1998 JAGUAR X308 fuel regulator

Fuel D
istribution
Fuel is supplied to th
e engine
via eight fuel injectors (one pe r cylinder). The injectors are located in two fuel rails which r un
the length of each cylinder bank and ar e integral with the air intake manifold.
Fuel pumped from the tank enters a feed pipe at the rear of bank 2. Fuel flow is along bank 2 fuel rail, across the top front
of the engine (cross-over pipe) and through bank 1 fuel rail, the unused fuel re turning to the tank via a pressure regulator.
The fuel injectors are each controlled electrically from the engine control module (ECM).
A test valve is fitted to the cross-over pipe connecting the fu el rails at the front of the intake manifold. This valve allows the
fuel system to be depr essurized during servicin g and troubleshooting.
Fuel Injector

Eight, side-fed, dual straight-jet fuel injectors are fi tted in the fuel rails.
The injector consists of a solenoid, core, needle valve and ho using. When a control signal from the ECM is applied to the
solenoid coil, the needle valve lifts up and fuel is injected under pressure into the intake port. The fuel sprays from the
injectors are directed onto the back of the intake valves.
The injection quantity is determined by the length of time that the ECM signal is applied to the solenoid coil.
The injectors installed in the fuel rails of supercharged engines are of a higher flow rating than those installed in normally
aspirated engines and are secured in position by spring clips. Seals are instal led between the injector mounts of the fuel
rails and the related re cesses in the charge air cooler adaptors.
Pressure Regulator

Pa
rts List
The pressure regulator is a diap hragm-operated valve that regula tes fuel-rail pressure at 3,0 bar above the intake manifold
pressure. A pipe connects the throttle induction elbow to the pressure regulator to provide the vacuum control signal. On
supercharged engines, the pressure regulator vacuum feed is taken from the top of the supercharger outlet duct.
The regulator is fitted between the rear end of the right-hand fuel rail (bank 1) and the fuel return line to the tank.
Circuit Diagram, Fuel Injection Syst em - Normally Aspirated Vehicles

Ite
m
Par
t
Number
De
scr
iption
1—F
u
el Return
2—F
u
el Pressure Regulator
3—Inta
k
e Manifold Pressure

(ECT) se
nsor
Blocked part-load breather
(s
ervice action S474)
Injec
t
or leak
Engine stalls
soon
after start
F
u
el pump relay
ECM relay Thr
o
ttle contaminated
CMP/CKP sen
s
or
synchronization malfunction
Harness Fuel
pump
MAF
s
ensor malfunction
Engine coolan
t
temperature
(ECT) sensor
Fue l
lines
Air leakage Fu

el pressure regulator
F
o
r fuel pump relay tests,
GO to Pinpoint Test E.
.
F or ECM
relay tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
Check bull etins for throttl
e cleaning procedure. For

CMP/CKP sensor tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
Chec k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Ge
n
eral
Informati
o
n
.
F or MAF sensor and
ECT sensor tests,
REFER to Section 303
-14 Electronic En
gine
Controls.
For fuel l
ine information,
REFER to Section 310
-01
Fuel Tank and Lines
.
F or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
F o
r fuel pressure regulato
r check, GO to Pinpoint
Test D.
.
Engine h e
sitates/poor
acceleration
Fue l
pump
Exhaus
t gas
recirculation
(EGR)
Air leakage Stop lamp swi t
ch
Throttl
e
sensors
Throttl
e
motor
Spark plugs

