuel costs are giving the customer the belief that the vehicle is at fault Especially if the customer adds fuel to the vehicle in set amounts of dollars every week etc Towing Roof Racks Bars Even though many Nissan vehicles have remarkable towing capacities the fuel consumption
3. Starvation Injection Duration OK Excess of Air to Fuel Due to low fuel pressure blocked filter blocked injectors etc this results in a short burn time due to the lack of fuel This again results in some O2 content being left over This left over content of O2 is expelled amp then seen by the O2 sensor This signals to the ECM that the mix was lean therefore will result in an abnormal increase in the rate of injection for the next cycle in order to compensate for the lack of fuel condition 11 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 O2 MEASUREMENT LEAN by Intake Air Leak un metered air Injection Duration OK Excess of Air to Fuel Due to an air leak on the intake leaking intake manifold gasket hole in air intake tube etc the MAFS sensor only measures a certain amount of air This signal is sent to the ECM therefore the ECM adds a specific amount of fuel which is relevant to the amount of air measured Air which is leaking through a hole or a leaky gasket is added to the combustion chamber with an insufficient amount of fuel Combustion takes place but there is left over O2 in the exhaust gases amp therefore is seen by the O2 sensor This signals the ECM to increase the injection rate above what it thinks is normal False LEAN Signal due to Exhaust Leak Injection Duration OK Air Fuel Ratio normal REMEMBER If the O2 sensor sees Oxygen it means LE
4. Systems These are slowly being With phased out as new model engines are introduced Injectors Intake Manifold NOTE Pressure Y61 TB48DE is the only vehicle that currently uses a Fuel d Return Fuel System Damper Per aeu Pressure Regulator The Pressure Regulator is located on the end of the fuel rail after the last injector and it varies fuel pressure depending on engine load manifold vacuum A small vacuum hose connected above the regulator diaphragm keeps the pressure difference between the fuel rail and the manifold constant This enables consistent injection quantity based only on changes in injector pulse width Fuel Pump Filter and Sender Typical fuel pressures are y oe almodel At idle vacuum hose On 240 kPa e Vacuum hose Off 290 kPa Fuel Filter Not all models Fuel Return This difference in fuel pressure is simply the difference in manifold pressure vacuum between engine idle and engine OFF or at Wide Open Throttle Once the fuel rail is pressurised excess fuel continually returns to the tank via the pressure regulator valve Fuel Damper A fuel damper is usually located at the fuel rail Some engines may use two fuel dampers Fuel Filter The fuel filter may be located externally or within the tank with the fuel pump Refer to the Service Manual for the location NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 RETURN amp RETURNLES
5. amp associated circuit is functioning correctly Inspect for open circuit brake light globes amp or wiring connections amp grounds are OK Specifically on N16 Hatch with ETC 16 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 PETROL ENGINE TROUBLE DIAGNOSIS Sm s Bes Basic Service 1 Idle Speed Check With CONSULT select ENGINE amp then DATA MONITOR amp view the idle speed by viewing Engine Speed in Main Signals 2 Ignition Timing Inspection Given that the engine is installed with a CKPS monitoring the movement amp position of the Crankshaft flywheel amp a CMPS monitoring the movement amp position of the inlet camshaft the ECM has the ability to see where the Crankshaft is in relation to the Camshaft amp adjust the timing by itself accordingly Therefore it is NOT necessary to check the ignition timing at normal service intervals etc HOWEVER it maybe necessary to inspect the ignition timing as part of a Trouble Diagnosis procedure If so desired the actual Ignition Timing can be inspected in the traditional manner to ensure the CKPS amp CMPS systems are operating correctly FTN ALa Vehicle As shown right remove No 1 ignition coil install S f 7 NN front Special Service Tool SST E7032 amp check the HNN ignition timing The engine must be idling at operating temperature amp ALL accessories OFF Compare the reading s
6. for fuel leaks 3 Start engine and read fuel pressure Compare to specifications in the Service Manual Check the following items if fuel pressure is too Low e Blocked filter or fuel pump pick up e Restricted fuel lines e Faulty pressure regulator NOTE e If fuel pressure is LOW carefully squeeze the return line resulting in blocking it amp watch a sharp amp rapid increase to approximately double the normal Fuel Pressure spec Only do this for a maximum of 3 seconds If the pressure increase does occur the fuel pressure regulator is faulty If not either the level of fuel in the tank is low the fuel pump output is weak a fuel line is blocked or the fuel filter is blocked e If fuel pressure is too HIGH either the pressure regulator is faulty or the return line is restricted Intake Manifold Fuel Pressure _ Damper 7 Pressure Regulator Fuel Pressure Fuel Filter Gauge Not all models Fuel Return Fuel Pump Filter and Sender Unit Not all models Fuel Tank NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 RETURN amp RETURNLESS FUEL SYSTEMS Injector Rail Return less Fuel Systems With Injectors Return less Fuel systems are easily recognised since they have no fuel return line They run at a constant pressure that does not change regardless of engine load One of the benefits of the Return less Fuel system is a reduction in fuel tank
