14.4 MISFIRING CYLINDER 14.4.1 Troubleshooting
Contents
1. a If the engine is not misfiring no further troubleshooting is required Shut down the engine b If the engine is misfiring check for improper valve clearance or worn or damaged camshaft lobes or rollers Shut down the engine refer to section 14 4 5 All information subject to change without notice 14 50 From Bulletin 1 MBE900 03 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION MBE 900 SERVICE MANUAL 14 4 5 Troubleshooting Procedure for Improper Valve Clearance Worn or Damaged Camshaft Lobes and Rollers Intake and exhaust valve clearance are adjusted by means of an adjusting set screw and locknut located at the push rod end of the rocker arm See Figure 14 1 for intake valves Exhaust valve is similar A VALVE LASH B VALVE LIFT 42307 1 Rocker Arm 3 Intake Valves 2 Pushrod 4 Valve Bridge Figure 14 1 Intake Valves To determine if improper valve clearance is causing the cylinder to misfire determine if a worn or damaged cam lobe or followers is causing the misfire 1 Barthe engine over and inspect the camshaft and roller followers for wear or damage a If damage is found on the camshaft lobes or roller followers replace damaged components as necessary b If no damage was found to camshaft or roller followers continue with task Verify the proper lash setting following the procedure in the Valve Lash2. 1 Use the Service Link to detect any fault codes 2 Make sure that the transfer tube is installed at the proper torque Refer to section 2 3 2 A leaking transfer tube may be identified by cylinder cut out evaluation 14 4 7 Faulty Fuel Nozzle Unit Pump Repair Refer to the Injector Unit Pump section for unit pump and nozzle replacement Refer to section 2 1 All information subject to change without notice 14 52 From Bulletin 1 MBE900 03 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION MBE 900 SERVICE MANUAL 14 4 7 1 Verification of Repair for Faulty Fuel Nozzle Unit Pump Perform the following steps to determine if the replaced fuel nozzle unit pump resolved the misfiring cylinder conditions Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system 1 Start the engine 2 Run the engine speed up to the occurrence of the misfiring 3 Listen for misfiring cylinder a If the engine is not misfiring shut down the engine No further troubleshooting is required b If the engine is misfiring shut down the engine and check for a faulty PLD MR control unit refer to section
3. All information subject to change without notice 14 56 From Bulletin 1 MBE900 03 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION
4. 14 4 8 14 4 8 Troubleshooting Procedure for a Faulty PLD MR Control Unit To determine if a faulty PLD MR control unit is causing the cylinder to misfire install a test PLD MR control unit NOTE Carefully disengage the lock tab on the vehicle wiring harness and engine wiring harness connectors when removing Follow instructions in the PLD MR Control Unit section refer to section 2 5 1 14 4 9 Faulty PLD MR Control Unit Repair There is no authorized repair for the PLD MR control unit 14 4 9 1 Verification of Repair for Faulty PLD MR Control Unit Perform the following steps to determine if the test PLD MR Control Unit has resolved the misfiring cylinder condition All information subject to change without notice 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION From Bulletin 1 MBE900 03 14 53 14 4 MISFIRING CYLINDER To avoid injury before starting and running the engine ensure the vehicle is parked on a level surface parking brake is set and the wheels are blocked Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system 1 Start the engine 2 Increase the engine speed up
5. Checking and Adjustment section refer to section 1 17 2 14 4 5 1 Verification of Repair for Improper Valve Clearance or Injector Height Setting Perform the following steps to determine if valve clearance adjustment resolved the misfiring cylinder condition All information subject to change without notice 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION From Bulletin 1 MBE900 03 14 51 14 4 MISFIRING CYLINDER To avoid injury before starting and running the engine ensure the vehicle is parked on a level surface parking brake is set and the wheels are blocked Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system 1 Start the engine 2 Run the engine at 1000 rpm 3 Listen for misfiring cylinder a If engine is not misfiring shut down the engine No further troubleshooting is required b If engine is misfiring shut down the engine and check for faulty fuel nozzle refer to section 14 4 6 14 4 6 Troubleshooting Procedure for Faulty Fuel Nozzle Unit Pump To determine if a faulty fuel nozzle or unit pump is causing the cylinder to misfire check for the following items
6. MBE 900 SERVICE MANUAL 14 4 MISFIRING CYLINDER There are several causes for the engine cylinder to be misfiring These probable causes are Poor Vehicle Ground Aerated Fuel Improper Valve Clearance Worn or Damaged Camshaft Lobes and Roller Followers Faulty Fuel Nozzle Faulty PLD MR Control Unit Worn or Damaged Valve or Cylinder Kit 14 4 1 Troubleshooting Procedure for Poor Vehicle Ground To determine if poor vehicle ground is causing the cylinder to misfire perform the following steps 1 Remove the alternator belt Refer to section 9 2 1 To avoid injury before starting and running the engine ensure the vehicle is parked on a level surface parking brake is set and the wheels are blocked Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system 2 Start the engine 3 Run the engine through operating range 4 Listen for engine misfiring a Ifthe engine is not misfiring refer to section 14 4 2 Shut down the engine b If the engine is still misfiring check for aerated fuel refer to section 14 4 3 14 4 2 Negative Lead Repair Perform the
7. esent shut down the engine Check for improper valve clearance and worn or damaged camshaft lobes and roller followers refer to section 14 4 5 14 4 4 Aerated Fuel Repair Perform the following steps to repair the air in the fuel l De Shut down the engine Tighten all fuel line connections between fuel tank and fuel pump refer to OEM guidelines Visually inspect all fuel lines between fuel tank and fuel pump for leaks Replace any damaged components Verify repair of fuel lines a If no air in the fuel return refer to section 14 4 4 1 b If air in the fuel return locate and repair Then refer to section 14 4 4 1 All information subject to change without notice 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION From Bulletin 1 MBE900 03 14 49 14 4 MISFIRING CYLINDER 14 4 4 1 Test the Engine with Repair for Aerated Fuel Perform the following steps to determine if the aerated fuel repair resolved the misfiring cylinder condition Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system 1 Start engine 2 Run the engine at 1000 rpm 3 Listen for misfiring cylinder