fouled
Check f
o
r water ingress into
spark plug wells
Ignition coil fail
ure(s)
HT sho
rt to ground (tracking)
check rubber
boots for
cracks/damage
ECM failu r
e
Chec
k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Ge
n
eral
Informati
o
n
.
F o
r EGR information,
REFER to Section 303
-08 En gin
e Emission
Control.
F or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
F or stop l
amp switch in
formation, refer to the
wiring diagrams. For throttle position sensor and throttle motor relay tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
For ign i
tion system,
REFER to Section 303
-07 En
gine Ignition
.
Contact dealer techn i
cal
support for advice on
possible ECM failure.
Engine ba ckfiresFuel
pump
Air leakage MAF s
e
nsor
HO2 sensors Spark plugs
Check fo
r water ingress into
spark plug wells
HT short to ground (tracking) check rubber
boots for
cracks/damage
Ignition coil fail
ure(s)
Chec
k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Ge
n
eral
Informati
o
n
.
F or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
For MAF and HO2
sensor circuit tests,
REFER to Section 303
-14 Electronic En
gine
Controls.
For igni
tion system,
REFER to Section 303
-07 En
gine Ignition
.
Engine
s
urges
Air leakage Fue
l
pump
Stop lamp swi
t
ch
MAF s
e
nsor
Harness Throttl
e
sensors
Throttl
e
motor
Spark plugs
Check fo
r water ingress into
spark plug wells
HT sho rt to ground (tracking)
check rubber
boots for
cracks/damage
ECM failu r
e
F
or i
ntake system information,
REFER to Section 303
-1 2
Intake Air Distribution
and F
ilt
ering
.
Chec k fu
el pressure,
REFER to Section 310
-00 Fu
el System
- Gen
e
ral
Informati
o
n
.
F or stop l
amp switch in
formation, refer to the
wiring diagrams. For MAF se nsor, throttle position
sensor and throttle motor relay tests,
REFER to Section 303
-14 Elec tronic En
gine
Controls.
For ign i
tion system,
REFER to Section 303
-07 En
gine Ignition
.
Contact dealer techn i
cal
support for advice on
possible ECM failure.

Default mode Definitions

MECH
ANICAL LIMP-HOME MODE:

No el
ectronic throttle operation (mechanical
operation for last quarter of pedal travel)
M
aximum 25° throttle opening,
depending on adjustment of th rottle mechanical linkage
Engine
speed restricted to 3000
rpm maximum, by fuel cut-off
Hi
gh idle speed (1200 rpm approx.)
Misfire

at idle, due to cylinder cut as a means of control
ling idle speed (the misfire will switch cylinders, as the
strategy varies th e cylinder cut)
Cruise (speed) contr
ol inhibited
REVERSE THROTTLE PROGRESSION ENABLED:
El
ectronic throttle operation, limited to maximum 25°
Cruise (speed) contr

ol inhibited
• NOTE: The throttle oper ation uses the same map as for reverse gear.
ENGINE SPEED LIMIT:
Engine
runs normally, up to 3000 rpm
Engine

speed restricted to 3000
rpm maximum, by fuel cut-off
Cruise (speed) contr
ol inhibited
LIMP-HOME UNAVAILABLE:
Cruise (speed) contr
ol inhibited
R

everse throttle pr
ogression engaged at second occurrence of DTC flagging
Diagnostic Trouble Code (D
TC) index
DT
C
Cond
ition
P
ossible Causes
Acti
on
P0171Right-hand cylinders combustion too

leanAir
intake leak between MAF
sensor and throttle
F
uel filter system blockage
F

uel injector blockage
F

uel pressure regulator failure (low

fuel pressure)
Low f
uel pump output
H0

2S harness wiring fault
E

xhaust leak (before catalyst)
ECM receivi

ng incorrect signal from

one or more of the following
sensors - ECT, MAF, IAT, TP.
Fo
r intake system,
REFER to Section 303
-12
Intake Air

Distribu
tion and Filtering
.
F
or fuel filter,
REFER to Section 310
-01
Fuel Tank
and Lines.
Chec
k the fuel injectors. Check the
fuel pressure regu lator. Check fuel
pressure. For HO2S circuit tests,
REFER to Section 303
-14
Electronic
Engine

Controls
.
F
or exhaust information,
REFER to Section 309
-00
Exhaust
Sy

stem
.
For se
nsor circuit tests,
REFER to Section 303
-14
Electronic
Engine

Controls
.
P0172Right-hand cylinders combustion too

ri
ch
Engine
misfire
Bl

ocked air filter
F

uel system return blockage
Leak

ing fuel injector(s)
F

uel pressure regulator failure
(high fuel pressure)
ECM receivi
ng incorrect signal from

one or more of the following sensors - ECT, MAF, IAT, TP
Chec
k for 'engine misfire detected'
DTCs. Check the air filter element,
REFER to Section 303
-12
Intake Air

