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CM850 Electronic Control System – CM850 Electronic Control System – Troubleshooting and Repair Manual

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Engine Performance Troubleshooting Tree for QSC and QSL Marine Engines with CM850 ECM

Symptoms

    • Engine Acceleration or Response Poor
    • Cranking Fuel Pressure is Low
    • Engine Operating Fuel Pressure is Low
    • Engine Decelerates Slowly
    • Engine Difficult to Start or Will Not Start (Exhaust Smoke)
    • Engine Difficult to Start or Will Not Start (No Exhaust Smoke)
    • Engine Power Output Low
    • Engine Runs Rough at Idle
    • Engine Runs Rough or Misfires
    • Engine Speed Surges at Low or High Idle
    • Engine Speed Surges Under Load or in Operating Range
    • Smoke, Black – Excessive
    • Smoke, White – Excessive
    • Engine Shuts Off or Dies Unexpectedly or Dies During Deceleration
    • Engine Starts But Will Not Keep Running
    • Engine Will Not Reach Rated Speed (rpm)
    • Intake Manifold Pressure (Boost) is Below Normal
    • Excessive Vibration in Marine Applications

How To Use This Tree

This symptom tree can be used to troubleshoot all performance 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 symptom. Perform the list of troubleshooting in the sequence shown in the Specifications/Repair section of the tree.

Shop Talk

Operational is a term that in general describes vessel performance on the water. Operational problems for an engine can be caused by several different factors. Some of the factors are engine-related and some are
not. Before troubleshooting, it is important to determine the exact complaint and whether the engine has a real operational problem or if it simply does
not meet owner expectations.

Low power is a term that is used in the field to describe many different performance problems. Low power is defined as the inability of the engine to produce the power necessary to move the vessel at a speed that can be reasonably expected under the given environment.

Poor acceleration or response is described as the inability of the vessel to accelerate satisfactorily from a stop. It can also be the lag in acceleration at conditions less than rated speed and load. Poor acceleration or response is difficult to troubleshoot, since it can be caused by several factors.

