Komatsu Galeo PC850-8 User Manual

PC800, 850-8 15
40 Troubleshooting SEN00795-02
S-6 Engine lacks output (or lacks power)
*1: Failure codes [CA559] and [CA2249]
*2: Failure codes [CA122] and [CA123]
*3: Failure codes [CA263] and [CA265]
General causes why engine lacks output
• Insufficient intake of air
• Insufficient supply of fuel
• Defective spray condition of fuel
• Improper selection of fuel
• There is overheating
→ 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)
Causes
Clogged air cleaner element Air leakage from air intake piping Seized turbocharger, interference of turbocharger Defective contact of valve and valve seat Improper valve clearance Worn piston ring, cylinder liner Clogged air breather hole of fuel tank cap Leaking, clogged fuel piping Clogged fuel filter, strainer Clogged feed pump gauze filter Stuck, seized supply pump plunger Clogged injector, defective spray (dirt in injector) Defective drive of injector (signal, solenoid) Defective installation of charge pressure sensor (air leakage) Defective charge pressure sensor, wiring harness Defective fuel temperature sensor, wiring harness
Questions
Confirm recent repair history
Degree of use of
machine
Operated for long period
EEEEE
Power was lost
Suddenly
QQQQ
Gradually
QQQQQQQ
Non-specified fuel is being used
QQ
Replacement of filters has not been carried out according to Operation and Mainte-
nance Manual
wQQ
Engine oil must be added more frequently
QQQ
Dust indicator is red (if indicator is installed)
w
Air breather hole of fuel tank cap is clogged
w
Fuel is leaking from fuel piping
w
Output becomes insufficient after short stop of operation
w
Check items
Color of exhaust gas
Black
ww
Blue under light load
w
When exhaust manifold is touched immediately after starting engine, temperature of
some cylinders is low
w
When engine is cranked, interference sound is generated around turbocharger
w
When engine is cranked, abnormal sound is generated around cylinder head
w
High idle speed is too low
Q
High idle speed under no load is normal, but speed suddenly drops when load is
applied
wwQ
Engine does not pick up smoothly and combustion is irregular
wQQw
There is hunting from engine (rotation is irregular)
QQQQ
Blow-by gas is excessive
w
Troubleshooting
Inspect air cleaner directly
q
Inspect air intake piping directly
q
When boost pressure is measured, it is found to be low
qqq
When compression pressure is measured, it is found to be low
qq
Inspect valve clearance directly
q
Inspect fuel filter, strainer directly
q
Inspect feed pump gauze filter directly
q
Carry out troubleshooting for “Rail Press (Very) Low Error. (*1)”. See *1 for failure code
q
When a cylinder is cut out for reduced cylinder mode operation, engine speed does
not change
qq
Inspect boost pressure sensor mount directly
q
Carry out troubleshooting for “Chg Air Press Sensor High (Low) Error. (*2)”
See *2 for failure code
q
Carry out troubleshooting for “Fuel Temp Sensor High (Low) Error. (*3)”
See *3 for failure code
q
Remedy
Clean Correct Replace Replace Adjust Replace Clean Correct Replace Clean Replace Replace Replace Correct Replace Replace

Komatsu Galeo PC850-8 Specifications

General

Brand	Komatsu
Model	Galeo PC850-8
Category	Excavators
Language	English