S-5 Engine Does Not Pick Up Smoothly - Komatsu PC88MR-10 Shop Manual

40 Troubleshooting
Troubleshooting of engine (S-mode)

S-5 Engine does not pick up smoothly

Engine does not pick-up smoothly.
Failure
Related
If any failure code is displayed, perform troubleshooting for that code first.
information
No. Cause
1 Insufficient fuel in tank
Clogged air breather hole in
2
fuel tank cap
Clogged fuel filter element
3
Foreign material in fuel
4
Air in fuel piping system
5
Leakage from fuel piping
6
system
Defective supply pump
7
Abnormally high crankcase
8
pressure
Defective injector
9
Seized or broken
10
turbocharger
11 Incorrect valve clearance
12 Defective engine controller
40-520
(D37-A30-400-A-Z0-A)
Point to check, remarks
Fuel tank is empty.
Air breather hole in fuel tank cap is clogged.
Check used hours of fuel filter. If used
beyond specified hours, fuel filter element
may be clogged.
Rust and water are found in fuel drained
from fuel tank.
Air is bled during air bleeding of fuel system.
(Reference: See Testing and adjusting,
"Bleeding air from fuel system".)
Fuel leaks from fuel piping.
(Reference: See Testing and adjusting,
"Testing fuel circuit for leakage".)
See Testing and adjusting, "Testing fuel
discharge, return and leakage".
When crankcase pressure high error (failure
code: CA555) is still displayed even after
KCCV filter is replaced, blowby pressure is
probably high (see Testing and adjusting,
"Testing blowby pressure"). In this case,
KVGT may be seized or damaged.
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".)
Unusual noise is heard from turbocharger.
Check whether turbocharger shaft rotates.
(Move turbocharger vanes with hand in axial
and radial directions to make judgment.)
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".)
Since this is an internal defect,
troubleshooting cannot be performed.
Remedy
Add fuel.
Flush air breather hole
in fuel tank cap and
clean surrounding
area.
Replace fuel filter
element.
Replace fuel.
Perform air bleeding.
Repair or replace fuel
piping.
Repair or replace fuel
piping related parts.
Replace supply pump
or pressure limiter.
Perform following
checks on causes 10
and after.
Replace injector.
Replace KVGT.
Adjusting valve
clearance
Replace engine
controller.
PC88MR-10