fuel regulator JAGUAR X308 1998 2.G Owner's Manual

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.

Fue
l pump
Engine coolan

t temperature

(ECT) sensor
Blocked part-load breather (
service action S474)
Injec

tor leak
Emiss
ions
.
Check bull
etins for throttle cleaning procedure.
Check fuel pressure. For ECT sensor circuit tests,
GO to Pinpoint Test C.
. Refer to Servi
ce action
S474 for part-load breather procedure. For
injector leak test, Refer to technical service bulletin 303-39.
D
ifficult to start after hot
soak (vehicle standing
after engine has reached operating temperature)
Roc
hester valve
Thr

ottle contaminated
Purge

valve
Fue

l pump
Engine coolan

t temperature

(ECT) sensor
Blocked part-load breather (
service action S474)
Injec

tor leak
Engine cranks too
fa
st/slow
Batt
ery
Starter relay Harness Cyl

inder compression loss
(NA short term only. Refer to technical service bulletin; 303-39)
R
efer to service action
S491
F
or battery information,
REFER to Section 414
-0
1 Battery, Mounting and

Cables.
F
or starting system.
REFER to Section 303
-06 Sta
rting System
.
R
efer to technical servic
e bulletins and service
actions.
Engine

stalls
Engine st
alls soon after
start
F
uel pump relay
ECM relay Thr

ottle contaminated
CMP/CKP sen

sor
synchronization malfunction
Harness Fue
l pump
MAF

sensor malfunction
Engine coolan

t temperature

(ECT) sensor
Fue
l lines
Air leakage


F

uel pressure regulator
Check r
elay dates. Chec
k for DTCs. For fuel
pump relay tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or ECM relay tests, GO to Pinpoint Test
AD.
.
Check bull
etins for throttle cleaning procedure.
For CMP sensor circuit test s, GO to Pinpoint Test
C.
, for
CKP sensor circuit tests, GO to Pinpoint
Test N.
. Check fuel
pressure. For MAF sensor
circuit tests, GO to Pinpoint Test A.
. For EC
T
sensor tests, GO to Pinpoint Test C.
. F
or fuel
system,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
and
REF
ER to Section 310
-0
1 Fuel Tank and Lines
. F

or intake system information,
REFER to Section 303
-1
2 Intake Air Distribution

and F
iltering
.
Engine

stalls on overrun
Thr
ottle contaminated
ECM relay F

uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Check bull
etins for throttle cleaning procedure.
Check relay dates. For ECM relay tests, GO to Pinpoint Test AD.
. F
or fuel pump relay tests,

REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s, GO to Pinpoint Test
O.
, for
CKP sensor circuit tests, GO to Pinpoint
Test N.
.
E
ngine stalls at steady
speed, with or without cruise enabled
Thr
ottle contaminated
ECM relay F

uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Harness Blocked part-load breather
(
service action S474)
Check bull
etins for throttle cleaning procedure.
Check relay dates. For EC M relay circuit tests,GO
to Pinpoint Test AD.
. F
or fuel pump relay circuit

tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s,GO to Pinpoint Test
O.
, for
CKP sensor circuit tests,GO to Pinpoint
Test N.
. Che
ck service actions.
Engine st

alls when
maneuvering
ECM relay F
uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Check r
elay dates. For EC
M relay circuit tests,GO
to Pinpoint Test AD.
. F
or fuel pump relay circuit

tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s,GO to Pinpoint Test
O.
, for
CKP sensor circuit tests,GO to Pinpoint
Test N.
.

Exhaus
t leak
Low e

xhaust temperature
Cat

alyst monitor sensor failure
P0151Le

ft-hand H02S sense circuit low
voltage
H02
S disconnected
H0

2S to ECM wiring open circuit
H0

2S short circuit to ground
H0

2S failure
F
or left-hand HO2S circuit tests, GO
to Pinpoint Test H.
.
P0152Le
ft-hand H02S sense circuit high
voltage
H02
S sensing circuit short circuit to
high voltage
H0
2S ground braided shield open
circuit
H0
2S failure
F
or left-hand HO2S circuit tests,GO to
Pinpoint Test H.
.
P0153Le
ft-hand H02S sense circuit slow
response
Engine
misfire
H02

S disconnected
H0

2S mechanical damage
H0

2S to ECM wiring intermittent
open circuit
H02
S sensing circuit short circuit to
high voltage
H0
2S short circuit to ground
H0

