Komatsu ecot3 PC300-8, Shop Manual

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SEN02634-02 40 Troubleshooting
14
PC300, 350-8
S-7 Exhaust smoke is black (incomplete combustion) 1
*1: Failure codes [CA559] and [CA2249]
*2: Failure codes [CA144] and [CA145]
General causes why exhaust smoke is black
• Insufficient intake of air
• Defective condition of fuel injection
• 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
C
logg
ed
ai
r
cl
ean
er
el
em
en
t
S
e
iz
ed
tur
b
o
c
ha
rge
r, i
n
ter
fere
n
ce
of
tur
boc
har
ger
D
e
fe
cti
v
e contact
of val
v
e and
val
v
e
se
at
Imp
ro
per
val
v
e
cl
ea
ra
nce
Lea
kag
e
o
f ai
r be
tw
ee
n tu
rb
ocha
rg
er
and
cyl
in
d
e
r he
ad
C
rus
hed
, cl
o
gge
d m
u
ff
le
r
E
xcessive
wea
r o
f p
is
ton
r
ing
, cylin
der
line
r
S
tuck
, sei
z
e
d
s
upp
ly
pu
mp
pl
un
ge
r
Clo
g
g
e
d
, se
ize
d
in
je
cto
r
Ab
n
o
rm
a
lly wo
rn
i
n
je
cto
r
Im
pr
op
e
r f
u
el
i
n
jec
ti
o
n t
im
ing
Im
pr
op
e
r f
u
el
i
n
jec
ti
o
n p
re
s
s
ur
e
D
e
fe
cti
v
e cool
a
n
t tem
per
atu
re
sen
s
or
, w
ir
in
g
ha
rne
s
s
Q
uest
ions
Confirm recent repair history
Degree of use of
machine
Operated for long period
E E E E
Color of exhaust gas
Suddenly became black
w w Q Q
Gradually became black
w Q Q Q
Black during light-load operation
w
Non-specified fuel is being used
Q Q
Oil must be added more frequently
w
Power was lost
Suddenly
w Q Q Q
Gradually
Q Q Q Q
Dust indicator is red (if indicator is installed)
w
Muffler is crushed
w
Air leaks between turbocharger and cylinder head, clamp is loosened
w
Ch
e
ck ite
m
s
Engine is operated in low-temperature mode at normal temperature
Q Q Q
When exhaust manifold is touched immediately after starting engine, temperature of some cylin-
ders is low
Q w
When engine is cranked, interference sound is generated around turbocharger
w
When engine is cranked, abnormal sound is generated around cylinder head
w
Torque converter stall occurred or pump relief speed is high (Fuel is injected excessively)
Q
Exhaust noise is abnormal
Q w Q
Engine does not pick up smoothly and combustion is irregular
Q Q Q Q Q w
Blow-by gas is excessive
w
If spill hose from injector is disconnected, abnormally much fuel spills
w
T
ro
u
bl
e
s
h
oo
ti
ng
Inspect air cleaner directly
q
When turbocharger is rotated by hand, it is found to be heavy
q
When compression pressure is measured, it is found to be low
q q
Inspect valve clearance directly
q
When muffler is removed, exhaust gas color improves
q
Carry out troubleshooting for “Rail Press (Very) Low Error.” See *1 for failure code.
q q
When a cylinder is cut out for reduced cylinder mode operation, engine speed does not change
q
Carry out troubleshooting for “Coolant Temp Sens High (Low) Error.” See *2 for failure code.
q
Confirm with INSITE or monitoring function on applicable machine side
q q
Remedy
C
lean
R
epl
a
c
e
R
epl
a
c
e
Ad
ju
s
t
Co
rr
e
c
t
R
epl
a
c
e
R
epl
a
c
e
R
epl
a
c
e
R
epl
a
c
e
R
epl
a
c
e
R
epl
a
c
e
R
epl
a
c
e
R
epl
a
c
e