1999 JAGUAR S TYPE fuel

ContentsAJ-V6/AJ28
1 G Gl
lo
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sa
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Abbreviations 2
I In
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3
V V6
6
E
En
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gi
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e
Introduction 4
Engine Specifications 5
Basic Engine 6
Cylinder Head Assembly 8
Exhaust Manifold 12
Engine Mountings 12
Lubrication System 13
Crankcase Ventilation 15
Exhaust Gas Re-circulation (EGR) 17
Variable Valve Timing (VVT) 19
Air Induction System 21
Throttle Control System 25
Fuel System 29
Ignition System 30
Engine Cooling 31
Front End Accessories Drive 37
Engine Management Sensors 40
V V8
8
E
En
ng
gi
in
ne
e
Introduction 45
Basic Engine 46
Cooling System 49
Air Induction System 51
Variable Valve Timing (VVT) 53
Engine Management Sensors 54
Ignition System 54
Fuel Injection 56
Front End Accessories Drive 59
A Au
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om
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Tr
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Introduction 61
Specification 61
Construction and Operation 63
M Ma
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Tr
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Introduction 64
Specification 64
Gear Selector Control 65
Flywheel and Clutch 65
Clutch Pedal Assembly 68
P Po
ow
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M
Ma
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Introduction 69
Powertrain Control Module (PCM) 69
Subject Page

Glossary
2The following abbreviations are used in this document:
A Ab
bb
br
re
ev
vi
ia
at
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on
nD
De
es
sc
cr
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ip
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AAC air assisted (injection) control valve
AAI air assisted injection
ABDC after bottom dead centre
A/C air conditioning
AH amp-hour
API American Petroleum Institute
APP accelerator pedal position (sensor)
ATDC after top dead centre
bank 1 A bank
bank 2 B bank
BBDC before bottom dead centre
BTDC before top dead centre
ûC degree Celsius
CHT cylinder head temperature (sensor)
CKP crankshaft position (sensor)
CMP camshaft position (sensor)
ECT engine coolant temperature (sensor)
EFT engine fuel temperature (sensor)
EGR exhaust gas recirculation
EMS engine management system
EOP engine oil pressure (sensor)
EOT engine oil temperature (sensor)
EVAP evaporative emission
ûF degrees Fahrenheit
HO2 heated oxygen (sensor)
Hz Hertz (cycles per second)
IAT intake air temperature (sensor)
IMT intake manifold tuning (valve)
IP injector pressure (sensor)
JTIS Jaguar Technical Information System
KS knock sensor (sensor)
LH lefthand
MAF mass air flow (sensor)
N/A normally aspirated
NAS North American specification
OBDII on-board diagnostics stage 2
PAS power assisted steering
PCM powertrain control module
PCV positive crankcase ventilation
PWM pulse width modulated
RH righthand
RPM revolutions per minute
SAE Society of Automotive Engineers (USA)
SCP standard corporate protocol
TAC throttle actuator control (module)
TP throttle position (sensor)
VVT variable valve timing
W watts
AJ-V6/AJ28

IntroductionAJ-V6/AJ28
3 The new S-TYPE sports sedan has an in-line powertrain and rear wheel drive configuration and is
available with either a 3 Litre V6 or a 4 Litre V8 engine, both normally aspirated. The V6 engine,
designated AJ-V6 is new to the Jaguar range and provides expected Jaguar levels of performance with
smooth power delivery, economy and excellent torque characteristics across the engine speed/load
range. The engine is of a lightweight but rigid design with particular attention paid to minimising noise
and vibration. A major innovation is the use of a variable geometry air intake manifold, which is
controlled, via valves, by the engine management system and produces optimised volumetric efficiency
at all engine speeds. Two stage variable valve timing is also fitted and both systems are optimised
together to achieve the wide torque delivery at all engine speeds.
The V8 engine, designated AJ28, is a developement of the now established engine fitted to the
successfull XK Series sports and XJ Series sedan and incorporates the latest modifications fitted to the
AJ27 variant, in particular the continuously variable valve timing system and air assisted fuel injection.
Both the V6 and V8 engines are fitted with a new, common, electronic throttle which does not require a
mechanical cable. Another new feature, also common to both engines, is the use of a returnless fuel
system to reduce the formation of fuel vapour (evaporative emissions).
A new 5-speed automatic transmission is fitted (with slight differences) to both engines. In certain
markets only, an optional 5-speed manual transmission, with new self-adjusting clutch, is available for
the V6 engine only.
Both engines and the automatic transmission are controlled by a completely new powertrain control
system.

4
Introduction
D.303.1201
AJ-V6 ENGINEThe AJ-V6 is a water cooled six cylinder engine
configured as two banks of cylinders in a 60û V
formation. Valve operation is via chain driven
double overhead camshafts on each cylinder
bank. The engine is naturally aspirated but with a
unique air intake system which significantly
improves power output. Lightweight materials are
used extensively but the structural design is such
as to maintain a strong rigid assembly.The main features of the power unit are:
¥ three stage variable geometry intake manifold
¥ electronic throttle with cable-less operation
¥ two position variable valve timing
¥ returnless fuel system
¥ fail safe cooling system
V6 Engine
D.303.1202D.303.1201 &1202
AJ-V6/AJ28

