mvp-er service manual
Contents
1. Injection When the ECM determines the injector should fire the fol lowing sequence of events occurs e ECM sends signal pulse to injector solenoid Solenoid is fully energized almost instantly creating a strong magnetic pull on the armature The armature is connected to the poppet valve The injec tion process begins when e Magnetic pull of solenoid overcome spring tension holding the poppet closed e Poppet is quickly raised off its seat When poppet valve opens e Upper poppet land closes off path to drain Page 13 17 MVP ER SERVICE MANUAL Page 13 18 e Lower land opens poppet chamber to incoming high pressure oil e High pressure oil flows around poppet to the top of intensifier piston Pressure on the top of the intensifier forces it down along with the plunger The downward movement of the plunger pressurizes the fuel in the plunger cavity and nozzle When the fuel pressure reaches Valve Opening Pressure VOP of about 4 500 psi the nozzle valve lifts off its seat and injection begins As long as the solenoid is energized the poppet remains open and pressurized oil continues to flow in pushing down the intensifier and plunger Injection pressure ranges from 5 000 21 000 psi depending on engine requirements Injection continues until the solenoid is de energized allowing the poppet spring to close the poppet and shut off the high pressure oil INJECTION E Atmospheric Pressure B Injector2. 34 not to damage transmission 35 oil pan with transmission 36 jack and that the unit cannot slip on jack Disconnect air line at D 2 governor Disconnect pressure hose from hydraulic pump Disconnect oil pressure hose from engine block at rear of power steering pump Remove fuel filter assembly from it s mounting bracket remove with engine package Disconnect fuel return hose at rear of engine Disconnect fan clutch air line at fan clutch solenoid pull hose back over to radiator side Remove battery positive cable from starter post Remove battery ground cable and chassis ground cable from starter ground post Disconnect chassis harness from ECU module Disconnect intake air temperature sensor harness at con nector Disconnect coolant temperature sensor s at front of engine Disconnect alternator field and tachometer wires at alter nator All above circuits are included into a 1 2 convoluted har ness Cut tie wraps and pull this harness back to rear and right side of chassis Remove battery cable from alternator pull cable off to right side of chassis Remove heater hoses at engine cut off valves Disconnect exhaust pipe from turbocharger hang off out of way Remove transmission dipstick tube from transmission Disconnect transmission oil temperature sensor wire Disconnect chassis harness from transmission at the con nector on right side of transmission Disconnect from sen sor wire Disconnect trans
3. Throttle Position Sensor Test Procedure To test the TPS for being functional a meter that measures fre quency and duty cycle is required such as the FLUKE model 87 This particular meter is also a volt ohm meter 1 Ignition switch must be OFF 2 Disconnect the harness connector going to the throttle sensor not any other connector This connector is locat ed behind the left side windshield wiper motor access door 3 Install a breakout T harness between the sensor and the chassis harness 4 Turn Ignition switch ON 5 Set the meter to Duty Cycle position Measure the duty cycle across Ground pin B and Signal pin 6 Closed throttle reading should be 10 22 Full throttle should be 75 90 If the percentage figures fall within these ranges the sen sor is good The same test can be made using the Caterpillar Electronic Analyzer and Programmer toll their model 8T9697 and tool 8C9801 PWM Signal Adapter Page 13 7 MVP ER SERVICE MANUAL To make up a breakout T harness 1 Join three 12 10 AWG wires in the center of each with a 6 20 AWG wire making sure of 100 bond 2 Place male Deutch connector DT 04 3P E004 on one end of the three 12 wires 3 Place a female Deutch connector on the opposite end and on the 6 lead 4 Using Caterpillar crimping tool 1U5804 crimp the termi nals onto each wire See Figure 1 EMALE DEUTCH DT 06 35 E003 FEMALE DEUTCH MALE DEUTCH DT O6 3S
