Fiat Kobelco EX355 Tier2, Technical Manual

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EX355 W5-6-1
ENGINE FUEL
SERVICE PRECAUTION
• Be sure to use the correct fastener in the proper
location. If a used fastener is replaced with a
new one, the new fastener must be identical to
the previous one.
• Some fasteners must always be replaced with
new ones following removal. These fasteners
are specified in this Manual.
• Some fasteners require thread locker or thread
sealant. These fasteners are specified in this
Manual.
• Supplemental fastener coatings (paint, grease,
or corrosion inhibitor) affect fastener torque
and clamping force. They may damage the fas-
tener. Do not use them unless specifically
called for.
• Tighten all fasteners to the specified torque. If
there is a tightening sequence, follow it exactly.
GENERAL DESCRIPTION
Fuel System Operation
The fuel injection pump is driven by the crankshaft.
The fuel injection pump drives the fuel feed pump.
The fuel feed pump draws fuel from the fuel tank. The
fuel is delivered to the injection pump through the fuel/
water separator and the secondary fuel filter.
The governor regulates the flow of fuel to the delivery
valves.
The plunger in the injection pump delivers fuel at high
pressure through the delivery valves to the individual
fuel injectors at precise intervals.
The pressure generated by the fuel in the fuel injector
forces open a needle valve. Fuel is injected from the
injection nozzle holes into the cylinder as a very fine
spray.
Excess fuel is returned to the fuel tank through the fuel
return line.
When working on the fuel system -
• Disconnect the negative battery cable.
• Have a dry chemical (Class B) fire extinguisher
where it can be reached quickly.
• Release the fuel line pressure before servicing
system components.
• Carefully read and understand the appropriate in-
structions.