2002 JEEP LIBERTY Fuel pump psi

FUEL PUMP
DESCRIPTION
The electric fuel pump is located inside of the fuel
pump module. A 12 volt, permanent magnet, electric
motor powers the fuel pump. The electric fuel pump
is not a separate, serviceable component.
OPERATION
Voltage to operate the electric pump is supplied
through the fuel pump relay.
Fuel is drawn in through a filter at the bottom of
the module and pushed through the electric motor
gearset to the pump outlet.
Check Valve Operation:The bottom section of
the fuel pump module contains a one-way check
valve to prevent fuel flow back into the tank and to
maintain fuel supply line pressure (engine warm)
when pump is not operational. It is also used to keep
the fuel supply line full of gasoline when pump is not
operational. After the vehicle has cooled down, fuel
pressure may drop to 0 psi (cold fluid contracts), but
liquid gasoline will remain in fuel supply line
between the check valve and fuel injectors.Fuel
pressure that has dropped to 0 psi on a cooled
down vehicle (engine off) is a normal condition.
Refer to the Fuel Pressure Leak Down Test for more
information.
The electric fuel pump is not a separate, service-
able component.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FUEL PUMP
CAPACITY TEST
Before performing this test, verify fuel pump
pressure. Refer to Fuel Pump Pressure Test.
Use this test in conjunction with the Fuel Pres-
sure Leak Down Test.
(1) Release fuel system pressure. Refer to Fuel
Pressure Release Procedure.
(2) Disconnect fuel supply line at fuel rail. Refer to
Quick-Connect Fittings. Some engines may require
air cleaner housing removal before line disconnection.
(3) Obtain correct Fuel Line Pressure Test Adapter
Tool Hose. Tool number 6539 is used for 5/16º fuel
lines and tool number 6631 is used for 3/8º fuel lines.
(4) Connect correct Fuel Line Pressure Test
Adapter Tool Hose into disconnected fuel supply line.
Insert other end of Adaptor Tool Hose into a gradu-
ated container.
(5) Remove fuel fill cap.(6) To activate fuel pump and pressurize system,
obtain DRBtscan tool and actuate ASD Fuel System
Test.
(7) A good fuel pump will deliver at least 1/10 liter
of fuel in 7 seconds. Do not operate fuel pump for
longer than 7 seconds with fuel line disconnected as
fuel pump module reservoir may run empty.
(a) If capacity is lower than specification, but
fuel pump can be heard operating through fuel fill
cap opening, check for a kinked/damaged fuel sup-
ply line somewhere between fuel rail and fuel
pump module.
(b) If line is not kinked/damaged, and fuel pres-
sure is OK, but capacity is low, replace fuel filter.
Refer to Fuel Filter Removal/Installation for addi-
tional information.
(c) If both fuel pressure and capacity are low,
replace bottom section of fuel pump module. Refer
to Fuel Pump Module Removal/Installation.
DIAGNOSIS AND TESTING - FUEL PUMP
PRESSURE TEST
Use this test in conjunction with the Fuel Pump
Capacity Test, Fuel Pressure Leak Down Test and
Fuel Pump Amperage Test found elsewhere in this
group.
Check Valve Operation:The bottom section of
the fuel pump module contains a one-way check
valve to prevent fuel flow back into the tank and to
maintain fuel supply line pressure (engine warm)
when pump is not operational. It is also used to keep
the fuel supply line full of gasoline when pump is not
operational. After the vehicle has cooled down, fuel
pressure may drop to 0 psi (cold fluid contracts), but
liquid gasoline will remain in fuel supply line
between the check valve and fuel injectors.Fuel
pressure that has dropped to 0 psi on a cooled
down vehicle (engine off) is a normal condition.
When the electric fuel pump is activated, fuel pres-
sure shouldimmediately(1±2 seconds) rise to spec-
ification.
The fuel system is equipped with a separate fuel
pump module mounted, fuel pressure regulator. The
fuel filter is remotely mounted. The fuel pressure
regulator is not controlled by engine vacuum.
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE EVEN WITH THE ENGINE
OFF. BEFORE DISCONNECTING FUEL LINE AT
FUEL RAIL, THIS PRESSURE MUST BE RELEASED.
REFER TO THE FUEL SYSTEM PRESSURE
RELEASE PROCEDURE.
KJFUEL DELIVERY 14 - 15

(1) Remove protective cap at fuel rail test port.
