fuel JAGUAR X308 1998 2.G Workshop Manual

In
stallation
15.
Cle
an manifold and mating faces on cylinder heads.
1. Where necessary, install blanking plate to intake elbow.
Inst al
l new gasket.
Inst
al
l bolts (18-24Nm).

2. Inst al
l intake elbow to intake manifold.
1. Install new seal.
2. Install seven bolts.
3. Install new seals to the eight intake manifold ports. Ensure the
seals are fully seated.

4. Inst al
l intake manifold.
1. Install ten bolts.
5. Connect fuel feed hose to fuel rail feed pipe. Ensure hose is
fully installed.
6. Connect fuel return hose to fuel rail return pipe. Ensure hose is
fully installed.

7. Con n
ect electrical connectors to fuel injectors.
8. Install left-hand support brac ket to intake elbow and re-
connect pipework.
1. Install bolt.

Evaporative E
missions - Evaporative Emissions
Description an
d Operation

To reduce the emission of fuel vapour, th e fuel tank is vented to atmosphere through activated charcoal adsorption canister
(s) which collects the fuel droplets. The ch arcoal is periodically purged of fuel when the EVAP Canister Purge Valve opens
the vapour line between the canister(s) and the air intake induct ion elbow. This action allows manifold depression to draw
air through the canister atmospheric vent, taking up the deposited fuel from the charcoal adsorber and burning the resulting
fuel vapour in the engine.
The EVAP Canister Purge Valve is controlled by the engine management system ECM. Purging is carried out in accordance
with the engine management fu eling strategy (see below).
The fuel tank vapour outlet is via a removeable flange assemb ly on the top surface of the tank. The vapour storage canister
or canisters are fitted on the underside of the vehicle below the rear seats.
There are three variants of the evaporativ e system. All systems use the charcoal adsorber storage canisters and purge valve
and operate as described above. The specific features of each system are described below. The evaporative systems are
designated as :
sin g
le canister system
ru
nn
ing loss system
ru
nn
ing loss with On-board Re-fueling Vapour Recovery (ORVR) system
EVAP Canister Purge Valve

Ite
m
Par
t
Number
De
scr
iption
1—EVAP canister purge v
alve
2—Valve s
olenoid connector
3—Vapour outlet to indu
ction elbow
4—Vapour
inlet from canister(s)
5—Vacuum contro
l pi
pe from induction elbow
6—Vacuum contro
l pi
pe to vapour pressure control va
lve - applicable to single canister systems only
7—Vacuum
control connection to EVAP valve

The E
VAP canister purge valve controls th
e flow rate of fuel vapour drawn into the engine during the canister purge
operation. The valve is opened by a vacu um feed from the induction elbow : the vacu um feed is controlled by the integral
valve solenoid and is applied when the so lenoid is energised. The solenoid is pulsed on (energised) and off by a fixed
frequency (100Hz) variable pulse width control signal (pulse width modulation). By varying the pulse on to off time, the
ECM controls the duty cycle of the valve (time that the valve is open to time closed) and thus the vapour flow rate to the
engine.
With no ECM signal applied to the va lve solenoid, the valve remains closed.
Can
ister Purge Operation
The
following pre-conditions are ne
cessary for purging to commence :
aft
er battery disconnection/reconnection, engine
management adaptations must be re-instated.
engine has run for
at least 8 seconds.
engi

ne coolant temperature is not less than 70 °C.
engine

not running in the fuel
cut off condition (eg overrun).
t
he adaptive fuel correction
function has not registered a rich or lean failure
t
he evaporative emission leak test has not failed
no faults have been diagnosted in th
e rel
evant sensor and valve circuits -
Air Flow Meter (AFM), Engine Coolant
Temperature sensor, Evaporativ e Canister Purge valve and Canister Close Valve (CCV).
If these conditions have been satisfied, purging is started. If any failures are registered, purging is inhibited.
The canister(s) is purged during each driv e cycle at various rates in accordance with the prevailing engine conditions. The
engine management software st ores a map of engine speed (RPM) against engine load (grams of air inducted / rev). For
any given engine speed and load, a vapour purge rate is assigned (purge rate increases with engine speed and load).
The preset purge rates are base d on the assumption of a vapour concentratio n of 100%. The actual amount of vapour is
measured by the closed loop fueling system : the input of evaporative fuel into the engine causes the outputs from the
upstream oxygen sensors to change, the am ount of change providing a measure of the vapour concentration. This feedback
causes the original purge rate to be adju sted and also reduces the amount of fuel input via the injectors to maintain the
correct air to fuel ratio.
Engine speed/load mapping and the corresp onding purge rates are different for single canister, running loss and ORVR
evaporative systems.

