1995 JEEP XJ fuel type

FRAME AND BUMPERS
CONTENTS
page page
BUMPERS.............................. 5
BUMPERS............................. 16FRAME................................. 1
FRAME................................ 10
FRAME
INDEX
page page
Frame Dimensions......................... 1
Front Skid Plate........................... 1
Fuel Filler Hose Splash ShieldÐXJ Vehicles...... 4
Fuel Tank Skid Plate........................ 3Fuel Tank Support Strap..................... 4
General Information........................ 1
Transfer Case Skid Plate.................... 3
GENERAL INFORMATION
Jeep XJ Vehicles (Fig. 1) and the cab section of
Jeep are constructed as a unitized body and frame.
Jeep XJ unibodies are constructed from special
high-strength steel and coated metals. These types of
metals reduce weight and provide strength.
A vehicle constructed as a unibody reacts differ-
ently to the impact of a collision. While the damage
at the immediate point of impact is easily recogniz-
able, the damage must be diagnosed to expose it.
With unibody construction, there are five logical ar-
eas to examine to expose damage:
²Damage at the immediate point of impactÐpri-
mary damage.²The other (lessor) body damageÐsecondary dam-
age.
²Damage to the exterior trim and other surface-at-
tached components.
²Damage to the mechanical components.
²The interior trim and accessory damage.
When there is damage to a vehicle, the alignment
points must be returned too specifications.
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. 2).
FRONT SKID PLATE
REMOVAL
(1) Remove the screws that attach skid plate to
side sills (Fig. 3).
(2) Remove the nuts that attach the skid plate to
the crossmember (Fig. 3).
(3) Remove the skid plate from the vehicle (Fig. 3).
INSTALLATION
(1) Position the skid plate at front crossmember
and side sills (Fig. 3).
(2) Install the nuts to attach the skid plate to
crossmember.
(3) Install the screws to attach skid plate to side
sills.
Fig. 1 JeepÐXJ
JFRAME AND BUMPERS 13 - 1

FUEL SYSTEM
CONTENTS
page page
ACCELERATOR PEDAL AND THROTTLE CABLE.17
FUEL DELIVERY SYSTEM.................. 3
FUEL TANKS........................... 13
GENERAL INFORMATION.................. 1
MULTI-PORT FUEL INJECTION (MFI)Ð
COMPONENT DESCRIPTION/SYSTEMOPERATION.......................... 19
MULTI-PORT FUEL INJECTION (MFI)Ð
COMPONENT REMOVAL/INSTALLATION.... 58
MULTI-PORT FUEL INJECTION (MFI)Ð
GENERAL DIAGNOSIS.................. 35
SPECIFICATIONS........................ 67
GENERAL INFORMATION
Throughout this group, references are made to par-
ticular vehicle models by alphabetical designation
(XJ or YJ) or by the particular vehicle nameplate. A
chart showing a breakdown of the alphabetical desig-
nations is included in the Introduction section at the
beginning of this manual.
TheFuel Systemconsists of: the fuel tank, an
electric (fuel tank mounted) fuel pump and a fuel fil-
ter. It also consists of fuel tubes/lines/hoses, vacuum
hoses, throttle body and fuel injectors.
TheFuel Delivery Systemconsists of: the electric
fuel pump, fuel filter, fuel tubes/lines/hoses, fuel rail,
fuel injectors and fuel pressure regulator.
AFuel Return Systemis used on all vehicles.
The system consists of: the fuel tubes/lines/hoses that
route fuel back to the fuel tank.
TheFuel Tank Assemblyconsists of: the fuel
tank, filler tube, fuel fill and vent hoses, fuel gauge
sending unit/electric fuel pump module, a pressure
relief/rollover valve and a pressure-vacuum filler cap.
Also to be considered part of the fuel system is the
Evaporation Control System.This is designed to
reduce the emission of fuel vapors into the atmo-
sphere. The description and function of the Evapora-
tive Control System is found in Group 25, Emission
Control Systems.
FUEL USAGE STATEMENT
Your vehicle was designed to meet all emission reg-
ulations and provide excellent fuel economy using
high quality unleaded gasoline. Only use unleaded
gasolines having a minimum posted octane of 87.
If your vehicle develops occasional light spark
knock (ping) at low engine speeds, this is not harm-
ful. However,continued heavy knock at high
speeds can cause damage and should be re-
ported to your dealer immediately.Engine dam-
age as a result of heavy knock operation may not becovered by the new vehicle warranty.
In addition to using unleaded gasoline with the
proper octane rating,those that contain deter-
gents, corrosion and stability additives are rec-
ommended.Using gasolines that have these
additives will help improve fuel economy, reduce
emissions and maintain vehicle performance.
Poor quality gasolinecan cause problems such
as hard starting, stalling and stumble. If you experi-
ence these problems, use another brand of gasoline
before considering service for the vehicle.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with
materials that contain oxygen such as alcohol, MTBE
and ETBE. The type and amount of oxygenate used
in the blend is important. The following are generally
used in gasoline blends:
ETHANOL
Ethanol (Ethyl or Grain Alcohol) properly blended,
is used as a mixture of 10 percent ethanol and 90
percent gasoline.Gasoline with ethanol may be
used in your vehicle.
METHANOL
CAUTION: DO NOT USE GASOLINES CONTAINING
METHANOL.Use of methanol/gasoline blends may re-
sult in starting and driveability problems. In addition,
damage may be done to critical fuel system compo-
nents.
Methanol (Methyl or Wood Alcohol) is used in a va-
riety of concentrations blended with unleaded gaso-
JFUEL SYSTEM 14 - 1

