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ISM, ISMe, and QSM11 – ISM, ISMe, and QSM11 – Troubleshooting and Repair Manual

Vibration Excessive

Symptoms

    • Vibration excessive
    • Cab noise due to vibration

How To Use This Tree

This symptom tree can be used to troubleshoot all vibration-based symptoms listed above. Start by performing Step 1 troubleshooting. Step 2 will ask a series of questions and will provide a list of troubleshooting steps to perform, depending on the symptoms. Perform the list of troubleshooting steps in the sequence shown in the Specifications/Repair section of the tree.

Shop Talk

Vibration Troubleshooting Documentation Information Questions

1) What is the OEM make/model?

2) What are the mileage/hours?

3) Has there been any recent repair and/or maintenance history?

  • Any engine/clutch/transmission rebuild, removal, and installation?
  • History of repeatedly broken brackets and/or capscrews (alternator, fan, exhaust, etc.)?
  • Structural modifications to the vehicle from OEM built?

4) Description of vibration?

  • What is shaking (mirror, seat, steering wheel, cab/dash, etc.)?
  • Is there excessive noise in the cab during the vibration?

5) What are the conditions when the complaint occurs?

  • Power take-off (PTO)?
  • Power output (hard pull, during lug down, etc.)?
  • During acceleration and/or deceleration?
  • At idle?
  • With or without a trailer?
  • Does vibration increase with engine speed?
  • Does vibration increase with road speed?
  • Is the vibration at a certain engine RPM?

6) Has the vibration been present since new? (From new, recent repair, modification to equipment)

7) Can the vibration be easily duplicated?

8) Do you have another piece of equipment with the same specification which exhibits the same complaint? (If yes, get the engine serial number (ESN) and possibly test the vehicle)

9) Are you the
only operator of the equipment? (If no, are the symptoms noticed by other operators)?

General Information

Vibration complaints can be very difficult to troubleshoot and understand the root cause. This troubleshooting document was designed to help guide you through the logical steps of identifying the source. Vibration acceptance is very subjective; what is objectionable to one person can possibly be acceptable to another.

Vibration complaints can be caused by many parts in the system (system includes the engine, driven component, mounts, and equipment). The cause can be transmitted or generated from a remote point that is
not readily apparent.

Cummins Inc. experience has shown that the engine is rarely the cause of an operator complaint. The majority of the time, it is the engine mounts or design of the various components on the equipment. The engine is
only at fault if there is a misfire or an engine component that is out of balance.

Vibration complaints that occur
only at idle speed are most likely caused by the engine mounts. If the engine mount natural frequency is close to the engine firing frequency, the engine will cause the mounts to amplify the normal vibration on an engine idling and cause the adjacent components to vibrate excessively.

Natural Frequency

  • Natural frequency, as the name implies, is the frequency at which an object wants to naturally vibrate. The frequency is primarily dependent on mass and elasticity.

Types of Vibration

1) Linear

a) Rotating components

b) Torque reaction

  • Caused by unbalanced rotating components and cylinder firing impulses.
  • Can be felt and observed visibly.
  • When excessive, can cause operator discomfort and destruction of components.

2) Torsional – twisting stresses

  • Cyclic speeding and slowing of rotating components.
  • Controlled by flywheel mass and vibration damper.
  • Can
    NOT be felt by the operator.
  • Can damage gears and splines.

3) Resonant – component excited at natural frequency

  • Is actually linear vibration.
  • Resonant vibration occurs when a system or component is excited by linear vibration at its natural frequency.
  • Vibration will increase in amplitude as the system’s natural frequency is approached. Amplitude will decrease as the exciting forces (engine firing frequency) increase in frequency beyond the system’s natural frequency.
  • Resonant vibration can be many times larger in amplitude than the exciting force.
  • Vibration
    must be controlled by design of mounts (engine and cab) and components.