7. not burning O2 4 20 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 PETROL ENGINE TROUBLE DIAGNOSIS Basic Service 6 A F ALPHA Inspection DATA MONITOR SPEC MONITOR NO DTC ENG SPEED _XXXrpm_ 0 1600 3200 4800 6400 A F ALPHA B1 Well above 100 indicates there is an excess of AIR in comparison to fuel is entering the combustion chamber amp is being burned Well below 100 indicates there is an excess of FUEL in comparison to air is entering the combustion chamber amp is being burned RICH _ LEAN TS 100 0 A F ALPHA B2 6 cylinder engine displayed 2 separate banks of cylinders 4 cylinder has 1 bank Procedure 1 Road Test vehicle briskly for 10 km s Engine amp Transmission should be at operating temperature 2 Confirm that the IAVL can be successfully completed 3 Ideally the vehicle should have more than 5000km s on it Vehicle has been properly run in 4 Ensure that the engine has been properly serviced Ensure the correct grade type of oil is in the engine amp the level is correct Ensure components such as spark plugs air filters etc are serviceable genuine parts Ensure that the correct Part Numbered components have been installed 5 Ideally the barometric pressure should be 98 3 104 3 kPa 6 Ideally the atmospheric temperature is between 20 30 deg C 7 Engine speed is idling The IAV
8. will be greatly affected as a result of towing Especially if the vehicle is towing something on or close to the maximum towing capacity If roof racks or bars are fitted with or without contents this will greatly effect fuel consumption Wrong Engine Oil Poor Service History Modern engines are extremely sensitive to Engine Oil viscosity Ensure that only Nissan 7 5W 30 engine is used Irregular servicing will easily cause poor fuel consumption concerns as well Incorrect Wheels Tyres Vehicle is Overweight amp or Modified Aftermarket accessories Ensure that the original soec wheels amp tyres are fitted to the vehicle in question Increased rolling resistance will cause poor fuel consumption Additional parts on the exterior of a vehicle such as roof racks and spoilers or having the window open increases fuel consumption in some cases by over 20 Tyre Pressures Driven in Auto Lock mode 4WD AWD Incorrect Handbrake Adjustment Ideally the vehicle should be driven in 2WD at all times unless the road surface conditions are unstable Ensure that the tyres are set to the correct specification amp MAKE SURE the handbrake has NOT been over adjusted Driveline Friction Ensure the driveline is properly serviced Transmission Transfer Final drive oils the correct type amp are they set to the correct level Ensure the brakes are not dragging Driving Style Driving Pattern Carefully question the customer on their driv
9. AN Therefore if O2 leaks into an exhaust manifold due to a cracked exhaust manifold or a leaking exhaust manifold gasket the false O2 content will make the ECM increase the injection rate EVEN IF THE INJECTION RATE WAS PERFECT False LEAN Signal due to Spark Missfire Injection Duration OK Air Fuel Ratio normal REMEMBER NO spark means NO burn Even if TOO MUCH fuel entered the combustion chamber if it doesn t burn neither does the O2 content Unburnt O2 means LEAN As a result the ECM increases the injection rate to add more fuel to an engine that doesn t need anymore fuel 12 INTAKE AIR LEAK AIR LEAKS V EXHAUST REECE SE Be ae a a Sensor EXHAUST MANIFOLD LEAK EXHAUST UD i NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 O2 MEASUREMENT RICH Normal Air Quantity with Excess Fuel lf there is an excess amount of fuel added leaking injectors or excessive injection duration etc not all of the fuel will burn because in this case the burning will stop due to all the oxygen being burnt up RAW FUEL WITHOUT OXYGEN WILL NOT BURN ON IT S OWN The excess fuel will be expelled out of the exhaust valve however the reason why the O2 sensor will indicate RICH is because it cannot sense any O2 in the expelled exhaust gases NOT because of the raw fuel left over AN OXYGEN SENSOR CAN ONLY SEE OXYGEN It cannot see raw fuel RUNNING RICH FLOO
10. APPS are seen by the ECM The ECM must continually see the same voltage reading EACH time Confirm this by making your own observations in DATA MONITOR on CONSULT II Ign SW ON About 5 sec About 5 sec About 5 sec About 5 sec About 5 sec Ign SW OFF 10 sec 10 sec 10 sec 10 sec 10 sec THIS TIMING IS CRITICAL 2 Listen for the sound of the Throttle Valve being opened amp closed on the Engine each time the ignition is turned OFF Once it rests it must rest in the same position it rested previously If it rests in a different position the TPS voltage output will be different each time the ignition is turned on again THIS SIMPLE OPERATION IS CRITICAL Ensure the time frame suggested above for each key position is observed 10 sec means 10 actual seconds on an accurate watch or stop watch NOT 10 mini seconds or 10 that ll be right seconds This 2 in 1 learning operation is an EXTREMELY important operation that MUST be carried out for any of the following reasons e After the Reprogramming of an ECM BUT BEFORE THE ENGINE IS STARTED e A new or substitute ECM is installed in the vehicle Along with reprogramming ALL of the NATS ignition keys Make sure you get ALL THE KEYS from the owner driver e A new or substitute Throttle Body Unit is installed on the vehicle e The existing throttle body unit is cleaned e Battery power has been lost for a long period of time e Prior to carrying the Id
