Komatsu ecot3 PC300LC-8 Shop Manual page 633

40 Troubleshooting
Defective injector
3 (including high pressure pip-
ing in head)
4 Defective supply pump
Possible causes
and standard
value in normal
state
5 Defective pressure limiter
Defective supply pump
6
plunger
7 Air in low pressure circuit
Note 1: When low-pressure circuit equipment is defective, check the following:
1) Fuel level
2) Clogged fuel tank breather
3) Stuck or worn feed pump, clogged filter
4) Leaked or clogged low-pressure fuel pipe
5) Bypass valve malfunction, defective assembly of other parts
6) Clogged fuel filter
7) Fuel in oil pan (fuel leakage in head cover)
PC300, 350-8
Cause Standard value in normal state/Remarks on troubleshooting
a
Return rate from
a
Return rate from sup-
a
Leakage through
pressure limiter
a
There may be air in low pressure circuit. Check it directly according
to the following procedure.
1) Remove pressure pickup plug (outlet side) of fuel main filter.
2) Operate feed pump of fuel pre-filter.
3) Check pressure pickup plug for leakage of fuel and air.
• If this error occurs during air bleeding after the fuel filter was
replaced, air may remain in the fuel circuit. Keep running the
engine at low idle for about three minutes. As air is bled from the
fuel circuit, the engine speed will be stabilized, erasing the error
indication.
For check of return rate from injector, see Testing and adjust-
ing, Checking fuel return rate and leakage.
During cranking
(if engine cannot be
started)
injector
During low idle
(if engine can be
started)
For check of return rate from supply pump, see Testing and
adjusting, Checking fuel return rate and leakage.
During cranking
(if engine cannot be
started)
ply pump
During low idle
(if engine can be
started)
For check of leakage through pressure limiter, see Testing and
adjusting, Checking fuel return rate and leakage.
At low idle
Remove the supply pump head, and directly check that the
plunger is not damaged.
SEN02630-05
Max. 100 cc/30 sec.
Max. 300 cc/45 sec.
Max. 200 cc/30 sec.
Max. 300 cc/30 sec.
Below 30 drops/
60 sec.
31