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

WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
Inspect all hose connections such as clamps, cou-
plings and fittings to make sure they are secure and
leaks are not present. The component should be re-
placed immediately if there is any evidence of degra-
dation that could result in failure.
Never attempt to repair a plastic fuel line/tube. Re-
place as necessary.
Avoid contact of any fuel tubes/hoses with other ve-
hicle components that could cause abrasions or scuff-
ing. Be sure that the plastic fuel lines/tubes are
properly routed to prevent pinching and to avoid heat
sources.
The lines/tubes/hoses used on fuel injected vehicles
are of a special construction. This is due to the
higher fuel pressures and the possibility of contami-
nated fuel in this system. If it is necessary to replace
these lines/tubes/hoses, only those marked EFM/EFI
may be used.
The hose clamps used to secure rubber hoses on
fuel injected vehicles are of a special rolled edge con-
struction. This construction is used to prevent the
edge of the clamp from cutting into the hose. Only
these rolled edge type clamps may be used in this
system. All other types of clamps may cut into the
hoses and cause high-pressure fuel leaks.
Use new original equipment type hose clamps.
Tighten hose clamps to 1 Nzm (15 in. lbs.) torque.
QUICK-CONNECT FITTINGS
Also refer to the previous Fuel Tubes/Lines/Hoses
and Clamps section.
Different types of quick-connect fittings are used to
attach various fuel system components. These are: a
single-tab type, a two-tab type or a plastic retainer
ring type.
SINGLE-TAB TYPE
This type of fitting is equipped with a single pull
tab (Fig. 15). The tab is removable. After the tab is
removed, the quick-connect fitting can be separated
from the fuel system component.
CAUTION: The interior components (O-rings, spac-
ers) of this type of quick-connect fitting are not ser-
viced separately, but new pull tabs are available. Do
not attempt to repair damaged fittings or fuel lines/
tubes. If repair is necessary, replace the complete
fuel tube assembly.WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from battery.
(2) Perform the fuel pressure release procedure.
Refer to the Fuel Pressure Release Procedure in this
section.
(3) Clean the fitting of any foreign material before
disassembly.
(4) Press the release tab on the side of fitting to re-
lease pull tab (Fig. 15).
CAUTION: If this release tab is not pressed prior to
releasing the pull tab, the pull tab will be damaged.
(5) While pressing the release tab on the side of
the fitting, use a screwdriver to pry up the pull tab
(Fig. 16).
(6) Raise the pull tab until it separates from the
quick-connect fitting (Fig. 17). Discard the old pull
tab.
(7) Disconnect the quick-connect fitting from the
fuel system component being serviced.
(8) Inspect the quick-connect fitting body and fuel
system component for damage. Replace as necessary.
(9) Prior to connecting the quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean the parts with a lint-free
cloth. Lubricate them with clean engine oil.
(10) Insert the quick-connect fitting into the fuel
tube or fuel system component until the built-on stop
on the fuel tube or component rests against back of
fitting.
Fig. 15 Single-Tab Type Fitting
14 - 10 FUEL DELIVERY SYSTEMJ