Connect the 0±414 kPa (0-60 psi) fuel pressure gauge
(from gauge set 5069) to test port pressure fitting on
fuel rail (Fig. 20).The DRBtIII Scan Tool along
with the PEP module, the 500 psi pressure
transducer, and the transducer-to-test port
adapter may also be used in place of the fuel
pressure gauge.
(2) Start and warm engine and note pressure
gauge reading. Fuel pressure should be 339 kPa   34
kPa (49.2 psi   5 psi) at idle.
(3) If engine runs, but pressure is below 44.2 psi,
check for a kinked fuel supply line somewhere
between fuel rail and fuel pump module. If line is not
kinked, but specifications for either the Fuel Pump
Capacity, Fuel Pump Amperage or Fuel Pressure
Leak Down Tests were not met, replace lower section
of fuel pump module. Refer to Fuel Pump Module
Removal/Installation.
(4) If operating pressure is above 54.2 psi, electric
fuel pump is OK, but fuel pressure regulator is defec-
tive. Replace lower section of fuel pump module.
Refer to Fuel Pump Module Removal/Installation.
(5) Install protective cap to fuel rail test port.
DIAGNOSIS AND TESTING - FUEL PUMP
AMPERAGE TEST
This amperage (current draw) test is to be done in
conjunction with the Fuel Pump Pressure Test, Fuel
Pump Capacity Test and Fuel Pressure Leak Down
Test. Before performing the amperage test, be sure
the temperature of the fuel tank is above 50É F (10É
C).The DRBtScan Tool along with the DRB Low Cur-
rent Shunt (LCS) adapter (Fig. 21) and its test leads
will be used to check fuel pump amperage specifica-
tions.
(1) Be sure fuel tank contains fuel before starting
test. If tank is empty or near empty, amperage read-
ings will be incorrect.
(2) Obtain LCS adapter.
(3) Plug cable from LCS adapter into DRB scan
tool at SET 1 receptacle.
(4) Plug DRB into vehicle 16±way connector (data
link connector).
(5) Connect (-) and (+) test cable leads into LCS
adapter receptacles. Use10 amp (10A +)receptacle
and common (-) receptacles.
(6) Gain access to MAIN MENU on DRB screen.
(7) Press DVOM button on DRB.
(8) Using left/right arrow keys, highlight CHAN-
NEL 1 function on DRB screen.
(9) Press ENTER three times.
(10) Using up/down arrow keys, highlight RANGE
on DRB screen (screen will default to 2 amp scale).
(11) Press ENTER to change 2 amp scale to 10
amp scale.This step must be done to prevent
damage to DRB scan tool or LCS adapter
(blown fuse).
(12) Remove cover from Power Distribution Center
(PDC).
(13) Remove fuel pump relay from PDC. Refer to
label on PDC cover for relay location.
Fig. 20 FUEL PRESSURE TEST GAUGE (TYPICAL
GAUGE INSTALLATION AT TEST PORT)
1 - SERVICE (TEST) PORT
2 - FUEL PRESSURE TEST GAUGE
3 - FUEL RAIL
Fig. 21 LOW CURRENT SHUNT
1 - LOW CURRENT SHUNT ADAPTER
2 - PLUG TO DRB
3 - TEST LEAD RECEPTACLES
14 - 16 FUEL DELIVERYKJ
FUEL PUMP (Continued)

CASE BEARINGS - REMOVAL,
DIFFERENTIAL...............3-110,3-43,3-79
CASE, NV231 - TRANSFER............21-206
CASE, NV242 - TRANSFER............21-244
CASE SKID PLATE - INSTALLATION,
TRANSFER...........................13-7
CASE SKID PLATE - REMOVAL,
TRANSFER...........................13-7
CASE, SPECIFICATIONS - NV242
TRANSFER.........................21-244
