1998 JAGUAR X308 body

Engine Emission
Control - Engine Emission Control
D
iagn
osis and Testing
I
n
spection and Verification
1.
1. Veri fy the customer concern.
2. 2. Vis
ually inspect for obvious signs of mechanical
or electrical damage, correct fitment, etc.
Vi
sual Inspection Chart
3.
3. Veri fy the foll
owing syst
ems are working correctly:
Air intake
system
Coo
ling system

Charging system
Fu
el charging system
Ignition sys
t
em
4. 4. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding
to the next step
5. 5. Where the Jaguar approved diagnostic sy stem is available, complete the S93 report before clearing any or all fault
codes from the vehicle.
• NOTE: If a DTC cannot be cleared, then there is a permanent fault present that flag s again as soon as it is cleared (the
exception to this is P1260, which will only clear following an ignition OFF/ON cycle after rectification).
6. 6. If the cause is not visually evident and the Jaguar approv ed diagnostic system is not available, use a fault code
reader to retrieve the fault codes be fore proceeding to the Diagnostic Trou ble Code (DTC) Index Chart, or the
Symptom Chart if no DTCs are set.
7. 7. Using the Jaguar approved diagnostic system where available, and a scan tool where not, check the freeze frame
data for information on the conditions applicable when the fault was flagged. The format of this will vary,
depending on the tool used, but can pr ovide information useful to the technician in diagnosing the fault.
CAUTION: When probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit,
part number 3548-1358-00.
• NOTE: When performing electrical voltag e or resistance tests, always use a digital multimeter (DMM) accurate to 3
decimal places, and with an up-t o-date calibration certificate. When testing resistance, always take the resistance of the
DMM leads into account.
• NOTE: Check and rectify basic faults before beginning diagnostic ro utines involving pinpoint tests.
Sym
ptom Chart
MechanicalElectrical
Engi
ne
oil level
Coo
ling system coolant level

Fue
l
level
Fuel contaminatio
n
/
grade/quality
Throttle body Poly
-ve
e belt
Engine breath
er
system
pipework/connections
EGR pipework
condition (cracking, etc)
F
u
ses
W
i
ring harness
E
l
ectrical connector(s)
Sens
o
r(s)
Engine
control module (E
CM)
Sy
m
ptom
(general)
S y
mptom (specific)
Possib
l
e source
Acti
o
n
Poor
dr iveabilityEngine h e
sitates/poor
acceleration
Fue l
pump
Air leakage F
u
el pressure regulator
Chec
k fu
el pressure,
REFER to Section 310
-00 Fu
el
Sy
ste
m
- General Informati
on.

6. R
emove the EGR valve to throttle
body elbow retaining bolts.
Remove an
d discard the EGR valve to throttle body elbow
gasket.

7. R
emove the exhaust manifold to EGR valve tube retaining
bolts.
Remove an
d discard the exhaust manifold to EGR valve
tube gasket.

8. N
OTE: Note the orientation of the coolant hose to EGR valve
before removal.
Remove the coolant hose.
9. NOTE: Note the orientation of the coolant hose to EGR valve
before removal.
• NOTE: Cap the coolant hose to minimize coolant loss.
Remove the EGR valve.

In
stallation


1.
NO TE
: Make sure the EGR valve to the coolant hose is installed
to the orientation noted during removal.
• NOTE: Un-cap the coolant hose.
Install the EGR valve.

2. NO TE
: Make sure the EGR valve to the coolant hose is installed
to the orientation noted during removal.
Install the coolant hose.

3. NOTE:
Install a new exhaust manifold to EGR valve tube
gasket.
• NOTE: Install a new EGR valve to throttle body elbow gasket.
Loosely install the exhaust manifold to EGR valve tube and the
EGR valve to throttle body elbow.
4. Tighten the exhaust manifold to EGR valve tube retaining
bolts.
Tigh te
n to 21 Nm.

5. Tigh
ten the EGR valve to throttle body retaining bolts.
Tigh

ten to 12 Nm.

6. Con
nect the EGR valve electrical connector.

7. NO
TE: Un-cap the coolant hose.
Connect the coolant hose.
8. Attach the evaporative emission canister purge valve.
Tigh
ten to 6 Nm.

Intake Air Distribution and Filtering -
Torque Specificat
ions


Comp

onent
Nm
Thr
o
ttle intake elbow to intake manifold
18
-
24
Thro
tt
le body to throttle intake elbow
18
-
24
Left-hand support
bracket to
th
rottle intake elbow
16
-
20
Right-hand support
bracket to
throttle intake elbow
16
-
20
B
l
anking plate to throttle intake elbow
18
-
24
Inta
k
e manifold to engine
20
-
22
Supe
rcharger
drive belt idler pulley bolt
34
-
46
Supercharger
drive belt te
nsioner to alternator mounting bracket bolt
39
-
51
Supercharger
to eng
ine bolts
18
-
24
Charge air cooler in
let assembly to charge ai
r cooler bolts
18
-
24
Supercharger
outlet duct to supercharger bolts9-1
1
Charge air cooler in
let assembly to superchar
ger ou
tlet duct bolts
18-
24
Charge air cool
er to charge
air cooler adaptor
11
-
13
B
y
-pass valve to throttle intake elbow
8-
1
2

