Troubleshooting

• Prolonged operation at idle speed
• Engine operating speed
• Air intake and exhaust system
• Cooling fan
• Reduced pressure of intake air
• Valve lash
Recommended Actions
Note: The procedures have been listed in order of
probability. Complete the procedures in order.
Table 38
Troubleshooting Test Steps
Values Results
1. Diagnostic Codes
Note: Certain diagnostic codes and/or event codes indicate the
cause of high fuel consumption.
A. Use the electronic service tool to check for active or logged
codes.
Diagnostic
codes
Result: A diagnostic code is present.
Repair: Troubleshoot the diagnostic code and then verify
that the fuel consumption is normal. Refer to Troubleshoot-
ing, “Diagnostic Trouble Codes”.
Result: A diagnostic code is not present.
Proceed to Test Step 2.
2. Misreading of Fuel Level
Note: Misreading of the fuel gauge can give a false indication of
fuel consumption.
A. Monitor the fuel consumption over a period of 50 engine
hours.
Fuel level Result: Fuel consumption is normal for the operating
conditions.
Return the unit to service.
Result: Fuel consumption is high for the operating
conditions.
Proceed to Test Step 3.
3. Fuel Leakage
A. Check the engine for signs of fuel leakage.
Fuel leaks Result: Evidence of a fuel leak is found.
Repair: Repair or replace the component that is leaking
fuel.
Result: No evidence of a fuel leak is found.
Proceed to Test Step 4.
(continued)
UENR0612-07 91
Symptom Troubleshooting
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