4. Pressures An intensifier piston in the HEUI injector multiplies hydraulic force on the plunger By varying hydraulic input pressure injec tion pressure can be controlled in a range from 5 000 to 21 000 psi These high pressures are available at idle as well as high engine speeds The higher injection pressures improve fuel economy performance and emission capabilities High Injector Actuation Pressure Control Valve Signal from ECM to injector solenoids IAPCV High Pressure Ol Manifold So a A i J Pressure Oil Pump HEUI System Components 1 Electronic Control Module ECM The ECM is a microprocessor based system which mon itors various inputs and sensors from the vehicle and engine as it controls the operation of the entire fuel sys tem It contains information defining optimum fuel system operational parameters The ECM also has many more external operational inputs than a mechanical governor such as engine speed timing rail pressure boost pres sure etc It can determine optimum fuel rate and injection timing for any condition It sends a precisely controlled signal to energize the injector solenoid Electronic con Page 13 13 MVP ER SERVICE MANUAL trols such as these are invaluable in meeting new stan dards of exhaust emissions and noise while maintaining excellent fuel econ
5. and bleeding the cooling system Fan belt installation and adjustment is also covered in this section A Caution Take See Caution in the margin extreme care to see that no 7 After all fluids lubricants etc have been installed loose bolts nuts washers remove the fuel solenoid wire from the fuel solenoid Spin debris are inside any of the the engine over with the starter until pressure is regis pipes hoses used in the tered on the oil pressure gauge Reconnect the solenoid engine intake air system wire start the engine and check for leaks proper opera otherwise severe damage tion can be caused to the tur g Top off all fluid levels Test drive unit for several miles for bocharger and inside the proper performance leaks etc combustion chambers Page 13 25
6. flash rapidly 90 seconds before the engine shuts down The driver can over ride the timer by depressing the brake pedal if necessary by doing so while the light is flashing This is only if idle shutdown timer has been programmed to be overridden Engine Water Temperature Monitoring System One of the features of the ECM system monitors the temperature of the coolant At 2250F 1070C the Check Engine lamp will come ON If programmed at that point the engine will gradually derate in horsepower to a minimum of 120 hp and road speed will gradually reduce to 45 mph This gives the operator ample time to get off the road and prevent damage to the engine All drivers should be advised of this feature Page 13 3 MVP ER SERVICE MANUAL The ECM System Diagnostics The ECM provides a flash code in the dash mounted Check Engine lamp in the event of malfunction in or of some compo nent of the electronic control system When the ECM detects a problem the Check Engine light will come ON or is activated At that time a failure diagnostic code will be entered and stored in the ECM memory The failure code can be retrieved by 1 using the Caterpillar Electronic Control Service tool or 2 using the Check Engine light if the bus is equipped with cruise con trol Check Engine Light Operation When the ignition switch is turned ON the lamp will illuminate for 5 seconds which is a check to insure the lamp is working The ECM can
7. Actuation Pressure Fuel Supply Pressure W injector Pressure MVP ER SERVICE MANUAL 3 End of Injection Drain Cycle The end of the injection cycle begins when the ECM terminates the electric pulse to the solenoid The fol lowing events occur a The magnetic field of the solenoid collapses and is no longer able to overcome poppet spring ten sion to hold the poppet off its seat The poppet closes shutting off high pressure oil from entering the injector When the poppet is seated the upper land of the poppet opens the poppet cavity to drain Pressurized oil in the intensifier chamber and poppet chamber flows upward around the poppet seat through the vent holes in the poppet sleeve and out the adapter drain hole The pressure of the fuel in the plunger cavity exerts an upward force on the plunger and inten sifier As the pressure of the pressurized oil above the intensifier drops so does the downward force on the intensifier END OF INJECTION Atmospheric Pressure 8 Injector Actuation Pressure W Fuel Supply Pressure Page 13 19 MVP ER SERVICE MANUAL The upward force from the pressurized fuel almost instantly becomes greater than the down ward force on the intensifier so the downward motion of the intensifier and plunger stops When the plunger stops fuel flow also stops With the check still open the remaining pressure on the fuel pushes a tiny amount of additional fuel out the orific
