Fuel from the tank (A) leaves the primary fuel filter (2)
and then passes to the diaphragm type fuel transfer
pump (1). The fuel transfer pump (1) is driven by an
eccentric on the camshaft. Fuel leaves the fuel
transfer pump (1) under pressure and passes through
the secondary fuel filter (3) to the fuel injection pump
(5). The secondary fuel filter (3) is a twin filter.
Extra fuel is circulated through the injection pump (5).
The extra fuel is then returned to the fuel tank.
A fuel heater or cooler may be installed between the
filter head and filter canister.
The fuel injection pump (5) sends fuel through the fuel
injection lines (4) to each of the fuel injection nozzles
(7). The fuel injection lines (4) to the fuel injection
nozzles (7) are equal lengths. This ensures even
pressure and correct injection timing at each fuel
injection nozzle (7). The fuel injection nozzle (7)
sprays the fuel into the cylinder. Fuel that is not
injected flows through the fuel return line (6) to the top
of the secondary fuel filter. The fuel then flows back to
the fuel tank (B).
The engine must not be started until the fuel injection
pump is full of fuel that is free of air. The fuel injection
pump requires fuel for lubrication. The precision parts
of the pump are easily damaged without lubrication.
The fuel system must be primed when any of the
following conditions occur:
• The fuel filter is changed.
• The fuel line is removed.
• The fuel injection pump is removed.
Fuel System Components
Fuel Injection Pump
General Operation
Illustration 6
g01352237
Typical example
(1) Fuel injection pump
(2) Locking screw
(3) Washer
The fuel injection pump is a pressurized system that
is totally enclosed. The pump sends the correct
amount of fuel under high pressure at the correct time
through the fuel injection nozzles to the individual
cylinders. The fuel injection pump regulates the
amount of fuel that is delivered to the fuel injection
nozzles. This action controls the engine rpm by the
governor setting or the position of the throttle control.
The Delphi DP310 fuel injection pump must be
serviced by an authorized Delphi technician. For
repair information, contact your Perkins distributor.
High idle and low idle of the fuel injection pump are
factory set. Idle adjustments cannot be made to the
fuel pump. The fuel injection pump has a boost
control and an engine stop solenoid. The Delphi
DP310 fuel injection pump has a feature that vents
air from the pump.
The fuel injection pump has a cold starting aid. The
cold starting aid advances the timing of the pump
when the engine is cold. The cold starting aid is
electrically operated.
Cold Start Advance Unit (If equipped)
The cold start advance unit holds the timing of the
fuel injection pump in an advance position when the
engine is cold.
UENR0617
11
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