Cummins mercruiser qsd 2 8 170 hp diesel engine service repair manual sn:88300400 and above

Page 120

Troubleshooting Cause

Special Information

Air leaks: suction side fuel line or water separating fuel filter Questionable fuel quality Leaking head gaskets Engine overheating

Internal engine damage

Exhaust Gas Temperature HIGH Cause

Special Information

Excessive load Faulty wastegate

Refer to Section 7C—Turbocharger.

Faulty Injectors

Refer to Section 5—Fuel System.

LOW Cause

Special Information

Excessive idling time or light loads

Turbocharger Cause

Special Information Not enough air getting to engine air intake Clogged air filter

Smoke from exhaust

Boost pressure too low See Engine Smoking—Black, Blue, or White of this section. Not enough air getting to engine air intake Clogged air cleaner Boost pressure too low

Loss of power due to turbocharger

Poor lubrication of turbocharger Defective wastegate valve. Excessive oil residue buildup in compressor turbine housing Rubbing of compressor or turbine impellers against housing Air leaking from high‑pressure side of turbocharger Poor lubrication of turbocharger

Unusual noises and vibrations at turbocharger

Rubbing of compressor or turbine impellers against housing Air leaking from high‑pressure side of turbocharger

Rubbing of compressor or turbine impellers against housing Oil leakage from compressor side

CMD-4082040 / 90-866941 NOVEMBER 2007

Poor lubrication of turbocharger Low oil pressure at turbocharger Defective bearings in turbocharger Clogged air cleaner Boost pressure too low

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