11. All new low friction engine design Dual HO2S before amp after catalyst ECM software calibrated to suit emission requirements New OBD system more DTC possibilities Electric Power Steering deletion of the need to drive a power steering pump EURO Ill EMISSIONS Changes to Nissan vehicles J31 Z50 Z33 VQ35DE R51 D40 VQ40DE e 2x Front O2 sensors changed to Air Fuel ratio sensors Wide Band O2 sensors e ECM software re calibrated to suit emission requirements e New OBD system more DTC possibilities e CVT Z50 amp J31 only Note Z50 R51 amp D40 have complied since release Y61 TB48DE e Twin Catalyst Exhaust manifold design Additional under floor mounted Catalyst 3 x Catalysts in total e Dual HO2S before amp after catalyst Now 4 x HO2S Bank 1 amp Bank 2 Split Control System similar to VQ engine e Additional CKPS for improved OBD performance Located in Gearbox housing Sensor plate forms part of the drive plate e Ignition system changes platinum spark plugs e ECM software re calibrated to suit emission requirements e New OBD system more DTC possibilities e Deletion of Sub Fuel Tank T30 QR25DE e Dual HO2S before amp after catalyst e ECM software calibrated to suit emission requirements e New OBD system more DTC possibilities D22 VG33E Petrol variants discontinued These items have an indirect effect on vehicle emissions They assist with maintaining a vehi
12. DING Using Air Fuel Alpha in CONSULT Il to indicate measured Oxygen Content Display A F ALPHA in DATA MONITOR or DATA MONITOR SPEC CONSULT If the A F Alpha shows a reading close to 100 typically 95 105 then the engine is running close to or at It s originally programmed map l e The ECM see no problems with the content of left over O2 it s measuring in the exhaust gases The balance of Fuel Quantity to Air Quantity in the engine is normal DATA MONITOR SPEC 0 1600 3200 4800 6400 Well below 100 indicates there is an excess of FUEL in comparison to air is entering the combustion chamber amp is being burned RICH LEAN Well above 100 indicates there is an excess of AIR in comparison to fuel is entering the combustion chamber amp is being burned Conventional O2 Sensor Wide Band Type 1 RICH 1 i i et E a ee 14 771 Ideal h 2 Output voltage mV on a a a i i i i i i i i i i qe annj eee ee i i i I Oo F 1 i l i I i i i 10 12 14416 18 20 22 24 Air fuel ratio 0 10 12 14816 18 20 22 24 26 28 30 Air fuel ratio ASF 14 7 LEAN 14 731 T30 K12 C11 J10 R51 D40 250 Z33 6 wire T31 Z51 J32 Z33 Z34 4 wire Constantly switches from 0 1V to Ideal 1 5V Ideal 2 2V 0 9V Average of 0 5V RICH towards 1V RICH towards 0 5V LEAN towards 4V LEAN towards 5V 13 NISSAN Learning Academy Petrol Engine Trouble Diag
13. Idle Ignition Timing check adjust amp Mixture Ratio Feedback inspection 14 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 PETROL ENGINE TROUBLE DIAGNOSIS 1 POWER AND GROUND more detail further on a Battery Is it charged Can it hold a charge Is it being charged Does it pass a load test a tb nae Can it cope with high electrical loads Switch on all accessories amp check it s output under oa b Condition of battery terminals Fusible links are in good condition terminals clean amp tight Main ground connections are in good condition b c d Fuses they are in the correct place amp OK There are typically 3 x different locations where fuses are located CHECK ALL LOCATIONS HAS THE VEHICLE GOT DECENT POWER SUPPLY amp GROUND CONNECTIONS 2 FUEL a Is there Fuel in the tank Who was the last to put Fuel in the tank What kind of Fuel went into the tank Run engine on known good fresh fuel if in doubt b Fuel Pressure 1 Measure it with a known good FP gauge amp write the figures on the R O Measure the FP at idle amp again under FULL LOAD Ensure the tank pick up pump filter return system if applicable is OK Refer to section EC Basic Service in the Service Manual c Fuel Pressure 2 Can the system maintain a residual pressure with the Engine OFF If the pressure drops away over 20min where is it going Ba
14. L must have achieved a CMPLT 8 With CONSULT select options in the following order ENGINE DATA MONITOR SPEC SELECTION FROM MENU A F ALPHA select the 2 of them for a 6 cyl engine There are 2 banks of cylinders that need to be monitored START The screen in the graphic above should now appear 9 With the engine under the conditions requested in steps 1 6 what does the black bar indicator do i Does it remain stable amp central within the hashed area If so all is OK See next page for B FUEL SCHEDULE inspection ii Does it move out of the hashed area below 100 If so see next page for RICH trouble indication iii Does it move out of the hashed area above 100 If so see next page for LEAN trouble indication 21 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 PETROL ENGINE TROUBLE DIAGNOSIS A F ALPHA Indicates RICH Well below 100 Check the following Items e Engine Oil is contaminated with excessive fuel or it is the wrong viscosity or overdue for changing Change engine oil amp filter if in doubt e Air Flow through the air intake is restricted check for interference of airflow e Fault with EVAP system fuel is being drawn directly from fuel tank breathing system amp entering inlet manifold e Leaking injectors e Excessively high fuel pressure e Fuel Pressure regulator is leaking fu
15. ON Ensure Fuel Pump activates amp then stops after a few seconds Check for fuel leaks 3 Start engine and read fuel pressure Compare to specifications in the Service Manual Fuel Damper e Blocked filter or fuel pump pick up e Restricted fuel lines e Faulty pressure regulator Check the following items if fuel pressure is too LOW NOTE Fuel Tank e DO NOT SQUEEZE OR CRIMP FUEL LINES e If fuel pressure is too HIGH replace the pressure regulator which is located in the fuel tank Fuel Pump Eae Filter and Regulator Sender Unit Pre set non variable Fuel Return Residual Pressure Retention Both types of Fuel Systems Ensure that when the engine amp fuel pump is switched OFF fuel pressure is retained in the lines for the specified period Typically this should be no more than a 10 drop over 10 seconds lf pressure is dropping away excessively consideration needs to be given to the following items e Leakage in the reverse direction back to the tank e Leakage in the forward direction through leaking injectors or fuel pressure regulator on Return Systems only If this is the case the engine will be difficult to start amp black smoke will be emitted from the exhaust Typical SST requirements for Fuel Pressure Testing Adapter y Adapter KV 101118400 ay KV 10117600 AUS p i Pa Dmm Gauge and Adapter Fuel Line Removal 7211 and 7273 Tool 16441 6N210 NISSAN Learning Academy Petro Engine Trou