Troubleshooting Steps

STEPS SPECIFICATIONS
STEP 1. Perform basic troubleshooting procedures.  
  STEP 1A. Check for active fault codes or high counts of inactive fault codes. Active fault codes or high counts of inactive fault codes?
  STEP 1B. Perform basic troubleshooting checks. Can the problem be verified?
  STEP 1C. Perform basic troubleshooting checks. All steps have been verified to be correct?
STEP 2. Determination of engine symptom.  
  STEP 2A. Low power, poor acceleration, or poor response. Is the engine symptom low power, poor acceleration, or poor response?
  STEP 2B. Engine misfire, engine speed surge, or engine speed unstable. Is the engine symptom engine misfire, engine speed surge, or engine speed unstable?
  STEP 2C. Excessive white or black smoke. Is the engine symptom excessive white or black smoke?
  STEP 2D. Low intake manifold pressure. Is the engine symptom low boost pressure
  STEP 2E. Engine will not start or difficult to start, engine shuts off unexpectedly. Is the engine symptom engine will not start or difficult to start or engine shuts off unexpectedly?
  STEP 2F. Engine vibration excessive. Is the engine symptom Engine Vibration Excessive occurring when the engine is in or out of gear?
STEP 3. Engine starting and running troubleshooting procedures.  
  STEP 3A. Verify the fuel supply and return valves are open. Are the fuel supply and return valves in the open position?
  STEP 3A-1. Check the fuel cooler for damage due to high fuel return back pressure.
  STEP 3B. Verify the low pressure fuel lines are routed correctly. Are the low pressure fuel lines connected properly to the ECM cooling plate?
  STEP 3C. Check the engine speed during cranking. Is the engine cranking speed greater than 150 rpm?
  STEP 3D. Check the electronic control module (ECM) keyswitch voltage. Is the keyswitch voltage equal to battery voltage?
  STEP 3E. Check the ECM battery supply voltage. Is the ECM battery supply voltage equal to the battery voltage?
  STEP 3F. Verify the rail fuel pressure sensor accuracy. Is the rail fuel pressure sensor (measured) value less than 30 bar [435 psi]?
  STEP 3G. Check for fuel rail pressure while cranking the engine. Did Fault Code 2215 or 559 become active during the failed start attempt?
  STEP 3G-1. Check the fuel gear pump pressure.
  STEP 3G-2. Check the fuel lift pump pressure.
STEP 4. Fuel system troubleshooting procedures.  
  STEP 4A. Check for air in the high-pressure pump fuel supply Is air present in the fuel supply?
  STEP 4B. Measure the fuel inlet restriction Is the fuel inlet restriction above specification?
  STEP 4C. Perform the single cylinder cutout test. Can the miss or excessive smoke be attributed to a single cylinder?
  STEP 4D. Perform the cylinder balance diagnostic test. Does the Cylinder Performance Test identify any cylinder that is contributing to a power imbalance?
  STEP 4E. Measure the fuel drain line restriction. Is the drain line restriction within specification?
STEP 5. Air handling troubleshooting procedures.  
  STEP 5A. Check the intake manifold pressure sensor accuracy. Is the reading within 101.6 mm-Hg [4 in-Hg] of local barometric pressure?
  STEP 5B. Check the air intake system for leaks. Were any air intake system leaks found?
  STEP 5C. Check the air intake restriction. Is the air intake restriction greater than the specification?
  STEP 5D. Inspect the turbocharger blades for damage. Are the turbocharger blades damaged?
  STEP 5E. Determine if the turbocharger is a waste gated turbocharger. Is the turbocharger a waste gated turbocharger?
  STEP 5F. Inspect the wastegate actuator hose. Are holes or cracks found in the wastegate actuator hose?
  STEP 5G. Inspect the turbocharger wastegate capsule for air leaks. Did the wastegate actuator rod move?
  STEP 5G-1. Inspect the turbocharger wastegate for proper operation.
  STEP 5G-2. Inspect the turbocharger wastegate for proper operation.
  STEP 5H. Measure turbocharger axial and radial clearance. Are the axial and radial clearances within specification?
  STEP 5I. Inspect the aftercooler. Is the aftercooler free of cracks or damage?
STEP 6. Electronic feature troubleshooting procedures.  
  STEP 6A. Verify the throttle travel. Does the throttle position read 0 when the throttle is released and 100 percent when the throttle is actuated?
STEP 7. Base engine troubleshooting procedures.  
  STEP 7A. Verify the overhead adjustments are correct. Are the overhead settings within the reset limits?
  STEP 7B. Check the exhaust restriction. Is the exhaust back pressure less than 75 mm-Hg [3 in-Hg] or 1016 mm-H
2O [40 in-H
2O]?
  STEP 7C. Check the engine blowby. Are the engine blowby measurements within specification?
  STEP 7C-1. Verify turbocharger contribution to engine blowby.
STEP 8. Excessive vibration troubleshooting procedures.  
  STEP 8A. Check the gear ratio and propeller configuration. Are the gear ratio and the propeller incorrectly matched to the engine power?
  STEP 8B. Check for correct engine mount isolators and for proper installation requirements. Are the engine mount isolators correct and installed correctly?
  STEP 8C. Check for damaged engine mounts and isolators. Are the engine mounts and isolators in good condition?
  STEP 8D. Check the exhaust system. Is the exhaust system deficient?
  STEP 8E. Check the engine driven accessories. Is an engine driven accessory malfunctioning?
  STEP 8F. Check the shaft coupling to gear coupling alignment. Is the shaft coupling to gear coupling misaligned?
  STEP 8G. Check the propeller shaft for proper installation. Is the propeller shaft installed correctly?
  STEP 8H. Check the propeller shaft for straightness. Is the propeller shaft straightness within the OEM specification?
  STEP 8I. Isolate the engine. Does the engine vibration persist?
  STEP 8J. Check for strut/cutlass bearing misalignment. Is the strut/cutlass bearing misaligned or strut mounting not secure?
  STEP 8K. Check the propeller. Is the propeller out of balance or propeller not fitted properly to shaft?
  STEP 8L. Check the V-angle on the V-strut. Does the V-angle on the V-strut match the angle of the blade on the propeller?
  STEP 8M. Check the propeller tunnels. Does the entry and exit of the propeller tunnel match with the propeller blades?
  STEP 8N. Check the engine to transmission torsional coupling. Is the torsional coupling incorrect or worn?
  STEP 😯. Check the rudder. Does the rudder have excessive play in the rudder post?
  STEP 8P. Check the engine flywheel housing to cylinder block alignment. Is the flywheel housing alignment incorrect?

Guided Step 1 – Perform basic troubleshooting procedures.

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

Conditions

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

Action

Check for any active fault codes.

