Jeep Grand Cherokee WJ. Manual - part 389

Start the engine. Move the cardboard over the

high–pressure fuel lines and check for fuel spray onto
the cardboard (Fig. 17). If a high–pressure line con-
nection is leaking, bleed the system and tighten the
connection. Refer to the Air Bleed Procedure in this
group for procedures. Replace damaged, restricted or
leaking high–pressure fuel lines with the correct
replacement line.

CAUTION: The high–pressure fuel lines must be
clamped securely in the holders. The lines cannot
contact each other or other components. Do not
attempt to weld high–pressure fuel lines or to repair
lines that are damaged. Only use the recommended
lines when replacement of high–pressure fuel line
is necessary.

SERVICE PROCEDURES

AIR BLEED PROCEDURES

AIR BLEEDING AT FUEL FILTER

A certain amount of air may become trapped in the

fuel system when fuel system components are ser-
viced or replaced. Bleed the system as needed after
fuel system service according to the following proce-
dures.

WARNING: DO NOT BLEED AIR FROM THE FUEL
SYSTEM OF A HOT ENGINE. DO NOT ALLOW FUEL
TO SPRAY ONTO THE EXHAUST MANIFOLD WHEN
BLEEDING AIR FROM THE FUEL SYSTEM.

Some air enters the fuel system when the fuel fil-

ter or injection pump supply line is changed. This
small amount of air is vented automatically from the
injection pump through the fuel drain manifold tubes
if the filter was changed according to instructions.
Ensure the the fuel filter/water separator is full of
fuel

It may be necessary to manually bleed the system

if:

• The bowl of the fuel filter/water separator is not

partially filled before installation of a new filter

• The injection pump is replaced

• High–pressure fuel line connections are loosened

or lines replaced

• Initial engine start–up or start–up after an

extended period of no engine operation

• Running fuel tank empty

FUEL INJECTION PUMP BLEEDING

(1) If the fuel injection pump has been replaced,

air should be bled at the overflow valve before
attempting to start engine.

(a) Loosen the overflow valve (Fig. 18) at the

rear of the injection pump.

(b) Place a towel below the valve.

Fig. 17 Typical Fuel Pressure Test at Injection Pump

1 – FITTING
2 – HIGH PRESSURE LINE
3 – CARDBOARD

Fig. 18 Overflow Valve

1 – FUEL INJECTION PUMP ASSEMBLY
2 – FUEL RETURN LINE
3 – FUEL SUPPLY LINE
4 – FUEL INJECTION PUMP 10–WAY CONNECTOR
5 – TIMING SOLENOID
6 – OVERFLOW VALVE

14 - 12

FUEL SYSTEM—3.1L DIESEL ENGINE

DIAGNOSIS AND TESTING (Continued)

2000 JEEP GRAND CHEROKEE

WARNING: WHEN

CRANKING

THE

ENGINE

BLEED AIR FROM THE INJECTION PUMP, THE
ENGINE MAY START. PLACE THE TRANSMISSION
IN NEUTRAL OR PARK AND SET PARKING BRAKE
BEFORE ENGAGING THE STARTER MOTOR.

CAUTION: Do not engage the starter motor for
more than 30 seconds at a time. Allow 2 minutes
between cranking intervals.

(2) Crank the engine for 30 seconds at a time to

allow air trapped in the injection pump to vent out
the fuel injector drain tubes. Continue this procedure
until the engine starts. Observe the previous WARN-
ING and CAUTION.

(3) Tighten overflow valve.

HIGH–PRESSURE FUEL LINE BLEEDING

WARNING: THE INJECTION PUMP SUPPLIES HIGH-
–PRESSURE FUEL OF APPROXIMATELY 45,000 KPA
(6,526

PSI)

EACH

INDIVIDUAL

INJECTOR

THROUGH

THE

HIGH–PRESSURE

LINES.