2S ground braided shield open
circuit
H0
2S heater circuit fault
Exhaus

t leak
Low e

xhaust temperature
Injector fl

ow partially blocked
Catal

yst efficiency decrease
H0

2S failure
Chec
k for 'engine misfire detected'
DTCs. For HO2S circ uit tests, GO to
Pinpoint Test H.
. Check for exhaust
leak
s,
REFER to Section 309
-00
Exhaust
Sy

stem
.
Chec
k injectors,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P0155Left-hand H02S heater

circuit
malfunction
H02
S disconnected
H0

2S heater power supply open
circuit
H0
2S heater to ECM wiring short
circuit or open circuit
H0
2S heater failure
F
or left-hand HO2S heater circuit
tests,GO to Pinpoint Test I.
.
P0157Le
ft-hand catalyst monitor sensor
sense circuit low voltage
Catal
yst monitor sensor
disconnected
Catal
yst monitor sensor to ECM
wiring open circuit
Catal
yst monitor sensor short
circuit to ground
Cat
alyst monitor sensor failure
F
or left-hand catalyst monitor sensor
circuit tests,GO to Pinpoint Test J.
.
P0158Le
ft-hand catalyst monitor sensor
sense circuit high voltage
Catal
yst monitor sensor sensing
circuit short circuit to high voltage
Catalyst
monitor sensor ground
braided shield open circuit
Cat
alyst monitor sensor failure
F
or left-hand catalyst monitor sensor
circuit tests,GO to Pinpoint Test J.
.
P0160Le
ft-hand catalyst monitor sensor
sense circuit no activity
Catal
yst monitor sensor
disconnected
Catal
yst monitor sensor
mechanical damage
Catal
yst monitor sensor to ECM
wiring open circuit
Catal
yst monitor sensor sensing
circuit short circuit to high voltage
Catal
yst monitor sensor short
circuit to ground
Catalyst
monitor sensor ground
braided shield open circuit
Exhaus
t leak
Low e

xhaust temperature
Cat

alyst monitor sensor failure
F
or left-hand catalyst monitor sensor
circuit tests,GO to Pinpoint Test J.
.
Check f
or exhaust leaks,
REFER to Section 309
-00
Exhaust
Sy

stem
.
P0171Right

-hand cylinders combustion
too lean
Air
intake leak between MAF senso
r and th

rottle
F

uel filter system blockage
F

uel injector blockage
F

uel pressure regulator failure (low

fuel pressure)
Low f
uel pump output
Check ai
r intake system for leaks,
REFER to Section 303
-1
2 Intake Air
Distribu

tion and Filtering
.
Check the fuel fi
lter,
REFER to Section 310
-01
Fuel Tank
and Lines.
Chec
k the fuel injectors and fuel

H02S harness wiri
ng fault
E
x
haust leak (before catalyst)
ECM receivi
n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
pr essure regulator,
REF
ER to Section 303
-04
Fu
el
Charging and Con
t
rols
.
Chec k the
fuel pressure. Check the
exhaust system for leaks,
REFER to Section 309
-00 Ex
haust
Sy
ste
m
.
R e
fer to pinpoint tests for sensors
listed.
P0172Right -
hand cylinders combustion
too rich
Engine m
isfire
Bl
ocked air
filter
F
u
el system return blockage
Leak
i
ng fuel injector(s)
F
u
el pressure regulator failure
(high fuel pressure)
ECM receivi n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
Chec k for 'en
gine misfire detected'
DTCs. Check the air filter element,
REFER to Section 303
-1 2
Intake Air
Distribu
tion and Filterin
g
.
Chec k the
fuel lines,
REFER to Section 310
-01 Fu
el Tank
and Lines.
Chec k the
fuel injectors and fuel
pressure regulator,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
.
R e
fer to pinpoint tests for sensors
listed.
P0174L e
ft-hand cylinders combustion
too lean
Air in
take leak between MAF senso
r and th
ro
ttle
F
u
el filter system blockage
F
u
el injector blockage
F
u
el pressure regulator failure (low

fuel pressure)
Low fu
el pump output
H0
2S harness wiri
ng fault
E
x
haust leak (before catalyst)
ECM receivi
n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
Check the ai r intak
e system for leaks,

REFER to Section 303
-1 2
Intake Air
Distribu
tion and Filterin
g
.
Check the fuel fi lter,
REF
ER to Section 310
-01
Fu
el Tank
and Lines.
Chec k the
fuel injectors and fuel
pressure regulator,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
.
Chec k the
fuel pressure. For HO2S
circuit tests,GO to Pinpoint Test H.
,
a n
dGO to Pinpoint Test
I.
. Check
the
exhaust system for leaks,
REFER to Section 309
-00 Ex
haust
Sy
ste
m
.
R e
fer to pinpoint tests for sensors
listed.
P0175L e
ft-hand cylinders combustion
too rich
Engine m
isfire
Bl
ocked air
filter
F
u
el system return blockage
Leak
i
ng fuel injector(s)
F
u
el pressure regulator failure
(high fuel pressure)
ECM receivi n
g incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP
Chec k for 'en
gine misfire detected'
DTCs. Check air filter element,
REFER to Section 303
-1 2
Intake Air
Distribu
tion and Filterin
g
.
Chec k the
fuel lines,
REFER to Section 310
-01 Fu
el Tank
and Lines.
Chec k the
fuel injectors and fuel
pressure regulator,
REFER to Section 303
-04 Fu
el
Charging and Cont