(11) Obtain a new pull tab. Push the new tab down
until it locks into place in the quick-connect fitting.
(12) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(13) Connect negative cable to battery.
(14) Start engine and check for leaks.
TWO-TAB TYPE FITTING
This type of fitting is equipped with tabs located on
both sides of the fitting (Fig. 18). These tabs are sup-
plied for disconnecting the quick-connect fitting from
component being serviced.
CAUTION: The interior components (O-rings, spac-
ers) of this type of quick-connect fitting are not ser-
viced separately, but new plastic retainers are
available. Do not attempt to repair damaged fittings
or fuel lines/tubes. If repair is necessary, replace
the complete fuel tube assembly.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from the bat-
tery.
(2) Perform the fuel pressure release procedure.
Refer to the Fuel Pressure Release Procedure in this
section.
(3) Clean the fitting of any foreign material before
disassembly.
(4) To disconnect the quick-connect fitting, squeeze
the plastic retainer tabs against the sides of the
quick-connect fitting with your fingers. Tool use is
not required for removal and may damage plastic re-
tainer. Pull the fitting from the fuel system compo-
nent being serviced. The plastic retainer will remain
on the component being serviced after fitting is dis-
connected. The O-rings and spacer will remain in the
quick-connect fitting connector body.
(5) Inspect the quick-connect fitting body and com-
ponent for damage. Replace as necessary.
CAUTION: When the quick-connect fitting was dis-
connected, the plastic retainer will remain on the
component being serviced. If this retainer must be
removed, very carefully release the retainer from
the component with two small screwdrivers. After
removal, inspect the retainer for cracks or any dam-
age.
(6) Prior to connecting the quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean the parts with a lint-free
cloth. Lubricate them with clean engine oil.
Fig. 16 Disconnecting Single-Tab Type Fitting
Fig. 17 Removing Pull Tab
Fig. 18 Typical Two-Tab Type Quick-Connect Fitting
JFUEL DELIVERY SYSTEM 14 - 11

(7) Insert the quick-connect fitting to the compo-
nent being serviced and into the plastic retainer.
When a connection is made, a click will be heard.
(8) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(9) Connect negative cable to battery.
(10) Start engine and check for leaks.
PLASTIC RETAINER RING TYPE FITTING
This type of fitting can be identified by the use of a
full-round plastic retainer ring (Fig. 19) usually black
in color.
CAUTION: The interior components (O-rings, spac-
ers, retainers) of this type of quick-connect fitting
are not serviced separately. Do not attempt to repair
damaged fittings or fuel lines/tubes. If repair is nec-
essary, replace the complete fuel tube assembly.WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH THE ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSES,
FITTINGS OR LINES, THE FUEL SYSTEM PRES-
SURE MUST BE RELEASED. REFER TO THE FUEL
PRESSURE RELEASE PROCEDURE IN THIS
GROUP.
DISCONNECTION/CONNECTION
(1) Disconnect negative battery cable from the bat-
tery.
(2) Perform the fuel pressure release procedure.
Refer to the Fuel Pressure Release Procedure in this
section.
(3) Clean the fitting of any foreign material before
disassembly.
(4) To release the fuel system component from the
quick-connect fitting, firmly push the fitting towards
the component being serviced while firmly pushing
the plastic retainer ring into the fitting (Fig. 19).
With the plastic ring depressed, pull the fitting from
the component.The plastic retainer ring must be
pressed squarely into the fitting body. If this re-
tainer is cocked during removal, it may be dif-
ficult to disconnect fitting. Use an open-end
wrench on the shoulder of the plastic retainer
ring to aid in disconnection.
After disconnection, the plastic retainer ring will
remain with the quick-connect fitting connector body.
(5) Inspect fitting connector body, plastic retainer
ring and fuel system component for damage. Replace
as necessary.
(6) Prior to connecting the quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean the parts with a lint-free
cloth. Lubricate them with clean engine oil.
(7) Insert the quick-connect fitting into the compo-
nent being serviced until a click is felt.
(8) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(9) Connect negative battery cable to battery.
(10) Start engine and check for leaks.
Fig. 19 Plastic Retainer Ring Type Fitting
14 - 12 FUEL DELIVERY SYSTEMJ