16. PS 2 Accelerator Pedal Position Sensor The ECM monitors the Accelerator Pedal Position Sensor to determine the driver s input It uses this signal along with its other inputs to determine the amount of throttle opening requested It contains two potentiometers and the combination of the two signals allows the ECM to calculate an average voltage output from the two This allows the pedal position to be determined with greater accuracy and reliability than if only a single potentiometer sensor was used NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 ELECTRIC THROTTLE CONTROL Soe oy ETC unit with The Throttle body contains a spring mechanism that TPS amp Motor holds the throttle valve in a slightly open position around A 10 open The Throttle Actuator Motor will OPEN or CLOSE the throttle valve from this default position to provide the desired engine speed The Throttle Actuator Motor is a DC motor that drives the throttle valve through a reduction gear set It is driven by a Pulse Width Modulation PWM signal also called a varying duty cycle signal When the ignition is switched OFF the Throttle Actuator Motor will remain powered for a few seconds to allow it to reposition the throttle valve to the closed position View with Air Duct pipe removed E C M TPS sends movement signal back to ECM Driver P w command gt turns gears amp s
17. S FUEL SYSTEMS Measurement of the Fuel Pressure Petrol Engines As part of an Engine no poor running diagnosis the Fuel Pressure is an important measurement to record in order to narrow down the cause of a fault Measuring Fuel Pressure will measure the pressure that the fuel is under prior to entering the injector Obviously the Fuel won t spray properly if the pressure is incorrect too low Also the amount of fuel entering the combustion chamber will be insufficient if the pressure is too low Fuel starvation lf the Fuel Pressure is too high then the engine will have a rich running excessive fuel consumption issue Fuel system tests are e Pressure e Residual Pressure Retention Ensure there is sufficient fuel in the tank before conducting tests Fuel Pressure Release On all systems it is important to safely release residual fuel pressure before removing fuel hoses e Perform FUEL PRESSURE RELEASE with CONSULT in Work Support Mode Ensure that engine stalls and will not restart e Without CONSULT remove the fuel pump fuse run the engine until it stalls and ensure that it will not restart WARNING Great care must be taken to avoid fires when opening the fuel system Fuel Pressure Test on Return Systems 1 Install the Fuel Pressure gauge on the engine Refer to Section EC Basic Service in the Service Manual 2 Switch Ignition ON Ensure Fuel Pump activates amp then stops after a few seconds Check
18. TORY a Oil level is correct Is it over under full Due for changing Is it the correct grade viscosity for the engine Coolant level amp condition is OK Genuine coolant used Cooling system is functioning OK b c d Have you got records of other PREVIOUS WORK HISTORY Nissan dealer or Non Nissan Dealer FITMENT OF NON GENUINE PARTS amp AFTER MARKET ACCESSORIES 15 NISSAN Learning Academy Petrol Engine Trouble Diagnosis PETROL ENGINE TROUBLE DIAGNOSIS Checklist Continued 7 NATS All keys start the car OK Remove keys from key ring set amp retry Ensure there are no other electronic devices that interfere with NATS keys operation when starting 8 ILLOGICAL INPUTS INTO THE ECM a Whilst being driven as well as stationary ensure that inputs such as P N Posi Sw amp Brake Sw are input correctly For a complete reference list refer to section B EC TROUBLE DIAGNOSIS CONSULT Reference Value in Data Monitor Mode of the Service Manual b If possible drive the vehicle fitted with a KNOWN GOOD Mass Air Flow Sensor 9 PRE PROGRAMMED ECM FAILSAFE OPERATIONS a Ensure the customer does NOT drive with the brake pedal applied Specifically on T31 amp Z34 b Ensure that the brake pedal amp brake pedal switches Stop Lamp amp ASCD cut are correctly adjusted Ensure the clutch pedal ASCD cut switch is correctly adjusted where fitted c Ensure the brake lights globes
19. ator pedal is depressed it will then advance the ignition timing to obtain the full effect of the default 10 open throttle Accelerator Pedal Position Sensor APPS If the ECM cannot receive reliable information from the Accelerator Pedal Position Sensor it will disable the Throttle Actuator Motor so it returns to the default 10 position Throttle Position Sensor TPS If the ECM cannot receive reliable information from the Throttle Position Sensor it will disable the Throttle Actuator Motor so it returns to the default 10 position Relearning Functions The ECM constructs various self learning functions that are critical to Electronic Throttle Control operation If the ECM APPS or TPS connectors are removed OR there are idle concerns the following procedures MUST be carried out e Accelerator Pedal Released Position Learning using ignition key switching e Throttle Valve Closed Position Learning using ignition key switching e Idle Air Volume Learning using CONSULT Refer to Basic Service in Section EC of the Service Manual for more detail NOTE ETC systems are affected by carbon build up at the throttle valve and bore and may require periodic cleaning to restore correct idle performance Relearning functions MUST also be conducted whenever the throttle is cleaned NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 O2 MEASUREMENT Measurement of Oxygen Content after Combustion A