FUEL

UNDER THIS AMOUNT OF PRESSURE CAN PENE-
TRATE THE SKIN AND CAUSE PERSONAL INJURY.
WEAR SAFETY GOGGLES AND ADEQUATE PRO-
TECTIVE CLOTHING AND AVOID CONTACT WITH
FUEL SPRAY WHEN BLEEDING HIGH–PRESSURE
FUEL LINES.

WARNING: DO NOT BLEED AIR FROM THE FUEL
SYSTEM OF A HOT ENGINE. DO NOT ALLOW FUEL
TO SPRAY ONTO THE EXHAUST MANIFOLD WHEN
BLEEDING AIR FROM THE FUEL SYSTEM.

Bleed air from one injector at time.
(1) Loosen the high–pressure fuel line fitting at

the injector (Fig. 19).

(2) Crank the engine until all air has been bled

from the line. Do not operate the starter motor
for longer than 30 seconds. Wait 2 minutes
between cranking intervals.

(3) Start the engine and bleed one injector at a

time until the engine runs smoothly.

FUEL INJECTION PUMP TIMING

Refer to the Fuel Injection Pump Removal and

Installation procedure in Service Procedures later in
this Group.

REMOVAL AND INSTALLATION

AIR CLEANER ELEMENT

REMOVAL

(1) Loosen 4 clamps holding air cleaner housing

halves together.

(2) Remove top of air cleaner housing.
(3) Remove element from air cleaner housing.

INSTALLATION

(1) Install a new element in housing.
(2) Position housing halves together.
(3) Snap clamps into place.

FUEL DRAIN TUBES

The fuel drain tubes (Fig. 20) are low–pressure

type.

Pull each tube from the injector for removal. Push

on for installation. Clamps are not required for these
tubes.

FUEL FILTER/WATER SEPARATOR

The fuel filter/water separator is located in the

engine compartment on the left side behind the gen-
erator (Fig. 21).

Fig. 19 Bleeding High–Pressure Fuel Line—Typical

1 – FUEL INJECTOR
2 – LINE FITTING
3 – HIGH-PRESSURE FUEL LINE
4 – FUEL DRAIN TUBES

FUEL SYSTEM—3.1L DIESEL ENGINE

14 - 13

SERVICE PROCEDURES (Continued)

2000 JEEP GRAND CHEROKEE

The fuel filter/water separator assembly contains

the fuel filter, fuel heater element, and fuel drain
valve.

DRAINING WATER FROM FILTER BOWL

Moisture (water) collects at the bottom of the filter/

separator in a plastic bowl. Water entering the fuel
injection pump can cause serious damage to the
pump. Note that the bulb will be illuminated for
approximately 2 seconds each time the key is
initially placed in the ON position. This is done
for a bulb check.

WARNING: DO NOT ATTEMPT TO DRAIN WATER
FROM THE FILTER/SEPARATOR WITH THE ENGINE
HOT.

(1) The bottom of the filter/separator bowl is

equipped with a drain valve. The drain valve is
equipped with a fitting. Attach a piece of rubber hose
to this fitting. This hose is to be used as a drain
hose.

(2) Place a drain pan under the drain hose.
(3) With the engine not running, open the drain

valve (unscrew—drain valve has right hand threads)
from the filter/separator bowl. To gain access to this
fitting, the two filter–to–mounting bracket nuts may
have to be loosened a few turns.

(4) Hold the drain open until clean fuel exits the

drain.

(5) After draining, close drain valve.
(6) Remove rubber drain hose.
(7) Dispose of mixture in drain pan according to

applicable local or federal regulations.

FUEL FILTER REMOVAL

(1) Drain all fuel and/or water from fuel filter/wa-

ter separator assembly. Refer to the previous Drain-
ing Water From Filter Bowl.

(2) Unplug the electrical connectors at bottom of

plastic bowl.

(3) Remove plastic bowl from bottom of fuel filter

(unscrews).

(4) Remove fuel filter from bottom of filter base

(unscrews).

FUEL FILTER INSTALLATION

(1) Clean bottom of fuel filter base.
(2) Apply clean diesel fuel to new fuel filter gasket.
(3) Install and tighten filter to filter base. The bev-

eled part of the rubber gasket should be facing up
towards the filter base.