Distribu
tion and Filtering
.
Chec
k the fuel lines,
REFER to Section 310
-01
Fuel Tank
and Lines.
Chec
k the fuel injectors,
REFER to Fuel Injectors
- in t
his
section.
For fuel pressure regulator check,GO
to Pinpoint Test D.
.
Check the fuel
pressure,

REFE
R to Section 310
-00
Fu
el
Sy
ste
m
- General

Information
.
Check f o
r DTCs indicating a sensor
fault,
REFER to Section 303
-14 El
ectronic
Engine
C
ontrols
.
P0174
Left-hand cyl i
nders combustion too
lean
Air in
take leak between MAF
sensor and throttle
F u
el filter system blockage
F
u
el injector blockage
F
u
el pressure regulator failure (low

fuel pressure)
Low f u
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
F o
r air intake sy
stem information,
REFER to Section 303
-12 Int
ake 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,
REFER to Fuel Injectors
- in t h
is
section.
For fuel pressure regulator check,GO
to Pinpoint Test D.
. Ch
eck the fuel
pressure,
REFER to Section 310
-00 Fu
el
Sy
ste
m
- General

Information
.
Check f o
r DTCs indicating which HO2

sensor is faulty,
REFER to Section 303
-14 El
ectronic
Engine
C
ontrols
.
Check f o
r DTCs indicating a sensor
fault,
REFER to Section 303
-14 El
ectronic
Engine
C
ontrols
.
P0175Left-hand cyli

nders 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
Check for 'en
gine misfire detected'
DTCs. Check the air filter element,
REFER to Section 303
-12 Int
ake 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,
REFER to Fuel Injector
- Vehicles Wi
thout: Supercharger
/

Fue
l Injector
- Ve
hicles With
:
Supercharger
in this
section.
For fuel pressure regulator check,GO
to Pinpoint Test D.
. Check for DT
Cs
indicating a sensor fault,
REFER to Section 303
-14 El
ectronic
Engine
C
ontrols
.
P0201F
u
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,GO to
Pinpoint Test A.
.
P0202Fu
el injector circuit malfunction, Cyl

3
P0203F u
el injector circuit malfunction, Cyl

5
P0204F u
el injector circuit malfunction, Cyl

7
P0205Fu
el injector circuit malfunction, Cyl

2
P0206Fu
el injector circuit malfunction, Cyl

4
P0207F u
el injector circuit malfunction, Cyl

6
P0208F u
el injector circuit malfunction, Cyl

8
P0300Ran d
om misfire detected
ECM t
o
ignition coil primary circuit
faults (cylinder misfire detected DTCs also logged)
Ignition coil ground circuit; open
ci
rcuit, high resistance
F
u
el injector circuit fault(s)
(injector DTCs also logged)
F o
r ignition circuit tests,
REFER to Section 303
-07 En
gine
Ignition.
F or engi
ne information,
REFER to Section 303
-00 En
gine
Sy
ste
m
- General

Information
.
F o
r fuel injector circuit tests,GO to

C2: CHECK THE FUEL
PUMP 2 RELAY TO ECM CIRCUIT
Di

sconnect the battery negative terminal.
1

D
isconnect the ECM electrical connector, EM13.
2

Meas
ure the resistance between the rela
y base, pin 02 and EM13, pin 09 (KB).
3

Is th
e resistance greater than 5 ohms?
Yes REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. CLEAR the

DTC. TEST the system for normal operation.
No INSTALL a new fuel pump 2 relay. CLEAR the DT C. TEST the system for normal operation.
P
INPOINT TEST D : CHECK THE FUEL PRESSURE REGULATOR FUNCTION
CAUTI
ON: Do not run the engine for more than
30 seconds with the vacuum hose disconnected.
T
EST CONDITIONS
D
ETAILS/RESULTS/ACTIONS
D

