nuts to 22 Nzm (16 ft. lbs.) torque. Tighten the lower
bolt nuts to 8 Nzm (6 ft. lbs.) torque.
(4) If applicable, tighten the bumper guard bolts/
nuts to 56 Nzm (41 ft. lbs.).
(5) Position and support the bumper with the
bracket holes aligned with the sill crossmember
holes. Install the bracket-to-crossmember bolts.
Tighten the bolts to 42 Nzm (31 ft. lbs.) torque.
(6) If removed, install the trailer hitch. If neces-
sary, refer to the installation procedure within Group
23, Body Components.
REAR TOW HOOK
REMOVAL
(1) Remove the bolts that attach tow hook bracket
to the frame rail and reinforcement bracket (Fig. 16).
The reinforcement bracket is held on the
frame rail with two blind rivets.
(2) Remove the bracket and tow hook from frame
rail.
INSTALLATION
(1) Position bracket and tow hook on the frame
rail.
(2) Install bolts that attach tow hook bracket to
frame rail and reinforcement bracket. Tighten bolts
to 75 Nzm (55 ft. lbs.) torque.
Fig. 15 Bumper Guard Removal/InstallationÐXJ
VehiclesFig. 16 Rear Tow HookÐXJ Vehicles
JXJÐBUMPERS 13 - 9
FRAME
INDEX
page page
Frame Dimensions........................ 13
Frame Repairs........................... 13
Frame Straightening....................... 13
Fuel Tank Skid Plate....................... 15
General Information....................... 10Generator Splash Shield.................... 13
Safety Precautions and Warnings............. 10
Tow Hooks.............................. 13
Transfer Case Skid Plate.................... 15
SAFETY PRECAUTIONS AND WARNINGS
WARNING: USE EYE PROTECTION WHEN GRIND-
ING OR WELDING METAL, SERIOUS EYE INJURY
CAN RESULT.
BEFORE PROCEEDING WITH FRAME REPAIR IN-
VOLVING GRINDING OR WELDING, VERIFY THAT
VEHICLE FUEL SYSTEM IS NOT LEAKING OR IN
CONTACT WITH REPAIR AREA, PERSONAL INJURY
CAN RESULT.
DO NOT ALLOW OPEN FLAME TO CONTACT
PLASTIC BODY PANELS. FIRE OR EXPLOSION CAN
RESULT.
WHEN WELDED FRAME COMPONENTS ARE RE-
PLACED, 100% PENETRATION WELD MUST BE
ACHIEVED DURING INSTALLATION. IF NOT, DAN-
GEROUS OPERATING CONDITIONS CAN RESULT.
STAND CLEAR OF CABLES OR CHAINS ON
PULLING EQUIPMENT DURING FRAME STRAIGHT-
ENING OPERATIONS, PERSONAL INJURY CAN RE-
SULT.
DO NOT VENTURE UNDER A HOISTED VEHICLE
THAT IS NOT SUPPORTED ON SAFETY STANDS,
PERSONAL INJURY CAN RESULT.
CAUTION: Do not reuse damaged fasteners, quality
of repair would be suspect.
Do not drill holes in top or bottom frame rail
flanges, frame rail failure can result.
Do Not use softer than Grade 3 bolts to replace
production fasteners, loosening or failure can re-
sult.When using heat to straighten frame components
do not exceed 566ÉC (1050ÉF), metal fatigue can re-
sult.
Welding the joints around riveted cross members
and frame side rails can weaken frame
GENERAL INFORMATION
The Jeep YJ (Fig. 1) frame is the structural center
of the vehicle. In addition to supporting the body and
payload, the frame provides a station for the engine.
The vehicle body is attached to the frame with hold-
downs (Fig. 2 and 3).
Fig. 1 JeepÐYJ
13 - 10 YJÐFRAMEJ
The frame is constructed of high-strength channel
steel siderails and crossmembers. The crossmembers
join the siderails and retain them in alignment in re-
lation to each other. This provides resistance to
frame twists and strains.
FRAME STRAIGHTENING
When necessary, a conventional frame that is bent
or twisted can be straightened by application of heat.
The temperature must not exceed 566ÉC (1050ÉF).
The use of a specially designed heat crayon can de-
termine the desired temperature. Excessive heat will
decrease the strength of the metal and result in a
weakened frame.
Welding the joints around riveted cross members
and frame side rails is not recommended.
A straightening repair process should be limited to
frame members that are not severely damaged.
FRAME REPAIRS
DRILLING HOLES
Do not drill holes in frame side rail top and bottom
flanges, metal fatigue can result causing frame fail-
ure. Holes drilled in the side of the frame rail must
be at least 38 mm (1.5 in.) from the top and bottom
flanges.
Additional drill holes should be located away from
existing holes.
WELDING
Use MIG, TIG or arc welding equipment to repair
welded frame components.
