Jeep XJ. Manual — part 337
FUEL GAUGE SENDING UNIT
The fuel gauge sending unit contains a variable
resistor (track). As the float moves up or down, elec-
trical resistance will change. Refer to Instrument
Panel and Gauges for Fuel Gauge testing. To test the
gauge sending unit only, it must be removed from
vehicle. The unit is part of the fuel pump module.
Refer to Fuel Pump Module Removal/Installation for
procedures. Measure the resistance across the send-
ing unit terminals. With float in up position, resis-
tance should be 20 ohms (+/- 5%). With float in down
position, resistance should be 270 ohms (+/- 5%).
FUEL INJECTOR TEST
To perform a complete test of the fuel injectors and
their circuitry, use the DRB scan tool and refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the injector only, refer to the following:
Disconnect the fuel injector wire harness connector
from the injector. The injector is equipped with 2
electrical terminals (pins). Place an ohmmeter across
the terminals. Resistance reading should be approxi-
mately 12 ohms
61.2 ohms at 20°C (68°F).
SERVICE PROCEDURES
FUEL SYSTEM PRESSURE RELEASE
PROCEDURE
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 DRB scan tool must be
used to erase a DTC.
QUICK-CONNECT FITTINGS
Also refer to Fuel Tubes/Lines/Hoses and Clamps.
Different types of quick-connect fittings are used to
attach various fuel system components, lines and
tubes. These are: a single-tab type, a two-tab type or
a plastic retainer ring type. Safety latch clips are
TERMINAL LEGEND
NUMBER
IDENTIFICATION
30
COMMON FEED
85
COIL GROUND
86
COIL BATTERY
87
NORMALLY OPEN
87A
NORMALLY CLOSED
Fig. 11 Type–2 Relay
TERMINAL LEGEND
NUMBER
IDENTIFICATION
1
COIL BATTERY
2
COIL GROUND
3
COMMON FEED
4
NORMALLY CLOSED
5
NORMALLY OPEN
Fig. 12 Type–3 Relay
14 - 10
FUEL SYSTEM
XJ
DIAGNOSIS AND TESTING (Continued)
used on certain components/lines. Certain fittings
may require use of a special tool for disconnection.
DISCONNECTING
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE (EVEN WITH ENGINE OFF).
BEFORE SERVICING ANY FUEL SYSTEM HOSE,
FITTING OR LINE, FUEL SYSTEM PRESSURE MUST
BE RELEASED. REFER TO FUEL SYSTEM PRES-
SURE RELEASE PROCEDURE.
CAUTION: The interior components (o-rings, spac-
ers) of some types of quick-connect fitting are not
serviced separately. If service parts are not avail-
able, do not attempt to repair a damaged fitting or
fuel line. If repair is necessary, replace complete
fuel line assembly.
(1) Perform fuel pressure release procedure. Refer
to Fuel Pressure Release Procedure in this group.
(2) Disconnect negative battery cable from battery.
(3) Clean fitting of any foreign material before dis-
assembly.
(4)
Single-Tab Type Fitting: This type of fitting
is equipped with a single pull tab (Fig. 13). The tab
is removable. After tab is removed, quick-connect fit-
ting can be separated from fuel system component.
(a) Press release tab on side of fitting to release
pull tab (Fig. 14). If release tab is not pressed
prior to releasing pull tab, pull tab will be
damaged.
(b) While pressing release tab on side of fitting,
use screwdriver to pry up pull tab (Fig. 14).
(c) Raise pull tab until it separates from quick-
connect fitting (Fig. 15).
(5) Two-Tab Type Fitting: This type of fitting is
equipped with tabs located on both sides of fitting
(Fig. 16). The tabs are supplied for disconnecting
quick-connect fitting from component being serviced.
(a) To disconnect quick-connect fitting, squeeze
plastic retainer tabs (Fig. 16) against sides of
quick-connect fitting with your fingers. Tool use is
not required for removal and may damage plastic
retainer.
(b) Pull fitting from fuel system component
being serviced.
(c) The plastic retainer will remain on compo-
nent being serviced after fitting is disconnected.
The o-rings and spacer will remain in quick-con-
nect fitting connector body.
(6)
Plastic Retainer Ring Type Fitting: This
type of fitting can be identified by the use of a full-
round plastic retainer ring (Fig. 17) usually black in
color.
(a) To release fuel system component from quick-
connect fitting, firmly push fitting towards compo-
nent being serviced while firmly pushing plastic
retainer ring into fitting (Fig. 17). With plastic ring
depressed, pull fitting from component. The plas-
tic retainer ring must be pressed squarely
into fitting body. If this retainer is cocked
during removal, it may be difficult to discon-
nect fitting. Use an open-end wrench on
shoulder of plastic retainer ring to aid in dis-
connection.
(b) After disconnection, plastic retainer ring will
remain with quick-connect fitting connector body.