20. ble Diagnosis Nissan Australia May 2009 ELECTRIC THROTTLE CONTROL Electric Throttle Control ETC All new petrol engine vehicles are now fitted with Electronic Throttle Control ETC systems fly by wire There is no mechanical connection between the accelerator pedal amp the throttle valve on the engine ETC is a closed loop system that provides the ECM with direct feedback from the Throttle Position Sensor The ECM will modify the actual throttle valve opening compared to accelerator pedal movement based on various program strategies including the need to minimise emissions The benefits of ETC are e Moving parts are reduced as well as the noise transmission path of a cable e Integration of idle control cruise control traction control and vehicle dynamic control systems Note ETC systems have no external means to alter the idle speed It is controlled directly by the ECM DO NOT attempt to alter ANYTHING on the throttle body Mechanical Throttle Control MTC The previous system was a very complex one even though it was mechanically controlled The actual throttle valve was connected via cable to the Accelerator Pedal amp directly operated by the driver However if there is a change in idle speed required without input from the driver e g when A C cuts in there needs to be a system in place to open an air passage amp increase air flow which in turn increases engine speed Therefore with MTC air bypass
21. ck to the tank Through leaking injectors or fuel pressure regulator diaphragm Leaking injectors or F P regulator will contribute to hard start amp black smoke emission 3 IGNITION SYSTEM a The CORRECT type of spark plugs for the engine are fitted Spark plugs are worn due for replacement Ignition leads distributor cap is in good condition Ignition coil unit coil power supply is coil ground connection OK A poor coil ground can cause premature coil failures b C d 4 COMPRESSION Air a Measure with a known good compression gauge amp write the figures on the R O Do both a DRY amp then followed by a WET compression check Refer to section EM of the Service Manual for procedure b Air intake system Are their any air leaks oil cap dip stick throttle body gasket amp bypass hoses vacuum hoses fitted correctly c Air intake system Blockage or air flow interference d Air outlet system Exhaust Blockage Leaking manifold gaskets or cracked exhaust manifold e EGR amp crankcase ventilations systems operating OK 5 ENGINE MECHANICAL TIMING INDICATION SYSTEM a CKPS amp CMPS signal plates functioning OK Serviceable Sensors mounted correctly Flywheel has been fitted in the correct place oe Crankshaft timed correctly Variable camshaft timing mechanism amp timing chain condition 6 ENGINE OIL COOLANT amp PREVIOUS WORK HISTORY HAS THE VEHICLE GOT A DECENT SERVICE HIS
22. cles overall performance amp fuel economy without impacting on emission performance
23. een by the timing light with the Ignition Timing reading in Data Monitor on CONSULT RECORD No 1 ignition coil ARI s res A SSN Te Timing Cee To Typical Scenario s which may cause the Ignition timing light ee to be out of specification e The Driveplate Flywheel has been removed amp re installed in the wrong place 1 bolt hole out etc Only use the Timing Light adapter SST NEVER e The inlet camshaft variable timing mechanism has use the loop wire in the harness jammed in the advanced or retarded position Typically due the engine oil never being changed e Foreign object has damaged the sensor pick up ring on the Driveplate Flywheel Remove the starter motor or inspection plate to check inside the bell housing e Foreign object material has damaged obstructed the camshaft signal plate sensor e Idle Air Volume Learn IAVL hasn t Completed CMPLT e Target Ignition Timing Adj located in WORK SUPPORT in CONSULT is incorrectly set a i Ay i QX Z 2 NOTE Y61 TB48 engines require inspection adjustment of the ignition timing every 20 000km s 17 NISSAN Learning Academy Petrol Engine Trouble Diagnosis PETROL ENGINE TROUBLE DIAGNOSIS Basic Service 3 Accel r Pedal Released Pos n Learning amp Throttle Valve Closed Pos n Learning 1 Voltage value s output from Throttle Position Sensor TPS amp Accelerator Position Sensor
24. el Fuel entering combustion chamber via the vacuum hose connected to it This applies to engines with a return type fuel system only e Try a known good Mass Air Flow Sensor 22 A F ALPHA Indicates LEAN Well above 100 Check the following Items e Air Leaks before amp after the throttle or in the Inlet Manifold Gaskets seals hoses cracks etc e Air Leaks in the Engine Gaskets seals rocker cover oil cap dip stick rear main oil seal etc e Air Leaks in Exhaust Manifold gaskets flange gaskets cracks etc e Engine is lacking Fuel Fuel pressure is too low pump output is poor fuel filter tank pick up Is blocked hoses kinked blocked or the pressure regulator not maintaining the pressure correctly e Cylinder miss fire due to bad spark Worn non genuine spark plug faulty coil coil connection coil ground connection e Cylinder miss fire due to bad no injector operation injector dribbling fuel not spraying e Interference with the airflow through the air intake Possible blockage or modified air intake system e Try a known good Mass Air Flow Sensor NISSAN Learning Academy Petrol Engine Trouble Diagnosis PETROL ENGINE TROUBLE DIAGNOSIS 7 B FUEL SCHDL Inspection Base Fuel Schedule DATA MONITOR SPEC 0 1600 3200 4800 6400 Fuel Delivery Decrease pe Fuel Delivery Increase Procedure 1 Road Test vehicle briskly for 10 km s Engine amp Transmission sh
