Komatsu ecot3 PC300-8, Shop Manual

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SEN02634-02 40 Troubleshooting
10
PC300, 350-8
S-3 Engine does not pick up smoothly 1
*1: Failure codes [CA559] and [CA2249]
General causes why engine does not pick up smoothly
• Insufficient intake of air
• Insufficient supply of fuel
• Defective condition of fuel spray
• Improper selection of fuel
• Controller is controlling in derate mode
(limiting injection rate (output) because of an error in electrical system)
Cause
Clogged air cleaner el
em
ent
Def
e
ct
ive cont
act
of
valv
e
and valve seat
Im
pr
oper v
a
lve
clearance
S
e
ized t
u
rboc
harger
, i
n
te
rf
erence
of
t
u
rbochar
g
er
E
xces
s
ive wear of
pist
o
n
ring,
c
y
lind
er
liner
Clogged air breat
he
r
hole of
f
uel t
ank
c
a
p
Leak
ing
or clogged f
uel pipi
n
g,
ent
ry
of
air
Clogged f
uel
f
ilt
er
S
tuck
, seized supply pum
p
plunger
Clogged
inject
or
, def
ect
iv
e
s
p
ray
Q
uest
ions
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 Man-
ual
w w
Oil must be added more frequently
w
Dust indicator is red (if indicator is installed)
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
Chec
k
it
em
s
When exhaust manifold is touched immediately after starting engine, temperature of some cyl-
inders is low
Q w
Color of exhaust
gas
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
roubleshoot
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, strainer 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
Remedy
Cl
e
a
n
Replace Adj
u
st
Replace Replace Cl
e
a
n
Correct Replace Replace Replace