INSPECTING FOR HIGH - PRESSURE FUEL LEAKS.
FUEL UNDER THIS AMOUNT OF PRESSURE CAN
PENETRATE SKIN CAUSING PERSONAL INJURY
OR DEATH. INSPECT FOR HIGH - PRESSURE FUEL
LEAKS WITH A SHEET OF CARDBOARD. WEAR
SAFETY GOGGLES AND ADEQUATE PROTECTIVE
CLOTHING WHEN SERVICING FUEL SYSTEM.

The fuel system on the 2.5L OR 2.8L Common Rail

Diesel (CRD) Engine uses a high pressure pump and
an Electronic Control Module (ECM). (Fig. 1)

The fuel delivery system consists of the:
• Accelerator pedal

• Air cleaner housing/element

• Fuel filter/water separator

• Fuel heater

• Fuel heater relay

• Fuel/Lift pump

• High Pressure Fuel injection pump

• Fuel injectors

• Fuel tank

• Fuel tank filler/vent tube assembly

• Fuel tank filler tube cap

• Fuel tank module containing fuel tank vent

valves and a fuel gauge sending unit (fuel level sen-
sor).

• Fuel tubes/lines/hoses

• High-pressure fuel injector lines

• Low-pressure fuel supply lines

• Low-pressure fuel return line

• Overflow valve

• Quick-connect fittings

• Water draining

WARNING - HIGH FUEL SYSTEM PRESSURE

WARNING: HIGH-PRESSURE FUEL LINES DELIVER
FUEL UNDER EXTREME PRESSURE FROM THE
INJECTION

PUMP

THE

INJECTORS.

THIS

MAYBE AS HIGH AS 1600BAR (23,200PSI). USE
EXTREME CAUTION WHEN INSPECTING FOR HIGH-
PRESSURE

FUEL

LEAKS.

FUEL

UNDER

THIS

AMOUNT OF PRESSURE CAN PENETRATE SKIN
CAUSING PERSONAL INJURY OR DEATH. INSPECT
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD. WEAR SAFETY GOGGLES AND ADE-
QUATE PROTECTIVE CLOTHING WHEN SERVICING
FUEL SYSTEM.

FUEL SYSTEM

14a - 1

Fig. 1 CRD FUEL SYSTEM

1 - FUEL INJECTOR

8 - HIGH PRESSURE INJECTION PUMP

2 - INJECTOR LUBRACATION POINT

9 - FUEL PRESSURE SOLENOID

3 - HIGH PRESSURE FUEL LINE

10 - INJECTION PUMP FUEL RETURN FITTING

4 - FUEL RAIL

11 - FUEL INJECTOR FUEL RETURN HOSE

5 - FUEL RAIL PRESSURE SENSOR

12 - FUEL FLOW BACK VALVE

6 - FUEL RAIL SUPPLY LINE

13 - WASHER AND O-RING

7 - INJECTION PUMP HIGH PRESSURE OUTLET

14 - FUEL INJECTOR HOLD DOWN

14a - 2

FUEL SYSTEM

FUEL SYSTEM 2.5L / 2.8L TURBO DIESEL (Continued)

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - AIR IN FUEL
SYSTEM

Air will enter the fuel system whenever fuel supply

lines, separator filters, injection pump, high-pressure
lines or injectors are removed or disconnected. Air
trapped in the fuel system can result in hard start-
ing, a rough running engine, engine misfire, low
power, excessive smoke and fuel knock.

Inspect the fuel system from the fuel tank to the

injectors for loose connections (Refer to 14 - FUEL
SYSTEM - WARNING). Leaking fuel is an indicator
of loose connections or defective seals. Air can also
enter the fuel system between the fuel tank and the
injectors because the lift pump only runs to prime
the system. It does not run while the engine is run-
ning. Inspect the fuel tank and fuel lines for damage
or loose connections that might allow air into the sys-
tem.

With the DRBIII

t connected to the vehicle, select

Engine and the select Sensor Display. Page down to
view Fuel Pressure Set Point and Actual Fuel Pres-
sure. Start the engine and observe the Fuel Pressure
Set Point and the Actual Fuel Pressure. If the Actual
Fuel Pressure Oscillates above and below the Fuel
Pressure Set Point in a regular cycle, perform the
Fuel System Air Purge procedure (Refer to 14 -
FUEL SYSTEM - STANDARD PROCEDURE).

If the Actual Fuel Pressure gradually drops below

the Fuel Pressure Set Point then spikes well above
the Fuel Pressure Set Point, replace the fuel pres-
sure solenoid (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/FUEL

PRESSURE

SOLENOID

REMOVAL), then perform the Fuel System Air Purge
procedure (Refer to 14 - FUEL SYSTEM - STAN-
DARD PROCEDURE).

DIAGNOSIS AND TESTING - FUEL SUPPLY
RESTRICTIONS

LOW-PRESSURE LINES

Fuel supply line restrictions or a defective fuel/lift

pump can cause starting problems and prevent
engine from accelerating.

Test all fuel supply lines for restrictions or block-

age. Flush or replace as necessary. Purge fuel system
of air once a fuel supply line has been replaced (Refer
to 14 - FUEL SYSTEM - STANDARD PROCEDURE).

HIGH-PRESSURE LINES

CAUTION: High pressure lines cannot contact each
other or other components. Do not attempt to weld
high-pressure fuel lines or to repair lines that are
damaged. High pressure lines must be replaced at
each disassembly. Use only recommended lines
when replacement of high-pressure fuel line is nec-
essary.

Restricted (kinked or bent) high-pressure lines can

cause starting problems, poor engine performance,
engine mis-fire and white smoke from exhaust (Refer
to 14 - FUEL SYSTEM - WARNING).

DIAGNOSIS AND TESTING - FUEL DELIVERY
SYSTEM

NOTE: Air Intrusion is the most common failure of a
fuel system. If air intrusion is suspect, perform the
Fuel System Air Purge procedure first.(Refer to 14 -
FUEL SYSTEM - STANDARD PROCEDURE).

CONDITION

POSSIBLE CAUSES

CORRECTION

No Start/Hard Start/Start and

Stall

Contaminated Fuel

Drain, Flush and Refill Fuel System

Low Fuel Pressure

Check Fuel/Lift Pump Pressure. Refer to
Fuel Pump Pressure Test in this section

Restricted Fuel Filter

Replace Fuel Filter

Fuel/Lift Pump Relay Inoperative

Test Fuel/Lift Pump Relay, refer to Fuel/Lift
Pump Relay in this section.

Fuel Heater Inoperative

Test Fuel Heater and circuitry. Refer to
Fuel Heater in this section.

Restricted or Leaking Fuel Lines

Inspect/ Replace necessary fuel line(s),
perform Fuel System Air Purge

Stored Diagnostic Trouble Codes

Refer to the appropriate Diagnostic
Service Manual

FUEL SYSTEM

14a - 3

FUEL SYSTEM 2.5L / 2.8L TURBO DIESEL (Continued)

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