CASTER ADJUSTMENT - STANDARD
PROCEDURE, CAMBER..................2-5
CASTER AND TOE ADJUSTMENT -
STANDARD PROCEDURE, CAMBER........2-5
CATALYTIC CONVERTER - DESCRIPTION . . . 11-2
CATALYTIC CONVERTER - INSPECTION....11-3
CATALYTIC CONVERTER - INSTALLATION . . . 11-3
CATALYTIC CONVERTER - REMOVAL......11-2
CAUSES OF BURNT FLUID - DIAGNOSIS
AND TESTING......................21-125
CAUTION - SERVICE CAUTIONS.........24-39
CAUTION, HALF SHAFT.................3-10
CAUTION, REFRIGERANT HOSES/LINES/
TUBES PRECAUTIONS.................24-40
CAUTIONS, CAUTION - SERVICE.........24-39
CD CHANGER - DESCRIPTION...........8A-7
CD CHANGER - INSTALLATION...........8A-7
CD CHANGER - OPERATION.............8A-7
CD CHANGER - REMOVAL..............8A-7
CENTER - DESCRIPTION, POWER
DISTRIBUTION....................8W-97-6
CENTER - OPERATION, POWER
DISTRIBUTION....................8W-97-7
CENTER - REMOVAL, POWER
DISTRIBUTION....................8W-97-7
CENTER ASSEMBLY, ASSEMBLY -
POWER DISTRIBUTION.............8W-97-10
CENTER BEZEL - INSTALLATION,
INSTRUMENT PANEL.................23-154
CENTER BEZEL - REMOVAL,
INSTRUMENT PANEL.................23-154
CENTER DISASSEMBLY, DISASSEMBLY -
POWER DISTRIBUTION..............8W-97-7
CENTER HIGH MOUNTED STOP LAMP
BULB - INSTALLATION................8L-19
CENTER HIGH MOUNTED STOP LAMP
BULB - REMOVAL....................8L-18
CENTER HIGH MOUNTED STOP LAMP
UNIT - INSTALLATION.................8L-19
CENTER HIGH MOUNTED STOP LAMP
UNIT - REMOVAL....................8L-19
CENTER SEAT BELT & RETRACTOR -
INSTALLATION, REAR.................8O-33
CENTER SEAT BELT & RETRACTOR -
REMOVAL, REAR....................8O-32
CENTERING - STANDARD PROCEDURE,
CLOCKSPRING......................8O-14
CERTIFICATION LABEL - DESCRIPTION,
VEHICLE SAFETY...................Intro.-9
CHAIN COVER(S) - INSTALLATION,
TIMING BELT.........................9-76
CHAIN COVER(S) - REMOVAL, TIMING
BELT ...............................9-74
CHAIN WEAR, STANDARD PROCEDURE -
MEASURING TIMING...................9-71
CHANGER - DESCRIPTION, CD...........8A-7
CHANGER - INSTALLATION, CD..........8A-7
CHANGER - OPERATION, CD.............8A-7
CHANGER - REMOVAL, CD..............8A-7
CHANNEL - INSTALLATION, GLASS RUN . 23-123,
23-130
CHANNEL - REMOVAL, GLASS RUN....23-123,
23-130
CHARGE - STANDARD PROCEDURE,
REFRIGERANT SYSTEM...............24-41
CHARGE CAPACITY - SPECIFICATIONS....24-42
CHARGING - STANDARD PROCEDURE,
BATTERY............................8F-8
CHARGING INDICATOR - DESCRIPTION . . . 8J-15
CHARGING INDICATOR - OPERATION.....8J-15
CHARGING SYSTEM - DESCRIPTION
.....8F-22
CHARGING SYSTEM - DIAGNOSIS AND
TESTING
...........................8F-22
CHARGING SYSTEM - OPERATION
.......8F-22
CHART - DIAGNOSIS AND TESTING,
COOLING SYSTEM DIAGNOSIS
............7-6
CHART, SPECIFICATIONS - TORQUE
.....19-15,
19-19,19-8CHART, SPECIFICATIONS - TORQUE....2-17,2-8
CHECK - STANDARD PROCEDURE, FLUID
LEVEL............................21-126
CHECK - STANDARD PROCEDURE, OIL
PUMP VOLUME.....................21-148
CHECK STRAP - INSTALLATION . . 23-121,23-128,
23-135
CHECK STRAP - REMOVAL.....23-121,23-128,
23-135
CHECK VALVE - DESCRIPTION, FRONT....8R-8
