Engine Lacks Output (Or Lacks Power) - Komatsu WA250-6 Shop Manual

600 Troubleshooting of engine (S-mode)
S-6 Engine lacks output (or lacks power)
S-6 Engine lacks output (or lacks power)
General causes why engine lacks output
Insufficient intake of air
q
Insufficient supply of fuel
q
Defective condition of fuel injection
q
Improper selection of fuel
q
There is overheating
q
o See "S-14 Coolant temperature becomes too
high (Overheating)"
Controller is controlling in derate mode
q
(limiting injection rate (output) because of an
error in electrical system)
Confirm recent repair history
Degree of use of machine
Power was lost
Non-specified fuel is being used
Replacement of filters has not been carried out according to Operation and
Maintenance Manual
Oil must be added more frequently
Dust indicator is red
Air breather hole of fuel tank cap is clogged
Fuel is leaking from fuel piping
Output becomes insufficient after short stop of operation
Color of exhaust gas is
When exhaust manifold is touched immediately after starting engine, temperature of
some cylinders is low
When engine is cranked, interference sound is generated around turbocharger
When engine is cranked, abnormal sound is generated around cylinder head
High idle speed is too high
High idle speed under no load is normal, but speed suddenly drops when load is applied
Engine does not pick up smoothly and combustion is irregular
There is hunting from engine (rotation is irregular)
Blow-by gas is excessive
Inspect air cleaner directly
Inspect air intake piping directly
When boost pressure is measured, it is found to be low
When compression pressure is measured, it is found to be low
Inspect valve clearance directly
Inspect fuel piping
Inspect fuel filter, strainer directly
Inspect spill port check valve directly
Carry out troubleshooting according to "No-pressure feed by supply pump (*1)" in
display of code
When a cylinder is cut out for reduced cylinder mode operation, engine speed does
not change
Inspect boost pressure sensor mount directly
Carry out troubleshooting according to "Abnormality in boost pressure sensor (*2)"
in display of code
*1: Failure codes [CA559] and [CA2249] in the display of code
*2: Failure codes [CA122] and [CA123] in the display of code
WA250, 250PZ-6
Operated for long period
Suddenly
Gradually
Black
Blue under light load
E E E
Q w
Q Q
w
Q
w w
w
w
w w
w
w
w w
w
q
q
q q q
q
q
Remedy
SEN03850-00
Causes
E
Q Q
Q Q Q Q
Q Q Q
w
Q
w
w
w
w w
Q
Q w Q Q
Q Q w
Q Q Q Q Q
w
q
q
q
q
q q
q
40-600
1
Q Q
q
q
13