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

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

Reference Section TF in the Troubleshooting and Repair Manual, ISB, ISBe
4, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL, and QSL9 Engines, CM850 Electronic Control System, Bulletin
4021416 for fault code troubleshooting.

 No Repair
Repair complete

Guided Step 1B – Perform basic troubleshooting checks.

Conditions

None.

Action

Verify the following items.

  • Is the engine operating within the conditions it was intended to perform? For example, wide open throttle rpm, ambient versus engine room temperatures, load on the vessel, sea conditions, etc.
  • Are the customer’s expectations in line with the engine capability?
  • Is the engine performing according to the OEM sea trial?

Can the problem be verified?
YES NO
No Repair

The problem can
not be verified and no repair is possible.

Repair complete

Guided Step 1C – Perform the basic troubleshooting checks.

Conditions

None.

Action

The following items must be checked or verified before continuing.

  • Verify the fuel level in the tanks.
  • Verify there have
    not been any changes to the CPL (turbocharger, injectors, pistons, fuel pump, camshaft, etc.) components on the engine.
  • Verify the fuel grade is correct for the application.
  • Verify the engine is operating within the recommended altitude.
  • Verify the engine oil is at the correct level.
  • Verify none of the air vents are restricted or obstructed.
  • Verify the engine parasitics have
    not changed.
  • Verify the engine duty cycle has
    not changed.
  • Verify the engine cranking speed is greater than 150 rpm.
  • Verify the battery voltage is adequate.
  • Verify the drive train is correctly matched to the engine.
  • Verify the transmission is correct and is
    not malfunctioning.
  • Verify the propeller is at the correct pitch and is
    not damaged.
  • Verify the fuel inlet temperature to the fuel pump is within specification.
  • Verify the engine throttle and throttle wiring is correct for the engine response issues.
  • Verify the condition of the hull (clean and no damage).

All steps have been verified to be correct?
YES NO
No Repair

Correct the condition and verify the complaint is no longer present after the repair.

Repair complete

Guided Step 2 – Determination of engine symptom.

Guided Step 2A – Low power, poor acceleration, or poor response.

Conditions

None.

Action

Determine the engine symptom according to the engine performance.

Is the engine symptom low power, poor acceleration, or poor response?
YES NO

Perform the troubleshooting steps in the recommended order listed below.

  • Step 4 – Fuel System Checks
  • Step 5 – Air Handling Checks
  • Step 6 – Electronics Checks
  • Step 7 – Base Engine Checks
 No Repair
Perform the troubleshooting steps suggested in the repair procedure.

Guided Step 2B – Engine misfire, engine speed surge, or engine speed unstable.

Conditions

None.

Action

Determine the engine symptom according to the engine performance.

Is the engine symptom engine misfire, engine speed surge, or engine speed unstable?
YES NO

Perform the troubleshooting steps in the recommended order listed below.

  • Step 4 – Fuel System Checks
  • Step 5 – Air Handling Checks
  • Step 6 – Electronics Checks
 No Repair
Perform the troubleshooting steps suggested in the repair procedure.

Guided Step 2C – Excessive white or black smoke.

Conditions

None.

Action

Determine the engine symptom according to the engine performance.

Is the engine symptom excessive white or black smoke?
YES NO

Perform the troubleshooting steps in the recommended order listed below.

  • Step 5 – Air Handling Checks
  • Step 4 – Fuel System Checks
 No Repair
Perform the troubleshooting steps suggested in the repair procedure.

Guided Step 2D – Low intake manifold pressure.

Conditions

None.

Action

Determine the engine symptom according to the engine performance.

Is the engine symptom low boost pressure?
YES NO

Perform the troubleshooting steps in the recommended order listed below.

  • Step 5 – Air Handling Checks
  • Step 4 – Fuel System Checks
  • Step 7 – Base Engine Checks
 No Repair
Perform the troubleshooting steps suggested in the repair procedure.

Guided Step 2E – Engine will not start or difficult to start, engine shuts off unexpectedly.

Conditions

None.

Action

Determine the engine symptom according to the engine performance.

Is the engine symptom engine will
not start or difficult to start, engine shuts off unexpectedly?
YES NO

Perform the troubleshooting steps in the recommended order listed below.

  • Step 3 – No Start Checks
  • Step 4 – Fuel System checks
  • Step 5 – Air Handling Checks
  • Step 6 – Electronics Checks
 No Repair
Perform the troubleshooting steps suggested in the repair procedure.
Return to the correct symptom tree.