CHECK VALVE - DESCRIPTION, FUEL
TANK ..............................14-28
CHECK VALVE - DESCRIPTION, REAR....8R-34
CHECK VALVE - DESCRIPTION, VACUUM . . 24-28
CHECK VALVE - INSTALLATION, FRONT....8R-9
CHECK VALVE - INSTALLATION, FUEL
TANK ..............................14-28
CHECK VALVE - INSTALLATION, REAR....8R-35
CHECK VALVE - INSTALLATION, VACUUM . 24-28
CHECK VALVE - OPERATION, FRONT......8R-9
CHECK VALVE - OPERATION, FUEL TANK . . 14-28
CHECK VALVE - OPERATION, REAR......8R-34
CHECK VALVE - OPERATION, VACUUM....24-28
CHECK VALVE - REMOVAL, FRONT.......8R-9
CHECK VALVE - REMOVAL, FUEL TANK . . . 14-28
CHECK VALVE - REMOVAL, REAR.......8R-34
CHECK VALVE - REMOVAL, VACUUM.....24-28
CHECKING TRANSMISSION CLUTCH
OPERATION - DIAGNOSIS AND
TESTING, AIR.......................21-80
CHECKS - DIAGNOSIS AND TESTING,
PRELIMINARY.........................7-3
CHILD TETHER ANCHOR - DESCRIPTION . . 8O-13
CHILD TETHER ANCHOR - OPERATION . . . 8O-13
CHIME WARNING SYSTEM -
DESCRIPTION........................8B-1
CHIME WARNING SYSTEM - DIAGNOSIS
AND TESTING........................8B-6
CHIME WARNING SYSTEM - OPERATION . . . 8B-2
CHOKE AND RELAY - DESCRIPTION,
AMPLIFIER..........................8A-3
CHOKE AND RELAY - DIAGNOSIS AND
TESTING, AMPLIFIER..................8A-4
CHOKE AND RELAY - INSTALLATION,
AMPLIFIER..........................8A-4
CHOKE AND RELAY - OPERATION,
AMPLIFIER..........................8A-3
CHOKE AND RELAY - REMOVAL,
AMPLIFIER..........................8A-4
CIGAR LIGHTER OUTLET -
DESCRIPTION.....................8W-97-2
CIGAR LIGHTER OUTLET - DIAGNOSIS
AND TESTING.....................8W-97-2
CIGAR LIGHTER OUTLET - OPERATION . 8W-97-2
CLEVIS BRACKET - INSTALLATION........2-13
CLEVIS BRACKET - REMOVAL...........2-13
CLOCKSPRING - DESCRIPTION.........8O-13
CLOCKSPRING - INSTALLATION.........8O-16
CLOCKSPRING - OPERATION...........8O-14
CLOCKSPRING - REMOVAL............8O-15
CLOCKSPRING CENTERING - STANDARD
PROCEDURE........................8O-14
CLUSTER - ASSEMBLY, INSTRUMENT....8J-10
CLUSTER - DESCRIPTION, INSTRUMENT . . . 8J-2
CLUSTER - DIAGNOSIS AND TESTING,
INSTRUMENT........................8J-7
CLUSTER - DISASSEMBLY, INSTRUMENT . . . 8J-9
CLUSTER - INSTALLATION, INSTRUMENT . 8J-11
CLUSTER - OPERATION, INSTRUMENT.....8J-4
CLUSTER - REMOVAL, INSTRUMENT......8J-9
CLUSTER BEZEL - INSTALLATION.......23-147
CLUSTER BEZEL - REMOVAL..........23-147
CLUTCH - ASSEMBLY, LOW/REVERSE
. . . 21-146
CLUTCH - CLEANING, LOW/REVERSE
....21-146
CLUTCH - DESCRIPTION
.................6-1
CLUTCH - DIAGNOSIS AND TESTING
.......6-2
CLUTCH - DISASSEMBLY, LOW/REVERSE
. 21-145
CLUTCH - INSPECTION, A/C
COMPRESSOR
.......................24-14
CLUTCH - INSPECTION, LOW/REVERSE
. . 21-146
CLUTCH - INSTALLATION, A/C
COMPRESSOR
.......................24-14
CLUTCH - OPERATION
..................6-1
CLUTCH - REMOVAL, A/C COMPRESSOR
. . 24-13
CLUTCH - SPECIFICATIONS
...............6-5
CLUTCH - WARNING
....................6-2
CLUTCH ASSEMBLY - ASSEMBLY, INPUT
. 21-138CLUTCH ASSEMBLY - DESCRIPTION,
INPUT............................21-133
CLUTCH ASSEMBLY - DISASSEMBLY,
INPUT............................21-135
