Komatsu 170-3 Series, Руководство по ремонту, Страница: 181 / 454

170-3 SERIES
12-117
TROUBLESHOOTING
Confirm recent repair history
Degree of use of machine Operated for long period
More than for other machines of same model
Condition of fuel consumption Gradually increased
Suddenly increased
There is external leakage of fuel from engine
Engine oil level rises and smells of diesel fuel
Fuel pump outlet port coupler is pushed, almost no fuel comes out
Fuel pump outlet port coupler is pushed, air comes out together with fuel
When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low
Exhaust smoke color
Black
White
Questions
Check items
Inspect inside of head cover directly
When negative pressure at inlet port of fuel pump is measured, it is found to be high
Inspect fuel pump directly
When temperature of injector of each cylinder is measured, there are some cylinders that are low
When pressure at outlet port of fuel pump is measured, it is found to be low
Abnormality in fuel rail pressure sensor system is indicated ( 1)
Abnormality in timing rail pressure sensor system is indicated ( 1)
When flow of return fuel is checked visually, it is found to be low
Inspect sensor directly (Output voltage)
T
roubleshooting
Correct Clean Replace Replace Replace Replace Replace Clean Replace Replace
Remedy
Leakage of fuel inside head cover Clogged fuel filter
, strainer
Defective fuel pump Defective injector Cut, worn injector O-ring Failure fuel rail pressure sensor Failure timing rail pressure sensor High resistance, clogged fuel return circuit Defective atmospheric pressure sensor Defective boost pressure sensor
Causes
When engine is cranked with
starting motor, and
1. If an error code of the fuel rail pressure sensor system or timing rail pressure sensor
system is displayed, carry out the troubleshooting in "EA mode" or "EB mode".
S-10 Fuel consumption is excessive
General causes why fuel consumption is excessive
•
Leakage of fuel
• Defective condition of fuel injection
• Excessive injection of fuel
• Defective HPI sensor
S-10
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