8. CM is a programmed tamper resis tance This prevents the vehicle from exceeding its preset max imum road speed in the event the vehicle speed signal is lost Example Assume the rear axle ratio would allow the vehicle to run 72 mph at 2400 rpm however management wants a maxi mum of 60 mph This is programmed into the ECM by the facto ry which means the engine would be turning over only 1600 rpm These are only figures used for the purpose of explaining how the Vehicle Speed Limit works IF the speed signal is lost the bus would run 72 mph without the tamper resistance feature With this feature however it will run only 60 mph and under greatly reduced power Caterpillar Hydraulic Electronic Unit Injector System The Caterpillar Hydraulic Electronic Unit Injector HEUI system uses the ECM to control the injection of fuel using high pressure engine oil to provide the muscle instead of a cam shaft In a conventional mechanical fuel system fuel injection pressures increases proportionally with engine speed whereas the HEUI is electronically controlled independent of engine speed Both the start and end of injection are electronically controlled Plunger movement timing is NOT limited to the speed or shape of a camshaft The next several pages describe how the HEUI sys tem operates Page 13 10 DIAGNOSTIC FLASH CODE 01 Idle Shutdown Override 15 Injection Actuation Pressure Sensor Fault 17 Excessive Injection Actuation P
9. E003 DTO04 3P E008 Figure There may be times when it is more expedient to install a new sensor or a new ECM in a process of elimination which means it would be wise to have one of each in stock Troubleshooting the Throttle Position Sensor System Considerable training is required of the service technicians and investment must be made in some new sophisticated test equip ment as well as having on hand the appropriate service and troubleshooting manuals from Caterpillar The most critical man ual is Caterpillar Electronic Troubleshooting 7AS1 UP avail able from your area Caterpillar dealer This manual goes through a step by step sequence in checking any given fault code that appears on the dash light Other Items Related to Operating the 3126 HEUI Engine As mentioned earlier all who are involved in operating and ser vicing this engine are encouraged to study the 3100 HEUI Page 13 8 MVP ER SERVICE MANUAL Operation and Maintenance Manual furnished with the bus Most comments made herein are excerpts from that manual and are intended only to provide a broad overview of what the ECM does and how the 3126 differs from older engines as far as the fuel system is concerned 1 Operating units with winterfront shutters refer to the sec tion related to the cooling system 2 Fuel lubricating oil and coolant requirements are cov ered in the Caterpillar manual 3 Jump starting no special precautions n
10. MVP ER SERVICE MANUAL Caterpillar 3126 HEUI Engines The Caterpillar 3126 HEUI Engine introduces a new era of the diesel engine in the bus industry using the medium duty diesel engine The basic engine takes advantage of the 3116 s best features and years of experience and combines this with an electronically controlled fuel system larger displacement and other new features to produce the 3126 The fuel delivery system is controlled entirely by the Electronic Control Module hereafter called the ECM The actual delivery of the fuel into the combustion chambers is accomplished by the Hydraulic Electronic Unit Injector system HEUI which will be discussed later The ECM will identify short open sensors or operating conditions out of the normal range It will alert the driver mechanic through the use of failure codes that are displayed on the dash At this point be advised that all subjects related to the operation and maintenance of the engine are covered in the 3100 HEUI manual provided with the chassis manual Therefore no attempt is made herein to cover engine repairs Service and operating instructions found in the Caterpillar manuals should be followed When in need of information concerning the engine contact your local Caterpillar dealer or distributor who is fully qualified and capable of handling all engine warranty and service repairs Those responsible for operating and maintaining the buses pow Page 13 1 MVP E