Frame components that have been damaged should
be inspected for cracks before returning the vehicle
to use. If cracks are found in accessible frame com-
ponents perform the following procedures.
(1) Drill a hole at each end of the crack with a 3
mm (O.125 in.) diameter drill bit.
(2) Using a suitable die grinder with 3 inch cut off
wheel, V-groove the crack to allow 100% weld pene-
tration.
(3) Weld the crack.
(4) If necessary when a side rail is repaired, grind
the weld smooth and install a reinforcement channel
(Fig. 4) over the repaired area.
If a reinforcement channel is required, the
top and bottom flanges should be 0.250 inches
narrower than the side rail flanges. Weld only
in the areas indicated (Fig. 4).
FRAME FASTENERS
Bolts, nuts and rivets can be used to repair frames
or to install a reinforcement section on the frame.
Bolts can be used in place of rivets. When replacing
rivets with bolts, install the next larger size diameter
bolt to assure proper fit. If necessary, drill the hole
out just enough to receive the bolt.Conical-type washers are preferred over the split-
ring type lock washers. Normally, grade-5 bolts are
adequate for frame repair.Grade-3 bolts or softer
should not be used.Tightening bolts/nuts with the
correct torque, refer to the Introduction Group at the
front of this manual for tightening information.
FRAME DIMENSIONS
Frame dimensions are listed in millimeter scale.
All dimensions are from center to center of Principal
Locating Point (PLP), or from center to center of PLP
and fastener location (Fig. 5).
TOW HOOKS
REMOVAL
(1) Remove the two bolts that attach the tow hook
to the bumper rail and to the frame rail.
(2) Remove the tow hook.
INSTALLATION
(1) Position the tow hook on the bumper rail and
frame rail.
(2) Install the attaching bolts. Tighten the bolts to
102 Nzm (75 ft. lbs.) torque.
GENERATOR SPLASH SHIELD
REMOVAL
(1) Remove the shield retaining nut and washer
(Fig. 6) from the engine oil pan stud (2.5L engines
only).
(2) Pry the serrated retainers from the frame rail
holes at each side of the vehicle.
(3) Pry the serrated retainers from the fan shroud
holes (Fig. 6).
(4) Remove the shield from the vehicle.
Fig. 4 Frame Reinforcement
JYJÐFRAME 13 - 13
BUMPERS
INDEX
page page
Frame Crossmember Cover................. 16
Front Bumper............................ 16Rear Bumper............................ 16
Service Information........................ 16
SERVICE INFORMATION
In some cases, components in the following proce-
dures either support, or are hidden by other compo-
nents.
FRONT BUMPER
The YJ front bumper is a one-piece rail (Fig. 1). A
front crossmember cover (Fig. 1) is also installed on
all YJ vehicles.
BUMPER REMOVAL
(1) Disconnect and remove the fog lamps, if
equipped.
(2) Remove the nuts and bolts that retain the
bumper extensions to the bumper rail and remove
the extensions.
(3) Remove the nuts and bolts that attach the
bumper rail/tow hooks to the frame rails.
(4) Separate the bumper rail from the frame rails.
BUMPER INSTALLATION
(1) Position the front bumper on the frame rails.(2) Install the bolts and attach the front bumper
rail (and tow hooks, if equipped) to the frame rails.
(3) Tighten the bolts to 102 Nzm (75 ft. lbs.) torque.
(4) Position the bumper extensions on the bumper
rail and install the retaining bolts.
(5) Tighten the bolts to 104 Nzm (77 ft. lbs.) torque.
(6) Install the fog lamps, if equipped.
FRAME CROSSMEMBER COVER
REMOVAL
(1) Remove the screws that attach the crossmem-
ber cover and support to the frame rails.
(2) Remove the crossmember cover and support
from the frame rails.
INSTALLATION
(1) Position the support and crossmember cover on
the frame rails.
(2) Install the attaching screws.
(3) Tighten the screws to 8 Nzm (72 in. lbs.) torque.
REAR BUMPER
When equipped with a spare tire carrier attached
to the tailgate, a rear bumperette is attached to the
frame (Fig. 2 and 3).
Fig. 2 Rear Bumperette
Fig. 1 Front Bumper Rail, Crossmember Cover &
Tow Hooks
13 - 16 YJÐBUMPERSJ
line. You may encounter fuels containing 3 percent or
more methanol along with other alcohols called cosol-
vents.
Problems that are the result of using methanol/gas-
oline blends are not the responsibility of Chrysler
Corporation. They may not be covered by the vehicle
warranty.
