fuel pressure JEEP LIBERTY 2002 KJ / 1.G Repair Manual

(1) Remove protective cap at fuel rail test port.
Connect the 0±414 kPa (0-60 psi) fuel pressure gauge
(from gauge set 5069) to test port pressure fitting on
fuel rail (Fig. 20).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.
(2) Start and warm engine and note pressure
gauge reading. Fuel pressure should be 339 kPa   34
kPa (49.2 psi   5 psi) at idle.
(3) If engine runs, but pressure is below 44.2 psi,
check for a kinked fuel supply line somewhere
between fuel rail and fuel pump module. If line is not
kinked, but specifications for either the Fuel Pump
Capacity, Fuel Pump Amperage or Fuel Pressure
Leak Down Tests were not met, replace lower section
of fuel pump module. Refer to Fuel Pump Module
Removal/Installation.
(4) If operating pressure is above 54.2 psi, electric
fuel pump is OK, but fuel pressure regulator is defec-
tive. Replace lower section of fuel pump module.
Refer to Fuel Pump Module Removal/Installation.
(5) Install protective cap to fuel rail test port.
DIAGNOSIS AND TESTING - FUEL PUMP
AMPERAGE TEST
This amperage (current draw) test is to be done in
conjunction with the Fuel Pump Pressure Test, Fuel
Pump Capacity Test and Fuel Pressure Leak Down
Test. Before performing the amperage test, be sure
the temperature of the fuel tank is above 50É F (10É
C).The DRBtScan Tool along with the DRB Low Cur-
rent Shunt (LCS) adapter (Fig. 21) and its test leads
will be used to check fuel pump amperage specifica-
tions.
(1) Be sure fuel tank contains fuel before starting
test. If tank is empty or near empty, amperage read-
ings will be incorrect.
(2) Obtain LCS adapter.
(3) Plug cable from LCS adapter into DRB scan
tool at SET 1 receptacle.
(4) Plug DRB into vehicle 16±way connector (data
link connector).
(5) Connect (-) and (+) test cable leads into LCS
adapter receptacles. Use10 amp (10A +)receptacle
and common (-) receptacles.
(6) Gain access to MAIN MENU on DRB screen.
(7) Press DVOM button on DRB.
(8) Using left/right arrow keys, highlight CHAN-
NEL 1 function on DRB screen.
(9) Press ENTER three times.
(10) Using up/down arrow keys, highlight RANGE
on DRB screen (screen will default to 2 amp scale).
(11) Press ENTER to change 2 amp scale to 10
amp scale.This step must be done to prevent
damage to DRB scan tool or LCS adapter
(blown fuse).
(12) Remove cover from Power Distribution Center
(PDC).
(13) Remove fuel pump relay from PDC. Refer to
label on PDC cover for relay location.
Fig. 20 FUEL PRESSURE TEST GAUGE (TYPICAL
GAUGE INSTALLATION AT TEST PORT)
1 - SERVICE (TEST) PORT
2 - FUEL PRESSURE TEST GAUGE
3 - FUEL RAIL
Fig. 21 LOW CURRENT SHUNT
1 - LOW CURRENT SHUNT ADAPTER
2 - PLUG TO DRB
3 - TEST LEAD RECEPTACLES
14 - 16 FUEL DELIVERYKJ
FUEL PUMP (Continued)

WARNING: BEFORE PROCEEDING TO NEXT STEP,
NOTE THE FUEL PUMP WILL BE ACTIVATED AND
SYSTEM PRESSURE WILL BE PRESENT. THIS WILL
OCCUR AFTER CONNECTING TEST LEADS FROM
LCS ADAPTER INTO FUEL PUMP RELAY CAVITIES.
THE FUEL PUMP WILL OPERATE EVEN WITH IGNI-
TION KEY IN OFF POSITION. BEFORE ATTACHING
TEST LEADS, BE SURE ALL FUEL LINES AND
FUEL SYSTEM COMPONENTS ARE CONNECTED.
CAUTION: To prevent possible damage to the vehi-
cle electrical system and LCS adapter, the test
leads must be connected into relay cavities exactly
as shown in following steps.
Depending upon vehicle model, year or engine con-
figuration, three different types of relays may be
used: Type-1, type-2 and type±3.
