1999 JAGUAR S TYPE sensor

V6 Engine AJ-V6/AJ28
42
J.303.1291
KS SENSORS
J.303-1291
Knock (KS) Sensors
Two ÔdonutÕ type knock sensors are fitted, in
assymetrical positions. The bank 2 sensor is
located on top of the block near the oil separator
and the bank 1 sensor is fixed on the RH side of
the block above the starter motor.
D.303.1292
CMP SENSOR
D.303-1292
Camshaft Position (CMP) Sensors
Each inlet camshaft has a four tooth sensor ring
pressed on to the rear end of the camshaft with
the inductive sensor projecting through a hole in
the cylinder head behind and in line with the
sensor ring teeth. The use of a four tooth ring
enables the sensor to provide increased feedback
(position indication of each cylinder).

V6 EngineAJ-V6/AJ28
43 Intake Air Temperature (IAT) Sensor
The IAT sensor is a conventional thermistor type
device which is a push fit in the intake resonator
duct.
Mass Air Flow (MAF) Sensor
The MAF sensor is an integral assembly consisting
of a hot wire sensor unit and air duct and is non-
serviceable. The assembly is fitted between the air
cleaner and intake resonator tube.
D.303.1381
MAF AND IAT SENSORS
D.303-1381
J.303.1386
HO2 SENSORS
J.303-1386
Heated Oxygen (HO2) Sensors
HO2 sensors are fitted in both the upstream and
downstream positions on the catalytic converters.
Both sensors are standard types with a step
response at the stoichiometric (lambda) air/fuel
value. The upstream sensors provide the feedback
for stoichiometric fuelling control and the
downstream sensors monitor catalyst efficiency
and also provide long term fuelling adaptation
trim.
MAF SensorIAT Sensor

V8 EngineAJ-V6/AJ28
45
Introduction
The AJ28 engine is a variant of the 4.0L 90û V8 units fitted to the XJ and XK range of vehicles. The AJ28
shares some of the changes incorporated in the current AJ27 engine: both engines are derived from the
original AJ26 unit. A number of features are unique to the AJ28 or are shared with the AJ-V6 engine also
described in this publication.
Features of the AJ28 engine are:
¥ Continuously variable inlet valve timing over a 48û
+
-2û crank angle: as fitted to the AJ27 engine
¥ Full authority cable-less electronic throttle control: as fitted to the AJ-V6 engine
¥ Air assisted fuel injection: similar to system used on the AJ27 engine
¥ Unique induction manifold with centrally mounted throttle body
¥ Returnless fuel system: similar to AJ-V6 engine
¥ Twin wall exhaust manifold
¥ Engine management system as used on the AJ-V6
¥ New sensors
¥ Modified sump and oil cooler
¥ Modified front end ancillary drive and components
Engine Specification
Maximum power DIN - 209 kW (281 BHP) at 6100 RPM
EEC - 203 kW (276 PS) at 6100 RPM
Maximum torque DIN - 390 Nm (287 lbft) at 4300 RPM
EEC - 278 Nm (279 lbft) at 4300 RPM
Oil Specification
All markets except the USA and Canada
Engine oil for all markets except the USA and
Canada must be to API specification SJ/ACEA A1
or A3.
The recommended SAE viscosity for different
ranges of ambient temperature are shown in
table 1.
USA/Canada
Engine oil for USA and Canada must be to API
specification SJ/ILSAC GF-2.
The recommended SAE viscosity for different
ranges of ambient temperature are shown in
table 2. For maximum economy and in most
climate conditions, SAE 5W/30 is to be preferred
but SAE 10W/30 or 15W/40 are acceptable in
moderate to hot climates.
JOL.29550
50JOL.296
SAE/TEMPERATURE TABLE 2
SAE/TEMPERATURE TABLE 1

V8 Engine AJ-V6/AJ28
46
Basic Engine
Bottom End
Changes to the cylinder block, connecting rods
and pistons which were introduced for the AJ27
N/A engine are also applicable to the AJ28 unit
and are described in the ÔXK and XJ series 1999
MY updateÕ Technical Guide.
Oil Sump Body and Pan
A revised oil sump body and sump pan are
necessary to accommodate the V8 engine in the
S-TYPE model but the sump capacity is
unchanged.
D.303.1184
OIL SUMP AND PAN
D.303-1184
J.303.1317
TRANSMISSION DRIVE PLATE
J.303.1317
Transmission Drive Plate
The transmission drive plate is similar to AJ27 but
is fixed with eight bolts to an adaptor plate on the
torque converter (see Transmission sections). The
crankshaft sensor ring is fitted to the engine side
of the drive plate as for the previous V8 engines.

