pedal. When the ignition (key) switch is OFF, the
solenoid is shut off and fuel flow is not allowed to the
fuel injection pump. When the key is placed in the
ON or START positions, fuel supply is allowed at the
injection pump.

FUEL REQUIREMENTS—3.1L DIESEL

DESCRIPTION

Premium quality diesel fuel with a minimum Cet-

ane rating of 50 or higher is required.

FUEL SYSTEM—3.1L DIESEL ENGINE

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2000 JEEP GRAND CHEROKEE

FUEL DELIVERY SYSTEM—3.1L DIESEL ENGINE

TABLE OF CONTENTS

page

DESCRIPTION AND OPERATION

LOW-PRESSURE TYPE . . . . . . . . . . . . . . . . . . . 5

HIGH-PRESSURE FUEL LINES . . . . . . . . . . . . . . . 6
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . 2
QUICK-CONNECT FITTINGS—LOW

PRESSURE TYPE. . . . . . . . . . . . . . . . . . . . . . . . 6

DIAGNOSIS AND TESTING

AIR IN FUEL SYSTEM . . . . . . . . . . . . . . . . . . . . . . 9
FUEL HEATER RELAY TEST . . . . . . . . . . . . . . . . 10
FUEL INJECTION PUMP TEST . . . . . . . . . . . . . . . 11
FUEL INJECTOR / NEEDLE MOVEMENT

SENSOR TEST . . . . . . . . . . . . . . . . . . . . . . . . . 10

FUEL INJECTOR TEST . . . . . . . . . . . . . . . . . . . . 10
FUEL SHUTDOWN SOLENOID TEST . . . . . . . . . . 11
FUEL SUPPLY RESTRICTIONS . . . . . . . . . . . . . . 11
GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . 7
HIGH-PRESSURE FUEL LINE LEAK TEST . . . . . . 11
VISUAL INSPECTION. . . . . . . . . . . . . . . . . . . . . . . 7

SERVICE PROCEDURES

AIR BLEED PROCEDURES . . . . . . . . . . . . . . . . . 12
FUEL INJECTION PUMP TIMING . . . . . . . . . . . . . 13

REMOVAL AND INSTALLATION

SPECIFICATIONS

FUEL INJECTOR FIRING SEQUENCE . . . . . . . . . 22
FUEL SYSTEM PRESSURE . . . . . . . . . . . . . . . . . 22
FUEL TANK CAPACITY . . . . . . . . . . . . . . . . . . . . 22
IDLE SPEED . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

DESCRIPTION AND OPERATION

INTRODUCTION

This Fuel Delivery section will cover components

not controlled by the PCM. For components con-
trolled by the PCM, refer to the Fuel Injection Sys-
tem—3.1L Diesel Engine section of this group.

The fuel heater relay, fuel heater and fuel gauge

are not operated by the PCM. These components are
controlled by the ignition (key) switch. All other fuel
system electrical components necessary to operate
the engine are controlled or regulated by the PCM.

FUEL SYSTEM PRESSURE WARNING

DESCRIPTION

WARNING: HIGH–PRESSURE FUEL LINES DELIVER
DIESEL FUEL UNDER EXTREME PRESSURE FROM
THE INJECTION PUMP TO THE FUEL INJECTORS.
THIS MAY BE AS HIGH AS 45,000 KPA (6526 PSI).
USE EXTREME CAUTION WHEN INSPECTING FOR

HIGH–PRESSURE

FUEL

LEAKS.

INSPECT

FOR

HIGH–PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD

(Fig.

1).

HIGH

FUEL

INJECTION

PRESSURE CAN CAUSE PERSONAL INJURY IF
CONTACT IS MADE WITH THE SKIN.

FUEL TANK

DESCRIPTION

The fuel tank and tank mounting used with the

diesel powered engine is the same as used with gas-
oline powered models, although the fuel tank module
is different.

The fuel tank contains the fuel tank module and

one rollover valve. Two fuel lines are routed to the
fuel tank module. One line is used for fuel supply to
the fuel filter/water separator. The other is used to
return excess fuel back to the fuel tank.

The fuel tank module contains the fuel gauge elec-

trical sending unit. An electric fuel pump is not
used with the diesel engine.

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FUEL SYSTEM—3.1L DIESEL ENGINE

2000 JEEP GRAND CHEROKEE

FUEL TANK MODULE

DESCRIPTION

An electric fuel pump is not attached to the fuel

tank module for diesel powered engines. Fuel is
drawn by the fuel injection pump.

The fuel tank module is installed in the top of the

fuel tank. The fuel tank module contains the follow-
ing components:

• Fuel reservoir

• Electric fuel gauge sending unit

• Fuel supply line connection

• Fuel return line connection

• Wire harness

• Fuel inlet filter (Strainer)

FUEL GAUGE SENDING UNIT

DESCRIPTION

The fuel gauge sending unit is attached to the side

of the fuel pump module. The sending unit consists of
a float, an arm, and a variable resistor (track). The
track is used to send an electrical signal used for fuel
gauge operation.

As the fuel level increases, the float and arm move

up. This decreases the sending unit resistance, caus-
ing the PCM to send a signal to the fuel gauge on the
instrument panel to read full. As the fuel level
decreases, the float and arm move down. This

increases the sending unit resistance, causing the
PCM to send a signal to the fuel gauge on the instru-
ment panel to move toward empty.

FUEL FILTER/WATER SEPARATOR

The fuel filter/water separator is located in the

engine compartment on the left side behind the gen-
erator (Fig. 2).

The combination fuel filter/water separator pro-

tects the fuel injection pump by helping to remove
water and contaminants from the fuel. Moisture col-
lects at the bottom of the filter/separator in a plastic
bowl.

The fuel filter/water separator assembly contains

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

For information on the fuel heater, refer to Fuel

Heater in this group.

Refer to the maintenance schedules in Group 0 in

this manual for the recommended fuel filter replace-
ment intervals.

For periodic draining of water from the bowl, refer

to Fuel Filter/Water Separator Removal/Installation
in this group.

Fig. 1 Typical Fuel Pressure Test at Injection Pump

1 – FITTING
2 – HIGH PRESSURE LINE
3 – CARDBOARD

Fig. 2 Fuel Filter/Water Separator Location

1 – FUEL FILTER/WATER SEPARATOR
2 – FUEL FILTER/WATER SEPARATOR RETAINING NUTS
3 – FUEL INLET HOSE
4 – ELECTRICAL CONNECTORS
5 – FUEL OUTLET HOSE

FUEL SYSTEM—3.1L DIESEL ENGINE

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DESCRIPTION AND OPERATION (Continued)

2000 JEEP GRAND CHEROKEE

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