Komatsu ecot3 PC300-8, Shop Manual

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40 Troubleshooting SEN02634-02
PC300, 350-8
13
S-6 Engine lacks output (or lacks power) 1
*1: Failure codes [CA559] and [CA2249]
*2: Failure codes [CA122] and [CA123]
General causes why engine lacks output
• Insufficient intake of air
• Insufficient supply of fuel
• Defective condition of fuel spray
• Improper selection of fuel
• There is over heating
⇒
See “S-14 Coolant temperature becomes too high
(Overheating)”.
• Controller is controlling in derate mode
(limiting injection rate (output) because of an error in
electrical system)
Cause
Clogged a
ir cleaner element
Air leakage
from air int
ake piping
Seized turb
ocharger
, interference of turbo
charger
Defective co
nt
act of valve and valve
seat
Improper va
lve clearance
Excessive we
ar of piston ring, cylinder liner
Clogged a
ir breather hole of fuel t
a
nk cap
Leaking, c
logged fuel piping
Clogged fu
el filter
S
tuck, seized supply pump plu
nger
Clogged in
jector
, defective spray (dirt in injecto
r)
Defective d
rive of injector (signal, solenoid)
Defective in
st
allation of boost
pressure se
nsor (air leakage)
Defective b
oost pressure sensor
, wiring harne
ss
Clogged sp
ill piping
Questions
Confirm recent repair history
Degree of use of
machine
Operated for long period
E E E E
Power was lost
Suddenly
Q w Q Q Q Q
Gradually
Q Q Q Q Q Q
Non-specified fuel is being used
Q Q Q
Replacement of filters has not been carried out according to Operation and Maintenance
Manual
w w
Engine oil must be added more frequently
Q Q
Dust indicator is red (if indicator is installed)
w w
Air breather hole of fuel tank cap is clogged
w w
Fuel is leaking from fuel piping
w
Output becomes insufficient after short stop of operation
w
Check items
Color of exhaust gas
Black
w w
Blue under light load
w
When exhaust manifold is touched immediately after starting engine, temperature of some
cylinders is low
w w
When engine is cranked, interference sound is generated around turbocharger
w
When engine is cranked, abnormal sound is generated around cylinder head
w
High idle speed is too low
Q
High idle speed under no load is normal, but speed suddenly drops when load is applied
Q w Q Q
Engine does not pick up smoothly and combustion is irregular
w w Q Q w
There is hunting from engine (rotation is irregular)
Q Q Q Q Q
Blow-by gas is excessive
w w
T
roubleshoo
ting
Inspect air cleaner directly
q
Inspect air intake piping directly
q
When boost pressure is measured, it is found to be low
q q q
When compression pressure is measured, it is found to be low
q q
Inspect valve clearance directly
q
Inspect fuel piping
q
Inspect fuel filter, strainer directly
q
Inspect spill port check valve directly
q
Carry out troubleshooting for “Rail Press (Very) Low Error.” See *1 for failure code.
q
When a cylinder is cut out for reduced cylinder mode operation, engine speed does not
change
q q
Inspect boost pressure sensor mount directly
q
Carry out troubleshooting for “Chg Air Press Sensor High (Low) Error.” See *2 for failure
code.
q
Remedy
Clean Correct Replace Replace Adjust Replace Clean Correct Replace Replace Replace Replace Correct Replace Replace