11. R SERVICE MANUAL ered by the 3126 engine are encouraged to read and study the Caterpillar Operation and Maintenance manual at the earliest opportunity Certain operational characteristics should be dis cussed with the bus operators to familiarize them on how the ECM controls various functions Electronic Control Module The ECM controls its various functions through signals from the following sensors Injection Actuation Pressure Turbo Boost Pressure Engine Speed Engine Timing Coolant Temperature Air Intake Temperature Throttle Position Vehicle Speed The ECM provides total electronic control of the start and dura tion of fuel injection Data furnished by the sensors enable the ECM to control the fuel injected into each cylinder which opti mizes performance related to Normal and Cold weather starting warm up emissions noise fuel economy and driveability Top Engine Limit The ECM controls the top rpm of the engine which is 2640 set at the factory by limiting the fuel to the injectors The engine does not have a mechanical governor Start Up and Emission Control White smoke is reduced by controlling injection timing and deliv ery during cold operation and acceleration The ECM uses vari ous sensor inputs to calculate timing and delivery that will not produce smoke Vehicle Speed Limit Maximum road speed is predetermined by the owner operator at time of writing the specifications for the bus and is programme
12. be programmed to notify the driver of an active fault or condition by blinking the lamp every 5 seconds after start up The Check Engine lamp is also used to warn by flashing rapid ly that the Idle Shutdown Timer will shut the engine down in 90 seconds The driver can override the timer by depressing the brake pedal if necessary by doing so while the light is flashing This is only if idle shutdown timer has been programmed to be overridden Retrieval of a Failure Code If the bus is equipped with Cruise Control the failure code can be determined by the procedure outlined below If not so equipped it will be necessary to use an Electronic Control Service tool that is available from your Caterpillar dealer or from certain other major tool suppliers Use of the service tool will enable the mechanic to retrieve codes stored in the ECM memory system for periods longer than a day Using the Cruise Control to Determine a Failure Code 1 Start the engine 2 Turn the Cruise Control switch to the OFF position 3 Move the SET RESUME switch to either position and hold that position until the Check Engine lamp begins to Page 13 4 MVP ER SERVICE MANUAL flash The lamp will then flash to indicate a 2 digit code Release the Cruise Control switch at this point Count the first sequence of flashes to determine the first digit of the failure code After a 2 second pause the second digit of the failure code will be flashed by the
13. controlled engines have several harnesses and hoses that are a part of the engine package and can be removed with the engine assembly Removing them and replacing them with the engine in place can be very time consuming Study these items before beginning the engine removal process The following suggestions are intended to remove the engine and transmission as a package along with some of the hoses and harnesses The limited space between the engine and frame rail on the right side makes access difficult to some of the connections Some may elect to remove the transmission first this is a local decision Engine Removal 1 2 o on 10 All steps mentioned above have been observed Remove the engine compartment rear door if a fork lift is to be used to pull the engine Remove body rear bumper assembly Remove chassis rear bumper and chassis upper cross bar Remove fan drive belt See Cooling Section Remove charge air cooler hoses and piping Cover all openings Remove intake air cleaner piping and hoses as neces sary Cover opening Disconnect all coolant hoses from engine Remove hydraulic reservoir from chassis for better access to right side of engine Disconnect main discharge air line from air compressor Page 13 22 MVP ER SERVICE MANUAL 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 caution Make sure
14. d Page 13 2 MVP ER SERVICE MANUAL Note All circuits powered by the ignition switch will remain HOT after the timer shuts OFF To avoid draining the batteries the ignition switch must be turned OFF at that time Note Excessive coolant temperature will not shut down the engine into the ECM by the factory When the programmed speed limit is reached the fuel to the injectors is limited and will remain lim ited until the bus slows to a speed below the limited speed Provisions have been made in the 3126 HEUI furnished by Thomas to allow for the fuel to be gradually reduced as maxi mum speed is approached or about 2 5 mph before This process called Soft Vehicle Speed Limiting prevents a sudden reduction of fuel at the top limit The soft vehicle speed limiting causes the engine to operate at a reduced rpm while maintaining the desired maximum road speed a must if the best fuel economy is to be realized Engine Fast Idle The engine is set to idle at 700 rpm by the factory however pro visions can be made for a fast idle of 1000 rpm on buses oper ating in cold climates This requires a dash mounted ON OFF switch with an Enabled Indicator Light on the switch Idle Shutdown Timer The idle shutdown timer is designed to shut the engine OFF after a predetermined period of idling This can be between 3 minutes and 60 minutes depending on the initial programming The Check Engine light on the dash will begin to