MTBE/ETBE
Gasoline and MTBE (Methyl Tertiary Butyl Ether)
blends are a mixture of unleaded gasoline and up to
15 percent MTBE. Gasoline and ETBE (Ethyl Ter-
tiary Butyl Ether) are blends of gasoline and up to
17 percent ETBE. Gasoline blended with MTBE or
ETBE may be used in your vehicle.CLEAN AIR GASOLINE
Many gasolines are now being blended that con-
tribute to cleaner air, especially in those areas of the
country where air pollution levels are high. These
new blends provide a cleaner burning fuel and some
are referred to asReformulated Gasoline.
In areas of the country where carbon monoxide lev-
els are high, gasolines are being treated with oxygen-
ated materials such as MTBE, ETBE and ethanol.
Chrysler Corporation supports these efforts toward
cleaner air and recommends that you use these gaso-
lines as they become available.
14 - 2 FUEL SYSTEMJ
FUEL DELIVERY SYSTEM
INDEX
page page
Fuel Filter................................ 9
Fuel Pressure Leak Down Test................ 8
Fuel Pressure Release Procedure.............. 6
Fuel Pump Capacity Test.................... 7
Fuel Pump Electrical Control.................. 5Fuel Pump Module......................... 3
Fuel System Pressure Test................... 6
Fuel Tubes/Lines/Hoses and Clamps............ 9
Quick-Connect Fittings..................... 10
FUEL PUMP MODULE
The fuel pump module is installed in the top of the
fuel tank. The fuel pump module contains the follow-
ing components:
²Electric fuel pump
²Fuel pump reservoir
²In-tank fuel filter
²Fuel gauge sending unit
²Fuel supply and return tube connections
The fuel pump used on all vehicles is a turbine
type pump. It is driven by a permanent magnet 12
volt electric motor that is immersed in the fuel tank.
The electrical pump is integral with the fuel sender
unit. The pump/sender assembly is installed inside
the fuel tank.
The fuel pump has a check valve at the outlet end
that consists of a ball held against a seat by force ap-
plied from a spring. When the pump is operating,
fuel pressure overcomes spring pressure and forces
the ball off its seat, allowing fuel to flow. When the
pump is not operating, spring pressure forces the ball
back against the seat preventing fuel backflow
through the pump.
Fuel system pressure is maintained at approxi-
mately 214 kPa (31 psi). This is when the pump is
operating and vacuum is supplied to the fuel pres-
sure regulator. If vacuum is not supplied to the pres-
sure regulator, fuel pressure will be approximately
55-69 kPa (8-10 psi) higher. This may be due to a
broken or clogged vacuum line. When the fuel pump
is not operating, fuel system pressure of 131-269 kPa
(19-39 psi) is maintained for approximately 2 to 6
hours. This is done by the fuel pump outlet check
valve and the vacuum assisted fuel pressure regula-
tor.
REMOVALÐXJ MODELS
The fuel pump/gauge sender unit assembly can be
removed from the fuel tank without removing the
tank from the vehicle.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING THE FUEL PUMP MODULE,
THE FUEL SYSTEM PRESSURE MUST BE RE-LEASED. REFER TO THE FUEL PRESSURE RE-
LEASE PROCEDURE IN THIS GROUP.
WARNING: EXTINGUISH ALL TOBACCO SMOKING
PRODUCTS BEFORE SERVICING THE FUEL SYS-
TEM. KEEP OPEN FLAME AWAY FROM FUEL SYS-
TEM COMPONENTS.
(1) Remove fuel filler cap. Perform the Fuel Pres-
sure Release Procedure as outlined in this group.
(2) Disconnect negative battery cable.
(3) Using an approved portable gasoline siphon/
storage tank, drain fuel tank until fuel level is below
one quarter (1/4) full.
(4) Raise and support vehicle.
WARNING: WRAP SHOP TOWELS AROUND FUEL
HOSES TO ABSORB ANY FUEL SPILLAGE DURING
FUEL TANK REMOVAL.
(5) Disconnect fuel vent supply and return tubes
from fittings on fuel pump module.
(6) Disconnect fuel pump module electrical harness
connector from main harness.
(7) Using a brass punch and hammer, remove fuel
pump module lock ring by carefully tapping it coun-
terclockwise (Fig. 1).
Fig. 1 Removing Lock RingÐXJ ModelsÐTypical
JFUEL DELIVERY SYSTEM 14 - 3
FUEL PRESSURE RELEASE PROCEDURE
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39 PSI).
THIS PRESSURE MUST BE RELEASED BEFORE
SERVICING ANY FUEL SUPPLY OR FUEL RETURN
SYSTEM COMPONENT.
(1) Disconnect negative battery cable.
(2) Remove fuel tank filler neck cap to release fuel
tank pressure.
WARNING: DO NOT ALLOW FUEL TO SPILL ONTO
THE ENGINE INTAKE OR EXHAUST MANIFOLDS.