(14) If equipped withtype±1 relay(Fig. 22),
attach test leads from LCS adapter into PDC relay
cavities number 30 and 87. For location of these cav-
ities, refer to numbers stamped to bottom of relay
(Fig. 22).
(15) If equipped withtype±2 relay(Fig. 23),
attach test leads from LCS adapter into PDC relay
cavities number 30 and 87. For location of these cav-
ities, refer to numbers stamped to bottom of relay
(Fig. 23).
(16) If equipped withtype±3 relay(Fig. 24),
attach test leads from LCS adapter into PDC relay
cavities number 3 and 5. For location of these cavi-
ties, refer to numbers stamped to bottom of relay
(Fig. 24).
Fig. 22 FUEL PUMP RELAY - TYPE 1
Fig. 23 FUEL PUMP RELAY - TYPE 2
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 24 FUEL PUMP RELAY - TYPE 3
TERMINAL LEGEND
NUMBER IDENTIFICATION
1 COIL BATTERY
2 COIL GROUND
3 COMMON FEED
4 NORMALLY CLOSED
5 NORMALLY OPEN
KJFUEL DELIVERY 14 - 17
FUEL PUMP (Continued)

(17) When LCS adapter test leads are attached
into relay cavities, fuel pumpwill be activated.
Determine fuel pump amperage on DRB screen.
Amperage should be below 10.0 amps. If amperage is
below 10.0 amps, and specifications for the Fuel
Pump Pressure, Fuel Pump Capacity and Fuel Pres-
sure Leak Down tests were met, the fuel pump mod-
ule is OK.
(18) If amperage is more than 10.0 amps, replace
fuel pump module assembly. The electric fuel pump
is not serviced separately.
(19) Disconnect test leads from relay cavities
immediately after testing.
FUEL PUMP MODULE
DESCRIPTION
The fuel pump module assembly is located in the
fuel tank (Fig. 1). The assembly is divided into 2±sec-
tions, upper and lower. The lower section is locked to
the bottom of the fuel tank. The complete assembly
contains the following components:
²A fuel pressure regulator
²A separate fuel pick-up, or inlet filter
²An electric fuel pump
²A lockring to retain upper section of pump mod-
ule to tank
²A rollover valve
²A vent fitting for ORVR system
²A soft gasket between tank flange and module
²A fuel gauge sending unit (fuel level sensor)
²Two fuel line connections (supply and return)
The fuel gauge sending unit may be serviced sepa-
rately. If the electrical fuel pump, primary inlet filter
or fuel pressure regulator require service, the lower
section of the fuel pump module must be replaced.
OPERATION
Refer to Fuel Pump, Inlet Filter, Fuel Pressure
Regulator and Fuel Gauge Sending Unit.
REMOVAL
The fuel pump module is divided into 2 sections,
upper and lower. To service the check (control) valve,
replace only the upper section. To service the fuel
gauge sending unit, remove the upper section. To ser-
vice the electric fuel pump, fuel pressure regulator or
primary inlet filter, remove both sections and replace
lower section.
Fuel tank removal will not be necessary for
fuel pump module removal. Access is from rear
cargo area.
(1) Four cargo holdown clamps are located inside
the vehicle on the floor of the rear cargo area.Remove the 2 rearward mounted clamps by drilling
out the clamp rivets.
(2) Fold carpeting forward to gain access to fuel
pump module access plate (Fig. 25).
(3) Remove 4 fuel pump module access plate nuts
(Fig. 25).
(4) While applying heat from a heat gun, carefully
pry up fuel pump module access plate. Take care not
to bend plate.
(5) Thoroughly clean area around top of pump
module to prevent contaminants from entering fuel
tank or fuel lines.
WARNING: THE FUEL SYSTEM IS UNDER A CON-
STANT PRESSURE EVEN WITH ENGINE OFF.
BEFORE SERVICING THE FUEL PUMP MODULE,
FUEL SYSTEM PRESSURE MUST BE RELEASED.
(6) Release fuel system pressure. Refer to Fuel
System Pressure Release procedure.
(7) Disconnect 2 fuel lines at fuel pump module
(Fig. 26) by pressing on 2 buttons at sides of fitting.
(8) Disconnect electrical connector (Fig. 26) at top
of fuel pump module by sliding red colored tab first
to unlock, and push grey colored tab down for
removal.
(9) Disconnect ORVR hose clamp and hose (Fig.
