2002 JEEP LIBERTY Lines

DIAGNOSIS AND TESTING - EXHAUST SYSTEM
EXHAUST SYSTEM DIAGNOSIS CHART
CONDITION POSSIBLE CAUSE CORRECTION
EXCESSIVE EXHAUST NOISE OR
LEAKING EXHAUST GASES1. Leaks at pipe joints. 1. Tighten clamps/bolts to specified
torque at leaking joints.
2. Rusted or blown out muffler. 2. Replace muffler. Inspect exhaust
system.
3. Broken or rusted out exhaust
pipe.3. Replace exhaust pipe.
4. Exhaust pipe leaking at manifold
flange.4. Tighten/replace flange attaching
nuts/bolts.
5. Exhaust manifold cracked or
broken.5. Replace exhaust manifold.
6. Leak between exhaust manifold
and cylinder head.6. Tighten exhaust manifold to
cylinder head bolts.
7. Catalytic converter rusted or
blown out.7. Replace catalytic converter assy.
8. Restriction in exhaust system. 8. Remove restriction, if possible.
Replace restricted part if necessary.
CAUTION:
When servicing and replacing exhaust system components, disconnect the oxygen sensor connector(s). Allowing
the exhaust to hang by the oxygen sensor wires will damage the harness and/or sensor.
CATALYTIC CONVERTER
DESCRIPTION - CATALYTIC CONVERTER
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
CAUTION: DO NOT remove spark plug wires from
plugs or by any other means short out cylinders.
Failure of the catalytic converter can occur due to a
temperature increase caused by unburned fuel
passing through the converter.
The stainless steel catalytic converter body is
designed to last the life of the vehicle. Excessive heat
can result in bulging or other distortion, but exces-
sive heat will not be the fault of the converter. If
unburned fuel enters the converter, overheating may
occur. If a converter is heat-damaged, correct thecause of the damage at the same time the converter
is replaced. Also, inspect all other components of the
exhaust system for heat damage.
Unleaded gasoline must be used to avoid con-
taminating the catalyst core.
50 State emission vehicles incorporate two mini
catalytic converters located after the exhaust mani-
folds and before the inline catalytic converter.
REMOVAL
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
(1) Raise and support the vehicle.
(2) Saturate the bolts and nuts with heat valve
lubricant. Allow 5 minutes for penetration.
(3) Remove the bolts from the crossover pipe to the
catalytic converter connection.
(4) Disconnect oxygen sensor wiring.
(5) Loosen and remove the nuts from the clamp
that hold the catalytic converter to the exhaust pipe
flange connection.
11s - 2 EXHAUST SYSTEMKJ
EXHAUST SYSTEM (Continued)

CROSS-OVER PIPE
REMOVAL
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
(1) Raise and support the vehicle.
(2) Saturate the bolts and nuts with lubricant.
Allow 5 minutes for penetration.
(3) Remove the retaining fasteners holding cross-
over pipe to exhaust pipe.
(4) Remove the fasteners from the crossover pipe
to the catalytic converter connection.
(5) Remove the crossove pipe from the hanger
insulator (Fig. 3).
INSTALLATION
WARNING: IF TORCHES ARE USED WHEN WORK-
ING ON THE EXHAUST SYSTEM, DO NOT ALLOW
THE FLAME NEAR THE FUEL LINES.
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
(1) Install the crossove pipe into the hanger insu-
lator.
(2) Install and torque the fasteners in the cross-
over pipe to the left and right catalytic converter con-
nection.
(3) Install and torque the retaining fasteners hold-
ing the crossover pipe to exhaust pipe.
(4) Lower vehicle..
(5) Start engine and check for leaks.
HEAT SHIELDS
DESCRIPTION
Heat shields (Fig. 4) are needed to protect both the
vehicle and the environment from the high tempera-
tures developed by the catalytic converter. The cata-
lytic converter releases additional heat into the
exhaust system. Under severe operating conditions,
the temperature increases in the area of the con-
verter. Such conditions can exist when the engine
misfires or otherwise does not operate at peak effi-
ciency.