Engine and Cab Mounts

  • The mounts
    must be designed to isolate or reduce the transmission of engine and equipment component vibrations.
  • For maximum isolation, it is desired that the natural frequency of the mount be as low as possible.
  • Good engine mounts will reduce the amount of engine vibration transmitted to the chassis frame by at least 50 percent at idle.
  • Hard engine mounts will give little or no isolation, and can actually magnify the vibration transmitted to the chassis.
  • Stiffness (durometer) and size of the isolator, along with the weight of the engine or component applied are the determining factors when designing a mounting system. An isolator that is correct for one engine, can possibly
    not be right for another. Likewise, because of weight differential, a particular isolator designed for the rear of an engine, probably will
    not be ideal for the front.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Perform the basic troubleshooting procedures.  
  STEP 1A. Document the information questions in the Shop Talk section of this tree. Documentation completed?
  STEP 1B. Duplicate the complaint based on the customer description. Can the customer’s complaint be duplicated?
  STEP 1C. Check for active fault codes or high counts of inactive fault codes. Active fault codes or high counts of inactive fault codes?
  STEP 1D. Perform the basic troubleshooting checks. Are all steps verified to be correct?
  STEP 1E. Determine if the engine is running rough. Is the engine running rough?
  STEP 1F. Perform a visual inspection of the engine mounts (without removal). Is there visible engine mount damage?
  STEP 1G. Check for an engine mounted component contacting the frame or body. Engine mounted components touching the frame or body?
  STEP 1H. Marine application. Is the engine installed in a marine application?
  STEP 1I. Do an engine RPM sweep. Is the vibration present stationary below 1050 RPM?
  STEP 1J. Do an engine RPM sweep. Is the vibration present stationary above 1050 RPM?
  STEP 1K. Check the vibration engine speed range. Is the vibration speed range greater than 300 to 400 RPM?
STEP 2. Perform low RPM checks.  
  STEP 2A. Check that the accessory load is not excessive for the idle speed setting. Are all steps verified to be correct?
  STEP 2B. Check that the Fast Idle Warm-Up feature is activating (if applicable). Is the Fast Idle Warm-Up feature inactive?
  STEP 2C. Check that the Alternator Failure Warning feature is activating (if applicable). Is the Alternator Failure Warning feature inactive?
  STEP 2D. Check for malfunctioning belt driven accessories. Did the vibration go away with the drive belts removed?
  STEP 2E. Check for equipment structural modifications. Are any structural modifications to the equipment present?
  STEP 2F. Check the engine mount transmissibility for the rear mount. Does the vibration go away during the test condition?
  STEP 2F-1. Check the engine mount transmissibility for all mounts.
  STEP 2G. Inspect the engine mounts. Are all steps verified to be correct?
  STEP 2H. Complaint since new. Has the problem been occurring since the equipment was new?
STEP 3. Perform higher RPM checks.  
  STEP 3A. Inspect the engine mounts. Are all steps verified to be correct?
  STEP 3B. Check for malfunctioning belt driven accessories. Did the vibration go away with the drive belts removed?
  STEP 3C. Check for a damaged vibration damper. Is the vibration damper damaged or out of specification?
  STEP 3D. Check the air compressor timing. Is the air compressor timing correct?
  STEP 3E. Check the overhead adjustments. Are the overhead adjustments correct?
  STEP 3F. Check for malfunctioning gear driven components. Did the vibration go away?
  STEP 3G. Check for a damaged PTO. Did the vibration go away?
  STEP 3H. Check for a malfunctioning engine internal balancer assembly (4 cylinder B-Series only). Does the internal balancer meet specification?
  STEP 3I. Check the clutch or torque converter for vibration. Did engaging and disengaging the clutch affect the vibration?
  STEP 3J. Check for a loose or damaged flywheel or flex plate. Does the flywheel meet specifications?
  STEP 3K. Check the flywheel housing for correct alignment. Does the flywheel housing meet specifications?
  STEP 3L. Check to see if the crankshaft has been balanced. Is the crankshaft balanced?
  STEP 3M. Check for internal engine damage. Is there internal engine damage?
STEP 4. Operate the mobile equipment.  
  STEP 4A. Perform a diagnostic road test. Is the vibration present during a diagnostic road test?
  STEP 4A-1. Perform a diagnostic road test.
  STEP 4B. Inspect the engine mounts. Are all steps verified to be correct?
  STEP 4C. Check for drive train components that are worn, unbalanced, malfunctioning, or are not correct. Are all steps verified to be correct?
STEP 5. Marine applications.  
  STEP 5A. Check the gear ratio and propeller configuration. Are the gear ratio and the propeller incorrectly matched to the engine power?
  STEP 5B. Check for the correct engine mounting isolators and for proper installation requirements. Are the engine mount isolators correct and installed correctly?
  STEP 5C. Check for damaged engine mounts and isolators. Are the engine mounts and isolators in good condition?
  STEP 5D. Check the exhaust system. Is the exhaust system deficient?
  STEP 5E. Check the engine driven accessories. Is an engine driven accessory malfunctioning?
  STEP 5F. Check the shaft coupling to gear coupling alignment. Is the shaft coupling to gear coupling misaligned?
  STEP 5G. Check the propeller shaft for proper installation. Is the propeller shaft installed correctly?
  STEP 5H. Check the propeller shaft for straightness. Is the propeller shaft straightness within the OEM specification?
  STEP 5I. Isolate the engine. Does the engine vibration persist?
  STEP 5J. Check for strut/cutlass bearing misalignment. Is the strut/cutlass bearing misaligned or strut mounting not secure?
  STEP 5K. Check the propeller. Is the propeller out of balance or not fitted properly to the shaft?
  STEP 5L. Check the V-angle on the V-strut. Does the V-angle on the V-strut match the angle of the blade on the prop?
  STEP 5M. Check the propeller tunnels. Does the entry and exit of the propeller tunnel match with the propeller blades?
  STEP 5N. Check the engine to transmission torsional coupling. Is the torsional coupling incorrect or worn?
  STEP 5O. Check the rudder. Does the rudder have excessive play in the rudder post?
  STEP 5P. Check the engine flywheel housing to cylinder block alignment. Is the flywheel housing alignment incorrect?