26) at pump module fitting.
(10) Remove module lockring (Fig. 26) using a
brass drift and hammer (counter-clockwise).
(11) Carefully lift upper section of pump module
(Fig. 26) from fuel tank exposing connections(lift
upper section from tank very slowly until rub-
ber gasket can be retained. If not, gasket will
fall into fuel tank.)
(a) Disconnect electrical connector (Fig. 27) at
bottom of upper pump module section.
(b) Disconnect fuel pressure regulator (Fig. 27)
at bottom of upper pump module section. Press on
2 locking tabs.
(c) Disconnect fuel return line (Fig. 27) at bot-
tom of upper pump module section. Press on 2
locking tabs.
(d) Remove upper section of pump module (Fig.
28) from fuel tank.
(12) Using an approved gas holding tank, drain
fuel tank through pump module opening.If check
(control) valve, or, only upper section of pump
module is being serviced, tank draining is not
necessary. If any other fuel pump module com-
ponent is being serviced, the tank must be com-
pletely drained to the bottom.
(13) To remove lower section of pump module from
fuel tank:
(a) Using finger pressure, push on plastic
release tab (Fig. 29) while sliding lock tab upward.
14 - 18 FUEL DELIVERYKJ
FUEL PUMP (Continued)

(b) The sides of pump module are equipped with
tension springs (Fig. 29). These springs hold mod-
ule to bottom of fuel tank into 2 formed guides
(Fig. 30). Release module assembly from these 2
guides by sliding toward right side of fuel tank.
(c) Lift assembly from fuel tank.
INSTALLATION
CAUTION: Whenever fuel pump module is serviced,
pump module gasket must be replaced.
(1) Position lower section of fuel pump module
assembly into fuel tank.
(2) The bottom of fuel tank has 2 formed guides.
Lock module assembly into these 2 guides by sliding
toward left side of fuel tank.
(3) Push down on plastic tab to lock module to fuel
tank guides.
(4) Connect fuel supply line to bottom of upper
pump module section.
(5) Connect fuel pressure regulator to bottom of
upper pump module section.
(6) Connect electrical connector to bottom of upper
pump module section.
(7) Position pump module into fuel tank. Notch on
module must be facing rear of tank.(8) Position lock ring to module. Tap lockring
using a brass drift and hammer (clockwise) until
rotated up to built-on stops.
(9) Attach (snap on) 2 fuel filter fuel lines to top of
fuel pump module.
(10) Connect hoses/lines to ORVR components.
(11) Fill fuel tank with fuel.
(12) Start engine and check for fuel leaks.
(13) Apply silicone sealant to bottom of fuel pump
module metal access plate.
(14) Install fuel pump module metal access plate
and 4 nuts. Tighten nuts to 3 N´m (26 in. lbs.)
torque.
(15) Position carpet and install 2 new cargo clamp
rivets into each cargo holdown clamp.
Fig. 25 ACCESS PLATE
1 - FLOORPAN AT REAR
2 - FUEL PUMP MODULE ACCESS PLATE
3 - NUTS (4)
4 - OPENING TO PUMP MODULE
Fig. 26 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 - 19
FUEL PUMP MODULE (Continued)

Fig. 27 FUEL PRESSURE REGULATOR/SENDING
UNIT ELECTRICAL CONNECTOR
1 - UPPER SECTION OF PUMP MODULE
2 - QUICK-CONNECT FITTINGS
3 - FUEL PRESSURE REGULATOR
4 - 4-WIRE ELECTRICAL CONNECTOR
5 - FUEL TANK CHECK (CONTROL) VALVE
Fig. 28 UPPER SECTION - FUEL PUMP MODULE
1 - UPPER SECTION - FUEL PUMP MODULE
2 - FUEL TANK CHECK (CONTROL) VALVE
Fig. 29 LOWER SECTION - FUEL PUMP MODULE
1 - LOWER SECTION - FUEL PUMP MODULE
2 - RELEASE LOCK AND TAB
3 - TENSION SPRINGS
Fig. 30 FUEL PUMP MODULE GUIDES (IN FUEL
TANK)
1 - FUEL TANK (INSIDE/LOWER)
2 - FUEL PUMP MODULE GUIDES
14 - 20 FUEL DELIVERYKJ
FUEL PUMP MODULE (Continued)

FUEL RAIL
DESCRIPTION
2.4L
The fuel injector rail is used to mount the fuel
injectors to the engine (Fig. 31). On the 2.4L 4-cylin-
der engine, afuel damperis located near the front
of the fuel rail (Fig. 31).
