The chart below shows the most common questions asked by owners of Detroit Diesel® engines 2-71 natural when trying to troubleshoot why their engines underperform.  It categorizes areas of possible malfunction, likely cause and recommended action to bring your new, rebuilt or used  Detroit Diesel® engine back to proper operation.  The chart will give you confidence when speaking with your Detroit Diesel® engine mechanic or ordering parts.  As a quick reference guide only, the chart must not be thought of as a substitute for the use of your Detroit Diesel® engine 2-71 natural Owner's operating or service manual. PROBLEM POSSIBLE REASON CHECK
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Engine will not start
Lack of air intake or restricted air intake
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Broken blower shaft
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Worn out blower shaft
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Defective fuel pump
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Defective starter
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Discharged battery
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High exhaust back pressure
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Black smoke coming out of engine
Defective injector
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Contaminated fuel
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Broken or worn cylinder parts
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Engine overloaded
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Faulty intercooler or aftercooler (for turbo engines only)
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White smoke coming out of engine
Broken piston ring
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Incorrectly installed ring set
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Defective injector
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Fuel quality or grade
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Long idle periods
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Broken or bent push rod
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Injector or governor improperly adjusted
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Low engine oil pressure
Water in engine oil pan
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Fuel in engine oil pan
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Defective oil cooler
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Engine overloaded
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Crankcase overfilled
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Low engine RPM
Improperly working injector
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Governor calibration
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Hi engine RPM
Governor calibration
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Engine overheating
Defective fresh water pump
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Defective raw water pump (marine engines only)
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Defective thermostat or thermostat seal
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Clogged radiator or heat exchanger (marine engine only)
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Grey smoke coming out of engine
Long idle periods
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Defective intercooler or aftercooler (for turbo engine only)
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Restricted air intake
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Defective injector
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Contaminated fuel
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Blower or turbocharger seals leaking
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Geartrain makes noises
Low oil level
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Engine driven accesories
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Damage main or rod bearing
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