2002 LAND ROVER DISCOVERY battery

FUEL DELIVERY SYSTEM - TD5
19-1-10 DESCRIPTION AND OPERATION
Water sensor
The water sensor has a three pin electrical connector. When the sensor detects water in the filter it illuminates a
warning lamp in the instrument pack .

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
The water sensor attachment thread has a slot machined down one side. The filter can be purged of water by partially
unscrewing the sensor which aligns the slot in the threads with a corresponding hole in the sensor. When aligned,
water and fuel can flow down the slot and flows from a small cast tube on the side of the sensor. Re-tightening the
sensor misaligns the slot and stops the flow of fuel.
The water sensor receives a battery supply from the fuel pump relay in the engine compartment fusebox on one of
the electrical connector pins. The two remaining pins are connected to the instrument pack and an earth header joint.
The sensor operation uses the measurement of resistance between two electrodes submerged in the fuel and
activated by the presence of water.
When the ignition is moved to position II the warning lamp will illuminate for approximately two seconds to check
warning lamp functionality. TestBook can also illuminate the warning lamp to check its functionality.
When the filter is full with fuel and no water is present the resistance of the Diesel fuel will show a reading of 15 mA
maximum on the feed wire to the instrument pack. This current will not illuminate the water sensor warning lamp in
the instrument pack. When sufficient water surrounds both electrodes the resistance of the water will show a reading
of 130 mA maximum. This will supply sufficient voltage to the instrument pack to illuminate the warning lamp to alert
the driver to the presence of water in the fuel system.

FUEL DELIVERY SYSTEM - TD5
DESCRIPTION AND OPERATION 19-1-11
Operation
When the ignition switch is moved to position II, the fuel pump relay in the engine compartment fusebox is energised
by the ECM. Battery voltage is supplied from the fuel pump relay to the fuel pump which operates. If engine cranking
is not detected by the ECM within a three minute period, the ECM will 'time-out', de-energising the fuel pump relay.
When the ignition is turned off the ECM timer will reset.
The low pressure stage of the fuel pump draws fuel from the swirl pot and pumps it into the fuel filter. The high
pressure stage of the fuel pump draws the fuel from the fuel filter and pumps it along the fuel feed pipe to the cylinder
head.
The fuel enters the cylinder head through a connection on the fuel pressure regulator housing and supplies each
injector with pressurised fuel. The fuel pressure regulator maintains the fuel pressure at the injectors at 4 bar (58
lbf.in
2) by returning excess fuel back to the fuel filter. The returned fuel passes through the fuel cooler in the engine
compartment before it passes to the fuel filter.
When the engine is running, each injector is operated by an overhead camshaft which depresses a push rod in each
injector at a timed interval. When the cam has depressed the push rod and the push rod is returning to its extended
position, fuel is drawn from the fuel supply drilling into the injector.
When the ECM determines that injection is required, the ECM transmits an electrical pulse which energises the fast
acting solenoid, closing the spill valve on the injector and locking fuel in the injector body. As the cam begins to
depress the push rod, the fuel in the injector is rapidly pressurised. When the pressure exceeds the nozzle spring
pressure, the nozzle opens and injects fuel at very high pressure into the cylinder.
When the ECM determines that the injection period should end, the solenoid is rapidly de-energised, opening the spill
valve on the injector and allowing fuel to pass into the return circuit.
The ECM controls the injection timing by altering the time at which the solenoid is energised and the injection period
by controlling the period for which the solenoid is energised.