Thi s
system uses a single charcoal canister with a pressure
control valve between the canister and the fuel tank vapour
outlet. A vacuum control pipe is connecte d from the engine intake induction elbow to the pressure control valve. The vapour
outlet from the fuel tank is taken via a safety rollover valve fitted to the re moveable flange at the top of the tank.
With the engine stopped, the pressure control valve is closed, maintaining a slight positive pre ssure in the tank : any further
increase in pressure causes the valve to open and release vapour to the canister.
When the engine is running, manifold depr ession (via the vacuum control pipe) holds the pressure control valve open. Air is
drawn into the tank to maintain atmospheric pressure as fuel is used and vapourised fuel is deposited in the charcoal
canister.
Canister purge operation is as described in Evaporative Emissions Control.
It e
m
Par
t
Number
De
scr
iption
1—Evaporative flan
ge assembly
2—Vapour outlet rol
lover valve
3—Tank vapour outlet pipe
4—Breather
pipe
5—Pressure control valve
6—Induct
ion vacuum control pipe
7—Charcoal can
i
ster
8—Canister vapour outlet pipe
9—EVAP canister purge v
a
lve
10—Vacuu
m
control sign
al from induction
11—EVAP ca
nister purge valve outlet
12—Canist
er vent
to atmosphere
Single Ca
nister System

The evaporative l
oss flange assembly is fitted to the top of the tank via a seal and locking ring. The assembly is removeable
complete with the fitted components.
The vapour vent / rollover valve is a push fit via a sealing grommet. The fuel pump connector is push fitted and crimped
into a location tube on the underside of the flange.
It
em
Par
t Number
De
scription
1—Vapour vent /

rollover protection valve
2—Fue

l pump connector
3—Evaporative loss flange locking rin

g
Evaporative Flang
e Assembly

The ru nning loss
system has the following features :
a
normall
y open pressure control valve is fi
tted at the lefthand side of the tank.
two charcoal
canisters are connected in series to reduce th
e concentration of fuel in vapour vented to atmosphere.
a t
ank pressure sensor and canister close
valve are fitted to allow the on-board di agnostic facility to test for leaks in
the fuel and evaporative system.
The pressure control valve allows continuo us venting of vapour to the charcoal canisters during normal running but prevents
fuel entering the vent line duri ng refueling. Fuel vapour from the tank passes through the valve to the lefthand canister and
a third pipe connects the valve to the fill er neck. When refueling, the difference in pressure betw een the tank interior and
the open filler neck causes the valve to cl ose, shutting off the vapour vent line. Wh en the fuel cap is replaced, the pressures
are equalised and the pressure control valve opens the vent line to the canisters.
The canister close valve is a solenoid operated device controlled by the ECM. The valve is normally open and is closed only
during the leak test sequence.
The fuel pressure sensor is fitted to th e evaporative loss flange and provides a volt age to the ECM which is proportional to
Ite
m
Par
t
Number
De
scr
iption
1—Vapour outl
et rol
lover valve
2—Evaporative flan
ge assembly
3—Tank vapour outlet pipe
4—Breather pipe
5—Pressure control
valve
6—Vapour pipe to canister
7—Charcoal cani
sters
8—Cani
st
er close valve
9—Vent pi
pe ai
r filter
10—Canister purge ou
tlet pipe
11—Vapour pipe conn
ecting canisters
12—EVAP canister purge v
a
lve
13—Vacuu
m
control signal from induction elbow
14—EVAP pu
rge valve outlet to induction elbow

Running Loss Sys
tem

tank vapou
r pressure.
Canister purge operation is as described in Evaporative Emissions Control.
Evaporative Flange Assembly

The evaporative loss flange assembly is fitted to the top of the tank via a seal and locking ring. The assembly is removeable
complete with the fitted components.
The vapour vent / rollover valve and pressure sensor are a pu sh fit via sealing grommets. The fuel pump connector is push
fitted and crimped into a location tu be on the underside of the flange.
It
em
Par
t Number
De
scription
1—Vapour vent /