25. he Engine Powertrain Control Module ECM PCM Dual knock sensors Air Fuel Ratio Sensors Wide Band O2 Sensors Reducing engine idle speed Electric Power Steering to delete the need for the engine to drive a Power Steer Pump Increasing the compression ratio e g from 9 7 1 to 10 3 1 Changing to a lower viscosity engine oils e g Change to 5W30 from 10W30 Optimising valve opening duration via dual independent variable camshaft timing Adding a smart alternator requiring less engine power Adding a new fast warm up transmission oil heat exchanger Revised shift strategy for automatic transmission and reducing torque converter lockup ON speed e g reduce the switch ON speed by 230 rom to 1300 rpm e Reduction of Hydrocarbons via o Improved sealing of fuel tanks amp fuel tank emission EVAP system improvements o Improved plastic materials plastics are a source of hydrocarbons as well Another major change with the implementation of Euro Ill is the inclusion of OBD or On Board Diagnostics OBD is an on board diagnostic system that constantly monitors the emission control system for any possible change in emission performance If the system monitors any event that results in emissions exceeding the ADR prescribed OBD thresholds the system logs the event lf a similar event occurs in the same drive or the next drive the driver is made aware of the two incidents via an indicator light in the dashboard e C11 MR18DE
26. ignal sent to ECM ECM Drives throttle 12V DC valve MOTOR Throttle position sensor in CH 5 v S a 2 0 3 n D Ss t E a 5 5o Oo 4 _ 0 45 30 135 0 Accelerator pedal opening angle deg Throttle valve opening angle deg NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 ELECTRIC THROTTLE CONTROL Duty Control Numerous electrical devices are controlled via Duty Control This can also be referred to as Pulse Width Modulation This is a simple means of variable current control of a device to any desired speed or position dependant on the device being controlled such as solenoids or motors Example Control of a Simple 12V DC Fan Motor 1 The 1st diagram to the above right shows the Fan Motor controlled switched internally via an ECM It is currently OFF Therefore it s rotation speed is Orpm 2 The 2 diagram shows the Fan motor switched to ON It s rotation speed is 3000rpm There are NO resistors in the wiring or switches It is being fed the full amount of battery power 3 Here the ECM switches the small switch ON amp OFF repeatedly The switch is ON for 1 second The switch then goes OFF for another second Then it goes back to ON for 1 second Half the time OFF vs Half the time ON means the fan motor only works at approximately half speed 1500rpm If the switch was ON for 2 seconds amp OFF for 1 second the fan would rotate at approx
27. imately 2000rpm Obviously the ON amp OFF switching will cause a notable speed up amp slow down of the motor every 1 second It s operation won t be very smooth Therefore the ECM switches ON to OFF in smaller increments of time such as Milliseconds to smooth out the operation of the device 4 The last diagram shows the traditional means of current control via a simple hand operated switch There are only 3 speed possibilities available Orom 1500rpm amp 3000rpm Lo speed 1500rpm is achieved via the current being fed to the motor through a resistor The Hi speed circuit has no resistor Switch pulsed continuously ON amp OFF f TRADITIONAL MEANS OF VARIABLE CURRENT CONTROL THERE ARE ONLY 3 POSSIBILITES NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 ELECTRIC THROTTLE CONTROL ETC Failure Modes Throttle Actuator Motor Should there be a failure of the Throttle Actuator Motor the ECM will be unable to control the throttle valve In this case the internal spring mechanism will provide around 10 throttle opening which will allow the engine to run up to approx 1 100 2 000 RPM and be driven to a place of repair The ECM will still have small amount of control over engine speed If the Accelerator Pedal Position Sensor is working normally the ECM will vary the ignition timing retarding or injector operation to pull the engine speed lower for idle When the acceler
28. ing styles patterns Short stop start trips only Aggressive driving style vs gentle 26 DF EURO Ill EMISSIONS Euro Ill or ADR 79 01 is a new tailpipe emission level requirement that restricts hydrocarbon emissions to 0 2gm km oxides of nitrogen to 0 15 grams per kilometre and carbon monoxide to 2 3 grams per kilometre Current exhaust emission limits ADR 79 00 or Euro II restrict hydrocarbon and oxides of nitrogen emissions to 0 5 grams per kilometre and carbon monoxide to 2 2 grams per kilometre Table 1 Vehicle emission guidelines Guidelines Date of Allowable emissions g km implementation in Carbon Hydrocarbons Oxides of nitrogen Australia monoxide CO NOx ADR 37 00 1986 9 3 0 93 1 93 ADR 37 01 1997 99 2 1 0 26 0 63 ADR 79 00 Euro 2 2003 04 2 2 0 5 combined ADR 79 01 Euro 3 2005 06 2 3 0 2 0 15 Under Euro Ill requirements all new vehicles must meet the new lower tailpipe emission levels for at least 80 000 kilometres from new A new condition included in Euro Ill testing is a more stringent low ambient temperature tailpipe requirement which entails testing at 7 degrees Celsius Typical Design Changes amp Features Certifying all engines to the new ADR 79 01 Euro III generally has been achieved in various ways by vehicle manufacturers as follows e Upgrade to the catalytic converter e g split brick design or additional catalytic converters Upgrades to the existing software in t