Guided Step 2F – Engine vibration excessive.

Conditions

None.

Action

Determine the engine symptom according to the engine performance.

Is the symptom Engine Vibration is Excessive occurring when the engine is in or out of gear?
YES NO

Perform the troubleshooting steps in the recommended order listed below.

  • Step 4 – Fuel System Checks
  • Step 5 – Air Handling Checks
  • Step 6 – Electronics Checks
  • Step 7 – Base Engine Checks
  • Step 8 – Excessive Vibration Checks
 No Repair
Perform the troubleshooting steps suggested in the repair procedure.
Return to the correct symptom tree.

Guided Step 3 – Engine starting and running troubleshooting procedures.

Guided Step 3A – Verify the fuel supply and return valves are open.

Conditions

  • Turn keyswitch OFF.

Action

Verify the fuel supply and return valves are in the open position.

If the vessel is new or work has been completed on the vessel, the fuel valves could have been left in the closed position.

Are the fuel supply and return valves in the open position?
YES NO
No Repair

Turn the fuel supply and return valve to the open position and verify that no engine damage has occurred.

Guided Step 3A-1 – Check the fuel cooler for damage due to high fuel return back pressure.

Conditions

None.

Is the fuel cooler damaged or collapsed internally?
YES NO

Remove and replace the fuel cooler.

For QSL9 engines, refer to Procedure 006-062 (Fuel Cooler) in Section 6 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

For QSC8.3 engines, refer to Procedure 008-129 (Marine Gear Oil and Fuel Cooler Assembly) in Section 8 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

No Repair
Repair complete

Guided Step 3B – Verify the low pressure fuel lines are routed correctly.

Conditions

None.

Action

It is sometimes possible to get the low pressure fuel lines connected to the ECM cooling plate installed improperly.

The top connection to the ECM cooling plate is the inlet and the bottom connection is the outlet.

Verify these connections are correct if the low pressure fuel lines have been removed and installed on the engine.

Are the low pressure fuel lines connected properly to the ECM cooling plate?
YES NO
No Repair

Properly connect the low pressure fuel lines to the ECM cooling plate. The fuel inlet is the top connection.

Repair complete

Guided Step 3C – Check the engine speed during cranking.

Conditions

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

Action

Use INSITE™ electronic service tool to monitor Engine Speed while cranking the engine.

If the engine does
not crank at all, reference the Engine Will Not Crank or Cranks Slowly troubleshooting symptom tree in the Troubleshooting and Repair Manual, ISB, ISBe4, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL, and QSL9 Engines, CM850 Electronic Control System, Bulletin
4021416.

Is the engine cranking speed greater than 150 rpm?
YES NO
No Repair

Find and correct the cause for low cranking speed. Check the batteries, engine starting motor and accessory loads. Reference the Engine Will Not Crank or Cranks Slowly troubleshooting symptom tree.

Repair complete

Guided Step 3D – Check the ECM keyswitch voltage.

Conditions

  • Turn keyswitch OFF.
  • Disconnect the OEM harness from the ECM.
  • Turn keyswitch ON.

Action

Measure the signal voltage.

  • Measure the signal voltage from the keyswitch input SIGNAL wire of the OEM harness to the engine block ground.

Measure the keyswitch voltage with the keyswitch in the “ON” position and also with the keyswitch in the “Cranking” position.

Refer to the wiring diagram for connector pin identification.

Is the keyswitch voltage equal to the battery voltage?
YES NO
No Repair

Repair or replace the keyswitch harness and/or keyswitch. Check the battery connections.

The keyswitch harness can be supplied by the OEM.

Repair complete

Guided Step 3E – Check the ECM battery supply voltage.

Conditions

  • Turn the keyswitch OFF.
  • Disconnect the ECM power harness from the ECM.

Action

Measure the voltage.

  • Measure the voltage from the ECM battery supply (-) to the ECM battery supply (+) pins in the ECM power harness connector.

Measure the ECM voltage with the keyswitch in the ON position and also with the keyswitch in the “Cranking” position.

Refer to the wiring diagram for connector pin identification.

Is the ECM battery supply voltage equal to the battery voltage?
YES NO
No Repair

Repair or replace the ECM power harness.

Check the battery connections and fuse terminals.

Repair complete

Guided Step 3F – Verify the rail fuel pressure sensor accuracy.

