Fuel Level Sending Unit / Sensor; Filter/Regulator Removal And Installation; Fuel Tube And Clamp; Tightening Fuel Tube Clamp - Dodge 2001 Ram 1500 Owner's Manual

BR/BE
FUEL FILTER/PRESSURE REGULATOR (Continued)
Fig. 6 Filter/Regulator Removal and Installation—
1 - RUBBER GROMMET
2 - FUEL FILTER/FUEL PRESSURE REGULATOR
Fig. 7 Fuel Tube and Clamp—TYPICAL
1 - FUEL FILTER/FUEL PRESSURE REGULATOR
2 - TUBE CLAMP
3 - FUEL TUBE
(4) Press filter/regulator (by hand) into rubber
grommet. The assembly should be pointed towards
drivers side of vehicle (Fig. 4) or (Fig. 5).
(5) Install fuel tank. Refer to Fuel Tank Removal/
Installation.
(6) Check for fuel leaks.
TYPICAL
FUEL DELIVERY - GASOLINE
Fig. 8 Tightening Fuel Tube Clamp—TYPICAL
1 - TOOL C-4124
2 - TUBE CLAMP
3 - FUEL TUBE
FUEL LEVEL SENDING UNIT /
SENSOR
DESCRIPTION
The fuel gauge sending unit (fuel level sensor) is
attached to the side of the fuel pump module. The
sending unit consists of a float, an arm, and a vari-
able resistor track (card).
OPERATION
The fuel pump module has 4 different circuits
(wires). Two of these circuits are used for the fuel
gauge sending unit for fuel gauge operation, and for
certain OBD II emission requirements. The other 2
wires are used for electric fuel pump operation.
For Fuel Gauge Operation: A constant current
source of about 32 mA is supplied to the resistor
track on the fuel gauge sending unit. This is fed
directly from the Powertrain Control Module (PCM).
The resistor track is used to vary the voltage depend-
ing on fuel tank float level. As fuel level increases,
the float and arm move up, which decreases voltage.
As fuel level decreases, the float and arm move
down, which increases voltage. The varied voltage
signal is returned back to the PCM through the sen-
sor return circuit. Output voltages will vary from
about .6 volts at FULL, to about 8.6 volts at EMPTY
(Jeep models), or, about 7.0 volts at EMPTY (Dodge
Truck models). NOTE: For diagnostic purposes,
this voltage can only be verified with the fuel
gauge sending unit circuit closed (i.e. having all
of the sending units electrical connectors con-
nected).
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