V8 EngineAJ-V6/AJ28
47
Cylinder Head
The cylinder head incorporates the modifications
first introduced for the AJ27 engine except for the
camshaft sensor ring and cam cover.
Camshaft Sensor Ring
Cam position sensing is similar to that used on the
AJ27 engine, except that the sensor ring fitted to
each inlet camshaft has five triggering teeth.
Camshaft Covers
To improve accessibility, an extension tube is
fitted to the oil filler hole on the bank 2 cam
cover. Due to the position of the throttle and air
intake ducting, the part load breather outlet is
taken from bank 1 cam cover and the full load
breather outlet from bank 2 (the reverse of AJ27).
Front Cover
The front cover is modified from the AJ27 to
include a mounting boss for a new idler pulley
(see Front End Accessories Drive).
Lubrication
The lubrication system includes the uprated oil
pump (for the linear VVT system) and the same oil
temperature sensor as fitted to the AJ27 engine.
The oil sump and pan are modified as described
on page 46.
The external oil system components are located
laterally across the front of the sump body and
consist of an oil filter, oil cooler and oil filter head
assembly. The oil cooler is an oil to water heat
exchanger similar to the V6 oil cooler and the
cooler matrix is also connected via hoses to a
circulator orifice in the radiator bottom hose (see
Cooling System). The oil filter screws on to the
cooler which connects to the sump body through
an adaptor, the oil filter head assembly.
J.303.1189
CAMSHAFT SENSOR RING
D.303.1189
D.303.1185
CAMSHAFT COVER/OIL FILLER
D.303.1185
D.303.1186
OIL FILTER, COOLER AND ADAPTOR
D.303.1185
Oil temperature sensor
Oil pressure switch
Oil Cooler

V8 EngineAJ-V6/AJ28
49
Cooling System
The AJ28 engine retains the same basic cooling
system as the previous V8 engines but shares the
radiator, fan shroud assembly, de-gas circuit and
bottom hose oil cooler circulator features with the
V6. The coolant specified for the V6 is also
applicable to the V8 engine.
Particular features of the AJ28 cooling system are:
¥ The thermostat is located in the engine
mounted housing as in previous V8 engines.
¥ The thermostat housing is modified with an
extra stub pipe for the new heater returnhose.
¥ The throttle adaptor is heated from the main
cooling system to provide throttle de-icing.
¥ Both heater hoses, feed and return, are now
routed forward to the heater control valve.
¥ An electric pump is fitted in the heater
coolant circuit (ÔS-TYPE IntroductionÕ
Technical Guide).
¥ The coolant reservoir (de-gas bottle) is fitted
with a level sensor which provides a low level
warning on the instrument panel message
J.303.1366
V8 ENGINE COOLING SYSTEM
1. Radiator
2. Top hose
3. Bottom hose
4. Thermostat
5. Coolant pump6. Engine oil cooler
7. Reservoir bottle
8. Electronic throttle
9. V8 engine
10. AC/heater pump
110512
9
4
6
2
3
8
7
J.303.1365
11
13
11. Heater control valve
12. AC/heater unit
13. Bleed

V8 EngineAJ-V6/AJ28
51
Air Induction System
Charge air is supplied to the cylinders via an air
cleaner, induction tube, throttle body, throttle
body adaptor and induction manifold.
The throttle body and system operation is
identical to that of the V6 engine.
Induction Manifold
(see illustration on page 52)
To accommodate the V8 engine in the S-TYPE
model, the throttle body is re-located and now
supplies charge air via an inlet at the top centre of
the induction manifold. The manifold is
manufactured from a plastic material and has an
integral injector air supply tube on each side with
holes for the fuel injectors, but as on the AJ27
engine, the fuel feed pipes are not incorporated
into the manifold (see Fuel System). Two stub
pipes at the top of the manifold provide vacuum
connections for the vacuum hose and the brake
servo hose.
A polypropylene covered foam noise isolation pad
fits between the manifold assembly and the block.Throttle Adaptor
The throttle body is mounted to the induction
manifold via a cast aluminium adaptor. The
throttle body adaptor provides input ports for the
evaporative emissions (top stub) and part load
breather (lower side stub) and also mounts the air
assisted injection control (AAC) valve. Input and
output ports for the side mounted AAC valve are
an integral part of the adaptor casting (the ports
do not connect to the induction airstream).
Throttle de-icing is achieved by a coolant feed
through the base of the adaptor instead of the
throttle body itself as on the V6 engine (see
cooling section).
D.303.1278
AIR INDUCTION LAYOUT
D.303.1278
Air Cleaner
Induction Tube
MAF SensorIAT Sensor
Throttle Body
Throttle Body Adaptor

V8 EngineAJ-V6/AJ28
53
J.303.1359
INDUCTION VACUUM AND AIR SUPPLY CONNECTIONS
J.303.1359
Induction and Vacuum System
Emission and vacuum connections to the
induction system are shown in the illustration
above.Variable Valve Timing (VVT)
The inlet valve timing gear is fitted with the same
continuously VVT system as is used on the AJ27
engine. Operation is as described in the ÔXJ and
XK Series 1999MY UpdateÕ Technical Guide, with
the following variations:
¥ engine management system
¥ PWM solenoid control frequency is 300Hz
¥ the use of five toothed sensor rings for cam
position feedback
Note that the use of this VVT system eliminates
the need for external EGR components.
AAI Valve Inlet
Brake Servo
Vacuum
EVAP Emissions
EVAP Valve
Vacuum Control
Part Load
Breather
IP Sensor
Vacuum
Full Load
Breather