PLACE SHOP TOWELS UNDER AND AROUND THE
PRESSURE PORT TO ABSORB FUEL WHEN THE
PRESSURE IS RELEASED FROM THE FUEL RAIL.
WARNING: WEAR PROPER EYE PROTECTION
WHEN RELEASING FUEL SYSTEM PRESSURE.
(3) Remove protective cap from pressure test port
on the fuel rail (Fig. 7).
(4) Obtain the fuel pressure gauge/hose assembly
from fuel pressure gauge tool set 5069. Remove the
gauge from the hose.
(5) Place one end of hose (gauge end) into an ap-
proved gasoline container.
(6) Place a shop towel under the test port.
(7) To release fuel pressure, screw the other end of
hose onto the fuel pressure test port.
(8) After fuel pressure has been released, remove
the hose from the test port.
(9) Install protective cap to fuel test port.
FUEL SYSTEM PRESSURE TEST
The fuel system is equipped with a vacuum as-
sisted fuel pressure regulator (Fig. 8). With engine atidle speed, system fuel pressure should be approxi-
mately 214 kPa (31 psi) with the vacuum line con-
nected to the regulator. With the vacuum line
disconnected from the regulator, fuel pressure should
be approximately 269 kPa (39 psi). This is 55-69 kPa
(8-10 psi) higher.
(1) Remove the protective cap at the fuel rail (Fig.
7). Connect the 0-414 kPa (0-60 psi) fuel pressure
gauge (from Gauge Set 5069) to test port pressure fit-
ting on fuel rail (Fig. 9).
(2) Note pressure gauge reading. Fuel pressure
should be approximately 214 kPa (31 psi) at idle.
(3) Disconnect vacuum line (hose) at fuel pressure
regulator (Fig. 8). Note gauge reading. With vacuum
line disconnected, fuel pressure should rise to ap-
proximately 269 kPa (39 psi).
Fuel pressure should be approximately 55-69 kPa
(8-10 psi) higher with vacuum line removed from reg-
ulator. If not, inspect pressure regulator vacuum line
for leaks, kinks or blockage. If vacuum line checks
Fig. 7 Pressure Test PortÐTypical
Fig. 8 Fuel Pressure RegulatorÐTypical
Fig. 9 Fuel Pressure Test ConnectionÐTypical
14 - 6 FUEL DELIVERY SYSTEMJ
codes are not displayed, the problem may be mechan-
ical rather than electronic.
FUEL FILTER
The fuel filter protects the fuel injectors and fuel
pressure regulator from dirt, water and other foreign
matter. The filter is located under the vehicle along
the frame rail (Figs. 13 or 14). Replace fuel filter at
intervals specified in the Lubrication and Mainte-
nance Schedule chart found in Group 0, Lubrication
and Maintenance.
REMOVAL
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT FUEL PRESSURE (EVEN WITH THE ENGINE
OFF) OF APPROXIMATELY 131-269 KPA (19-39 PSI).
THIS PRESSURE MUST BE RELEASED BEFORE
SERVICING THE FUEL FILTER.
(1) Disconnect negative battery cable. Remove fuel
filler cap.
WARNING: FUEL PRESSURE MUST BE RELEASED
BEFORE DISCONNECTING ANY FUEL SYSTEM
COMPONENT.
(2) Release fuel system pressure. Refer to Fuel
Pressure Release Procedure in this group.
(3) Raise and support vehicle.
(4) On YJ models remove the fuel filter shield (Fig.
13).
(5) Remove hoses and clamps from inlet and outlet
sides of filter (Figs. 13 or 14). For procedures, refer to
Fuel Tubes/Lines/Hoses and Clamps. Also refer to
Quick-Connect Fittings. These can be found in the
Fuel Delivery System section of this group.
(6) Remove retaining strap bolt.
(7) Remove filter from vehicle.
INSTALLATION
CAUTION: The ends of the fuel filter are marked for
correct installation. Install filter with the end marked
IN towards fuel tank and the end marked OUT to-
wards engine.
(1) Place fuel filter in retaining strap with the
marked ends in the correct position.
(2) Install retaining strap bolt and tighten to 12
Nzm (106 in. lbs.) torque.
(3) Install inlet and outlet hoses and hose clamps.
For procedures, refer to Fuel Tubes/Lines/Hoses and
Clamps. Also refer to Quick-Connect Fittings. These
can be found in the Fuel Delivery System section of
this group.
(4) On YJ models, install fuel filter shield (Fig. 13).
(5) Lower vehicle.
(6) Connect negative battery cable.
(7) Start engine and check for leaks.
FUEL TUBES/LINES/HOSES AND CLAMPS
Also refer to the proceeding section on Quick-Con-
nect Fittings.
Fig. 13 Fuel Filter and ShieldÐYJ Models
Fig. 14 Fuel FilterÐXJ Models
JFUEL DELIVERY SYSTEM 14 - 9