Conditions

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

Action

Monitor the rail fuel pressure sensor.

Use INSITE™ electronic service tool to monitor the rail fuel pressure sensor (measured) with the keyswitch ON and the engine
not running.

Is the rail fuel pressure sensor (measured) value less than 30 bar [435 psi]?
YES NO
No Repair

Replace the rail fuel pressure sensor.

Refer to Procedure 019-115 (Rail Fuel Pressure Sensor) in Section 19 in the Troubleshooting and Repair Manual, ISB, ISBe4, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL, and QSL9 Engines, CM850 Electronic Control System, Bulletin 4021416.

Repair complete

Guided Step 3G – Check for fuel rail pressure while cranking the engine.

Conditions

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

Action

Check for fuel rail pressure.

  • Attempt to start the engine by engaging the engine starter for at lease 30 continuous seconds.
  • Use INSITE™ electronic service tool to monitor the Fuel Rail pressure (Measured) and Fuel Rail Pressure (Commanded).
  • Use INSITE™ electronic service tool to read the fault codes.

Attempting to start the engine for 30 continuous seconds allows the fault code logic time to run. If either Fault Code 2215 or 559 becomes active, then fuel rail pressure is
not being developed. Refer to Bulletin
4021416 Troubleshooting and Repair Manual, ISB, ISBe4, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL, and QSL9 Engines, CM850 Electronic Control System.

If the engine starts during this attempt, it is possible that fuel prime to the high pressure pump has been lost. Look for loose fuel lines or filters that allow for loss of fuel prime.

Did either Fault Code 2215 or 559 become active during the failed start attempt?
YES NO
No Repair No Repair

Guided Step 3G-1 – Check the fuel gear pump pressure.

Conditions

  • Turn keyswitch ON.

Action

Install a pressure gauge at the pressure side fuel filter head.

Cranking speed
must be greater than 150 rpm.

Is the fuel gear pump pressure greater than 69 kPa [10 psi] while cranking?
YES NO

Follow Fault Code 2215 troubleshooting tree. Refer to Bulletin
4021416 Troubleshooting and Repair Manual, ISB, ISBe4, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL, and QSL9 Engines, CM850 Electronic Control System.

 No Repair
Repair complete

Guided Step 3G-2 – Check the fuel lift pump pressure.

Conditions

  • Turn keyswitch ON.

Action

Install a pressure gauge at the inlet port of the fuel pump.

At initial key-on, the lift pump will run for 60 seconds then stop. The lift pump will run for 30 seconds at key-on and 30 seconds after starting the engine.

Is the fuel lift pump pressure greater than the specifications?
YES NO

Replace the fuel pump.

Refer to Procedure 005-025 (Fuel Pump Gear Pump) in Section 5 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Replace the fuel lift pump.
Refer to Procedure 005-045 (Fuel Lift Pump) in Section 5 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Repair complete
Repair complete

Guided Step 4 – Fuel system troubleshooting procedures.

Guided Step 4A – Check for air in the high pressure pump fuel supply.

Conditions

None.

Is air present in the fuel supply?
YES NO

Locate and correct the cause of air ingestion in the fuel supply system. Sources of air ingestion include loose fuel filters, loose fuel line fittings, loose or cracked fuel tank stand-pipes, or severe restrictions in the fuel supply lines and filters.

 No Repair
Repair complete

Guided Step 4B – Measure the fuel inlet restriction.

Conditions

None.

Action

Measure the fuel inlet restriction at the customer connection.

Refer to Procedure 006-020 (Fuel Inlet Restriction) in Section 6 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Maximum fuel inlet restriction at the customer connection.

  • New filter: 63.5 mm-Hg [2.5 in-Hg]
  • Dirty Filter: 101.6 mm-Hg [4.0 in-Hg]

Is the fuel inlet restriction above specification?
YES NO

Find and correct the cause of high fuel inlet restriction. Look for plugged OEM fuel filters or screens, a restricted ECM cooler, restricted lift pump bypass check valve (in the ECM cooler), pinched OEM fuel lines, or a restricted stand pipe in the OEM fuel tank.

Replace the fuel gear pump.
Refer to Procedure 005-025 (Fuel Pump Gear Pump) in Section 5 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Repair complete
Repair complete

Guided Step 4C – Perform the single cylinder cutout test.

