40 Troubleshooting SEN04125-02
PC130-8
15
S-6 Engine lacks output (or lacks power) 1
*1: Displayed failure codes [CA559] and [CA2249]
*2: Displayed failure codes [CA122] and [CA123]
General causes why engine lacks output
q Insufficient intake of air
q Insufficient supply of fuel
q Defective condition of fuel injection
q Improper selection of fuel
q There is overheating
o See “S-14 Coolant temperature becomes too
high (Overheating)“
q 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 and aftercooler
Seized turbocharger, interference of turbocharger
Defective contact of valve and valve seat
Improper valve clearance
Worn piston ring, cylinder
Clogged air breather hole of fuel tank cap
Leaking, clogged fuel piping
Clogging of fuel filter
Stuck, seized supply pump plunger
Clogged injector, defective spray (dirt in injector)
Defective drive of injector (signal, solenoid)
Defective installation of boost pressure sensor
(air leakage)
Defective boost pressure sensor, wiring harness
Clogged fuel spill piping
Questions
Confirm recent repair history
Degree of use of machine Operated for long period EEEE
Power was lost
Suddenly Qw Q Q QQ
Gradually QQQQQQ
Non-specified fuel is being used QQQ
Replacement of filters has not been carried out according to Operation and
Maintenance Manual
ww
Oil must be added more frequently QQ
Dust indicator is red ww
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 is
Black ww
Blue under light load w
When exhaust manifold is touched immediately after starting engine, temperature of
some cylinders is low
ww
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 high Q
High idle speed under no load is normal, but speed suddenly drops when load is applied Q wQQ
Engine does not pick up smoothly and combustion is irregular ww QQ w
There is hunting from engine (rotation is irregular) QQQ QQ
Blow-by gas is excessive ww
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 piping q
Inspect fuel filter directly q
Inspect spill port check valve directly q
Carry out troubleshooting according to “No-pressure feed by supply pump (*1)”
indicated by code
q
When a cylinder is cut out for reduced cylinder mode operation, engine speed does
not change
qq
Inspect charge pressure sensor mount directly q
Carry out troubleshooting according to “Abnormality in charge pressure sensor (*2)”
indicated by code
q
Remedy
Clean
Correct
Replace
Correct
Adjust
Replace
Clean
Correct
Replace
Replace
Replace
Replace
Correct
Replace
Replace
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