Guided Step 1 – Perform the basic troubleshooting procedures.

Guided Step 1A – Document the information questions in the Shop Talk section of this tree.

Conditions

  • None

Action

Perform the basic troubleshooting questionnaire.

Complete the vibration troubleshooting documentation information questions contained in the Shop Talk section of this procedure.

Documentation completed?
YES NO
No Repair

Complete the documentation.

Guided Step 1B – Duplicate the complaint based on the customer description.

Conditions

  • None.

Action

Operate the equipment based on the description from the customer to duplicate the complaint.

Can the customer’s complaint be duplicated?
YES NO
No Repair No Repair

Repair complete

Guided Step 1C – Check for active fault codes or high counts of inactive fault codes.

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Check the fault codes.

  • Use INSITE™ electronic service tool to read the fault codes.

Active fault codes or high counts of inactive fault codes?
YES NO

See the corresponding Electronic Control System Troubleshooting and Repair manual for the engine being serviced.

 No Repair
Repair complete

Guided Step 1D – Perform the basic troubleshooting checks.

Conditions

  • As required.

Action

Check or verify the following items before continuing.

  • Battery voltage is low (engine running)
  • Lubricating oil level is above specification
  • External fuel leak
  • Engine idle speed is set too low
  • Engine idle speed is set too high
  • Throttle lever or pedal, return spring, or air throttle damaged or improperly adjusted (use INSITE™ electronic service tool for electronic engines)
  • Air in the fuel
  • Fuel pressure
  • Inlet restriction.

Are all steps verified to be correct?
YES NO
No Repair No Repair

Repair complete

Guided Step 1E – Determine if the engine is running rough.

Conditions

  • Engine running at idle speed (less than 900 RPM).
  • Accessories off (air conditioning, fan, PTO).
  • Engine at operating temperature (greater than 338°C [170°F]).

Action

Determine if the engine is running rough at engine idle.

Refer to the Engine Runs Rough symptom tree in Section TS or the Engine Performance Troubleshooting Tree in Section TT.

Is the engine running rough?
YES NO

Refer to the Engine Runs Rough symptom tree.

 No Repair
Complete Engine Runs Rough troubleshooting tree

Guided Step 1F – Perform a visual inspection of the engine mounts (without removal).

Conditions

  • Engine
    not running.
  • Engine mounts installed.

Action

Perform a visual inspection of the engine mounts.

Look for obvious damage or something shorting against the mounts, preventing isolation.

Note: A more detail inspection will be carried out later in the procedure.

Is there visible engine mount damage?
YES NO

Repair or replace the engine mounts. Refer to Procedure
016-010 in Section 16 in the appropriate service manual.

No Repair
Repair complete

Guided Step 1G – Check for an engine mounted component contacting the frame or body.

Conditions

  • Engine
    not running.
  • Engine mounts installed.

Action

Check for an engine mounted component touching the frame or body.

Inspect the engine and engine mounted components to make sure none of them are touching the frame and/or body.

Including but not limited to the following:

  • Clamps
  • Mounting hardware
  • Exhaust system
  • Air intake piping
  • Cooling package support
  • Etc.