15. e fuel in the plunger cavity causing the noz zle to open Thus 3 000 psi oil provides fuel injection pressures of 21 000 psi Electronic Solenoid Poppet Valve Poppet Seat Intensifier Piston Plunger Fill Ball Check 4 Nozzle Assembly The nozzle assembly is of conventional design with the exception of the fill check This check ball seats and seals during the downward stroke of the plunger to prevent leakage of the high pressure fuel During the return stroke it unseats allowing the plunger cavity to fill The nozzle valve is an inwardly opening type which lifts off its seat when pressure overcomes the spring force Fuel is then atomized at high pressure through the nozzle tip Stages of Injection There are three stages of injection with HEUI 1 Fill Cycle During pre injection all internal components have returned to their spring loaded non actuated positions Page 13 16 2 MVP ER SERVICE MANUAL The solenoid is not energized and the poppet valve is blocking high pressure oil from entering the injector The plunger and intensifier are at the top of their bore and the plunger cavity is full of fuel Fuel pressure in the plunger cavity is the same as fuel rail pressure about 30 psi depending on conditions FILL CYCLE Atmospheric Pressure 2 Injector Actuation Pressure W Fuel Supply Pressure
16. e holes This causes a large pressure drop which lowers nozzle pressure below Valve Closing Pressure VCP of 3 200 psi Spring ten sion on the check then reseats the check and injection stops b Fill Cycle When the check closes injection stops and the fill cycle starts as follows Page 13 20 The poppet and intensifier cavities are open to atmospheric pressure through the poppet valve and adapter drain hole Pressure drops very rapidly in the intensifier and plunger cavities to near zero FILL CYCLE Atmospheric Pressure 84 Injector Actuation Pressure W Fuel Supply Pressure MVP ER SERVICE MANUAL e The plunger return spring pushes upward on the plunger and intensifier forcing oil around the pop pet through the holes in the poppet sleeve and out the adapter drain hole e As the plunger rises pressure in the plunger cav ity also drops to near zero The fuel rail pressure unseats the plunger fill check allowing the plunger cavity to fill with fuel e The fill cycle ends when the intensifier is pushed to the top of its bore e The plunger cavity is full and the fill check returns to its seat e Pressure in the intensifier and poppet chambers is zero e The injection cycle is complete and is ready to begin again Engine Replacement No attempt is made herein to cover subjects related to mainte nance and repairs to the Caterpillar Engine These services are covered in the engine manual furnished by the Ca
17. eed to be taken to protect the electronic system other than what you would normally do in any jump starting operation Welding on the Chassis Before welding on this bus equipped with an electronically con trolled engine the following precautions should be observed 1 Disconnect all cables connected to the batteries 2 Disconnect both electrical connectors at the ECM 3 Do NOT use the ECM or engine ground stud for ground ing the welder Customer Specifications The customer determines certain parameters when writing the specifications for this bus See page 13 12 At that time he or she was given the option of programming a password into the ECM Unless the correct password is entered it is impossible to change the maximum engine RPM originally programmed The same thing applies to the Vehicle Maximum Speed limit and any other parameters that the customer specified Certain features of the ECM system are controlled only by Caterpillar consequent ly Caterpillar has its own password However customer pass words are not required for the engine to operate The purpose is to prevent unauthorized alterations of the system as originally set up If the customer password s is are forgotten or misplaced arrangements have to be made with the Caterpillar dealer to obtain the factory password if a change in one of the features is desired Page 13 9 MVP ER SERVICE MANUAL Tamper Resistance One of the features of the E
