Komatsu PC88MR-10 Shop Manual page 1014

40 Troubleshooting
Troubleshooting of engine (S-mode)
No. Cause
17 Incorrect valve clearance
18 Defective injector
19 Defective engine controller
Defective contact between
20
valve and valve seat
21 Defective piston ring
40-526
Point to check, remarks
When engine is cranked, unusual noise is
heard from around cylinder head.
Check valve clearance.
(Reference: See Testing and adjusting,
"Testing and adjusting valve clearance".)
Some cylinder is found to be cool when
exhaust manifolds are touched by hand
immediately after engine is started.
When engine is run in cylinder cutout mode
with some cylinder cut out, engine speed
does not change.
(Reference: See Testing and adjusting,
"Handling cylinder cutout mode operation".)
Since this is an internal defect,
troubleshooting cannot be performed.
Measure compression pressure (see
Standard value table).
(Reference: See Testing and adjusting,
"Testing compression pressure".)
Check valve clearance.
(Reference: See Testing and adjusting,
"Testing and adjusting valve clearance".)
Open exhaust color inspection hole that is
just upstream of the KDOC muffler, and
check exhaust gas.
(Reference: See Testing and adjusting,
"Testing exhaust gas color".)
Measure compression pressure (see
Standard value table).
(Reference: See Testing and adjusting,
"Testing compression pressure".)
Check piston ring and piston ring groove.
Remedy
Adjusting valve
clearance
Replace injector.
Replace engine
controller.
Correct contact
between valve and
valve seat or replace
them.
Replace piston ring or
piston.
PC88MR-10