Engine mounted components touching the frame or body?
YES NO

Correct the mounting of the engine mounted component.

 No Repair
Repair complete

Guided Step 1H – Marine application.

Conditions

None

Action

Is this engine in a marine application?

Is the engine installed in a marine application?
YES NO
No Repair No Repair

Guided Step 1I – Do an engine RPM sweep.

Conditions

  • Engine running.
  • INSITE™ electronic service tool connected.
  • 0 vehicle speed.

Action

Perform a slow (at 100 RPM per second) RPM sweep and note where the vibration occurs.

Note the engine speed at which any usual vibration or vibration related noise occurs (mirrors, panels, doors, seat, etc.). Note any speed points or ranges with excessive vibration.

If a resonance is passed through quickly in getting up to the operating speed range and doesn’t exist in the idle speed or peak operating range, it represents no major problem.

Is the vibration present stationary below 1050 RPM?
YES NO
No Repair No Repair

Guided Step 1J – Do an engine RPM sweep.

Conditions

  • Engine running.
  • INSITE™ electronic service tool connected.
  • 0 vehicle speed.

Action

Perform a slow (at 100 RPM per second) RPM sweep and note where the vibration occurs.

Does the vibration increase progressively from idle to maximum speed? If so, rotating or reciprocating unbalance is the source. This can be caused by any rotating components or engine mount isolation.

Is the vibration present stationary above 1050 RPM?
YES NO
No Repair No Repair

Guided Step 1K – Check the vibration engine speed range.

Conditions

  • Engine running.
  • INSITE™ electronic service tool connected.
  • 0 vehicle speed.

Action

Perform a slow (at 100 RPM per second) RPM sweep and note where the vibration occurs.

This step is to identify if the vibration progressively increases with engine speed or if it starts and stops within a slow engine RPM band. If the vibration progressively increases with engine speed and has a peak band greater than 300 RPM, this can indicate a rotating component that is out of balance.

If the vibration peak is in a tight band of approximately 300 to 400 RPM or less, this indicates that a structural component of the engine or equipment is going into resonance because its natural frequency is close to or the same as the engine firing frequency.

Is the vibration speed range greater than 300 to 400 RPM?
YES NO
No Repair No Repair

Guided Step 2 – Perform low RPM checks.

Guided Step 2A – Check that the accessory load is not excessive for the idle speed setting.

Conditions

  • Engine running at idle speed (less than 900 RPM).
  • Accessories off (air conditioning, fan, and PTO).
  • Engine at operating temperature (greater than 77°C [170°F]).

Action

Disable all engine driven accessories and PTOs to make sure they are not applying excessive load to the engine.

Are all steps verified to be correct?
YES NO
No Repair

Repair as required.

Repair complete

Guided Step 2B – Check that the Fast Idle Warm-Up feature is activating (if applicable).

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Check the Fast Idle Warm-Up status.

Use INSITE™ electronic service tool Data Monitor/Logger to check the status of the Fast Idle Warm-Up feature.

Is the Fast Idle Warm-Up feature inactive?
YES NO
No Repair

Disable the Fast Idle Warm-Up feature and retest for the customer’s complaint.

Repair complete

Guided Step 2C – Check that the Alternator Failure Warning feature is activating (if applicable).

Conditions

  • Turn keyswitch ON.
  • Connect INSITE™ electronic service tool.

Action

Check to see if the Alternator Failure Warning feature is active.

Use INSITE™ electronic service tool Data Monitor/Logger to check that the Alternator Failure Warning feature is active.

Is the Alternator Failure Warning feature inactive?
YES NO
No Repair

Disable the Alternator Failure Warning feature and retest for the customer’s complaint.

Repair complete

Guided Step 2D – Check for malfunctioning belt driven accessories.

Conditions

  • Drive belt(s) removed.

Action

Remove the drive belt(s) and operate the engine under the conditions where the vibration occurs.

Caution: For engines with a belt driven water pump, do not allow the engine to overheat during the test. Engine damage will occur.

Did the vibration go away with the drive belts removed?
YES NO

Repair or replace the malfunctioning belt driven component.

 No Repair
Repair complete

Guided Step 2E – Check for equipment structural modifications.

Conditions

  • Visual inspection.

Action

Check for any structural modifications to the equipment.

Check for any structural modifications to the equipment in the engine area that were completed by the OEM after equipment manufacture.

