Exhaust Smoke Is Black (Incomplete Combustion) - Komatsu ecot3 PC300LC-8 Shop Manual

SEN02634-02
S-7 Exhaust smoke is black (incomplete combustion)
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)
Confirm recent repair history
Degree of use of
Operated for long period
machine
Suddenly became black
Color of exhaust gas Gradually became black
Black during light-load operation
Non-specified fuel is being used
Oil must be added more frequently
Suddenly
Power was lost
Gradually
Dust indicator is red (if indicator is installed)
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 cylin-
ders 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 occurred 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
If spill hose from injector is disconnected, abnormally much fuel spills
Inspect air cleaner directly
When turbocharger is rotated by hand, it is found to be heavy
When compression pressure is measured, it is found to be low
Inspect valve clearance directly
When muffler is removed, exhaust gas color improves
Carry out troubleshooting for "Rail Press (Very) Low Error." See *1 for failure code.
When a cylinder is cut out for reduced cylinder mode operation, engine speed does not change
Carry out troubleshooting for "Coolant Temp Sens High (Low) Error." See *2 for failure code.
Confirm with INSITE or monitoring function on applicable machine side
*1: Failure codes [CA559] and [CA2249]
*2: Failure codes [CA144] and [CA145]
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Remedy
40 Troubleshooting
1
Cause
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PC300, 350-8