Conditions

  • Connect INSITE™ electronic service tool.
  • Turn keyswitch ON.
  • Start the engine and run at low idle.

Action

Perform the single cylinder cutout test.

  • Operate the engine at load.
  • Use INSITE™ electronic service tool to perform the Cylinder Cutout test. Disable individual injectors.

Can the miss or excessive smoke be attributed to a single cylinder?
YES NO

Look for a cause of the complaint including valve lash and excessive crankcase pressure that can indicate power cylinder damage, or camshaft lobe wear. If no other damage is found, replace the fuel injector in the cylinder that was identified using the single cylinder cutout test.

Refer to Procedure 006-026 (Injector) in Section 6 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

No Repair
Repair complete

Guided Step 4D – Perform the cylinder balance diagnostic test.

Conditions

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

Action

Perform the cylinder balance diagnostic test.

  • Use INSITE™ electronic service tool to perform the Cylinder Performance Test. Determine if a single cylinder is contributing to the engine symptom.

Does the Cylinder Performance Test identify any cylinder that is contributing to a power imbalance?
YES NO

Look for a cause of the power imbalance including valve lash and excessive crankcase pressure that can indicate power cylinder damage or camshaft lobe wear. If no other damage is found, replace the fuel injector in the cylinder contributing to the power imbalance.

Refer to Procedure 006-026 (Injector) in Section 6 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

No Repair
Repair complete

Guided Step 4E – Measure the fuel drain line restriction.

Conditions

None.

Is the fuel drain line restriction within specification?
YES NO
No Repair

Look for causes of high drain line restriction, such as kinked or blocked fuel lines.

Repair complete

Guided Step 5 – Air handling troubleshooting procedures.

Guided Step 5A – Check the intake manifold pressure sensor accuracy.

Conditions

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

Action

Monitor the reading for intake manifold pressure with the engine off.

Is the intake manifold pressure reading less than 50.8 mm-Hg [2 in-Hg] of local barometric pressure?
YES NO
No Repair

Replace the intake manifold pressure sensor.

Refer to Procedure 019-061 (Intake Manifold Pressure Sensor) in Section 19 in the Troubleshooting and Repair Manual, ISB, ISBe4, QSB4.5, QSB5.9, QSB6.7, ISC, QSC8.3, ISL, and QSL9 Engines, CM850 Electronic Control System, Bulletin 4021416.

Repair complete

Guided Step 5B – Check the air intake system for leaks.

Conditions

None.

Were any air intake system leaks found?
YES NO

Repair or replace the damaged component.

 No Repair
Repair complete

Guided Step 5C – Check the air intake restriction.

Conditions

  • Install vacuum gauge Part Number ST-1111-3 into the air intake system.
  • Turn keyswitch ON.
  • Engine operating at rated speed and full load.

Action

Measure the intake system restriction.

Refer to Procedure 010-031 (Intake Air Restriction) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Maximum air intake restriction:

Clean filter: 381 mm-H
2O [15 in-H
2O]

Dirty filter: 635 mm-H
2O [25 in-H
2O]

Is the air intake restriction greater than the specification?
YES NO

Correct the cause of high intake air restriction. Check for plugged air filter or restricted air intake piping.

 No Repair
Repair complete

Guided Step 5D – Inspect the turbocharger blades for damage.

Conditions

  • Turn keyswitch OFF.
  • Remove the intake and exhaust pipes from the turbocharger.

Are the turbocharger blades damaged?
YES NO

Replace the turbocharger assembly.

Refer to Procedure 010-033 (Turbocharger) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

No Repair
Repair complete

Guided Step 5E – Determine if the turbocharger is a wastegated turbocharger.

Conditions

None.

Action

Determine if the turbocharger is a wastegated turbocharger.

Is the turbocharger a wastegated turbocharger?
YES NO
No Repair No Repair

Guided Step 5F – Inspect the wastegate actuator hose.

Conditions

  • Turn keyswitch OFF.
  • Remove the turbocharger if the wastegate actuator is inaccessible.

Are holes or cracks found in the wastegate actuator hose?
YES NO

Replace the wastegate actuator hose.

Refer to Procedure 010-050 (Turbocharger Wastegate Actuator) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

No Repair
Repair complete

Guided Step 5G – Inspect the turbocharger wastegate capsule for air leaks

Conditions

  • Engine OFF.
  • Remove the wastegate actuator hose from the wastegate actuator.

Action

Perform a leak test on the wastegate actuator capsule.

