Komatsu Galeo PC800-8, Shop Manual

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12
PC800, 850-8
SEN00795-02
40 Troubleshooting
S-3 Engine does not pick up smoothly
*1: Failure codes [ CA1228 ] and [ CA1625 ]
*2: 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)
• EGR valve is stuck open
(There is much EGR gas and intake of air is insufficient)
Causes
C
logg
ed
ai
r
cl
ean
er
el
em
en
t
S
tuck E
G
R
va
lve
D
efe
cti
ve
contact
of v
al
ve
and
val
ve
se
at
Imp
rop
er
val
ve
cl
ea
ra
nce
S
e
iz
ed
tur
bo
char
ge
r, i
n
terf
ere
nce
of
tur
boc
har
ger
W
orn
pi
st
on r
ing
, cyl
in
d
er
li
ner
C
logg
ed
ai
r
bre
ath
er
hol
e
of
fue
l t
a
nk ca
p
Lea
ki
ng
or
cl
og
ged
fue
l pi
p
ing,
ent
ry o
f a
ir
C
logg
ed
fue
l fi
lter
, str
ai
ne
r
C
logg
ed
fee
d p
ump
ga
uze
fi
lte
r
S
tuck,
sei
ze
d su
pp
ly
pu
mp
pl
un
ge
r
D
efe
cti
ve
ope
rat
ion
of f
lo
w
da
mp
er
(La
rg
e l
ea
kag
e f
rom
in
je
ctor
)
C
logg
ed
in
je
ct
or
,
def
ecti
ve
spr
ay
Que
s
tio
ns
Confirm recent repair history
Degree of use of
machine
Operated for long period
E E E E E E
Engine pick-up suddenly became worse
Q w Q Q Q
Non-specified fuel is being used
w w w w
Replacement of filters has not been carried out according to Operation and Mainte-
nance Manual
w 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 w
Fuel is leaking from fuel piping
w
When priming pump is operated, it makes no reaction or it is heavy
w Q Q
Ch
eck i
tem
s
When exhaust manifold is touched immediately after starting engine, temperature of
some cylinders 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 w
There is hunting from engine (rotation is irregular)
Q Q w Q
Blow-by gas is excessive
w
T
roub
le
s
ho
ot
ing
Inspect air cleaner directly
q
Carry out troubleshooting for “EGR Valve Servo Error. (*1)”. See *1 for failure code.
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
Inspect feed pump gauze filter directly
q
Carry out troubleshooting for “Rail Press (Very) Low Error. (*2)”. See *2 for failure code.
q
When a cylinder is cut out for reduced cylinder mode operation, engine speed does
not change
q q
Remedy
Clean Replac
e
Replac
e
Ad
ju
st
Replac
e
Replac
e
Clean Corr
ec
t
Clean Clean Replac
e
Replac
e
Replac
e