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

COMMON FEED

COIL GROUND

COIL BATTERY

NORMALLY OPEN

87A

NORMALLY CLOSED

Fig. 11 Type–2 Relay

TERMINAL LEGEND

NUMBER

IDENTIFICATION

COIL BATTERY

COIL GROUND

COMMON FEED

NORMALLY CLOSED

NORMALLY OPEN

Fig. 12 Type–3 Relay

14 - 10

FUEL SYSTEM

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).

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.

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

FUEL SYSTEM

14 - 11

SERVICE PROCEDURES (Continued)

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.

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

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

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

FUEL SYSTEM

14 - 13

SERVICE PROCEDURES (Continued)

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