29. le Air Volume Learn IAVL operation 18 NISSAN Learning Academy Petrol Engine Trouble Diagnosis PETROL ENGINE TROUBLE DIAGNOSIS Basic Service ax eal e TOA 4 Idle Air Volume Learn IAVL WEM YEZ The completion of this operation in around 15 20 seconds is a good indication that the engine operation is OK Reasons why the IAVL will not CMPLT e Both Target settings found in WORK SUPPORT on CONSULT are not set to 0 PLT e Engine is not at operating temperature Even though the Engine may feel hot make sure this temperature is indicated in DATA MONITOR on CONSULT e Engine is too hot above 90 deg C e Poor Power Supply to ECM e Bad Ground Connections for ECM Position Learn procedure e An Electrical Load is ON Heater fan lights audio For all other ETC engines carry out the Idle e Switch inputs such as P N Posi Power Steering Air Volume Learn procedure pressure are indicating that the transmission is in Neutral or the Power Steering system is under load e There is a BASIC ENGINE MECHANICAL problem such as an intake system air leak compression issues fuel supply issues or ignition system issues e The Accelerator Pedal Released Position Learning amp Closed Throttle Position Learning has NOT been carried out properly It may need to be repeated up to 20 times e Throttle valve isn t closed properly Typically excessive carbon is fouling the operation of the thro
30. livery Decrease inspection 23 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 PETROL ENGINE TROUBLE DIAGNOSIS B F SCHDL Indicates a Fuel Delivery Decrease Check the following Items Interference with Air Flow through the intake system e Restriction of Air Flow e Blocked Air Filter e Modified Air Intake System Non standard components in Air Intake system have been fitted e Valve clearances incorrect e Engine Compression is not to spec Try a known good MAFS B F SCHDL Indicates a Fuel Delivery Increase Check the following Items Excessive Engine Friction e High viscosity Engine Oil Use correct grade of engine oil for the engine e Engine Oil Level too high e Engine Oil is overdue for changing High viscosity e Excessive external drive belt tension e Mechanical fault with engine High engine load required to turn engine e Mechanical fault in Transmission High engine load required to drive transmission Insufficient Combustion e Valve clearances incorrect e Valve Timing incorrect Correlation between camshaft amp crankshaft is incorrect e Intake Valve Timing Control mechanism fault Valve timing advance retard unit could be jammed Other e Interference with the airflow through the air intake Possible blockage or modified air intake system e Try a known good MAFS NISSAN Learning Academy Petrol Engine Trouble
31. ll modern petrol engines have Oxygen Sensors installed in the exhaust manifold These sensors generate a voltage signal amp sends this voltage back to the ECM A varying amount of Oxygen seen by the sensor will create a varying voltage signal The ECM sees this varying voltage amp then it MAKES AN ASSUMPTION ON HOW MUCH FUEL ENTERED THE COMBUSTION CHAMBER If the Oxygen Sensor O2S measures a HIGH level of Oxygen This will tell the ECM the A F Ratio was LEAN Therefore on the engines next cycle the ECM will add MORE Fuel If the Oxygen Sensor O2S measures a LOW level of Oxygen This will tell the ECM the A F Ratio was RICH Therefore on the engines next cycle the ECM will add LESS Fuel Small Amount of Fuel LEAN This condition will create a situation where the A F mix will have a short burn time There is not enough fuel to make a long burn time Since the small quantity of fuel has quickly burnt up the burning will stop amp there will be a certain amount of Oxygen remaining amongst the exhaust gases These gases are expelled out the exhaust valve the O2 Sensor samples these spent gases amp there it will see this remaining O2 content This will create a voltage signal which indicates to the ECM that the amount of fuel that was sprayed out of the injector was a small amount therefore next cycle it will increase the injection rate Large Amount of Fuel RICH This condition will create a situation where the A F mix will have a lo
32. ng burn time There is now more fuel to make a longer burn time Since the larger quantity of fuel makes a longer burn time nearly the entire O2 content will burn The spent gases left over in the combustion chamber will contain very little if any O2 content These gases are expelled out the exhaust valve the O2 Sensor samples these spent gases amp there it will see that there is hardly any remaining O2 content This will create a voltage signal which indicates to the ECM that the amount of fuel that was sprayed out of the injector was a large amount therefore next cycle it will decrease the injection rate 10 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 O2 MEASUREMENT Ideal Air Fuel Mix 14 7 1 The right amount of Air to Fuel will result in an ideal ise R ANAS burn k Coen TY AWN EXHAUST LEAN by Short Injection Duration Excess of Air to Fuel The injector is opened for a short period of time by the ECM Only a small amount of fuel enters the combustion chamber This results in a short burn time therefore some O2 content will be left over after the burning has stopped This left over content of O2 is i ih expelled amp then seen by the O2 sensor This signals to j 7 I the ECM that the mix was lean therefore will result in gl Bi 02i an increased rate of injection more fuel for the next Sensor cycle i SMALL INJECTION QUANTITY LEAN by Fuel
33. nosis Nissan Australia May 2009 PETROL ENGINE TROUBLE DIAGNOSIS STEP 1 Check In STEP 2 STEP 2a Verify on the vehicle what the incident is amp compare 7 to what is described by the Customer eli PECAN Wii Are there any Fault Codes DTC s STEP 4a STEP 5a No The fault is basic FUEL AIR SPARK POWER GROUND Yes STEP 5b STEP 4b 1 Refer to page in SM that is 1 Refer to Symptoms Matrix Chart in relevant to the DTC the SM in conjunction with the 2 Inform TechLine of the fault and information on the following pages the actions that YOU have so far 2 Inform TechLine of the fault and carried out amp other info gathered if the the actions that YOU have so far problem persists carried out amp other info gathered if the problem persists PRIOR TO COMPLETION OF REPAIR AND HANDING BACK TO THE CUSTOMER 1 Go through the checklist on the following page Consider each item in the list in relation to the problem experienced REGARDLESS if the problem is there or not 2 Carry out the IDLE AIR VOLUME LEARN IAVL operation in WORK SUPPORT Ensure CMPLT is achieved 3 Carry out the A F ALPHA inspection with CONSULT II in DATA MONITOR SPEC 4 Carry out the B FUEL SCHDL inspection with CONSULT II in DATA MONITOR SPEC 5 Take vehicle on a thorough road test re check for any DTC s amp re do IAVL on return from road test For earlier vehicles carry out Base