FUEL DELIVERY SYSTEM - TD5
ADJUSTMENTS 19-1-13
ADJUST ME NTS
Fuel system purging
$% 19.50.07
If the vehicle runs out of fuel, or the fuel level is so
low that the fuel system draws air into the fuel rail,
the fuel rail will need to be purged before the engine
will start. This can be achieved by following the
procedure below.
If this procedure is carried out on a vehicle that
has not run out of fuel or otherwise drawn air into
the fuel rail, it can lead to the engine flooding and
failing to start.
Purge
1.Turn the ignition switch off and wait 15
seconds.
2.Turn the ignition switch to position II and wait 3
minutes (this ensures that the fuel system
purges all the air from the fuel rail within the
cylinder head).
3.Fully depress the throttle pedal.
4.Keeping the throttle pedal fully depressed,
crank the engine.
5.As soon as engine speed exceeds 600 rev/min,
release the throttle pedal and the ignition
switch.The engine must not be cranked
continuously for more than 30 seconds at
any one time.
6.If the engine fails to start, repeat the above
procedure.
Fuel tank - drain
$% 19.55.02
Drain
1.Disconnect both leads from battery.
WARNING: Always disconnect the negative
lead first. Disconnection of the positive lead
while the negative lead is connected could
result in a short circuit through accidental
grounding and cause personal injury.
2.Remove fuel pump.

+ FUEL DELIVERY SYSTEM - Td5,
REPAIRS, Pump - fuel.
3.Using a fuel recovery appliance, drain the fuel
from the tank into a sealed container. Follow
the manufacturers instructions for the
connection and safe use of the appliance.
Refill
1.Fit fuel pump.

+ FUEL DELIVERY SYSTEM - Td5,
REPAIRS, Pump - fuel.
2.Connect battery leads, positive terminal first.

FUEL DELIVERY SYSTEM - TD5
REPAIRS 19-1-15
REPAIRS
Switch - inertia - fuel cut-off
$% 19.22.09
Remove
1.Disconnect multiplug from fuel cut-off switch.
2.Remove 2 screws securing fuel cut-off switch to
bulkhead.
3.Remove fuel cut-off switch from bulkhead.
Refit
1.Position fuel cut-off switch to bulkhead and
secure with screws.
2.Connect multiplug to fuel cut-off switch.
3.To set the fuel cut-off switch, depress the top of
the fuel cut-off switch.
Pump - fuel
$% 19.45.08
NOTE: The fuel pump and fuel gauge tank unit are
integral parts of the fuel pump housing and cannot be
renewed separately
Remove
1.Release fixings and remove battery cover.
2.Disconnect battery earth lead.
3. Models with third row seats: Remove RH
third row seat.

+ SEATS, REPAIRS, Seat - third row.
4.Remove 5 trim clips securing lower edge of RH
'D' post trim casing.
5. Models with rear ICE controls: Remove
screw securing remote ICE controls to RH side
trim casing.
6. Models with rear ICE controls: Release ICE
controls from RH side trim casing. Disconnect
multiplug and remove ICE controls.
7.Partially remove tail door aperture seal in the
area of the RH side trim casing.

FUEL DELIVERY SYSTEM - TD5
19-1-16 REPAIRS
8.Remove 2 trim clips securing RH side trim
casing to body.
9.Remove rear lamp access panel from RH side
trim casing.
10.Remove trim clip securing RH side trim casing
to lower 'E' post.
11. Models with third row seats:Remove bolt
securing lower mounting of RH third row seat
belt to body.
12.Remove RH side trim casing.
13.Pull back loadspace carpet from fuel pump
access panel.
14.Remove 6 screws securing access panel.
15.Remove access panel.
16.Disconnect multiplug and 4 fuel hoses from fuel
pump housing.
CAUTION: Always fit plugs to open
connections to prevent contamination.17.Use LRT-19-009 to remove locking ring from
fuel pump housing.
18.Remove fuel pump housing.
19.Remove and discard sealing ring from fuel
pump housing.
Refit
1.Clean fuel pump housing and mating face on
fuel tank.
2.Fit new seal to mating face on fuel tank.
3.Fit fuel pump housing to fuel tank and use LRT-
19-009 to fit locking ring.
4.Connect multiplug and fuel hoses to fuel pump
housing. Ensure each hose is installed in the
connector with the corresponding colour
code.
5.Fit access panel and secure with screws.
6.Reposition loadspace carpet.
7.Fit RH side trim casing.
8. Models with third row seats:Fit bolt securing
lower mounting of RH third row seat belt to
body and tighten to 50 Nm (37 lbf.ft).
9.Fit trim clip securing RH side trim casing to
lower 'E' post.
10.Fit rear lamp access panel to RH side trim
casing.
11.Fit trim clips securing RH side trim casing to
body.
12.Fit tail door aperture seal.
13. Models with rear ICE controls: Connect
multiplug to remote ICE controls.
14. Models with rear ICE controls: Fit ICE
controls to trim casing and secure with screw.
15.Fit trim clips securing lower edge of 'D' post
trim casing to body.
16. Models with third row seats: Fit RH third row
seat.