1: CHECK FOR FUEL PRESSURE CHANGE
WHEN THE REGULATOR IS DISCONNECTED
Connect a
fuel pressure gauge set,
REFER to Section 310
-00
Fuel System
-

General Informati
on
. 1

St
art the engine.
2

N
ote the fuel pressure readin
g with the fuel pressure regu lator vacuum hose connected.
3

Di
sconnect the fuel pressu
re regulator vacuum hose.
4

N
ote the new reading.
5

Doe
s the fuel pressure increase when the hose is disconnected?
Yes Check for DTCs. Carry out the pinpoint tests indicated.
No INSTALL a new fuel presssure regulator. TEST the system for normal operation.
P
INPOINT TEST E : DTC P1230;
FUEL PUMP RELAY MALFUNCTION
•
NOTE: This DTC applies only to the N/A system si
ngle fuel pump, and the S/C system fuel pump 1
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
E1

: CHECK THE FUEL PUMP
RELAY BATTERY SUPPLY
R
emove the fuel pump relay.
1

Meas
ure the voltage between the
relay base, pin 03 and GROUND.
2

Is th
e voltage less than 10 volts?
Yes REPAIR the circuit between the rela y base, pin 03 and the battery power bus. This circuit includes the
trunk fuse box and the high power protection module . For additional information, refer to the wiring
diagrams. CLEAR the DTC. TEST th e system for normal operation.
No GO to E2
.
E2
: CHECK THE FUEL PUMP RELAY IGNITION SWITCHED SUPPLY
Turn the ignition swi

tch to the
ON position.
1

Meas
ure the voltage between the
relay base, pin 01 and GROUND.
2

Is th
e voltage less than 10 volts?
Yes REPAIR the circuit between the rela y base, pin 01 and battery. This circuit includes the trunk fuse box,

fuse 16 of the left-hand fuse box, the ignition po
sitive relay and the high power protection module.
For additional information, refer to the wiring diagrams. CLEAR the DTC. TEST the system for normal
operation.
No GO to E3
.
E3
: CHECK THE FUEL PUMP RELAY TO
ECM CIRCUIT FOR HIGH RESISTANCE
Di
sconnect the battery negative terminal.
1

D
isconnect the ECM electrical connector, EM83.
2

Meas
ure the resistance between EM83, pi
n 04 (WR) and the relay base, pin 02.
3

Is th
e resistance greater than 5 ohms?
Yes REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. CLEAR the
DTC. TEST the system for normal operation.
No

INSTALL a new fuel pump relay. CLEAR the DTC. TEST the system for normal operation. If the DTC is
repeated, contact dealer technical support for advice on possible ECM failure.

Fuel Char
ging and Controls - Fu
el Injection Supply Manifold RH
Remo
val and Installation
Remov
a
l
1.
Re
move fuel injectors; refer to (SC) 18.10.01.

2. Disc
onnect fuel pressure regulator.
1. Remove bolts.
2. Reposition pres sure regulator.
Disc
ard O-ring.

3. Re
move fuel rail from charge air cooler adaptor.
1. Remove three bolts.
2. Remove fuel rail; still co nnected to fuel crossover pipe
and fuel return pipe.

4. Re
move fuel rail from fuel cross-over pipe.
1. Remove bolt.
2. Discard O-ring.

5. Re
move fuel rail to charge air cooler adaptor seals.
1. Discard seals.
2. Clean and inspect mating faces.

I
nstallation


1.
Inst
all new seals between fuel rail and charge air cooler
adapter, ensuring they are fully seated.

2. Install
fuel rail to fuel cross-over pipe.
1. Install new O-ring and lubricate with petroleum jelly.
2. Install bolt.

3. Install
fuel rail to charge air cooler adaptor.
1. Align fuel rail to adaptor; still connected to fuel crossover pipe and fuel return pipe. Locate fuel rail
into adaptor.
2. Install three bolts which se cure fuel rail to adaptor.
Tighten to 18-24 Nm.

4. Install
fuel pressure regulator.
Install a new O-r

ing to fu
el pressure regulator and
lubricate with petroleum jelly
1. Install bolts.
5. Install fuel injectors; refer to (SC) 18.10.01.