  • Snow plows, frame rail extensions, front bumpers, etc.

Structural modifications can change the natural frequency of the frame and engine mounting system, which can result in a vibration complaint.

Are any structural modifications to the equipment present?
YES NO

Contact the equipment manufacturer. If possible, remove or isolate the structural modification.

 No Repair
Repair complete

Guided Step 2F – Check the engine mount transmissibility of the rear mount.

Conditions

  • Loosen the front engine mount capscrews.
  • Engine running at the documented RPM where the complaint occurs.

Action

Check the engine mounts.

This step is checking to see if the engine mounts are amplifying the firing frequency of the engine, since the vibration
only occurs in a low engine RPM range.

  • Loosen
    only the isolator capscrews for the front engine mount(s) and run the engine at idle.

Does the vibration go away during the test condition?
YES NO
No Repair No Repair

Guided Step 2F-1 – Check the engine mount transmissibility for all mounts.

Conditions

  • Loosen ALL engine mount capscrews.
  • Engine running at the documented RPM where the complaint occurs.

Action

Check the engine mounts.

This step is checking to see if the engine mounts are amplifying the firing frequency of the engine, since the vibration
only occurs in a low engine RPM range.

  • Loosen the isolator capscrews for ALL of the engine mounts and run the engine at idle.

Does the vibration go away during the test condition?
YES NO
No Repair No Repair

Guided Step 2G – Inspect the engine mounts.

Conditions

  • Engine
    not running.
  • Remove engine mount isolators.

Action

This step is a detailed inspection of the engine mount brackets, isolators, and mounting hardware.

  • Check the engine mount isolators for installation damage.
  • Check the alignment of the engine mount brackets.
  • Check for premature wear on the engine mount isolators and mounting hardware.

Are all steps verified to be correct?
YES NO
No Repair

Repair or replace the damaged components.

Repair complete

Guided Step 2H – Complaint since new.

Conditions

  • Record the odometer/hour meter.
  • Review the troubleshooting documentation information questions.

Action

Check the equipment.

Check the equipment mileage/hours and compare to the vibration customer interview form completed in Step 1A.

  • Low mileage is an indication that the complaint has been present since the equipment was new.
  • Complaints on new equipment are typically due to a manufacturing defect in the system or an inadequate engine mounting design.

Has the problem been occurring since the equipment was new?
YES NO

The engine mounts are
not the right specification for the application, or a structural resonance exists.

Recheck for shorts, a rough running engine, or malfunctioning engine mounts.
Contact a Cummins® Technical Support Specialist or the OEM
Contact a Cummins® Technical Support Specialist or the OEM

Guided Step 3 – Perform higher RPM checks.

Guided Step 3A – Inspect the engine mounts.

Conditions

  • Engine
    not running.
  • Remove the engine mount isolators.

Action

Inspect the engine mount brackets, isolators, and mounting hardware.

  • Check the engine mount isolators for installation damage.
  • Check the alignment of the engine mount brackets.
  • Check for premature wear on the engine mount isolators and mounting hardware.

Are all steps verified to be correct?
YES NO
No Repair

Repair or replace the malfunctioning components. Refer to Procedure
016-010 in Section 16 in the appropriate service manual.

Repair complete

Guided Step 3B – Check for malfunctioning belt driven accessories.

Conditions

  • Remove the drive belts.

Action

Check the belt driven accessories.

Remove the drive belts and operate the engine under the conditions where the vibration occurs.

Caution: For engines with a belt driven water pump, do not allow the engine to overheat during the test. Engine damage will occur.

Did the vibration go away with the drive belts removed?
YES NO

Repair or replace the malfunctioning belt driven accessory.

 No Repair
Repair complete

Guided Step 3C – Check for a damaged vibration damper.

Conditions

  • Engine not running.

Action

Remove and visually inspect the vibration damper.

Use Procedure 001-052 in the appropriate service manual for vibration damper inspection specifications.

Is the vibration damper damaged or out of specification?
YES NO

Replace the vibration damper. Reference the appropriate service manual.

 No Repair
Repair complete

Guided Step 3D – Check the air compressor timing.

Conditions

  • Engine not running.
  • Air compressor removed.

Action

Check the air compressor timing.

Reference Procedure 012-014 in the appropriate service manual.

Is the air compressor timing correct?
YES NO
No Repair

Correct the air compressor timing and retest for the vibration complaint. Reference Procedure 012-014 in the appropriate service manual.