(4) Clean the inside of bowl with a soap and water

mixture before installation. Carefully clean any resi-
due between the two metal probes at the top of the
water–in–fuel sensor. Do not use chemical cleaners
as damage to the plastic bowl may result.

Fig. 20 Fuel Injectors and Drain Tubes

1 – FUEL DRAIN TUBES
2 – FUEL INJECTORS
3 – FITTING AT PUMP

Fig. 21 Fuel Filter / Water Separator Position &

Orientation

1 – FUEL FILTER/WATER SEP. RETAINING NUTS
2 – FUEL PRIMING PUMP
3 – FUEL LINE FROM TANK
4 – FUEL FILTER
5 – FUEL LINE TO INJECTION PUMP
6 – FUEL FILTER/WATER SEPARATOR

14 - 14

FUEL SYSTEM—3.1L DIESEL ENGINE

REMOVAL AND INSTALLATION (Continued)

2000 JEEP GRAND CHEROKEE

(5) Pour diesel fuel into the plastic bowl before

installing bowl to bottom of fuel filter. Do this to help
prevent air from entering fuel injection pump while
attempting to starting engine.

(6) Install filter bowl to bottom of filter.
(7) Install the electrical connectors at bottom of

bowl.

(8) Tighten the filter–to–mounting bracket nuts

(Fig. 21) to 28 N·m (250 in. lbs.) torque.

FUEL HEATER

If the fuel heater element needs replacement, the

plastic filter bowl assembly must be replaced. Refer
to Fuel Filter/Water Separator for information.

FUEL HEATER RELAY

The fuel heater relay is located in the PDC. For

the location of the relay within the PDC (Fig. 22),
refer to label on PDC cover.

FUEL LEVEL SENSOR

The fuel level sensor is located on the side of the

fuel pump module.

REMOVAL

(1) Remove fuel tank. Refer to Fuel Tank Removal/

Installation.

(2) Remove fuel pump module. Refer to Fuel Pump

Module Removal/Installation

(3) Remove electrical wire connector at sending

unit terminals.

(4) Press on release tab (Fig. 23) to remove level

sensor from the pump module.

FUEL INJECTION PUMP

REMOVAL

(1) Disconnect the negative battery cable.
(2) Remove the intake air duct retaining bolts

from the top of the intake manifold.

(3) Disconnect the intercooler outlet hose from the

intercooler.

(4) Remove the engine intake air duct and hose

assembly from the vehicle.

(5) Remove the engine accessory drive belt. Refer

to Group 7, Cooling System for the procedure.

(6) Remove the generator assembly. Refer to Group

8C, Charging System for the procedure.

(7) Thoroughly the clean the area around the

injection pump and fuel lines of all dirt, grease and
other contaminants. Due to the close internal tol-
erances of the injection pump, this step must be
performed before removing pump.

(8) Remove the rubber fuel return and supply

hoses from the metal lines at the pump (Fig. 24).

(9) Disconnect the engine coolant temperature sen-

sor electrical connector (Fig. 25). Located closest to
the injection pump.

(10) Disconnect the Fuel Injection Pump electrical

connector at the pump. (Fig. 24).

(11) Disconnect the main engine wiring harness

from the glow plugs.

CAV

COLOR

FUNCTION

RD/TN

FUSED B(+)

IGNITION SWITCH
OUTPUT

GROUND

RD/BK

FUEL HEATER
RELAY OUTPUT

Fig. 22 Power Distribution Center (PDC)

Fig. 23 Fuel Level Sensor Release Tab

1 – ELECTRICAL CONNECTOR
2 – FUEL LEVEL SENSOR
3 – RELEASE TAB
4 – FUEL RESERVOIR MODULE

FUEL SYSTEM—3.1L DIESEL ENGINE

14 - 15

REMOVAL AND INSTALLATION (Continued)

2000 JEEP GRAND CHEROKEE

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