MUFFLER
DESCRIPTION
The 2.4L and 3.7L engine uses a galvanized steel
muffler (Fig. 5) to control exhaust noise levels and
exhaust back pressure.
REMOVAL
All original equipment exhaust systems are manu-
factured with the exhaust tailpipe welded to the muf-
fler. Service replacement mufflers and exhaust
tailpipes are either clamped together or welded
together.Fig. 3 Crossover Pipe
1 - Crossover-toCatalytic Converter flange
2 - Crossover Pipe
3 - Crossover Pipe to Tail Pipe Flange
4 - Hanger Bracket
11s - 4 EXHAUST SYSTEMKJ

FUEL SYSTEM
TABLE OF CONTENTS
page page
FUEL DELIVERY..........................1FUEL INJECTION........................29
FUEL DELIVERY
TABLE OF CONTENTS
page page
FUEL DELIVERY
DESCRIPTION..........................2
OPERATION............................3
DIAGNOSIS AND TESTING - FUEL
PRESSURE LEAK DOWN TEST...........3
STANDARD PROCEDURE - FUEL SYSTEM
PRESSURE RELEASE...................4
SPECIFICATIONS
FUEL SYSTEM PRESSURE..............5
TORQUE.............................5
SPECIAL TOOLS
FUEL SYSTEM........................6
FLOW MANAGEMENT VALVE
DESCRIPTION..........................6
OPERATION............................6
REMOVAL.............................6
INSTALLATION..........................7
FUEL FILTER
DESCRIPTION..........................7
REMOVAL.............................7
INSTALLATION..........................8
FUEL LEVEL SENDING UNIT / SENSOR
DESCRIPTION..........................9
OPERATION............................9
DIAGNOSIS AND TESTING - FUEL LEVEL
SENDING UNIT........................9
REMOVAL.............................9
INSTALLATION.........................10
FUEL LINES
DESCRIPTION.........................10
QUICK CONNECT FITTING
DESCRIPTION.........................10
STANDARD PROCEDURE - QUICK-CONNECT
FITTINGS...........................10
FUEL PRESSURE REGULATOR
DESCRIPTION.........................13OPERATION...........................14
REMOVAL.............................14
INSTALLATION.........................14
FUEL PUMP
DESCRIPTION.........................15
OPERATION...........................15
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - FUEL PUMP
CAPACITY TEST......................15
DIAGNOSIS AND TESTING - FUEL PUMP
PRESSURE TEST.....................15
DIAGNOSIS AND TESTING - FUEL PUMP
AMPERAGE TEST.....................16
FUEL PUMP MODULE
DESCRIPTION.........................18
OPERATION...........................18
REMOVAL.............................18
INSTALLATION.........................19
FUEL RAIL
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................22
INSTALLATION.........................24
FUEL TANK
DESCRIPTION.........................24
OPERATION...........................24
REMOVAL.............................25
INSTALLATION.........................27
FUEL TANK CHECK VALVE
DESCRIPTION.........................28
OPERATION...........................28
REMOVAL.............................28
INSTALLATION.........................28
INLET FILTER
REMOVAL.............................28
INSTALLATION.........................28
KJFUEL SYSTEM 14 - 1

FUEL DELIVERY
DESCRIPTION
The fuel delivery system consists of:
²the 2±section fuel pump module containing the
electric fuel pump, fuel pressure regulator, fuel gauge
sending unit (fuel level sensor) and a fuel filter
located inside the lower section of pump module
²fuel tubes/lines/hoses
²A separately mounted main fuel filter²quick-connect fittings
²fuel injector rail
²fuel tank
²fuel tank filler/vent tube assembly
²fuel tank filler tube cap
²accelerator pedal
²throttle cable
Certain fuel delivery components can be found in
(Fig. 1).