8. evel surface parking brake is set and the wheels are blocked Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system Start the engine Run the engine and bring the engine coolant temperature to normal operating range approximately 88 96 C 190 205 F Run vehicle to full load and rated speed Attach a manometer calibrated to read in H O to the oil dipstick opening Measure and record crankcase pressure Shut down the engine SOP hy ON an Remove the vehicle from the chassis dynamometer 10 Review the crankcase pressure test results a Ifthe crankcase pressure was greater than 1 50 kPa 6 in H O refer to section 14 4 11 b Ifthe crankcase pressure was less than 1 50 kPa 6 in H O perform a cylinder compression test Refer to section 1 2 2 2 11 Compare the cylinder compression test results to specifications refer to section 1 2 2 2 a If cylinder pressure is below specifications refer to section 14 4 11 b If cylinder pressure is within specifications call Detroit Diesel Technical Service Group 14 4 11 Worn or Damaged Valve or Cylinder Kit Repair Perform the
9. following steps for negative lead repair All information subject to change without notice 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION From Bulletin 1 MBE900 03 14 47 14 4 ati EN Me ie yea nS MISFIRING CYLINDER Shut down the engine Remove negative lead s at frame ground stud near battery box Clean ground stud refer to OEM guidelines Clean negative lead s terminal lugs with low grit sandpaper Repair any loose or damaged lead s using the splice method or rosin core solder Install negative lead s to frame ground stud refer to OEM guidelines Install alternator belt Refer to section 9 2 2 NOTE Drive belts Vee and poly vee should be replaced every 2 000 hours or 100 000 miles 160 000 km 8 Verify negative lead repair refer to section 14 4 2 1 14 4 2 1 Verification of Repair for Negative Lead Perform the following steps to determine if negative lead repair resolved the misfiring cylinder condition Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system 1 Start the engine 2 Run engine speed up to the occurrence of the misfiring 3 Listen for mi
10. following steps to determine a worn or damaged valve or cylinder kit All information subject to change without notice 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION From Bulletin 1 MBE900 03 14 55 14 4 MISFIRING CYLINDER 1 Remove cylinder head refer to section 1 2 1 2 Inspect the cylinder head for worn or damaged valves refer to section 1 17 3 Inspect the cylinder head components for worn or damaged liners examine the pistons or piston rings 4 Verification of repairs made to cylinder valve s or cylinder kit components is required refer to section 14 4 11 1 14 4 11 1 Verification of Repair for Worn or Damaged Valve or Cylinder Kit Perform the following steps to determine if the repaired valve or cylinder kit resolved the misfiring cylinder condition Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system 1 Start the engine 2 Run the engine speed up to the occurrence of the misfiring 3 Listen for misfiring cylinder a If the engine is not misfiring no further troubleshooting is required b If the engine is misfiring call Detroit Diesel Technical Service Group
11. sfiring cylinder a Ifthe engine is not misfiring no further troubleshooting is required Shut down the engine b If the engine is misfiring check for aerated fuel Shut down the engine refer to section 14 4 3 14 4 3 Troubleshooting Procedure for Aerated Fuel To determine if aerated fuel is causing the cylinder to misfire perform the following steps 14 4 8 All information subject to change without notice From Bulletin 1 MBE900 03 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION MBE 900 SERVICE MANUAL Disconnect the fuel line return hose from the fitting located at the fuel tank Place the opened end of fuel line into a suitable container To avoid injury before starting and running the engine ensure the vehicle is parked on a level surface parking brake is set and the wheels are blocked Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer birth defects and other reproductive harm Always start and operate an engine in a well ventilated area If operating an engine in an enclosed area vent the exhaust to the outside Do not modify or tamper with the exhaust system or emission control system Start the engine Run the engine at 1000 rpm Visually check to see if air bubbles are rising to the surface of the fuel within the container a If air bubbles are present refer to section 14 4 4 b If air bubbles are not pr
12. to the occurrence of the misfiring 3 Listen for misfiring cylinder a Ifthe engine is not misfiring shut down the engine No further troubleshooting is required Replace the PLD MR Control Unit with a new unit b If the engine is misfiring shut down the engine install original PLD MR unit and check for worn or damaged valves and cylinder kits refer to section 14 4 10 14 4 10 Troubleshooting Procedure for Worn or Damaged Valve or Cylinder Kit Loss of compression in MBE 900 engines may result from a variety of sources including worn or broken fire or compression rings holes in pistons leaky valves scored or worn cylinder walls leaky or broken gaskets and cracked cylinder heads or cylinder liners The detection and elimination of the cause or causes of cylinder pressure losses is vital to engine life and efficient operation To assist the mechanic in effectively measuring the loss of cylinder pressure and locating the source of abnormal leaks in individual cylinders the following test procedure has been developed 1 Move the vehicle requiring test to the chassis dynamometer refer to OEM guidelines 2 Disconnect and remove the air compressor refer to section 3 1 1 All information subject to change without notice 14 54 From Bulletin 1 MBE900 03 6SE414 0303 Copyright 2003 DETROIT DIESEL CORPORATION MBE 900 SERVICE MANUAL To avoid injury before starting and running the engine ensure the vehicle is parked on a l
Download Pdf Manuals
Related Search