Use Wastegate Pressure Test Kit, Part Number 3823799, to apply a regulated air supply of 59 in-Hg to the wastegate actuator capsule. No air should be heard (a leaking noise) through a functional wastegate capsule.

Refer to Procedure 010-050 (Turbocharger Wastegate Actuator) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Did the wastegate actuator capsule leak air?
YES NO

Replace the wastegate actuator.
Refer to Procedure 010-050 (Turbocharger Wastegate Actuator) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

No Repair
Repair complete
5G-1

Guided Step 5G-1 – Inspect the turbocharger wastegate for proper operation.

Conditions

  • Engine OFF.
  • Remove the wastegate actuator hose from the wastegate actuator.

Action

Check for wastegate actuator rod for movement.

Use Wastegate Pressure Test Kit, Part Number 3823799, to apply a regulated air supply of [29 psi] to the wastegate actuator capsule. Check for wastegate actuator rod for movement.

Refer to Procedure 010-050 (Turbocharger Wastegate Actuator) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Did the wastegate actuator rod move?
YES NO
No Repair No Repair
5H

Guided Step 5G-2 – Inspect the turbocharger wastegate for proper operation.

Conditions

  • Engine OFF.
  • Remove the e-clip from the wastegate pin and disconnect the actuator rod from the wastegate lever.

Action

Check for wastegate actuator rod movement with it disconnected from the turbocharger wastegate.

Use Wastegate Pressure Test Kit, Part Number 3823799, to apply a regulated air supply of [29 psi] to the wastegate actuator capsule. Check for wastegate actuator rod for movement.

Refer to Procedure 010-050 (Turbocharger Wastegate Actuator) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Does the wastegate actuator rod move?
YES NO

Move the wastegate lever back and forth and check for smooth operation. If the wastegate lever does
not move freely or binds, spray a penetrating oil on the wastegate lever joint and try to free the wastegate lever by working the lever back and forth. If the lever does
not become free, then replace the turbocharger.

Refer to Procedure 010-033 (Turbocharger) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Replace the wastegate actuator.
Refer to Procedure 010-050 (Turbocharger Wastegate Actuator) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Repair complete
Repair complete

Guided Step 5H – Measure turbocharger axial and radial clearance.

Conditions

  • Engine OFF.
  • Disconnect the exhaust and intake connections from the turbocharger.

Are the axial and radial clearances within specification?
YES NO
No Repair

Replace the turbocharger assembly.

Refer to Procedure 010-033 (Turbocharger) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

5I
Repair complete

Guided Step 5I – Inspect the aftercooler.

Conditions

None.

Action

Inspect the aftercooler.

Is the aftercooler free of cracks or damage?
YES NO
No Repair

Repair or replace the aftercooler assembly.

Refer to Procedure 010-005 (Aftercooler Assembly (Sea Water) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Repair complete

Guided Step 6 – Electronic feature troubleshooting procedures.

Guided Step 6A – Verify the throttle travel.

Conditions

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

Action

Verify the throttle travel.

  • Use INSITE™ electronic service tool to monitor the throttle position while fully depressing and releasing the throttle lever.

Does the throttle position read 0 when the throttle is released and 100 percent when the throttle is actuated?
YES NO
No Repair

Determine and correct the cause of the throttle lever restriction.

Repair complete

Guided Step 7 – Base engine troubleshooting procedures

Guided Step 7A – Verify the overhead adjustments are correct.

Conditions

  • Turn keyswitch OFF.

Are the overhead settings within the reset limits?
YES NO
No Repair

Adjust the overhead settings.
Refer to Procedure 003-004 (Overhead Set) in Section 3 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Repair complete

Guided Step 7B – Check the exhaust restriction.

Conditions

None.

Action

Install a pressure gauge into the exhaust system just past the turbocharger outlet to check the exhaust system back pressure.

Refer to Procedure 011-009 (Exhaust Restriction) in Section 11 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Is the exhaust back pressure less than 75 mm-Hg [3 in-Hg] or 1016 mm-H
2O [40 in-H
2O]?
YES NO
No Repair

Fix or clear the source of high exhaust restriction.

Repair complete

Guided Step 7C – Check the engine blowby.

Conditions

None.

Are the engine blowby measurements within specification?
YES NO
No Repair No Repair
Return to Step 2, or contact an authorized Cummins® service representative for further diagnostic and troubleshooting instructions.