3.7L
The fuel injector rail is mounted to the intake
manifold (Fig. 32). It is used to mount the fuel injec-
tors to the engine. The rail is equipped with a test
port (Fig. 33) to check/test fuel system pressure.
A fuel rail mounted, fuel damper is not used with
this engine.
OPERATION
2.4L
The fuel injector rail supplies the necessary fuel to
each individual fuel injector.The fuel damper is used only to help control fuel
pressure pulsations. These pulsations are the result
Fig. 31 FUEL RAIL-2.4L
1 - FUEL RAIL
2 - MOUNTING BOLTS
3 - TEST PORT
4 - QUICK-CONNECT FITTING
5 - INJ. #1
6 - DAMPER
7 - INJ #2
8 - INJ #3
9 - INJ #4
10- INJECTOR RETAINING CLIP
Fig. 32 FUEL RAIL - 3.7L
1 - MOUNTING BOLTS (4)
2 - QUICK-CONNECT FITTING
3 - FUEL RAIL
4 - INJ. #1
5 - INJ. #3
6 - INJ. #5
7 - INJ. #2
8 - INJ. #4
9 - INJ. #6
10 - CONNECTOR TUBE
Fig. 33 FUEL RAIL TEST PORT - 3.7L
1 - FUEL RAIL
2 - TEST PORT
KJFUEL DELIVERY 14 - 21

of the firing of the fuel injectors. It isnot usedas a
fuel pressure regulator. The fuel pressure regulator is
not mountedto the fuel rail on any engine. It is
located on the fuel tank mounted fuel pump module.
Refer to Fuel Pressure Regulator for additional infor-
mation.
The fuel rail is not repairable.
A quick-connect fitting with a safety latch is used
to attach the fuel line to the fuel rail.
3.7L
High pressure fuel from the fuel pump is routed to
the fuel rail. The fuel rail then supplies the neces-
sary fuel to each individual fuel injector.
A quick-connect fitting with a safety latch is used
to attach the fuel line to the fuel rail.
The fuel rail is not repairable.
REMOVAL
2.4L
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT PRESSURE EVEN WITH ENGINE OFF.
BEFORE SERVICING FUEL RAIL, FUEL SYSTEM
PRESSURE MUST BE RELEASED.
The fuel rail can be removed without removing the
intake manifold if the following procedures are fol-
lowed.(1) Remove fuel tank filler tube cap.
(2) Perform Fuel System Pressure Release Proce-
dure.
(3) Remove negative battery cable at battery.
(4) Remove air duct at throttle body.
(5) Disconnect fuel line latch clip and fuel line at
fuel rail. A special tool will be necessary for fuel line
disconnection. Refer to Quick-Connect Fittings.
(6) Remove necessary vacuum lines at throttle
body.
(7) Drain engine coolant and remove thermostat
and thermostat housing.
(8) Remove PCV hose and valve at valve cover.
(9) Remove 3 upper intake manifold mounting
bolts (Fig. 35), but only loosen 2 lower bolts about 2
turns.
(10) Disconnect 2 main engine harness connectors
at rear of intake manifold (Fig. 34).
(11) Disconnect 2 injection wiring harness clips at
harness mounting bracket (Fig. 35).
(12) Disconnect electrical connectors at all 4 fuel
injectors. To remove connector refer to (Fig. 37). Push
red colored slider away from injector (1). While push-
ing slider, depress tab (2) and remove connector (3)
from injector. The factory fuel injection wiring har-
ness is numerically tagged (INJ 1, INJ 2, etc.) for
injector position identification. If harness is not
tagged, note wiring location before removal.
(13) Remove 2 injection rail mounting bolts (Fig.
31).