Repair complete

Guided Step 3E – Check the overhead adjustments.

Conditions

  • Engine not running.
  • Rocker lever cover removed.

Action

Measure and adjust the overhead settings.

  • Check the overhead components for damage.

Reference Procedure 003-004 in the appropriate service manual.

Are the overhead adjustments correct?
YES NO
No Repair

Repair or adjust the overhead. Reference Procedure 003-004 in the appropriate service manual.

Repair complete

Guided Step 3F – Check for malfunctioning gear driven components.

Conditions

None.

Action

Check the hydraulic pump and air compressor.

If possible, isolate any gear-driven accessories and check for vibration.

Did the vibration go away?
YES NO

Repair or replace the gear driven components.

 No Repair
Repair complete

Guided Step 3G – Check for a damaged PTO.

Conditions

  • Disconnect the PTO.

Action

Check the PTO for damage and correct installation.

Refer to the OEM service manual.

Did the vibration go away?
YES NO

Repair the PTO. Refer to the OEM service manual.

 No Repair
Repair complete

Guided Step 3H – Check for a malfunctioning engine internal balancer assembly (4 cylinder B-Series only).

Conditions

  • None.

Action

Inspect the engine internal balancer assembly.

Reference Procedure 001-004 in the appropriate service manual.

Note: This applies to 4 cylinder B-Series engines
only.

Does the internal balancer meet specification?
YES NO
No Repair

Repair the internal balancer. Reference Procedure 001-004 in the appropriate service manual.

Repair complete

Guided Step 3I – Check the clutch or torque converter for vibration.

Conditions

  • Engine running.

Action

With engine running in the operating condition of the vibration, disengage and engage the clutch serval times.

If there is a significant vibration reduction, clutch plate(s) balance is the source.

Did engaging and disengaging the clutch affect the vibration?
YES NO

Repair or replace the clutch. Refer to the OEM service manual.

 No Repair
Repair complete

Guided Step 3J – Check for a loose or damaged flywheel or flex plate.

Conditions

  • Transmission removed.

Action

Check the flywheel.

  • Check the flywheel bore and face run out.
  • Check the flywheel for damage.

Reference Procedure 016-005 in the appropriate service manual.

Does the flywheel meet specifications?
YES NO
No Repair

Repair or replace the flywheel or flexplate. Reference Procedure 016-005 in the appropriate service manual.

Repair complete

Guided Step 3K – Check the flywheel housing for correct alignment.

Conditions

  • Transmission removed.
  • Flywheel/flexplate removed.

Action

Check the flywheel housing bore and face alignment.

Reference Procedure 016-006 in the appropriate service manual.

Does the flywheel housing meet specifications?
YES NO
No Repair

Repair or replace the flywheel housing. Reference Procedure 016-006 in the appropriate service manual.

Repair complete

Guided Step 3L – Check to see if the crankshaft has been balanced.

Conditions

  • Engine not running.
  • Lubricating oil pan removed.

Action

Remove the lubricating oil pan.

Reference Procedure 007-025 in the appropriate service manual.

Check the crankshaft to see if it has been balanced. Reference Procedure 001-016 in the appropriate service manual.

Note: This step
only applies if the complaint has been present since the engine was new or after a crankshaft replacement.

ISX engines built after 01-November-2008 have a marking on the crankshaft to indicate if it passed the balancing step in the manufacturing process. Refer to Procedure
001-016 in Section 1 of the ISX service manual.

Is the crankshaft balanced?
YES NO
No Repair

Replace the crankshaft. Contact a Cummins® Technical Support/Warranty specialist before proceeding with the repair.

Repair complete

Guided Step 3M – Check for internal engine damage.

Conditions

  • None.

Action

Contact a support specialist.

At this point, a significant amount of labor has been invested in the repair. Before disassembling the engine, seek troubleshooting assistance. Contact the appropriate Technical Support Channel for your facility. They will provide the necessary guidance and schedule on-site support, if deemed necessary.

  • Camshaft journals and number 1 camshaft bushing are severely damaged
  • Gear train backlash is excessive or the gear teeth are damaged
  • Idler gear bushing damaged or worn
  • Main or connecting rod bearing damage
  • Gears out of balance or gear bushing damage
  • Connecting rod damage.

Is there internal engine damage?
YES NO
No Repair No Repair
Contact Technical Support
Contact Technical Support

Guided Step 4 – Operate the mobile equipment.

