Komatsu 170-3 Series, Руководство по ремонту, Страница: 165 / 454

12-108
170-3 SERIES
TROUBLESHOOTING
Confirm recent repair history
Degree of use of machine Operated for long period
Exhaust smoke suddenly stopped coming out (when starting again)
Starting performance became worse gradually
Starts when engine is warm
Replacement of filters has not been carried out according to Operation Manual
When fuel tank is inspected, it is found to be empty
Air breather hole in fuel tank cap is clogged
Rust and water are found when fuel tank is drained
When fuel filter is drained, fuel does not come out
There is leakage from fuel piping
Wiring of fuel shut-off valve is loose
Cylinder block ground wiring is loose
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
Questions
Check items
When negative pressure at inlet port of fuel pump is measured, it is found to be high
Inspect fuel filter, strainer directly
Inspect fuel pump drive shaft directly
Inspect fuel shut-off valve directly
When starting switch is turned to START, voltage [24V] is not generated between fuel shut-off valve connector
pins
Inspect timing rail actuator screen directly
Inspect sensor directly (Output voltage and resistance)
Inspect actuator directly (Resistance and filter for clogging)
T
roubleshooting
Add Correct Clean Clean Replace Replace Replace Replace Replace
Remedy
Insuf
ficient fuel in tank
Clogged fuel tank cap Loose piping, fuel filter
, entry of air
Clogged fuel filter
, strainer
Broken fuel pump drive shaft Defective fuel shut-of
f valve
Defective fuel shut-of
f valve wiring
Clogged timing actuator screen Defective atmospheric pressure sensor
Causes
When engine is cranked with
starting motor, and
b) Engine turns but no exhaust smoke comes out (fuel is not being injected)
General causes why engine turns but no exhaust smoke comes out
• Fuel is not being supplied
• Supply of fuel is extremely small
• Improper selection of fuel (particularly in winter)
• Defective HPI sensor
• Defective HPI actuator
S-2
(10)
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