Komatsu Galeo PC138US-8, Shop Manual

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SEN02469-01 40 Troubleshooting
12
PC138US, USLC-8
S-3 Engine does not pick up smoothly 1
*1: Displayed failure codes [CA559] and [CA2249]
General causes why engine does not pick up smoothly
q
Insufficient intake of air
q
Insufficient supply of fuel
q
Defective condition of fuel injection
q
Improper selection of fuel
q
Controller is controlling in derate mode
(limiting injection rate (output) because of an error in electrical system)
Causes
Clogged
ai
r cleaner
eleme
n
t
Def
e
ct
iv
e cont
act
of
valve
and v
a
lv
e s
e
at
Im
proper valve clearanc
e
Seized
t
u
rbochar
ger
, int
e
rf
er
ence
of
t
u
rboc
harger
W
o
rn
pis
ton ring,
cylinder
Clogged
ai
r breat
her
hole of
f
u
el t
a
nk
cap
Leaking
or c
logged f
u
el piping,
ent
ry
of
air
Clogging of
f
uel f
ilt
er
S
tuck,
s
e
iz
ed s
u
pply
pump
plunger
Clogged i
n
ject
or
, def
e
ct
ive spray
Q
ues
tions
Confirm recent repair history
Degree of use of machine Operated for long period
E E E E
Engine pick-up suddenly became worse
w Q Q Q
Non-specified fuel is being used
w w w
Replacement of filters has not been carried out according to Operation and Maintenance
Manual
w w
Oil must be added more frequently
w
Dust indicator is red
w
Air breather hole of fuel tank cap is clogged
w
Rust and water are found when fuel tank is drained
w
Fuel is leaking from fuel piping
w
When priming pump is operated, it makes no reaction or it is heavy
w Q
C
h
e
ck i
tem
s
When exhaust manifold is touched immediately after starting engine, temperature of some
cylinders is low
Q w
Color of exhaust gas is
Blue under light load
w
Black
w Q w w
When engine is cranked, abnormal sound is generated around cylinder head
w
When engine is cranked, interference sound is generated around turbocharger
w
High idle speed under no load is normal, but speed suddenly drops when load is applied
Q w
There is hunting from engine (rotation is irregular)
Q Q Q
Blow-by gas is excessive
w
T
roublesh
oot
ing
Inspect air cleaner directly
q
When compression pressure is measured, it is found to be low
q q
Inspect valve clearance directly
q
When turbocharger is rotated by hand, it is found to be heavy
q
When air is bled from fuel system, air comes out
q
Inspect fuel filter directly
q
Carry out troubleshooting according to “No-pressure feed by supply pump (*1)” indicated by
code
q
When a cylinder is cut out for reduced cylinder mode operation, engine speed does not change
q
Remedy
Clean
Cor
rec
t
Adj
u
st
Replac
e
Replac
e
Clean
Cor
rec
t
Clean
Replac
e
Replac
e