Fig. 13 Single-Tab Type Fitting
1 – PULL TAB
2 – QUICK-CONNECT FITTING
3 – PRESS HERE TO REMOVE PULL TAB
4 – INSERTED TUBE END
Fig. 14 Disconnecting Single-Tab Type Fitting
1 – PULL TAB
2 – SCREWDRIVER
3 – QUICK-CONNECT FITTING
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FUEL SYSTEM
14 - 11
SERVICE PROCEDURES (Continued)
(c) Inspect fitting connector body, plastic retainer
ring and fuel system component for damage.
Replace as necessary.
(7) Latch Clips: Depending on vehicle model and
engine, 2 different types of safety latch clips are used
(Fig. 18) or (Fig. 19). Type-1 is tethered to fuel line
and type-2 is not. A special tool will be necessary to
disconnect fuel line after latch clip is removed. The
latch clip may be used on certain fuel line/fuel rail
connection, or to join fuel lines together.
(a) Type 1: Pry up on latch clip with a screw-
driver (Fig. 18).
(b) Type 2: Separate and unlatch 2 small arms
on end of clip (Fig. 19) and swing away from fuel
line.
(c) Slide latch clip toward fuel rail while lifting
with screwdriver.
Fig. 15 Removing Pull Tab
1 – FUEL TUBE OR FUEL SYSTEM COMPONENT
2 – PULL TAB
3 – QUICK-CONNECT FITTING
4 – FUEL TUBE STOP
Fig. 16 Typical Two-Tab Type Quick-Connect Fitting
1 – TAB(S)
2 – QUICK-CONNECT FITTING
Fig. 17 Plastic Retainer Ring Type Fitting
1 – FUEL TUBE
2 – QUICK CONNECT FITTING
3 – PUSH
4 – PLASTIC RETAINER
5 – PUSH
6 – PUSH
7 – PUSH
8 – PUSH
Fig. 18 Latch Clip—Type 1
1 – TETHER STRAP
2 – FUEL LINE
3 – SCREWDRIVER
4 – LATCH CLIP
5 – FUEL RAIL
14 - 12
FUEL SYSTEM
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SERVICE PROCEDURES (Continued)
(d) Insert special fuel line removal tool (Snap-On
number FIH 9055-1 or equivalent) into fuel line
(Fig. 20). Use tool to release locking fingers in end
of line.
(e) With special tool still inserted, pull fuel line
from fuel rail.
(f) After
disconnection,
locking
fingers
will
remain within quick-connect fitting at end of fuel
line.
(8) Disconnect quick-connect fitting from fuel sys-
tem component being serviced.
CONNECTING
(1) Inspect quick-connect fitting body and fuel sys-
tem component for damage. Replace as necessary.
(2) Prior to connecting quick-connect fitting to
component being serviced, check condition of fitting
and component. Clean parts with a lint-free cloth.
Lubricate with clean engine oil.
(3) Insert quick-connect fitting into fuel tube or
fuel system component until built-on stop on fuel
tube or component rests against back of fitting.
(4) Continue pushing until a click is felt.
(5) Single-tab type fitting: Push new tab down
until it locks into place in quick-connect fitting.
(6) Verify a locked condition by firmly pulling on
fuel tube and fitting (15-30 lbs.).
(7) Latch Clip Equipped: Install latch clip (snaps
into position). If latch clip will not fit, this indi-
cates fuel line is not properly installed to fuel
rail (or other fuel line). Recheck fuel line con-
nection.
(8) Connect negative cable to battery.
(9) Start engine and check for leaks.
REMOVAL AND INSTALLATION
FUEL FILTER/FUEL PRESSURE REGULATOR
The combination Fuel Filter/Fuel Pressure Regula-
tor is located on the fuel pump module. The fuel
pump module is located on top of fuel tank.
The
filter/regulator
may
be
removed
without
removing fuel pump module although fuel tank must
be removed.
REMOVAL
(1) Remove fuel tank. Refer to Fuel Tank Removal/
Installation.
(2) Clean area around filter/regulator.
(3) Disconnect fuel line at filter/regulator. Refer to
Quick-Connect Fittings in this group for procedures.
(4) Remove retainer clamp from top of filter/regu-
lator (Fig. 21). Clamp snaps to tabs on pump module.
Discard old clamp.
(5) Pry filter/regulator from top of pump module
with 2 screwdrivers. Unit is snapped into module.
(6) Discard gasket below filter/regulator (Fig. 22).
(7) Before
discarding
filter/regulator
assembly,
inspect assembly to verify that o-rings (Fig. 23) are
intact. If the smallest of the two o-rings can not be
found on bottom of filter/regulator, it may be neces-
sary to remove it from the fuel inlet passage in fuel
pump module.
Fig. 19 Latch Clip—Type 2
1 – LATCH CLIP
Fig. 20 Fuel Line Disconnection Using Special Tool
1 – SPECIAL FUEL LINE TOOL
2 – FUEL LINE
3 – FUEL RAIL
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FUEL SYSTEM
14 - 13
SERVICE PROCEDURES (Continued)
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