Fuel Valves - PREVOST H3-41 Maintenance Manual

2. FUEL SYSTEM
NOTE
For additional information concerning Volvo
D13 engine components or engine-related
components, consult Volvo Trucks Canada or
Volvo Trucks North America Web Site under:
Parts & Service. On Volvo web site, you will
find detailed service procedures for parts
replacement, repair and maintenance.
FIGURE 1: FUEL SYSTEM SCHEMATIC (VOLVO D13
ENGINE)
03086
Fuel is drawn up the fuel lines by the supply
pump (1) through the pickup tube in the tank (2)
and through the Engine Electronic Control Unit
(EECU) cooling coil (3) and into the fuel filter
housing (4). The fuel housing is equipped with a
primary fuel filter
consisting of a filter cartridge and a water
separation bowl.
The supply pump (1) forces the fuel into the fuel
filter housing through the secondary filter (main)
to a cylinder head longitudinal gallery (8). This
channel supplies each unit injector (9) with
pressurized fuel by a circular groove around
each unit injector in the cylinder head. The
overflow valve (10) controls the fuel supply
pressure to the unit injectors.
The return fuel from the overflow valve (10) is
returned back to the fuel filler housing and is
mixed with the fuel from the fuel tank in a
channel within the fuel filter housing (4).
(fuel/water separator)
PA1615 Maintenance Manual All Series
SECTION 03 : FUEL SYSTEM
Supply Pump Valves
Two valves are located in the supply pump (1).
The safety valve (11) allows fuel to flow back to
the suction side when the pressure becomes too
high, e.g., if the fuel filter is blocked or is too
restricted. The non-return valve (12) opens
when the hand-priming pump is used.
Automatic Bleeding
If air gets into the system, it is bled when the
engine starts. During bleeding, air is pressed out
through the fuel filter housing over to the fuel
tank through the return line (25). Bleeding for
the filter replacement is controlled by valves (17)
and (23).
Other
The fuel filter housing eliminates the need to
drain the fuel when replacing the filter. The valve
pegs (17) and (21) close when the fuel filter is
removed. It is not necessary to bleed the fuel
system after replacing the filter, since this is
performed automatically when the engine is
started and runs for more than 2 minutes.
The plugged outlet (18) is fitted on the fuel filter
housing. This outlet is used when measuring
supply pressure after the fuel filter with an
external pressure gauge. The pressure sensor
(19) on the fuel filter housing monitors the
supply pressure after the fuel filter. A fault code
is displayed on the instrument cluster if the fuel
supply pressure is less than the specified value.
Hand Priming Pump
The hand priming pump (13) is located on the
fuel filter housing and is used to pump fuel
(when engine is not running) after the fuel
system has been drained for repair, etc. The
non-return valve (22) for the hand priming pump
is also located in the fuel filter housing.

2.1 FUEL VALVES

The manual shut-off valve on engine fuel-supply
line is located on the R.H. side of engine
compartment. A manual shut-off valve is located
at the inlet side of the primary fuel filter or at the
inlet side of Davco Fuel Pro 382 fuel filter.
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Section 03 revised September 2016
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