Fig. 34 MAP SENSOR LOCATION-2.4L
1 - REAR OF INTAKE MANIFOLD
2 - MAP SENSOR
3 - ALIGNMENT PIN
4 - MOUNTING BOLT (TORX)
5 - ELECTRICAL CONNECTOR
6 - MAIN ENGINE HARNESS CONNECTORS
Fig. 35 FUEL RAIL MOUNTING-2.4L
1 - FUEL RAIL
2 - INJECTION HARNESS CLIPS
3 - LOWER MOUNTING HOLES
4 - UPPER MOUNTING HOLES
5 - INTAKE MANIFOLD
14 - 22 FUEL DELIVERYKJ
FUEL RAIL (Continued)

(14) Gently rock and pull fuel rail until fuel injec-
tors just start to clear machined holes in intake man-
ifold.
(15) Remove fuel rail (with injectors attached)
from intake manifold.
(16) If fuel injectors are to be removed, refer to
Fuel Injector Removal/Installation.
3.7L
WARNING: THE FUEL SYSTEM IS UNDER CON-
STANT PRESSURE EVEN WITH ENGINE OFF.
BEFORE SERVICING FUEL RAIL, FUEL SYSTEM
PRESSURE MUST BE RELEASED.
CAUTION: The left and right fuel rails are replaced
as an assembly. Do not attempt to separate rail
halves at connector tube (Fig. 36). Due to design of
tube, it does not use any clamps. Never attempt to
install a clamping device of any kind to tube. When
removing fuel rail assembly for any reason, be care-
ful not to bend or kink tube.
(1) Remove fuel tank filler tube cap.
(2) Perform Fuel System Pressure Release Proce-
dure.
(3) Remove negative battery cable at battery.
(4) Remove air duct at throttle body air box.
(5) Remove air box at throttle body.
(6) Disconnect fuel line latch clip and fuel line at
fuel rail. A special tool will be necessary for fuel line
disconnection. Refer to Quick-Connect Fittings.
(7) Remove necessary vacuum lines at throttle
body.
(8) Disconnect electrical connectors at all 6 fuel
injectors. To remove connector refer to (Fig. 37). Push
red colored slider away from injector (1). While push-
ing slider, depress tab (2) and remove connector (3)
from injector. The factory fuel injection wiring har-
ness is numerically tagged (INJ 1, INJ 2, etc.) for
injector position identification. If harness is not
tagged, note wiring location before removal.
(9) Disconnect electrical connectors at throttle
body sensors.
(10) Remove 6 ignition coils. Refer to Ignition Coil
Removal/Installation.
(11) Remove 4 fuel rail mounting bolts (Fig. 36).
(12) Gently rock and pullleftside of fuel rail until
fuel injectors just start to clear machined holes in
cylinder head. Gently rock and pullrightside of rail
until injectors just start to clear cylinder head holes.
Repeat this procedure (left/right) until all injectors
have cleared cylinder head holes.
(13) Remove fuel rail (with injectors attached)
from engine.
Fig. 36 FUEL RAIL REMOVE/INSTALL - 3.7L
1 - MOUNTING BOLTS (4)
2 - QUICK-CONNECT FITTING
3 - FUEL RAIL
4 - INJ. #1
5 - INJ. #3
6 - INJ. #5
7 - INJ. #2
8 - INJ. #4
9 - INJ. #6
10 - CONNECTOR TUBE
Fig. 37 REMOVE/INSTALL INJECTOR CONNECTOR
KJFUEL DELIVERY 14 - 23
FUEL RAIL (Continued)

REMOVAL
Fuel Tank Draining
WARNING: THE FUEL SYSTEM MAY BE UNDER
CONSTANT FUEL PRESSURE EVEN WITH THE
ENGINE OFF. THIS PRESSURE MUST BE
RELEASED BEFORE SERVICING FUEL TANK.
Two different procedures may be used to drain fuel
tank: removing fuel pump module access plate, or
using DRBtscan tool. Due to a one-way check valve
installed into the fuel fill opening fitting at the tank
(Fig. 38), the tank cannot be drained conventionally
at the fill cap.
The quickest draining procedure involves removing
fuel pump module access plate.
As an alternative procedure, the electric fuel pump
may be activated allowing tank to be drained at fuel
rail connection. Refer to DRB scan tool for fuel pump
activation procedures. Before disconnecting fuel line
at fuel rail, release fuel pressure. Refer to the Fuel
System Pressure Release Procedure for procedures.
Attach end of special test hose tool number 6541,
6539, 6631 or 6923 at fuel rail disconnection (tool
number will depend on model and/or engine applica-
tion). Position opposite end of this hose tool to an
approved gasoline draining station. Activate fuel
pump and drain tank until empty.