rollover protection valve
2—Pres

sure sensor
3—Fue

l pump connector
4—Evaporative loss flange locking rin

g

The system has the
following features :
o
n
-board refueling vapour recovery (ORVR) to reduce the fu
el vapour vented directly to atmosphere from the filler
nozzle when refueling.
two ch arcoal
canisters are connected in series to reduce th
e concentration of fuel in vapour vented to atmosphere.
a t
ank pressure sensor and canister close
valve are fitted to allow the on-board di agnostic facility to test for leaks in
the fuel and evaporative system.
The canister close valve is a solenoid operated device controlled by the ECM. The valve is normally open and is closed only
during the leak test sequence.
The fuel pressure sensor is fitted to th e evaporative loss flange and provides a volt age to the ECM which is proportional to
tank vapour pressure.
Op era
tion of ORVR System
The ORVR system enabl
e
s fuel vapour generated during re-fueling to be collected by
the charcoal canisters. During normal
running of the vehicle, the vapour is collected and purged in the same way as for non-ORVR systems.
Ite
m
Par
t
Number
De
scr
iption
1—Grade vent
valve outl
et
2—Vapour outl
et from fil
l level vent valve (FLVV)
3—F
L
VV pressure relief valve outlet pipe
4—N
a
rrow diameter fuel filler tube
5—Charcoal can
i
sters
6—Cani
st
er close valve
7—Vent pi
pe ai
r filter
8—Vapour pipe
conn
ecting canisters
9—Canister purge ou
tlet pipe
10—EVAP canister purge v a
lve (engine bay)
11—Vacuu
m
control signal from induction elbow
12—EVAP pu
rge valve outlet to induction elbow

Running Loss with On-board R
efuelin
g Vapour Recovery (ORVR) System

The OR
VR system features are :
N

arrow fuel filler pipe and tank check valve.
Fue

l level vent valve (FLVV) fitted to the evaporative flan
ge and consisting of a two stage shut-off valve with rollover
protection and a pressure relief valve.
Grade ven
t valve with rollover protection, fitted to the ev
aporative flange and with an outlet pipe connected to the
FLVV vapour outlet pipe.
Large bore vapour vent pipes.

The fuel filler pipe has a reduced diameter between the nozzle guide and the tank, providing a liquid seal when re-fueling
and preventing the fuel vapour venting directly to atmosphere. There is no breather tube fitted between the tank and the
filler nozzle. To prevent spit back when re-fueling, a check valv e is fitted at the lower end of the filler pipe inside the tank
(see Figure).
During re-fueling, the tank is vented to atmosphere via the fuel level vent valv e (FLVV), large bore vapour pipes and the
charcoal canisters. The FLVV incorp orates a float valve which is closed by the rising fuel level, creating a back pressure and
causing the fuel delivery to stop. In the closed position, the FLVV also sets the fuel level.
With the FLVV closed (tank full), any increase in pressure or overfilling is relieved by a separate rollover protected grade
vent valve. The outlet from this valve feeds into the main FLVV vapour outlet pipe, bypassing the closed FLVV.
When the fuel level is below full, the FLVV opens to allow unrestricted venting via the canisters.
A pressure relief valve is incorp orated into the FLVV assembly and has an outlet pipe to the filler nozzle,. If a blockage or
other restriction (eg, canister close valve failing in the closed position) occurs in the vapour vent system, the pressure reli ef
valve opens to allow venting to atmosphere via the filler nozzle guide and fuel filler cap.
Canister purge operation is as described in Evaporative Emissions Control.
Filler Tube and Check Valve

The fuel fil
ler cap is the same as
that used on non-ORVR systems.
The check valve assembly is a push fit into the end of the fuel filler tube and is accessible with the evaporative flange
removed. The valve has a light spring load ing and opens under the inflow of fuel.
ORVR Evaporative Loss Flange Assembly

The evaporative loss flange assembly is fitted to the top of the tank via a seal and locking ring arrangement identical to that
used for non-ORVR systems. The assembly is re moveable complete with the fitted components.
The fuel level vent valve (FLVV) is mounted in the ELF assembly via a bayonet fitting : it is turned approximately 90 °
clockwise to release. The grade vent valve and pressure sensor are push in fits via sealing gromme ts : note that, due to the
tight fit, removal of these components may require cutting the grommets. The fuel pump connector is push fitted and
crimped into a location tube on the underside of the flange.
It e
m
Par
t
Number
De
scr
iption
1—An
ti-s
urge valve
2—Pressure rel
i
ef pipe
3—Check v
a
lve
It
e
m
Par
t
Number
De
scr
iption
1—Fi
ll
level vent valve (FLVV) /
pressure relief valve assembly
2—Pres
sure
sensor
3—Grade vent
valve
4—Fue
l
pump connector
5—Lockin
g rin
g
6—Evaporative loss flange (ELF)
7—Seal
8—F
u
el pump link lead