18. engine lamp If additional faults have occurred the applicable failure code s will then be flashed after a short pause Flash code 55 signals No Detected Faults have occurred since the ignition switch was turned ON This subject is covered more in detail on pages 50 and 51 in the 3100 HEUI Operation and Maintenance Manual For various failure codes see the chart on page 13 11 for Diagnostic Flash Codes Engine Performance Relationship Initial Start Up When coolant temperature is below 64 F 18 C the ECM caus es the engine to operate in a COLD MODE During the COLD MODE operation the engine will operate at the predetermined FAST IDLE 1000 rpm horsepower is limited and under certain conditions the AIR INLET Heater may operate The engine should not be operated under full load until coolant temperature reaches 1600F 710C which will reduce the possibility of stick ing valves due to a build up of unburned fuel on the valve stems Inlet Air Heater and Lamp The Inlet Air system incorporates an Inlet Air Heater in the intake manifold and a MAN HTR Lamp on the dash connected in par allel When the heater is ON the dash lamp is ON at the same time The Inlet Air Heater is used to improve startability in cold weath er and reduce white smoke The ECM controls the heater and lamp through a relay mounted beside the intake manifold Heater operation is determined during three stages of engine operation Power up Preheat Cran
19. environmental conditions such as cold weather start up of engine or cold weather operation at high altitude 2 These Diagnostic Flash Codes reduce the effectiveness of the engine monitoring feature when active Shutdown Vehicle Drive the vehicle cautiously off the road and get immediate service Severe engine damage may result Service ASAP Driver should go to the nearest qualified service location Schedule Driver should have problem investigated when convenient SUGGESTED DRIVER ACTION Schedule Service Page 13 11 MVP ER SERVICE MANUAL Diagnostic Flash Code Engine Performance Relationship Chart Inside MVP ER SERVICE MANUAL CAT 3126 CUSTOMER PARAMETER WORKSHEET To accompany each order or parameters will be defaulted PARAMETER Vehicle Speed Limiting If customer doesn t specify speed will be set at 65 mph 105 km Actual maximum speed depends on axle ratio Seventy mph maximum speed allowed on school bus models Vehicle Speed Limiting Protection Idle Shutdown Timer Idle Shutdown Timer Override Maintenance Data PM Schedule Customer Password Customer Name PARAMETER SETTING MPH or KM Yes No Minutes 3 to 60 minutes Yes No Choose One Hours or Mileage KM Up to 8 digits letters or numbers Address City State Selling Distributor Distributor Order Number MVP ER SERVICE MANUAL Caterpillar 3126 Product News Higher Injection
20. ion of Page 13 14 MVP ER SERVICE MANUAL the pulse from the ECM and how long it keeps the sole noid energized As long as the solenoid is energized and the poppet valve is off its seat oil continues to push down the intensifier and plunger until the intensifier reaches the bottom of its bore Since the HEUI injector is the heart of the system let s look at its operation in detail Injector The HEUI injector is hydraulically actuated by high pressure engine oil supplied by the high pressure oil pump It consists of four major components 1 Solenoid The solenoid is a very fast acting electromagnet which when energized pulls the poppet valve off its seat Poppet Valve The poppet valve is held on its seat by a spring In this closed position high pressure inlet oil is blocked and the intensifier cavity is opened to drain When the solenoid is energized the poppet is quickly lifted off its seat The path to drain is closed and the inlet for high pressure oil is opened Intensifier Piston and Plunger When the poppet valve opens the inlet port high pressure oil enters the injector and acts on the top of the intensifi er piston Pressure builds on the intensifier pushing it and the plunger down The intensifier is six times larger in sur face area than the plunger providing six times multiplica Page 13 15 MVP ER SERVICE MANUAL tion of force The downward movement of the plunger pressurizes th