V6 EngineAJ-V6/AJ28
17
Exhaust Gas Re-circulation (EGR)
Operation
The EGR system is only fitted to vehicles in NAS
markets and comprises the following
components:
¥ EGR vacuum regulator valve
¥ EGR valve
¥ differential pressure feedback EGR sensor
¥ exhaust gas feedback pipe with internal
orifice
Exhaust gas is re-circulated back to the engine
intake in proportion to a measured pressure
differential in the feedback pipe. The amount of
gas re-circulated varies primarily with engine
speed and load but is also modified by the EMS to
allow for other factors, eg coolant temperature,
and also to achieve optimum emissions and fuel
economy.
The re-circulated exhaust gas is taken from the A
bank exhaust manifold and fed into the engine via
the EGR valve. The feedback pipe contains an
internal tube with a small diameter orifice that
creates a pressure differential in the feedback
pipe. Two small pipes, connected to the feedbackpipe each side of the orifice, transmit the pressure
differential to the differential pressure feedback
EGR sensor.
The sensor consists of a transducer (a vacuum
operated variable capacitor) and a processing
circuit which convert the input pressure/vacuum
value to a corresponding analogue voltage which is
sent to the PCM. The differential pressure feedback
EGR sensor has a linear response and the
variations in exhaust pressure produce outputs in
the approximate range 1V- 3.5V dc.
The EGR vacuum regulator valve and the EGR
valve comprise the actuating components of the
control loop. The EGR vacuum regulator valve has
a vacuum input from the manifold distribution
pipes, a vacuum output to the EGR valve and
receives a pulse width modulated (PWM) signal
from the PCM. The PWM signal switches the
vacuum control output to the EGR valve according
to input demand from the differential pressure
feedback EGR sensor or in response to override
conditions determined by the engine management
system. The EGR valve is a vacuum operated
EGR SYSTEM
J.303.1282
Exhaust Gas
Feedback Pipe
Differential Pressure
Feedback EGR sensor
EGR Vacuum
Regulator Valve
EGR valve
Orifice

V6 EngineAJ-V6/AJ28
21
Air Induction System
range, the manifold geometry can be set to three
different configurations, each of which maximises
the tuning effect over different parts of the range.
This variable geometry is achieved by the use of
two gate valves, the intake manifold tuning (IMT)
valves, which are controlled by the engine
management system.Air Intake
The air induction system consists of the intake
ducting and air cleaner, the throttle body, tuned
manifold assembly and lower manifold (see Fuel
System).
The air cleaner connects to the throttle body via a
lateral mounted intake pipe with resonator box. A
separate duct, housing the MAF sensor, fits
between the air cleaner and resonator pipe. The
IAT sensor is located in the intake resonator pipe.
Variable Intake System
(see illustration on page 23)
The induction manifold is specially designed to
optimise torque across the engine speed/load
range. The air charge enters the induction
manifold from the throttle body and passes
through a plenum chamber for distribution to the
cylinders via the manifold runners. The function
of the plenum chamber is to provide a resonance
(or maximising) effect such that large pulses of
charge air are produced which will arrive at the
inlet ports at the correct time for induction into
the cylinders. This ram charging action is only
effective over a restricted speed/load range for a
particular plenum chamber volume and geometry.
To extend the effect over the whole engine speed
J.303.1379
AIR INTAKE
J.303.1379
Air CleanerIntake DuctingMAF Sensor
IAT SensorThrottle Body
Tuned Manifold Assembly

V6 EngineAJ-V6/AJ28
29
D.303.1215
FUEL RAIL AND LOWER INTAKE MANIFOLD
Fuel Supply
D.303.1215
EFT Sensor
De-pressurisation
Valve
IP Sensor
Fuel System
Returnless Fuel System
The returnless fuel system is a one way system
which delivers fuel to the engine without the
requirement for fuel to be returned to the tank.
When a return line is used, the effects of fuel
pressurisation, de-pressurisation and engine heat
on the returning fuel causes extra vapour to be
generated in the tank. With increasing regulatory
controls on evaporative emissions, this is an
undesirable condition and elimination of a fuel
return line provides significant benefits.
The in-tank fuel pump supplies fuel and regulates
pressure to the injectors under control of the PCM
and the rear electronic module (REM) and a
pressure regulator is not therefore required on the
engine fuel rail. To provide feedback for closed
loop control, an injector pressure (IP) sensor on
the fuel rail detects the pressure differentialbetween the fuel and the intake manifold and the
engine fuel temperature (EFT) sensor monitors
fuel temperature. Analogue signals from both
sensors are sent to the PCM to indicate the
pressure of the fuel and to detect whether it has
reached the vapourisation point. In response to
the sensor inputs and driver or load demands, the
PCM requests the pump system to vary the fuel
flow; in particular, fuel pressure will always be
increased to avoid vapour formation and to
maintain flow through the injectors.
Fuel pump control is further described in the
ÔS-TYPE IntroductionÕ Technical Guide.
Fuel Rail and Lower Intake Manifold
The fuel injectors are seated in two lower intake
manifolds, made of a lightweight plastic
composite material, which are fitted between the
Fuel Rail
Lower Intake
Manifold

Ignition System
V6 Engine AJ-V6/AJ28
30cylinder heads and the upper intake manifold
assembly.
The injectors are of the top fed, split spray type
and are supplied from a common fuel rail
assembly which bolts to the lower manifold. The
integral fuel rail consists of an upper delivery pipe
and a lower pipe with six takeoff feeds for the
injectors. The IP sensor is bolted to a flange at the
junction of the two pipes and has an electrical
connection to the fuel rail harness and a vacuum
feed from the intake manifold. A steel cross-over
pipe provides the coupling to the vehicle
mounted fuel line and also carries the EFT sensor,
on a bracket, and the de-pressurisation valve. The
cross-over pipe is connected to the fuel rail via a
semi-rigid length of pipe.
All fuel injectors and sensors use a common
electrical harness with a single multi-way
connection to the main engine harness.
Six coil-on-plug ignition units fit directly on to the
spark plugs. The ignition units are driven by the
PCM and do not contain integral amplifiers.
D.303.1206D.303.1206
COIL-ON-PLUG UNITS