Dodge dakota 2002 Service Manual page 1775

14 - 78 FUEL DELIVERY - DIESEL
WATER IN FUEL SENSOR (Continued)
Fig. 29 FILTER HOUSING (LATE)
1 - FILTER HOUSING
2 - FUEL HEATER AND THERMOSTAT
3 - FUEL HEATER MOUNTING SCREWS
4 - FUEL HEATER ELEC. CONNECTOR
5 - WIF SENSOR
6 - WIF SENSOR ELEC. CONNECTOR
7 - DRAIN HOSE
8 - DRAIN VALVE MOUNTING SCREWS
9 - DRAIN VALVE
OPERATION
The sensor sends an input to the Engine Control
Module (ECM) when it senses water in the fuel filter/
water separator. As the water level in the filter/sep-
arator increases, the resistance across the WIF
sensor decreases. This decrease in resistance is sent
as a signal to the ECM and compared to a high
water standard value. Once the value reaches 30 to
40 kilohms, the ECM will activate the water-in-fuel
warning lamp through CCD bus circuits. This all
takes place when the ignition key is initially put in
the ON position. The ECM continues to monitor the
input at the end of the intake manifold air heater
post-heat cycle.
REMOVAL
The Water-In-Fuel (WIF) sensor is located at the
side of fuel filter/water separator canister. Refer to
Fuel Filter/Water Separator Removal/Installation for
WIF sensor removal/installation procedures.
FUEL DRAIN CIRCUIT
OPERATION
The Fuel Drain
sources of fuel return. Fuel travels from the fuel tank
to the fuel transfer pump and is forced through the
fuel filter. A portion of that fuel travels through the
fuel filter and into the fuel injection pump, while the
rest of the fuel flows through a passage in the fuel
filter housing. It then goes to a fuel drain line and
returns back to the fuel tank.
The fuel that flows to the fuel pump is pressurized
and sent into a passage in the fuel pump. At this
point the fuel is channeled into two passages. One
passage sends fuel to the FCA (Fuel Control Actua-
tor). The other passage sends fuel to the cascade
overflow valve. The overflow valve sends some fuel to
a lubrication passage. The rest of the fuel is sent to a
drain passage which connects to an external fuel
line. This fuel line is connected to the same fuel filter
housing passage that the fuel transfer pump is con-
nected to.
Fuel that travels through the FCA is pressurized
by the fuel injection pump and sent through an
external high pressure fuel line to the fuel rail. At
the fuel rail, fuel is sent to the fuel injectors. If fuel
pressure in the fuel rail becomes excessive, the pres-
sure limiting valve opens and sends fuel through an
external fuel line. This line is connected to the fuel
filter housing at the fuel pump drain.
At the fuel injector, fuel that is not injected is used
for lubrication of the fuel injectors. This fuel then
travels through an internal passage in the rear of the
cylinder head, an then into an external fuel line. This
line is connected to the vehicles fuel return line, and
returns excess fuel back to the fuel tank.
Circuit incorporates
DR
several