CLUTCH ASSEMBLY - OPERATION,
INPUT............................21-135
CLUTCH BREAK-IN - STANDARD
PROCEDURE, A/C COMPRESSOR........24-12
CLUTCH COIL - DIAGNOSIS AND
TESTING, A/C COMPRESSOR...........24-12
CLUTCH DISC - INSTALLATION............6-6
CLUTCH DISC - REMOVAL...............6-6
CLUTCH OPERATION - DIAGNOSIS AND
TESTING, AIR CHECKING
TRANSMISSION......................21-80
CLUTCH PEDAL - INSTALLATION.........6-10
CLUTCH PEDAL - REMOVAL.............6-10
CLUTCH PEDAL POSITION SWITCH -
DESCRIPTION........................6-11
CLUTCH PEDAL POSITION SWITCH -
DIAGNOSIS AND TESTING..............6-11
CLUTCH PEDAL POSITION SWITCH -
OPERATION..........................6-11
CLUTCH RELAY - DESCRIPTION, A/C
COMPRESSOR.......................24-15
CLUTCH RELAY - DIAGNOSIS AND
TESTING, COMPRESSOR...............24-15
CLUTCH RELAY - INSTALLATION, A/C
COMPRESSOR.......................24-16
CLUTCH RELAY - OPERATION, A/C
COMPRESSOR.......................24-15
CLUTCH RELAY - REMOVAL, A/C
COMPRESSOR........................24-16
CLUTCH RELEASE BEARING -
INSTALLATION.........................6-6
CLUTCH RELEASE BEARING - REMOVAL....6-6
CLUTCH SWITCH OVERRIDE RELAY -
DESCRIPTION........................6-10
CLUTCH SWITCH OVERRIDE RELAY -
INSTALLATION........................6-10
CLUTCH SWITCH OVERRIDE RELAY -
OPERATION..........................6-10
CLUTCH SWITCH OVERRIDE RELAY -
REMOVAL...........................6-10
CLUTCHES - DESCRIPTION, HOLDING . . . 21-131
CLUTCHES - OPERATION, HOLDING.....21-132
CMTC LAMP REPLACEMENT -
STANDARD PROCEDURE...............8M-2
COAT FINISH - DESCRIPTION, BASE
COAT/CLEAR.......................23-162
COAT/CLEAR COAT FINISH -
DESCRIPTION, BASE.................23-162
CODE - DESCRIPTION, PAINT..........23-162
CODES - DESCRIPTION, DIAGNOSTIC
TROUBLE............................25-2
CODES - SPECIFICATIONS, PAINT.......23-162
CODES - STANDARD PROCEDURE,
ERASING TRANSMITTER...............8M-8
CODES - STANDARD PROCEDURE,
SETTING TRANSMITTER...............8M-9
COIL - DESCRIPTION, IGNITION..........8I-9
COIL - DIAGNOSIS AND TESTING, A/C
COMPRESSOR CLUTCH...............24-12
COIL - INSTALLATION, IGNITION.........8I-10
COIL - OPERATION, IGNITION............8I-9
COIL - REMOVAL, IGNITION............8I-10
COIL CAPACITOR - DESCRIPTION,
IGNITION...........................8I-16
COIL CAPACITOR - INSTALLATION,
IGNITION...........................8I-16
COIL CAPACITOR - OPERATION,
IGNITION...........................8I-16
COIL CAPACITOR - REMOVAL, IGNITION . . . 8I-16
COIL RESISTANCE, 2.4L - IGNITION
.......8I-2
COIL RESISTANCE, 3.7L V-6 - IGNITION
....8I-3
COLLAPSIBLE SPACER - INSTALLATION
....3-70
COLLAPSIBLE SPACER - REMOVAL
.......3-70
COLUMN - DESCRIPTION
...............19-5
COLUMN - INSTALLATION
...............19-7
COLUMN - REMOVAL
..................19-5
COLUMN, SPECIAL TOOLS - STEERING
....19-8
COMBINATION FLASHER - DESCRIPTION
. . 8L-19
COMBINATION FLASHER - OPERATION
. . . 8L-19
COMBUSTION PRESSURE LEAKAGE -
DIAGNOSIS AND TESTING, CYLINDER
......9-8
COMMUNICATION - DESCRIPTION
........8E-8
COMMUNICATION - OPERATION
..........8E-8
KJINDEX 5
Description Group-Page Description Group-Page Description Group-Page