Fig. 1 FUEL DELIVERY COMPONENTS
1 - FUEL TANK 10 - EVAP CANISTER
2 - FUEL TANK STRAPS 11 - FLOW MANAGEMENT VALVE
3 - FUEL PUMP MODULE LOCK RING 12 - FRESH AIR TUBE
4 - CHECK (CONTROL) VALVE 13 - HOSE SLEEVE
5 - FUEL PUMP MODULE FLANGE 14 - FUEL FILTER
6 - FUEL FILL HOSE 15 - LEAK DETECTION PUMP
7 - FRESH AIR FILTER 16 - HEAT SHIELD
8 - FUEL FILL CAP/BEZEL 17 - SKID PLATE
9 - FUEL FILL TUBE
14 - 2 FUEL DELIVERYKJ

OPERATION
Fuel is picked up in the fuel tank by the fuel pump
module. This module is located on the bottom of the
fuel tank.
A fuel return system is provided within the fuel
pump module using check valves. A separate fuel
return line from the engine to the tank is not used.
The fuel pressure regulator and the main fuel filter
are not combined. They are separate items.
The fuel tank assembly consists of: the fuel tank,
fuel pump module assembly, fuel pump module lock
ring/gasket, ORVR components. Refer to 25, Emis-
sion Control System for ORVR information.
A fuel filler/vent tube assembly using a pressure/
vacuum, 1/4 turn fuel filler cap is used. The fuel
filler tube contains a flap door located below the fuel
fill cap. A one-way check valve is installed into the
tanks fuel fill fitting.
Also to be considered part of the fuel system is the
evaporation control system and ORVR system. This
is designed to reduce the emission of fuel vapors into
the atmosphere. The description and function of the
Evaporative Control System is found in 25, Emission
Control Systems.
Both fuel filters (mounted to front of fuel tank, and
inside the bottom fuel pump module) are designed for
extended service. They do not require normal sched-
uled maintenance. The bottom section of the fuel
pump module (with included filter) should only be
replaced if a diagnostic procedure indicates to do so.
Also, the fuel filter mounted to the front of the fuel
tank should only be replaced if a diagnostic proce-
dure indicates to do so.
DIAGNOSIS AND TESTING - FUEL PRESSURE
LEAK DOWN TEST
Use this test in conjunction with the Fuel Pump
Pressure Test and Fuel Pump Capacity Test.
Check Valve Operation:The electric fuel pump
outlet 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 oper-
ational. 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 elec-
tric fuel pump is activated, fuel pressure should
immediately(1±2 seconds) rise to specification.
Abnormally long periods of cranking to restart a
hotengine that has been shut down for a short
period of time may be caused by:
²Fuel pressure bleeding past a fuel injector(s).²Fuel pressure bleeding past the check valve in
the fuel pump module.
(1) Disconnect the fuel inlet line at fuel rail. Refer
to Quick Connect Fittings for procedures. On some
engines, air cleaner housing removal may be neces-
sary before fuel line disconnection.
(2) 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.
(3) Connect correct Fuel Line Pressure Test
Adapter Tool Hose between disconnected fuel line
and fuel rail (Fig. 2).
(4) Connect the 0-414 kPa (0-60 psi) fuel pressure
test gauge (from Gauge Set 5069) to the test port on
the appropriate Adaptor Tool.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.
The fittings on both tools must be in good
condition and free from any small leaks before
performing the proceeding test.
(5) Start engine and bring to normal operating
temperature.
(6) Observe test gauge. Normal operating pressure
should be 339 kPa +/±34 kPa (49.2 psi +/±5 psi).
(7) Shut engine off.
Fig. 2 CONNECTING ADAPTER TOOLÐTYPICAL
1 - VEHICLE FUEL LINE
2 - TEST PORT ªTº
3 - SPECIAL TOOL 6923, 6631, 6541 OR 6539
4 - FUEL PRESSURE TEST GAUGE
5 - FUEL LINE CONNECTION AT RAIL
6 - FUEL RAIL
KJFUEL DELIVERY 14 - 3
FUEL DELIVERY (Continued)

(8) Pressure should not fall below30 psi for five
minutes.
(9) If pressure falls below 30 psi, it must be deter-
mined if a fuel injector, the check valve within the
fuel pump module, or a fuel tube/line is leaking.
(10) Again, start engine and bring to normal oper-
ating temperature.
(11) Shut engine off.
(12)Testing for fuel injector or fuel rail leak-
age:Clamp off the rubber hose portion of Adaptor
Tool between the fuel rail and the test port ªTº on
Adapter Tool. If pressure now holds at or above 30
psi, a fuel injector or the fuel rail is leaking.