rols
.
Re
fer to pinpoint tests for sensors
listed.
P0201 Fu
el injector circuit malfunction,
cyl 1
Injector discon n
ected
Inject
or wir
ing open or short circuit

Injector fail
ure
F
o
r fuel injector
circuit tests,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
. P0202F
u
el injector circuit malfunction,
cyl 3
P0203F u
el injector circuit malfunction,
cyl 5
P0204F u
el injector circuit malfunction,
cyl 7
P0205F u
el injector circuit malfunction,
cyl 2
P0206F u
el injector circuit malfunction,
cyl 4
P0207F u
el injector circuit malfunction,
cyl 6
P0208F u
el injector circuit malfunction,

Fuel System - General Inform
ation - Fuel System
Description an
d Operation

The fuel tank is mounted across the vehicle behind the passenger compartment bulkhead.
Fuel is drawn by the fuel pump from the tank and then supplied to the two fuel rails, via a filter.
Fuel injectors are installed in the fuel ra ils on each side of the intake manifold.
The amount of fuel injected into th e engine is controlled by the ECM.
A cross-over pipe connects the two fuel ra ils together at the front of the manifold.
A test valve in the cross-over pipe allo ws the fuel rail to be pressurized and de-pressurized during the servicing and
troubleshooting procedures.
A pressure regulator on the rear of the right fuel rail controls the pressure in the fuel rails.
A return line directs excess fuel from the pressure regulator back to the fuel tank.
Operation and service procedures
The fuel injector
s, rails, pres
sure regulator and, wher e fitted, supercharger are described in greater detail in Section 303-04
together with servicing procedures.
The fuel tank, pump, fuel level senders and fuel lines are similarly covered in Section 310-01.

Fuel System - General Information - Fuel System Pre
ssure Check
Gen
eral Procedures
WARNING: Working on the fuel system re sults in fuel and fuel vapor being present in the atmosphere. Fuel vapor is
extremely flammable, hence great care must be taken whilst working on the fuel system. Adhere strictly to the following
precautions:
D
o not smoke in the work area
Di

splay
NO SMOKING signs around the work area
D
isconnect the battery before
working on the fuel system
Av
oid sparks
Make sure sui

table fire ex
tinguishers are at hand
Make sure absor
bent material is at
hand to soak up any spillage
Make sure the work area is
well ventilated
M

ake sure that the gauge is correctly conn
ected, and that all connections are secure BEFORE starting the engine
DO N
OT
disconnect the gauge from the schrader valve while the engine is running
Make su
re the schrader valve reseals once the gauge is disconnected
• NOTE: Depending on the design of the ga uge set, there may be a drain valve and tube. Make sure this valve is closed, and
the drain tube placed in a suitable container BEFORE connecting the gauge to the schrader valve.


1. Make sure the vehi
cle is in
Park for vehicles with automatic
transmission, Neutral for vehicles with manual transmission.
2. Apply the parking brake.
3. Place suitable absorbent material around the schrader valve to
absorb any spillage when connecting the gauge set.
4. Remove the protective cap from the schrader valve.
5. Connect the gauge, using adaptors if required.
6. Remove the absorbent material and dispose of safely.
7. Disconnect and plug the vacuum hose from the pressure
regulator.
8. Start the engine and record the fuel pressure reading.
As a gui
de, the fuel pressu
re should be approximately 3.0
bar (44.1 psi) with the regulator disconnected.
9. With the engine still running, reconnect the vacuum hose to
the pressure regulator an d record the reading.
Th
e pressure should dr
op to approximately 2.6 bar (38
psi) when the vacuum hose is reconnected.
10. Switch off the engine.
11. Place more absorbent material around the schrader valve.
12. Where fitted, open the drain valve and allow the fuel from the
gauge and line to flow into the container to depressurize the
system.
13. Disconnect and remove the gauge set and any adaptors.
14. Clean up any fuel which may have been spilt and remove the
absorbent material. Dispose of safely.
15. Refit and secure the protective cap to the schrader valve.
16. Reconnect the fuel pressure regulator vacuum hose.
17. Start the engine and make sure there are no leaks.