If electric fuel pump is not operating, fuel pump
module access plate must be removed for fuel drain-
ing. Refer to following procedures.Fuel tank removal will not be necessary for
fuel tank draining. Access for draining is from
rear cargo area.
(1) Open all windows in vehicle to allow for air
ventilation.
(2) Four cargo holdown clamps are located inside
the vehicle on the floor of the rear cargo area.
Remove the 2 rearward mounted clamps by drilling
out the clamp rivets.
(3) Fold carpeting forward to gain access to fuel
pump module access plate (Fig. 39).
(4) Remove 4 fuel pump module access plate nuts
(Fig. 39).
(5) While applying heat from a heat gun, carefully
pry up fuel pump module access plate. Take care not
to bend plate.
(6) Thoroughly clean area around top of pump
module to prevent contaminants from entering fuel
tank or fuel lines.
(7) Release fuel system pressure.
(8) Disconnect 2 fuel lines (Fig. 40) at fuel pump
module by pressing on tabs at side of fitting.
(9) Disconnect electrical connector (Fig. 40). Slide
red tab first to unlock, and push grey tab down for
removal.
(10) Disconnect ORVR hose (Fig. 40) at pump mod-
ule fitting.
Fig. 38 FUEL FILL CHECK VALVE
1 - ONE-WAY CHECK VALVE
2 - FUEL FILL FITTING
3 - SIDE OF FUEL TANK
Fig. 39 ACCESS PLATE
1 - FLOORPAN AT REAR
2 - FUEL PUMP MODULE ACCESS PLATE
3 - NUTS (4)
4 - OPENING TO PUMP MODULE
KJFUEL DELIVERY 14 - 25
FUEL TANK (Continued)

FUEL INJECTOR
DESCRIPTION
An individual fuel injector (Fig. 9) is used for each
individual cylinder.
OPERATION
OPERATION - FUEL INJECTOR
The top (fuel entry) end of the injector (Fig. 9) is
attached into an opening on the fuel rail.
The fuel injectors are electrical solenoids. The
injector contains a pintle that closes off an orifice at
the nozzle end. When electric current is supplied to
the injector, the armature and needle move a short
distance against a spring, allowing fuel to flow out
the orifice. Because the fuel is under high pressure, a
fine spray is developed in the shape of a pencil
stream. The spraying action atomizes the fuel, add-
ing it to the air entering the combustion chamber.
The nozzle (outlet) ends of the injectors are posi-
tioned into openings in the intake manifold just
above the intake valve ports of the cylinder head.
The engine wiring harness connector for each fuel
injector is equipped with an attached numerical tag
(INJ 1, INJ 2 etc.). This is used to identify each fuel
injector.
The injectors are energized individually in a
sequential order by the Powertrain Control Module(PCM). The PCM will adjust injector pulse width by
switching the ground path to each individual injector
on and off. Injector pulse width is the period of time
that the injector is energized. The PCM will adjust
injector pulse width based on various inputs it
receives.
Battery voltage is supplied to the injectors through
the ASD relay.
The PCM determines injector pulse width based on
various inputs.
OPERATION - PCM OUTPUT
The nozzle ends of the injectors are positioned into
openings in the intake manifold just above the intake
valve ports of the cylinder head. The engine wiring
harness connector for each fuel injector is equipped
with an attached numerical tag (INJ 1, INJ 2 etc.).
This is used to identify each fuel injector with its
respective cylinder number.
The injectors are energized individually in a
sequential order by the Powertrain Control Module
(PCM). The PCM will adjust injector pulse width by
switching the ground path to each individual injector
on and off. Injector pulse width is the period of time
that the injector is energized. The PCM will adjust
injector pulse width based on various inputs it
receives.
Battery voltage (12 volts +) is supplied to the injec-
tors through the ASD relay. The ASD relay will shut-
down the 12 volt power source to the fuel injectors if
the PCM senses the ignition is on, but the engine is
not running. This occurs after the engine has not
been running for approximately 1.8 seconds.
The PCM determines injector on-time (pulse width)
based on various inputs.
DIAGNOSIS AND TESTING - FUEL INJECTOR
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  1.2 ohms at 20ÉC (68ÉF).
Fig. 9 FUEL INJECTOR Ð TYPICAL
KJFUEL INJECTION 14 - 33