(13)Testing for fuel pump check valve, filter,
regulator check valve or fuel tube/line leakage:
Clamp off the rubber hose portion of Adaptor Tool
between the vehicle fuel line and test port ªTº on
Adapter Tool. If pressure now holds at or above 30
psi, a leak may be found at a fuel tube/line. If no
leaks are found at fuel tubes or lines, one of the
check valves in either the electric fuel pump, fuel fil-
ter or fuel pressure regulator may be leaking.
Note: A quick loss of pressure usually indicates a
defective check valve in the pressure regulator. A
slow loss of pressure usually indicates a defective
check valve in the bottom of the fuel pump module.
The check valves are not serviced separately. Also,
the electric fuel pump is not serviced separately.
STANDARD PROCEDURE - FUEL SYSTEM
PRESSURE RELEASE
Use following procedure if the fuel injector
rail is, or is not equipped with a fuel pressure
test port.
(1) Remove fuel fill cap.
(2) Remove fuel pump relay from Power Distribu-
tion Center (PDC). For location of relay, refer to label
on underside of PDC cover.(3) Start and run engine until it stalls.
(4) Attempt restarting engine until it will no
longer run.
(5) Turn ignition key to OFF position.
CAUTION: Steps 1, 2, 3 and 4 must be performed to
relieve high pressure fuel from within fuel rail. Do
not attempt to use following steps to relieve this
pressure as excessive fuel will be forced into a cyl-
inder chamber.
(6) Unplug connector from any fuel injector.
(7) Attach one end of a jumper wire with alligator
clips (18 gauge or smaller) to either injector terminal.
(8) Connect other end of jumper wire to positive
side of battery.
(9) Connect one end of a second jumper wire to
remaining injector terminal.
CAUTION: Powering an injector for more than a few
seconds will permanently damage the injector.
(10) Momentarily touch other end of jumper wire
to negative terminal of battery for no more than a
few seconds.
(11) Place a rag or towel below fuel line quick-con-
nect fitting at fuel rail.
(12) Disconnect quick-connect fitting at fuel rail.
Refer to Quick-Connect Fittings.
(13) Return fuel pump relay to PDC.
(14) One or more Diagnostic Trouble Codes (DTC's)
may have been stored in PCM memory due to fuel
pump relay removal. The DRBtscan tool must be
used to erase a DTC.
14 - 4 FUEL DELIVERYKJ
FUEL DELIVERY (Continued)

(3) Remove 4 fuel pump module access plate nuts
(Fig. 3).
(4) While applying heat from a heat gun, carefully
pry up fuel pump module access plate. Take care not
to bend plate.
(5) Disconnect flow management valve hose clamp
and hose (Fig. 4) at pump module fitting. Also discon-
nect small recirculation line at top half of manage-
ment valve.
(6) Raise vehicle.
(7) Disconnect opposite end of flow management
valve hose at EVAP canister (Fig. 1).
(8) Remove valve and 2 hoses as an assembly.
INSTALLATION
(1) Raise vehicle.
(2) Attach 2 large hoses and 1 small line to flow
management valve. Position this assembly to top of
fuel tank.
(3) Connect valve hose at EVAP canister.
(4) Lower vehicle.
(5) Attach valve hose and clamp to top of fuel
pump module.
(6) Apply silicone sealant to bottom of fuel pump
module metal access plate.(7) Install fuel pump module metal access plate
and 4 nuts. Tighten nuts to 3 N´m (26 in. lbs.)
torque.
(8) Position carpet and install 2 new cargo clamp
rivets.
FUEL FILTER
DESCRIPTION
The fuel pressure regulator and fuel filter are not
combined on this vehicle. The main fuel filter is
attached to the front of the fuel tank (Fig. 1) and is a
serviceable/replaceable item. Also refer to Inlet Filter
and Fuel Pressure Regulator.
REMOVAL
The main fuel filter is attached to the front of fuel
tank (Fig. 1). Three fuel lines are used at filter.
Fuel tank removal will not be necessary for
fuel filter removal. Access is from rear cargo
area.
