68 KENR6933
Troubleshooting Section
2. Remove the electronic unit injector from the
suspect cylind
er. Refer to Disassembly and
Assembly, “Electronic Unit Injector - Remove”.
3. Install a new e
lectronic unit injector. Refer to
Disassembly and Assembly, “Electronic Unit
Injector - Install”.
4. Repeat the test in 1. If the fault is still apparent,
remove the replacement electronic unit injector
and install t
he original electronic unit injector.
Refer to Disassembly and Assembly, “Electronic
Unit Injector - Remove” and Disassembly and
Assembly, “E
lectronic Unit Injector - Install”.
5. If the fault is not eliminated, check for active
diagnostic f
ault codes.
i02529009
Mechanical Noise (Kn ock) in
Engine
Probable Causes
•
Accessory equipment
•
Valve train components
•
Pistons
•
Connecting rod and main bearings
Recommended Actions
Accessory Equipment
1. Isolate the source of the noise. Remove the
suspect engine accessory. Inspect the suspect
engine accessory. Repair the engine accessory
and/or replace the engine accessory if any defects
are found.
2. If the mechanical noise is still apparent, refer to
“Valve Train Components”.
Valve Train Components
1. Remove the valve mechanism cover. Check
the following items for damage: camshaft, valve
springs, lifters, pushrods, and bridges. Thoroughly
clean the valve train components. If the camshaft
is being replaced, 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. Inspect the pistons for damage and wear. Replace
any damaged parts.
2. If the mechanical noise is still apparent, refer to
“Connecting Rod and Main Bearings”.
Connecting Rod and Main Bearings
Inspect the co
nnecting rod and main bearings.
Also, inspect the bearing surfaces (journals) on the
crankshaft. Replace any damaged parts.
i02529391
Noise Com ing from Cylinder
Probable Causes
•
Fuel quality
•
Valve lash
•
Pistons
•
Electronic unit injectors
Recommended Actions
Fuel Quality
1. Check the fuel quality. Refer to Testing and
Adjusting, “Fuel Quality - Test”.
2. If unsatisfactory fuel is found, perform the following
procedure.
a. Drain the fuel system.
b. Replace the fuel filters. Refer to the Operation
and Maintenance Manual, “Fuel System
Primary Filter (Water Separator) Element -
Replace” and Operation and Maintenance
Manual, “Fuel System Filter - Replace”.
c. Fill the fuel system with fuel that meets the
standard in Operation and Maintenance
Manual, “Fluid Recommendations”.
d. Prime the fuel system. Refer to Operation and
Maintenance Manual, “Fuel System - Prime”.
3. If the fault is not eliminated, refer to “Pistons”.
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