Guided Step 4A – Perform a diagnostic road test.

Conditions

  • Diagnostic road test.

Action

Perform a diagnostic road test, observing where the vibration occurs.

If the vibration can be duplicated on the road, place the transmission in neutral and allow the engine speed to drop to idle under the road speed conditions of the vibration.

Is the vibration present during a diagnostic road test?
YES NO
No Repair No Repair

No repair

Guided Step 4A-1 – Perform a diagnostic road test.

Conditions

  • Diagnostic road test.

Action

Perform a diagnostic road test, observing where the vibration occurs.

If the vibration can be duplicated on the road, place the transmission in neutral and allow the engine speed to drop to idle under the conditions of the vibration.

Is the vibration present with the transmission in neutral, under the road speed conditions, where the vibration was duplicated driving?
YES NO
No Repair No Repair

Guided Step 4B – Inspect the engine mounts.

Conditions

  • Engine not running.
  • Remove the engine mount isolators.

Action

This step is a detailed inspection of the engine mount brackets, isolators, and mounting hardware.

  • Check the engine mount isolators for installation damage.
  • Check the alignment of the engine mount brackets.
  • Check for premature wear on the engine mount isolators and mounting hardware.
  • If the equipment is new, check for the proper mount specification.

Reference Procedure 016-010 in the appropriate service manual.

Are all steps verified to be correct?
YES NO
No Repair

Repair or replace damaged components.

Repair complete

Guided Step 4C – Check for drive train components that are worn, unbalanced, malfunctioning, or are not correct.

Conditions

  • None.

Action

Compare the drive train components to the engine and equipment specifications.

Isolate the drive train components and check for vibrations. Refer to the OEM service manual.

Are all steps verified to be correct?
YES NO
No Repair No Repair
Contact Cummins® Technical Support and the OEM
Contact Cummins® Technical Support and the OEM

Guided Step 5 – Marine applications.

Guided Step 5A – Check the gear ratio and propeller configuration.

Conditions

  • Turn keyswitch OFF.

Action

Check for an incorrect matching of the gear ratio and propeller to the engine power.

Are the gear ratio and the propeller incorrectly matched to the engine power?
YES NO

Contact a Cummins® Distributor or a Marine District Field Service Manager.

 No Repair
Repair complete

Guided Step 5B – Check for the correct engine mounting isolators and for proper installation requirements.

Conditions

  • None.

Action

Check for the correct engine mount isolators and for propeller installation requirements.

Are the engine mount isolators correct and installed correctly?
YES NO
No Repair

Check for proper isolator installation requirements. Replace and repair vibration isolators as needed. Reference Procedure 016-026 in the appropriate service manual and Engine Mounting/Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649. If the isolators are
not manufactured by Cummins Inc., refer to the OEM service manual.

Repair complete

Guided Step 5C – Check for damaged engine mounts and isolators.

Conditions

  • None.

Action

Inspect the engine mount and isolators for damage.

Are the engine mounts and isolators in good condition?
YES NO
No Repair

Remove and replace the engine mount isolators. Reference Procedure 016-026 in the appropriate service manual and Engine Mounting/Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649. If the isolators are
not manufactured by Cummins Inc., refer to the OEM service manual.

Repair complete

Guided Step 5D – Check the exhaust system.

Conditions

  • None.

Action

Check for exhaust system deficiencies.

Is the exhaust system deficient?
YES NO

Repair or replace as needed. See the Exhaust System section in the Marine Recreational Installation Directions, Bulletin 3884649, and the OEM service manual.

 No Repair
Repair complete

Guided Step 5E – Check the engine driven accessories.

Conditions

  • Turn keyswitch ON.
  • Turn keyswitch OFF.

Action

Check for engine driven accessory malfunctions.

  • Isolate or disconnect the accessories and check for vibration.
  • Do
    not operate the engine if the sea water pump is disconnected.

Is an engine driven accessory malfunctioning?
YES NO

Determine the cause of the malfunctioning accessories and correct the problem. See the Exhaust System section in the Marine Recreational Installation Directions, Bulletin 3884649, and the OEM service manual.

 No Repair
Repair complete

Guided Step 5F – Check the shaft coupling to gear coupling alignment.

Conditions

  • Turn keyswitch OFF.

Action

Check the shaft coupling to gear coupling alignment.