WARNING: THE FUEL SYSTEM MAY BE UNDER A
CONSTANT PRESSURE (EVEN WITH THE ENGINE
OFF). BEFORE SERVICING MOST FUEL SYSTEM
COMPONENTS, THE FUEL SYSTEM PRESSURE
MUST BE RELEASED. REFER TO THE FUEL SYS-
TEM PRESSURE RELEASE PROCEDURE.
(1) Release fuel system pressure.
(2) Four cargo holdown clamps are located inside
vehicle on floor of rear cargo area. Two of these four
clamps must be removed. Remove 2 rearward
mounted clamps by drilling out clamp rivets.
(3) Fold carpeting forward to gain access to fuel
pump module access plate (Fig. 5).
(4) Remove 4 fuel pump module access plate nuts
(Fig. 5).
(5) While applying heat from a heat gun, carefully
pry up metal fuel pump module access plate. Take
care not to bend plate.
(6) Clean top of fuel pump module area around
fuel line connection points.
(7) Disconnect 2 fuel lines at fuel pump module
(Fig. 6) by pressing on tabs at side of fitting.
(8) Raise vehicle.
(9) Place drain pan under fuel filter.
(10) A third fuel line is attached to bottom of filter
(Fig. 7). The disconnection point for this 3rd line is
approximately 1 foot towards front of vehicle. Clean
fuel line connection point before disconnection. Dis-
connect by pressing on tabs at side of fitting.
(11) Disconnect 3rd fuel line from body retention
clip. Place a small screwdriver into side of clip and
twist for removal.
Fig. 4 TOP OF FUEL PUMP MODULE
1 - LOCK RING
2 - ALIGNMENT NOTCH
3 - FUEL FILTER FITTINGS (2)
4 - ORVR SYSTEM HOSE AND CLAMP
5 - FLOW MANAGEMENT VALVE
6 - ELECTRICAL CONNECTOR
7 - LEAK DETECTION PUMP
8 - FUEL TANK CHECK (CONTROL) VALVE
9 - FUEL PUMP MODULE (UPPER SECTION)
KJFUEL DELIVERY 14 - 7
FLOW MANAGEMENT VALVE (Continued)

(12) Remove filter ground strap at fuel tank
mounting strap.
(13) Remove 1 filter mounting nut (Fig. 7) and
remove filter.
INSTALLATION
(1) Raise vehicle.
(2) Position fuel lines on filter towards top of fuel
tank.
(3) Position filter to mounting stud on front of fuel
tank.
(4) Install filter mounting nut and tighten. Refer
to torque specifications.
(5) A third fuel line is attached to bottom of filter.
The connection point for this 3rd line is approxi-
mately 1 foot towards front of vehicle. Connect by
snapping together.
(6) Connect 3rd fuel line to body retention clip
(snaps in).
(7) Attach filter ground strap to tank mounting
strap.
(8) Lower vehicle.
(9) Attach (snap on) 2 filter fuel lines at fuel pump
module fittings.
(10) Start engine and check fuel line fittings for
leaks.
(11) Apply silicone sealant to fuel pump module
metal access plate.(12) Install fuel pump module metal access plate
and 4 nuts. Tighten 4 nuts. Refer to torque specifica-
tions.
(13) Position carpet and install 2 new cargo clamp
rivets in each cargo holdown clamp.
Fig. 5 ACCESS PLATE
1 - FLOORPAN AT REAR
2 - FUEL PUMP MODULE ACCESS PLATE
3 - NUTS (4)
4 - OPENING TO PUMP MODULE
Fig. 6 FUEL LINES AT PUMP MODULE
1 - FUEL PUMP MODULE LOCKRING
2 - FUEL LINES TO FUEL FILTER (2)
3 - QUICK-CONNECT FITTINGS (2)
4 - ROLLOVER VALVE
Fig. 7 FUEL FILTER LOCATION
1 - FUEL FILTER
2 - 3RD FUEL LINE TO ENGINE
3 - FILTER MOUNTING NUT
14 - 8 FUEL DELIVERYKJ
FUEL FILTER (Continued)