P
arts List
CAUTION: Do not attempt to renew or adjust the throttle cable without consulting the relevant procedure. Two
procedures apply: reconnection of an original cable (19.70.04) or the fitting of a new cable (19.20.06).
The filtered air from the intake duct is drawn downwards through the throttle body to the intake elbow on which the throttle
body is mounted. The airflow through the throttle body is vari ed by the electrically operated throttle valve according to
driver demand and engine mana gement system requirements.
The throttle body assembly has the following features:
Con
vential cable operated input shaft connected to the accelerator pedal.
M

echanical guard to limit throttle angl
e should driver demand exceed ECM co ntrolled parameters and a mechanical
back-up in the event of a throttle motor failure.
Vacuum actuator for operation of the mech anical guard in cru
ise control mode.
Thr

ottle valve (blade) to regula
te air flow into the engine.
Thermostatic air valve to allow and con
t
rol air by-pass around the throttle.
D
C electric motor to operate the thro
ttle in response to ECM control.
Three
sensors (accelerator pedal, mechan
ical guard and the throttle valve) to relay positional information about the
input shaft to the ECM.
R
eturn and control springs fitted to th
e input shaft, mechanical guard, thro ttle valve and dc motor drive gear.
Throttle Cont
rol Modes
There are seven throttle control

modes:
1. 1. Normal
It
em
Par
t Number
De
scription
1—Acce

lerator pedal and mechanic
al guard position sensors
2—Throttl
e (blade)
position sensor
Throttle Body

the
intake elbow provide connections for vacuum actuators and are also used to redirect emissions into the engine.
On the right-hand side of the elbow a la rge diameter pipe connects to the brake servo. The smaller pipe provides a vacuum
feed to the fuel rail pressure regulator and throttle cruise control system. On the le ft-hand side of the elbow the front pipe
supplies vacuum control for the evaporative emissions system valves.
Emissions from the engine part load breather (bank 2) and pu rged fuel vapor from the EVAP valve are drawn via a common
T piece into the left-hand side of the intake elbow. Re-cir culated exhaust gas enters the intake elbow via the EGR valve
which is mounted directly on the rear of the elbow : where the EGR system is not used, a blanking plate is fitted.
The fuel system, throttle and emission control system s are described more fully in the relevant sections.
Intake Manifold

Filtered air from the vehicle's intake ducting is metered by th e electronic throttle and distributed to the two cylinder banks
via an integral intake manifold.
The intake manifold is manufactured in plastic with integral plastic fuel rails and metal-thread inserts; the very smooth
internal surfaces give excellent air flow.
Individual ducts lead off a central chamber to the inlet valves of each cylinder.
Silicon-rubber gaskets, loca ted in channels in the intake manifold, seal th e joints between the ducts and the cylinder heads.
Engine Ventilation

The e
ngine is ventilated through two brea
thers; a part-load breather and a full-load breather, one on each camshaft cover.
The outlet hose for the part-load breather is connected between the bank 2 camshaft cover and the intake elbow. The full-
load outlet hose is connected from the bank 1 camshaft cover to the intake duct between the MAF sensor assembly and the
throttle body.
Constructed in plastic, the hoses incorporate O-ring seal s and quick-release connectors; refer to Section 303-01.
I
ntake Air Distribution and Filtering - Supercharged Vehicles
Ai
r is supplied to the supercharger via an
intake cleaner/duct, throttle assembly and intake elbow which are similar to those
used for normally aspirated engines. The su percharger delivers pressurized air to two separate charge air cooler units, each
unit being mounted on the cy linder bank which it supplies. Pr essurized cooled air is fed from the charge air coolers directly
into each inlet port.

The intake elbow di
rects the metered airflow from the electronic throttle outlet (und
erside of the throttle body) into the
intake of the supercharger.
The supercharger by-pass valve assembly is bolted to the intake elbow. The butterfly valve inside the assembly is opened
by a diaphragm actuator operated by vacu um feed from the elbow. At closed or partially open throttle positions, the
butterfly valve opens, allowing th e airflow from the two charge air cooler inlets to be directed back to the supercharger inlet .
This action inhibits the supercharging e ffect and reduces engine torque to non supercharged levels. Progressive opening of
the throttle causes the by-pass valve to gradually close.
On the right-hand side of the elbow a la rge diameter pipe connects to the brake servo. On the left-hand side the smaller
pipe supplies vacuum control for the evaporative emissions system valves.
Emissions from the engine part load breather (bank 1) and pu rged fuel vapor from the EVAP valve are drawn via a common
T piece into the left-hand side of the intake elbow. Re-cir culated exhaust gas enters the intake elbow via the EGR valve
which is mounted directly on the rear of the elbow. Where the EGR system is not used, a blanking plate is fitted.
The fuel system and emission control systems are described more fully in the relevant sections.
Fuel Pressure Regula
tion and
Cruise Control Vacuum Feed
The inlet v
acuum feed fo
r the fuel rail pressure regula tor and the cruise control system is taken from the supercharger
outlet duct. The feed pipe is located below the large charge air cooler coolant filler plug.
Superchar
ger
and associated components
Inta
ke Elbow and Bypass