Komatsu 75001, Shop Manual

Page: 993 / 1293

SEN03850-00
40-600
12
WA250, 250PZ-6
600 Troubleshooting of engine (S-mode)
S-5 Engine does not rotate smoothly
S-5 Engine does not rotate smoothly
1
*1: Failure code [CA689] in the display of code
*2: Failure code [CA778] in the display of code
General causes why engine does not rotate smoothly
q
Air in fuel system
q
Defective speed sensor (Error at degree that it is not indicated)
Causes
In
s
u
ffi
ci
e
n
t fu
e
l in
ta
n
k
C
log
ge
d
air
br
e
at
he
r h
ol
e o
f f
ue
l t
a
nk
c
ap
Le
ak
in
g or
cl
og
ge
d f
ue
l p
ip
in
g,
en
tr
y
o
f
a
ir
C
log
gi
ng
of
f
u
el
f
ilt
e
r
C
log
ge
d inj
ec
to
r,
de
fec
ti
ve
s
pr
a
y
(
d
ir
t in in
je
ct
or
)
D
e
fe
ct
ive
N
e
sp
ee
d se
nso
r,
w
ir
in
g
ha
rn
e
s
s
D
e
fe
ct
iv
e G
sp
ee
d
se
ns
or
, w
ir
in
g
h
a
rne
ss
Q
u
est
ion
s
Confirm recent repair history
Degree of use of machine Operated for long period E
Hunting
Occurs at a certain speed range
Q Q
Occurs at low idle Q Q Q Q Q
Occurs even when speed is raised Q Q Q
Occurs on slopes w
Replacement of filters has not been carried out according to Operation and Maintenance Manual
w
When fuel tank is inspected, it is found to be empty w
C
h
ec
k it
em
s Air breather hole of fuel tank cap is clogged
w
Rust and water are found when fuel tank is drained Q
Fuel is leaking from fuel piping
w
When priming pump is operated, it makes no reaction or it is heavy w Q
T
rou
bl
esh
oo
tin
g When air is bled from fuel system, air comes out
q
Inspect fuel filter, strainer directly
q
When a cylinder is cut out for reduced cylinder mode operation, engine speed does not change q
Carry out troubleshooting according to “Abnormality in Ne speed sensor (*1)” in display of code q
Carry out troubleshooting according to “Abnormality in Bkup speed sensor (*2)” in display of code q
Remedy
Ad
d
Cl
e
a
n
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