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.

CONDITION

POSSIBLE CAUSES

CORRECTION

No Start/Hard Start/Start

and Stall

Contaminated Fuel

Drain, Flush and Refill Fuel
System

Low Fuel Pressure to Fuel Filter

Test Fuel Pump Pressure

Restricted Fuel Filter

Replace Fuel Filter

Fuel Heater Inoperative

Test Fuel Heater and circuitry

Restricted or Leaking Fuel Lines

Inspect/ Replace necessary fuel
line(s)

Stored Diagnostic Trouble Codes

Refer to the appropriate
Diagnostic Service Manual

Stalls Under Aggressive

Maneuvers/Loss Of Fuel

Pressure

Restricted or Damaged Fuel Pump
Lower Filter

Test Fuel Pump Pressure

Contaminated Fuel

Drain, Flush and Refill Fuel
System

Damaged Fuel Tank

Replace Fuel Tank

14 - 6

FUEL DELIVERY

CONDITION

POSSIBLE CAUSES

CORRECTION

Restricted Fuel Filter

Replace Fuel Filter

Cannot Refill Fuel

Tank/Excessive Pressure in

Fuel Tank When Cap Is

Removed

Sticking or Damaged Fuel Tank
Fill/Vent Valve

Replace Fuel Tank

Restricted or Damaged Fuel Tank
Fill/Vent Valve Filter or Hose

Replace Fuel Tank Vent Filter

FUEL DRAIN TUBES

DESCRIPTION

The fuel drain tubes connect to the top of all four

injectors (Fig. 1). These tubes are used to return
unused fuel from the fuel injectors to the fuel filter.

FUEL INJECTION PUMP

DESCRIPTION

The fuel injection pump is a radial piston pump

with three pistons arranged at an angle of 120°. The
injection pump is driven by the intake camshaft. The
pump is mounted to the rear of the cylinder head
(Fig. 2).

OPERATION

LOW PRESSURE SIDE

The fuel supplied by the fuel delivery pump flows

through the fuel feed to the throttle valve. Any air
entrained by the fuel is directed through the restric-
tor to the return flow. The throttle valve opens
against the force of the spring at a pressure of

Fig. 1 FUEL SYSTEM COMPONENTS

1 - FUEL INJECTOR
2 - FUEL PRESSURE SOLENOID
3 - FUEL RETURN TO FILTER
4 - FUEL RETURN TO INJECTION PUMP
5 - FUEL RAIL
6 - HIGH PRESSURE FUEL LINE FROM PUMP TO RAIL
7 - FUEL PRESSURE SENSOR
8 - HIGH PRESSURE LINE FROM RAIL TO INJECTOR
9 - FUEL DRAIN TUBES

Fig. 2 INJECTION PUMP LOCATION

1 - INJECTION PUMP
2 - VACUUM PUMP
3 - EGR VALVE
4 - CYLINDER HEAD COVER

FUEL DELIVERY

14 - 7

FUEL DELIVERY (Continued)

approx. 0.4 bar and the fuel is able to flow along a
ring line to the individual pistons. The eccentric
shaft with its eccentric plate moves the pistons up
and down against the piston spring of the three
pump elements. The leak fuel from the pistons flows
along the return flow to the fuel tank. The fuel flow-
ing out of the throttle valve, also flows off along the
return flow.

HIGH PRESSURE SIDE

A. Filling the piston: The piston is moved down

as a result of the piston spring. The fuel supplied by
the fuel delivery pump flows along the ring passage,
the valve disk and the valve spring into the cylinder.
The ball valve prevents the fuel from being able to
flow back from the high pressure passage.

B. Producing high pressure:The piston is moved

up by the rising eccentric shaft and the fuel is thus
compressed. The valve disk shuts off the delivery vol-
ume to the fuel feed. Once the fuel pressure in the
cylinder rises beyond the pressure which exists in
the high pressure circuit, the ball valve opens and
the fuel is pumped into the high pressure circuit.

REMOVAL

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

(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE

COVER - REMOVAL).

(3) Disconnect MAF sensor electrical connector.
(4) Disconnect air inlet hose from air cleaner hous-

ing.

(5) Remove air cleaner housing assembly by pull-

ing straight up out of mounts (Refer to 9 - ENGINE/
AIR INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).

(6) Remove fuel line retainer and retaining bolt

from pump. Disconnect fuel supply and return lines
at pump (Fig. 3).

(7) Disconnect high pressure fuel line from pump

to rail at injection pump (Fig. 3).

(8) Remove injection pump retaining bolts and

remove pump from cylinder head (Fig. 4).

Fig. 3 INJECTION PUMP FUEL LINES

1 - RETURN LINE FROM FUEL RAIL
2 - INJECTION PUMP FEED LINE
3 - INJECTION PUMP
4 - HIGH PRESSURE LINE TO FUEL RAIL

Fig. 4 INJECTION PUMP RETAINING BOLTS

1 - INJECTION PUMP
2 - INJECTION PUMP RETAINING BOLTS
3 - HIGH PRESSURE LINE TO FUEL RAIL

14 - 8

FUEL DELIVERY

FUEL INJECTION PUMP (Continued)

INSTALLATION

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

(1) Align injection pump with pump drive and

slide into cylinder head.

(2) Install retaining bolts (Fig. 4). Torque to 14N·m

(124 lbs. in.).

(3) Install fuel supply and return lines to injection

pump (Fig. 3). Install bracket and retaining bolt.
Torque bolt to 9N·m (80 lbs. in.).

(4) Connect high pressure fuel line to fuel rail at

injection pump. Torque line to 22N·m (16 lbs.ft.).

(5) Install air cleaner housing assembly (Refer to 9

- ENGINE/AIR INTAKE SYSTEM/AIR CLEANER
HOUSING - INSTALLATION).

(6) Connect air cleaner inlet hose.
(7) Connect MAF sensor electrical connector.
(8) Connect negative battery cable.

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

(9) Start engine and check for leaks.
(10) Install engine cover (Refer to 9 - ENGINE

COVER - INSTALLATION).

FUEL RAIL

DESCRIPTION

The fuel rail acts like a high pressure store. It is

available to all injectors for drawing fuel which has
been compressed by the injection pump. The rail
pressure sensor, rail pressure solenoid, high pressure
line, and the return flow line are attached to the fuel
rail (Fig. 5).

OPERATION

The stored fuel volume inside the rail acts as a

damper

for

pressure

fluctuations

which

result

because of pulsating supply and brief large extrac-
tions of fuel during injector firing. The rail primarily
influences the atomization of fuel at the injector noz-
zle, and the accuracy of injected quantity during
injection.

Fig. 5 FUEL SYSTEM COMPONENTS

FUEL DELIVERY

14 - 9

FUEL INJECTION PUMP (Continued)

Content .. 215 216 217 218 ..