FUEL TANKS
INDEX
page page
Fuel Gauge Sending Unit................... 16
Fuel Tank............................... 13
Fuel Tank Capacities....................... 13
Fuel Tank Filler Tube Cap................... 13Fuel Tank Pressure Relief/Rollover Valve........ 16
General Information....................... 13
Heat Shields............................. 13
No-Lead Fuel Tank Filler Tube................ 13
GENERAL INFORMATION
All XJ and YJ models pass a full 360 degree roll-
over test without fuel leakage. To accomplish this,
fuel and vapor flow controls are required for all fuel
tank connections.
All models are equipped with a pressure relief/roll-
over valve mounted in the top of the fuel tank. The
return line from the fuel pump to the fuel tank con-
tains a one-way check valve.
An evaporative control system prevents raw fuel
vapor from escaping into the atmosphere. Fuel va-
pors from the fuel tank are collected in the EVAP
canister. When the engine is operating, the vapors
are drawn into the intake manifold to be used in
combustion. Refer to Group 25, Emission Control
System for more information.
Inspect all hose/tube connections for completeness.
Be sure that leaks are not present. Replace any hose
that is cracked, scuffed, swelled, has rubbed against
other vehicle components or shows any other sign of
wear that could lead to failure. If it is necessary to
replace a hose, only hose marked EFM/EFI may be
used.
When installing hoses, be sure that they are routed
away from contact with other vehicle components.
The hose clamps used on fuel injected vehicles are
of a special rolled edge construction to prevent the
edge of the clamp from cutting into the hose. Only
these rolled edge type clamps may be used on this
system. Other types of clamps may cut into the hoses
and cause high-pressure fuel leaks.
FUEL TANK CAPACITIES
Refer to the Specifications section at the end of this
group.
NO-LEAD FUEL TANK FILLER TUBE
All vehicles are designed to operate using Unleaded
fuels. The diameter of the opening in the fuel tank
filler neck is sized to only accept unleaded fuel noz-
zles. Gasoline station pumps for unleaded and leaded
fuels have different size nozzles. Leaded fuel nozzles
are larger in diameter than unleaded nozzles. The
fuel tank filler neck opening is also equipped with adeflector, which the smaller unleaded nozzle pushes
back upon entering the filler neck. The deflector will
prevent the larger diameter leaded fuel nozzles from
entering the filler neck and will deflect fuel away
from the filler neck. This happens if filling of the
tank with leaded fuel is attempted.
A label is attached to the instrument panel under
the fuel gauge that reads UNLEADED FUEL ONLY
as a reminder to the driver. A similar label is located
near the fuel tank filler.
FUEL TANK FILLER TUBE CAP
The loss of any fuel or vapor out of the filler neck
is prevented by the use of a safety filler cap. This
will release only under pressure of 10.9 to 13.45 kPa
(1.58 to 1.95 psi). The vacuum release is between .97
and 2.0 kPa (.14 and .29 psi). This cap must be re-
placed by a similar unit if replacement is necessary.
CAUTION: Remove the fuel tank filler tube cap prior
to removing or repairing fuel lines to relieve fuel
tank pressure.
HEAT SHIELDS
The sheet metal heat shields may have to be re-
moved when servicing the fuel tank, fuel lines or va-
por vent line. The heat shields must be installed to
protect the lines and tank from the heat of the ex-
haust system. Refer to Group 11, Exhaust System
and Intake Manifold for proper installation.
FUEL TANK
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 FUEL TANK.
REMOVALÐXJ MODELS
Perform the preceding Fuel System Pressure Re-
lease Procedure.
(1) Disconnect negative battery cable.
JFUEL TANKS 14 - 13

The engine will not operate if the PCM does not re-
ceive a crankshaft position sensor input.
ENGINE COOLANT TEMPERATURE SENSORÐPCM
INPUT
The engine coolant temperature sensor is installed
in the thermostat housing (Fig. 10) and protrudes
into the water jacket. The sensor provides an input
voltage to the powertrain control module (PCM) re-
lating coolant temperature. The PCM uses this input
along with inputs from other sensors to determine in-
jector pulse width and ignition timing. As coolant
temperature varies, the coolant temperature sensor's
resistance changes. The change in resistance results
in a different input voltage to the PCM.
When the engine is cold, the PCM will operate in
Open Loop cycle. It will demand slightly richer air-
fuel mixtures and higher idle speeds. This is done
until normal operating temperatures are reached.
Refer to Open Loop/Closed Loop Modes of Opera-
tion in this section of the group for more information.
EXTENDED IDLE SWITCHÐPCM INPUT
OPTIONAL POLICE PACKAGE ONLY
The extended idle switch is used to raise the en-
gine idle speed to approximately 1000 rpm. This is
when the shifter is in either the Park or Neutral po-
sition. A rocker-type 2-wire switch (extended idle
switch) is mounted to the instrument panel. This
switch will supply a ground circuit to the powertrain
control module (PCM).The switch is available
only with 4.0L engine when supplied with the
optional police package.
For testing and diagnosis of this switch and its cir-
cuit, refer to the MFI SystemÐGeneral Diagnosis
section of this group.
IGNITION CIRCUIT SENSEÐPCM INPUT
The ignition circuit sense input tells the powertrain
control module (PCM) the ignition switch has ener-
gized the ignition circuit. Refer to the wiring dia-
grams for circuit information.
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSORÐPCM INPUT
The MAP sensor reacts to absolute pressure in the
intake manifold. It provides an input voltage to the
powertrain control module (PCM). As engine load
changes, manifold pressure varies. The change in
manifold pressure causes MAP sensor voltage to
change. The change in MAP sensor voltage results in
a different input voltage to the PCM. The input volt-
age level supplies the PCM with information about
ambient barometric pressure during engine start-up
(cranking) and engine load while the engine is run-
ning. The PCM uses this input along with inputs
from other sensors to adjust air-fuel mixture.
Fig. 8 Sensor LocationÐ4.0L Engine
Fig. 9 Sensor LocationÐ2.5L Engine
Fig. 10 Engine Coolant Temperature SensorÐ
Typical
JFUEL SYSTEM COMPONENT DESCRIPTION/SYSTEM OPERATION 14 - 23