Is the shaft coupling to gear coupling misaligned?
YES NO

Repair or replace as needed. Reference Procedure 016-025 in the appropriate service manual and the Engine Mounting/Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649, and the gear manufacturer’s recommendations.

 No Repair
Repair complete

Guided Step 5G – Check the propeller shaft for proper installation.

Conditions

  • None.

Action

Check the propeller shaft for proper installation.

Is the propeller shaft installed correctly?
YES NO
No Repair

Repair or replace as needed. Reference Procedure 016-025 in the appropriate service manual and the Engine Mounting/Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649, and the gear manufacturer’s recommendations.

Repair complete

Guided Step 5H – Check the propeller shaft for straightness.

Conditions

  • None.

Action

Check the propeller shaft for straightness.

Is the propeller shaft straightness within the OEM specification?
YES NO
No Repair

Repair or replace the propeller shaft as needed. Refer to an Authorized OEM Service Location.

Repair complete

Guided Step 5I – Isolate the engine.

Conditions

  • Disconnect the drive shaft.

Action

Run the engine without the drive shaft attached at the coupler.

Does the engine vibration persist?
YES NO

Check the engine vibration damper for damage. Repair or replace as needed. Reference Procedure 001-052 in the appropriate service manual.

 No Repair
Repair complete

Guided Step 5J – Check for strut/cutlass bearing misalignment.

Conditions

  • Turn keyswitch OFF.

Action

Check for strut/cutlass bearing misalignment or strut mounting is not secure.

Is the strut/cutlass bearing misaligned or strut mounting not secure?
YES NO

Check the strut for mounting stiffness. Repair or replace as necessary. Refer to an Authorized OEM Service Location.

 No Repair
Repair complete

Guided Step 5K – Is the propeller out of balance or not fitted properly to the shaft?

Conditions

  • None.

Action

Check for propeller out-of-balance or propeller not fitted properly to shaft.

Is the propeller out of balance or not fitted properly to the shaft?
YES NO

Check the propeller for accuracy. Repair or replace as needed. Refer to an Authorized OEM Service Location.

 No Repair
Repair complete

Guided Step 5L – Check the V-angle on the V-strut.

Conditions

  • None.

Action

Check to see if the V-angle on the V-strut does not match the angle of the blade on the propeller.

Does the V-angle on the V-strut match the angle of the blade on the prop?
YES NO
No Repair

Does the V-angle on the V-strut match the angle of the blade on the prop?

Repair complete

Guided Step 5M – Check the propeller tunnels.

Conditions

  • None.

Action

Check if the propeller tunnels are properly matched with the propellers.

Does the entry and exit of the propeller tunnel match with the propeller blades?
YES NO
No Repair

Repair or replace as needed. Refer to an Authorized OEM Service Location.

Repair complete

Guided Step 5N – Check the engine to transmission torsional coupling.

Conditions

  • None.

Action

Check the engine to transmission torsional coupling.

Is the torsional coupling incorrect or worn?
YES NO

Replace the coupling. Refer to an Authorized OEM Service Location.

 No Repair
Repair complete

Guided Step 5O – Check the rudder.

Conditions

None.

Action

Check the rudder for excessive play in the rudder post.

Does the rudder have excessive play in the rudder post?
YES NO

Repair or replace as needed. Refer to an Authorized OEM Service Location.

 No Repair
Repair complete

Guided Step 5P – Check the engine flywheel housing to cylinder block alignment.

Conditions

  • None.

Action

Check the engine flywheel housing to cylinder block alignment.

Is the flywheel housing alignment incorrect?
YES NO

Align the flywheel housing to cylinder block. Reference Procedure 016-006 in the appropriate service manual.

The engine can possibly have internal damage that has
not been detected. Analyze the oil and inspect the filters to locate an area of probable damage. Reference Procedure 007-083 in the appropriate service manual.

The engine can possibly need to be rebuilt. Reference Procedure 000-001 and the engine rebuild specifications in the appropriate service manual. If the engine is
not damaged, the problem can possibly be the vessel design. Refer to an Authorized OEM Service Location.
Repair complete
Repair complete
Last Modified:  12-Feb-2009
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Published by Jack

Hello, I'm Jack, a diesel engine fan and a blogger. I write about how to fix and improve diesel engines, from cars to trucks to generators. I also review the newest models and innovations in the diesel market. If you are interested in learning more about diesel engines, check out my blog and leave your feedback.