21. king and Engine Started cycle Page 13 5 MVP ER SERVICE MANUAL The ECM is powered up when the ignition switch is turned ON The heater lamp should glow for 2 seconds or so regardless of coolant temperature If the combination of coolant temperature and inlet air temperature is less than 77 F 25 C the ECM will turn the Inlet Air Heater and lamp ON for 30 seconds as a pre heat and then go OFF If the operator attempts to start the engine during the preheat cycle the ECM will take over control of the heater during the cranking cycle During the cranking cycle the heater will come ON if the com bined temperatures of the coolant and the Inlet Air is less than 77 F 25 C and will stay ON while cranking If the engine fails to start the heater will resume the 30 second preheat cycle After the engine has started the heater operation is still deter mined by the combined temperatures of the coolant and Inlet Air The engine started cycle has two parts a continuous mode followed by an ON OFF cycle The continuous mode lasts for a maximum of 7 minutes The ON OFF mode causes the heater to cycle ON and OFF at 10 second intervals The ON OFF mode can last up to 13 minutes Either of these modes can or will be interrupted when the com bined temperatures of the coolant and inlet air reaches 95 F 35 C A failure or malfunction in either the inlet air sensor or the coolant temperature sensor will show up a
22. mission oil cooler hoses Remove propeller shaft from transmission Secure shaft out of way Remove engine mount bolts front and rear Connect lifting mechanism to front of engine Place trans mission jack beneath transmission Lift engine and transmission slightly Remove front and rear engine support crossmembers Using an assistant to guide the rear of the assembly carefully pull the package from the chassis Page 13 23 MVP ER SERVICE MANUAL A Caution When pulling the package from the chassis make sure that all hoses harnesses and cables are disconnected and secured from possible damage Caution When mov ing the assembly into the chassis be careful to pre vent damage to hoses har nesses cables etc Note It may be advanta geous to loosen the cross member mounting brackets on one side of the frame if difficulty is experienced in installing the crossmembers to their mounting brackets 37 If anew or replacement engine is to be installed transfer all accessories hoses and harnesses to the new engine Make sure all are installed in exactly the same position and location as removed from old engine If this engine has over 250 000 miles consider replacing or rebuilding the alternator starter power steering pump and air compressor at this time if they have not been replaced before If the radiator has not been cleaned consider flushing it at this time Engine Installation Assumi
23. ng all accessories hoses harnesses etc have been installed on the replacement engine in the same position as removed form the old engine prepare the package for installa tion into the chassis Temporarily tie wrap all loose hoses or harnesses closely to the package to prevent entanglement as the engine is moved into place 1 With the engine front lift mechanism in place and the transmission jack securely in place position the package to ensure a minimum of problems while moving the assembly into the chassis With one or two assistants carefully move the assembly in place 2 Install front and rear engine support crossmembers After all crossmembers are in place torque all bolts to the val ues shown below All fasteners used on the Thomas chassis are SAE grade 8 Bolt Size Torque Value 280 ft lbs 320 fi lbs 170 ft lbs 180 ft lbs 80 fi lbs 90 fi lbs 3 Place engine mount isolators in place lower engine in place and install engine mount bolts Torque front and rear bolts to 226 ft lbs Page 13 24 MVP ER SERVICE MANUAL 4 At this point the most critical area of the installation process lies in the proper routing connecting and secur ing all items to safeguard against chafing or interference with other objects 5 Reverse the procedures outlined in removing the pack age and proceed with the installation process 6 Follow the instructions outlined in the cooling system sec tion as to filling
24. omy The ECM has the ability to store data on mileage fuel consumed and hours operated 2 High Pressure Oil Supply Pump The hydraulic supply pump is a seven piston fixed dis placement axial piston pump It raises the system s oil pressure level from typical engine operating oil pressure of 40 psi to the actuation pressure required by the injec tors of 870 to 3300 psi During normal engine operation pump output pressure is controlled by the Injector Actuation Pressure Control Valve IAPCV which dumps excess flow back to the return circuit Pressures for spe cific engine conditions are determined by the ECM 3 Injector Actuation Pressure Control Valve The IAPCV is an electrically operated dump valve which closely controls pump output pressure by dumping excess flow back to the oil sump A variable signal from the ECM to the IAPCV determines pump output pressure Pressure while cranking a cold engine below 50 F 109C is slightly higher because cold oil is thicker and components in the injector move slower The higher pres sure and advanced injection timing helps the injector to fire faster until the viscosity of the oil is reduced 4 HEUI Injector The injector uses the hydraulic energy of the pressurized oil to cause injection The pressure of the incoming oil controls the speed of the intensifier piston and plunger movement and therefore the rate of injection The amount of fuel injected is determined by the durat
