KENR9126 65
Troubleshooting Section
5. If the repair does not eliminate the fault refer to
“Individual Ma
lfunctioning Cylinders”.
Individual Malfunctioning Cylinders
1. Use the electronic service tool to perform the
“Cylinder Cut-out Test”. Note if there is any
reduction in
engine speed. If a reduction in engine
speed is not noted, the isolated cylinder is not
operating under normal conditions. If the isolation
of a particu
lar cylinder results in a reduction of
engine speed that is less than normal, this may
indicate that the cylinder is operating below normal
performanc
e. Investigate the cause of the fault on
any cylinder that is not operating. Investigate the
cause of the fault on any cylinder that is operating
below norm
al performance.
2. If all cylinders have been checked and no faults
were detec
ted, proceed to “Electronic Unit
Injectors”.
Electron
ic Unit Injectors
1. Use the electronic service tool to perform the
“Cylind
er Cut-out Test”. Note if there is any
reduction in engine speed. If a reduction in engine
speed is not noted, the isolated electronic unit
injecto
r is not operating under normal conditions.
If the isolation of a particular cylinder results in a
reduction of engine speed that is less than normal,
this ma
y indicate that the electronic unit injector is
operating below normal performance.
2. Remove
the electronic unit injector from the
suspect cylinder.
3. Insta
ll a new electronic unit injector.
4. Repeat the test in 1. If the fault is still apparent,
remov
e the replacement electronic unit injector
and install the original electronic unit injector.
5. If th
e fault is not eliminated, repeat this test
procedure from Step 1.
i02529009
Mec
hanical N oise (Knock) in
Engine
Pr
obable Causes
•
Accessory equipment
•
Valve train components
•
P
istons
•
Connecting rod and main bearings
Recommended Actions
Accessory E quipment
1. Isolate the so
urce of the noise. Remove the
suspect engine accessory. Inspect the suspect
engine accessory. Repair the engine accessory
and/or repla
ce the engine accessory if any defects
are found.
2. If the mecha
nical noise is still apparent, refer to
“Valve Train Components”.
Valve Trai
n Components
1. Remove the valve mechanism cover. Check
the follow
ing items for damage: camshaft, valve
springs, lifters, pushrods, and bridges. Thoroughly
clean the valve train components. If the camshaft
is being r
eplaced, also replace the valve lifters.
Ensure that all of the valves move freely. Replace
any damaged parts.
2. If the mechanical noise is still apparent, refer to
“Pistons”.
Pistons
1. Inspec
t the pistons for damage and wear. Replace
any damaged parts.
2. If the m
echanical noise is still apparent, refer to
“Connecting Rod and Main Bearings”.
Conne
cting Rod and Main B earings
Inspect the connecting rod and main bearings.
Also,
inspect the bearing surfaces (journals) on the
crankshaft. Replace any damaged parts.
i04010489
Noise Coming from C ylin der
Probable Causes
•
Fuel quality
•
Valve lash
•
Electronic unit injectors
•
Pistons
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