Guided Step 7C-1 – Verify the turbocharger contribution to the engine blowby.

Conditions

  • Turn keyswitch OFF.
  • Start the engine.

Action

Verify the turbocharger contribution.

Has the total engine blowby dropped more than 30 percent of the total?
YES NO

Replace the turbocharger assembly.
Refer to Procedure 010-033 (Turbocharger) in Section 10 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

The engine may need to be rebuilt.

Refer to Procedure 000-001 (Engine Removal) in Section 0 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418 and the engine rebuild specifications.

Repair complete
Repair complete

Guided Step 8 – Excessive vibration troubleshooting procedures.

Guided Step 8A – 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 Marine District Field Service Manager.

 No Repair
Repair complete

Guided Step 8B – 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 as needed.

Refer to Procedure 016-026 (Marine Vibration Isolator) in Section 16 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Reference the Engine Mounting Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649.

If isolators are non-Cummins®, refer to the OEM service manual.

Repair complete

Guided Step 8C – Check for damaged engine mounts and isolators.

Conditions

None.

Action

Inspect the engine mounts and isolators for failure.

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

Remove and replace the engine mount isolators.

Refer to Procedure 016-026 (Marine Vibration Isolator) in Section 16 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Reference the Engine Mounting Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649.

If the isolators are non-Cummins®, refer to the OEM service manual.

Repair complete

Guided Step 8D – Check the exhaust system.

Conditions

None.

Action

Check for exhaust system deficiencies.

Is the exhaust system deficient?
YES NO

Repair or replace as needed. Reference the OEM service literature and instructions.

 No Repair
Repair complete

 CAUTION 

Some sea water pumps are belt driven. Operating the engine when the sea water pump is disconnected can result in engine damage due to overheating.
Guided Step 8E – Check the engine driven accessories.

Conditions

  • Turn keyswitch ON.
  • Turn keyswitch OFF.

Action

Check for engine driven accessories 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. If the accessory is
not installed by Cummins Inc., refer to the OEM service manual.

 No Repair
Repair complete

Guided Step 8F – 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.

Refer to Procedure 016-025 (Propeller Shaft) in Section 16 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Reference the Engine Mounting Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649.

Reference the gear manufacturer’s recommendations.

 No Repair
Repair complete

Guided Step 8G – 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.

Refer to Procedure 016-025 (Propeller Shaft) in Section 16 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

Reference the Engine Mounting Drive Systems section in the Marine Recreational Installation Directions, Bulletin 3884649.

Reference the OEM service literature.

Repair complete

Guided Step 8H – 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 8I – Isolate the engine.

Conditions

  • Turn keyswitch ON.
  • Turn keyswitch OFF.

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.
Refer to Procedure 001-052 (Vibration Damper, Viscous) in Section 1 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

No Repair
Repair complete

Guided Step 8J – 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 needed.

Refer to an authorized OEM Service Location.

 No Repair
Repair complete

Guided Step 8K – Check the propeller.

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 8L – 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 propeller?
YES NO
No Repair

Repair or replace as needed.

Refer to an authorized OEM Service Location.

Repair complete

Guided Step 8M – Check the propeller tunnels.

Conditions

None.

Action

Check to see 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 8N – Check the engine to transmission torsional coupling.

Conditions

None.

Action

Check for an incorrect or worn torsional coupling.

Is the torsional coupling incorrect or worn?
YES NO

Replace the coupling.

Refer to the OEM service literature.

 No Repair
Repair complete

Guided Step 😯 – 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.

If the engine is
not damaged, refer to an authorized OEM Service Location.
Repair complete

Guided Step 8P – 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

Realign the flywheel housing to cylinder block.
Refer to Procedure 016-006 (Flywheel Housing) in Section 16 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

The engine might have internal damage that has
not been detected. Analyze the oil and inspect the filters to locate an area of probable damage.
Refer to Procedure 007-083 (Lubricating Oil Filter and Analysis) in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418.

The engine might need to be rebuilt.
Refer to Procedure 000-001 (Engine Removal) in Section 0 in the ISC, ISCe, QSC8.3, ISL, ISLe3 and QSL9 Troubleshooting and Repair Manual, Bulletin 4021418. Refer to the engine rebuild specifications. If the engine is
not damaged, the problem might be the vessel design. Refer to an authorized OEM service location.
Repair complete.
Repair complete.
Last Modified:  01-Apr-2008
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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.