25. ressure Fault 1 18 Injection Actuation Pressure Control Valve Driver Fault 19 Injection Actuation Pressure System Fault 21 Sensor Supply Voltage Fault 1 2 25 Boost Pressure Sensor Fault 1 27 Coolant Temperature Sensor Fault 1 2 28 Check Throttle Sensor Adjustment 31 Loss of Vehicle Speed Signal 32 Throttle Position Sensor Fault 34 Engine RPM Signal Fault 35 Engine Overspeed Warning 36 Vehicle Speed Signal Fault 38 Air Inlet Temperature Sensor Fault 1 2 41 Vehicle Overspeed Warning 47 Idle Shutdown Occurrence 49 Inlet Air Heater Driver Fault 1 51 Intermittent Battery Power to ECM 55 No Detected Faults 56 Check Customer System Parameters 59 Incorrect Engine Software 61 High Very High Coolant Temperature Warning 71 Cylinder 1 Fault 72 Cylinder 2 Fault 73 Cylinder 3 Fault 74 Cylinder 4 Fault 75 Cylinder 5 Fault 76 Cylinder 6 Fault 42 Check Sensor Calibrations MVP ER SERVICE MANUAL DIAGNOSTIC FLASH CODE ENGINE PERFORMANCE RELATIONSHIP 3100 HEUI DIESEL ENGINE EFFECT ON ENGINE PERFORMANCE Engine Low Engine Speed Engine Shutdown Service Misfire Power Reduced Shutdown Vehicle ASAP i NOTE An X indicates that the effect on engine performance WILL occur if the code is active An asterisk mark indicates that effect on engine performance MAY occur if the code is active 1 These Diagnostic Flash Codes may affect the system only under specific
26. s a flash code on the Check Engine lamp Throttle Fuel Control The Electronic Control Module ECM controls the fuel flow to the cylinders Instead of a direct rod cable from the accelerator pedal to the fuel pump the ECM receives a Pulse Width Modulation PWM from a throttle position sensor which incor porates a potentiometer The sensor is located on the back side of the accelerator pedal The ECM supplies 8 volts as input voltage to the potentiometer not 12 volts from the chassis system The throttle position sen Page 13 6 MVP ER SERVICE MANUAL A Caution DO NOT attempt to measure resis tance of the TPS To do so can cause catastrophic damage to the sensor sor runs at a fixed frequency and amplitude The 8 volts remain the same as does the frequency throughout the full range of pedal movement the only thing that changes is the number of pulses within an extremely short period of time The internal cir cuitry in the sensor causes a variation in the pulse width in the frequency depending on the position of the accelerator pedal The output signal from the sensor to the ECM is referred to as the Duty Cycle or Pulse Width Modulation and is expressed as a percentage between 3 and 100 At Low Idle the sensor will produce a duty cycle of 10 22 At Full Throttle it will be 75 90 This sensor produced duty cycle is translated in the ECM which determines the timing and amount of fuel delivered to the cylinders
27. terpillar These instructions should be followed at all times Your local Caterpillar facility is dedicated and capable of performing warranty repairs and other engine maintenance repairs Contact your local Caterpillar distributor on any questions or problems related to engine performance Some basic suggestions should be considered when preparing to remove the engine 1 Place the bus on a clean level smooth floor to facilitate easy movement of the floor crane fork lift and transmis sion jack Leave adequate room behind the bus to allow for safe removal of the engine package Set parking brakes chock rear wheels 3 Disconnect battery cables If the bus is to be idle for an extended period remove the batteries and place them on a trickle charge or use them elsewhere 4 Close the heater shut off valves to prevent draining the entire system 5 Drain coolant in a clean receptacle and store in a clean container N Page 13 21 MVP ER SERVICE MANUAL Drain engine oil transmission fluid hydraulic fluids and dispose according to local ordinances If a new or rebuilt engine is installed or coolant is conta minated remove the radiator and send it out for cleaning and flow testing Important Install identification tags on each electrical cir cuit harness connector air lines and hoses as they are removed This will save much time and confusion later as the replacement engine is installed The electronically
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