Mitsubishi S4Q2 User Manual

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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
CAUSES OF ENGINE PROBLEMS AND
REMEDIES TROUBLESHOOTING
(• Refer to the separate troubleshooting chart.)
Problems/Symptoms
Hard starting
Glow plugs do not produce red heat Glow plugs do produce red heat to fast
Not enough
power
Exhaust
smoke
abnormal
Engine produces loud knocking sound Engine produces abnormal noice Engine produces irregular combustion sound
Engine
hunts
Engine turns
Cranking speed low
Engine
does
not turn
Small amount of exhaust smoke Large amount of white exhaust smoke Large amount of black exhaust smoke At idling
In
operation
At idling In operation
Possible causes
No exhaust smoke Small amount of exhaust smoke Large amount of exhaust smoke Engine can be cranked manually Engine can not be cranked manually White Black
Mechanical problems
Seizing of moving parts __ __ __ ⊗ __ ⊗ __ __ __ __ ⊗ __ __ ⊗ __ ⊗⊗__ __
Worn cylinder(s), piston(s) or
piston ring(s)
__ __ ⊗ __ __ __ __ __ __ ⊗ __ ⊗⊗__ ⊗⊗__ __ __
Worn piston ring(s) __ __ ⊗ __ __ __ __ __ __ ⊗ __ ⊗⊗__ ⊗ __ __ __ __
Excessive oil clearance
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ ⊗ __ __ __
Loose connecting rod cap
bolts
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ ⊗ __ __ __
Interference between valve(s)
and piston(s)
__ __ __ __ __ ⊗ __ __ __ __ __ __ __ __ __ ⊗ __ __ __
Damaged valve spring(s) __ __ ⊗ __ __ __ __ __ __ ⊗ __ ⊗⊗__ __ ⊗⊗⊗⊗
Excessive valve clearance
__ __ __ __ __ __ __ __ __ __ ⊗ __ __ ⊗ __ ⊗⊗⊗⊗
Foreign item in cylinder(s) __ __ __ __ __ ⊗ __ __ __ __ __ __ __ __ __ ⊗ __ __ __
Excessive gear backlash
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ ⊗ __ __ __

Mitsubishi S4Q2 Specifications

General

Brand	Mitsubishi
Model	S4Q2
Category	Engine
Language	English