Exhaust Smoke Is Black (Incomplete Combustion) - Komatsu WA250-6 Shop Manual

SEN03850-00
S-7 Exhaust smoke is black (incomplete combustion)
General causes why exhaust smoke is black
Insufficient intake of air
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
Color of exhaust gas is
Non-specified fuel is being used
Oil must be added more frequently
Power was lost
Dust indicator is red
Muffler is crushed
Air leaks between turbocharger and cylinder head, clamp is loosened
Engine is operated in low-temperature mode at normal temperature
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
Torque converter stall speed or pump relief speed is high (Fuel is injected excessively)
Exhaust noise is abnormal
Engine does not pick up smoothly and combustion is irregular
Blow-by gas is excessive
Much fuel returns from the injector
Inspect air cleaner directly
When turbocharger is rotated by hand, it is fount to be heavy
When compression pressure is measured, it is found to be low
Inspect valve clearance directly
When muffler is removed, exhaust sound improves
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
Carry out troubleshooting according to "Abnormality in coolant temperature sensor (*2)" in
display of code
Confirm with monitoring function
*1: Failure codes [CA559] and [CA2249] in the display of code
*2: Failure codes [CA144] and [CA145] in the display of code
14
40-600
Operated for long period
Suddenly became black
Gradually became black
Blue under light load
Suddenly
Gradually
600 Troubleshooting of engine (S-mode)
S-7 Exhaust smoke is black (incomplete combustion)
E E
w
w
w
Q Q
w
w
w
Q
Q Q Q Q
q
q
q
q
Remedy
Causes
E E
w Q Q Q
Q Q
w
Q Q
w
Q Q Q
Q Q
w
w
Q Q Q
Q w
Q
w Q
Q w
w
w
q
q
q q
q
q q
WA250, 250PZ-6
1
q