34. ould be at operating temperature 2 Confirm that the IAVL can be successfully completed 3 Ideally the vehicle should have more than 5000km s on it Vehicle has been properly run in 4 Ensure that the engine has been properly serviced Ensure the correct grade type of oil is in the engine amp the level is correct Ensure components such as spark plugs air filters etc are serviceable genuine parts Ensure that the correct Part Numbered components have been installed 5 Ideally the barometric pressure should be 98 3 104 3 kPa 6 Ideally the atmospheric temperature is between 20 30 deg C 7 Engine speed is idling The IAVL must have achieved a CMPLT 8 With CONSULT select options in the following order ENGINE DATA MONITOR SPEC SELECTION FROM MENU B FUEL SCHDL START The screen in the graphic above should now appear 9 With the engine under the conditions requested in steps 1 6 what does the black bar indicator do i Does it remain stable and central within the hashed area If so this is OK See earlier page for A F ALPHA inspection amp check If A F ALPHA as well as B FUEL SCHDL is OK engine condition is normal ii Does it move out of the hashed area below the indicated value If so see next page for Fuel Delivery Increase inspection iii Does it move out of the hashed area above the indicated value If so see next page for Fuel De
35. passages are made up to control airflow under certain conditions etc Numerous combinations of Idle Speed control are required to cope with numerous situations Therefore this saw the need for numerous passages amp idle solenoid devices to be added to the intake manifold throttle body in order to satisfy all these conditions Fast Idle Control Device FOCD For AIC Base Idle Screw Mechanically Adjustable Cable Controlled Throtihe Valve Cable connected to Accelerator Pedal Throttle Postion Sensor TF Ret Forces ong hee closed 7 Brown sending movement signal to ECM 1 Epas ng angle of valve as well as speed of move me Position Switch TP Sw Grey E AT only sending CLOSED or wide OPEN throttle signals to TC AAC Valve Heated electnically or by engine coolant NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 ELECTRIC THROTTLE CONTROL ETC System Components The ETC system consists of e Accelerator Pedal Position Sensor e Throttle Body with Throttle Actuator Motor e Throttle Position Sensor e ECM and associated wiring ALL AIR GOES PAST MAIN THROTTLE VALVE Air Flow continues 12V DC Motor to Engine Air from MAFS Accelerator p ee By nnansl eom Pedal Signal ECM drives the Throttle Valve motor sent to ECM lThrottle Valve movement is detected with 12V ON OFF control Duty Cycle by ECM via return signals from TPS 1 amp T
36. temperature which assists in minimising emission of Hydrocarbons from the fuel tank cap and lines Less components amp improved reliability are other benefits Current Models that use a Return less Fuel system are K12 C11 J31 J32 N16 with ETC R51 D40 T30 T31 J10 233 234 Z50 amp Z51 Pressure Regulator The Pressure Regulator is located in the fuel tank at the Fuel Pump Pressure fuel pump outlet It maintains fuel pressure typically at Filter and Regulator p p p yp y Sender Unit i Pre set non variable 350 kPa Modern engine management software and feedback from oxygen sensors allows the ECM to maintain correct fuel injection control with this constant Fuel Return fuel pressure Fuel Damper A fuel damper is usually located at the fuel rail and should not be confused with the old type pressure regulator as there is no return line or vacuum hose connected to it The fuel damper is only intended for noise reduction purposes Some engines may have two fuel dampers located at the fuel rail Fuel Filter The fuel filter is usually located in the tank with the fuel pump NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 RETURN amp RETURNLESS FUEL SYSTEMS Fuel Pressure Test on Return less Systems Injector Rail 1 Install the Fuel Pressure gauge on the engine Refer With Injectors to Section EC Basic Service in the Service Manual 2 Switch Ignition
37. ttle unit For T31 QR25 carry out the Closed Throttle 5 Fuel Pressure Check This is for engines that have a Returnless type of fuel aver pressure DOE O adapter KV10117600AUS q system only MNR O Ensure that there is a CONSTANT PRESSURE OF 350 M M kPa AT ALL TIMES whilst the engine is idling amp under full load The Fuel pressure should never vary Check the following items if the Fuel Pressure is too LOW e Blocked fuel pump pick up filter the fuel filter forms part of the pump assembly e Restricted fuel lines e Faulty fuel pressure regulator The pressure regulator also forms part of the fuel pump assembly If the Fuel Pressure is too HIGH replace the fuel pressure regulator 19 NISSAN Learning Academy Petrol Engine Trouble Diagnosis Nissan Australia May 2009 PETROL ENGINE TROUBLE DIAGNOSIS Basic Service el DA 6 Clearing the Self Learn Sei Select SELF LEARN CONTROL from the work Support menu amp then touch CLEAR SELF LEARNING CONT This operation clears the LONG TERM A F Alpha ono values stored in the ECM This should be carried out ea pm after a major engine service or after the repair of an engine running fault NOTE e ALPHA reading below 100 e g 75 indicates that the engine is running TOO RICH e ALPHA reading above 100 e g 125 indicates that the engine is running TOO LEAN or has a missfire condition
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