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Service Manual Mitsubishi L-Series diesel engines
Version 08/2004
TROUBLESHOOTING
ENGLISH
GENERAL
6.3 Knocking
Diesel engines are usually accompanied by fuel
combustion noise (diesel knocking sounds) because of
its inherent mechanism.
A trouble should be suspected only when the engine
makes abnormally large sounds.
6.3.1 Matters to be checked before
diagnosis
1. Clogging of the air cleaner
2. Use of poor-quality fuel (Low cetane number fuel
such as used for burner)
6.3.2 Diagnosis
Is injection timing correct? No Z Adjust injection timing.
V Yes
Do injection nozzles operate properly?
(Check for lowering of injection start pressure and improper shape of fuel
spray.)
No Z Inspect injection nozzles.
V Yes
Is cylinder compression proper? No Z
Inspect valves, pistons, piston
rings and cylinder head
gasket.
V Yes
Does injection pump operate properly?
(Check for uniformity of injection quantity.)
V Yes
Mechanical noise
(Worn or damaged main
moving parts)
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