+ SEATS, REPAIRS, Seat - third row.
17.Connect battery earth lead.

FUEL DELIVERY SYSTEM - V8
DESCRIPTION AND OPERATION 19-2-7
The fuel pump is a 'self priming' wet type pump which is immersed in fuel in the tank. The fuel pump operates at all
times when the ignition switch is in position II. If the engine is not started, the ECU will 'time-out' after 2 seconds and
de-energise the fuel pump relay to protect the pump. The pump receives a feed from the battery via fuse 10 in the
engine compartment fusebox and the fuel pump relay. The relay is energised by the ECM when the ignition switch is
moved to position II.
The fuel pump is retained with a locking ring and sealed with a rubber seal. The locking ring requires a special tool
for removal and fitment. An access panel for the fuel pump is located in the loadspace floor below the loadspace
carpet. The access panel is sealed to the floor with a rubber seal and retained by six self-tapping screws.
The fuel gauge sender is integral with the fuel pump. The sender is submerged in the fuel and is operated by a float
which moves with the fuel level in the tank.
Fuel pump
The fuel pump assembly comprises a top cover which locates the fuel pressure regulator, electrical connector and
fuel pipe coupling. The top cover is attached to a plastic cup shaped housing by two metal springs. The housing
locates the pump and the fuel gauge sender unit.
The lower part of the housing is the swirl pot, which maintains a constant fuel level at the fuel pick-up. A feed pipe
from the pump to the coupling connection and a return pipe from the regulator connect between the top cover and the
housing.
A coarse filter is attached to the base of the housing and prevents the ingress of large contaminants into the swirl pot.
A gauze filter prevents particles entering the fuel pump.
Surrounding the pump is a large fine paper filter element which further protects the fuel pressure regulator, engine
and injectors from particulate contamination. The paper filter is not a serviceable item and removes the requirement
for an external in-line filter.
A non-return valve is located in the base of the housing. When the fuel tank is full, fuel pressure keeps the valve lifted
from its seat allowing fuel to flow into the swirl pot. As the tank level reduces, the fuel pressure in the tank reduces
causing the valve to close. When the valve is closed fuel is retained in the swirl pot, ensuring that the swirl pot remains
full and maintains a constant supply to the fuel pump.
A four pin electrical connector is located on the top cover of the pump and provides power feed and return for fuel
pump and fuel gauge rotary potentiometer operation. A single quick release coupling connects the fuel feed pipe to
the outer top surface of the pump.
Two metal springs are attached to the top cover and the housing of the pump. When the pump is installed it seats on
the lower surface inside the tank. The springs exert a downward pressure on the pump and ensure that the pump is
located positively at the bottom of the fuel tank.
The fuel pump has a maximum current draw of 6.5 A at 12.5 V.
On NAS vehicles with vacuum type EVAP system leak detection capability only, the fuel pump top cover is fitted with
an On Board Diagnostics (OBD) pressure sensor. This sensor has a three pin electrical connector which provides a
connection between the sensor and the ECM. The sensor is sealed in the top cover with an 'O' ring and secured with
a clip. The sensor monitors tank pressure during OBD tests of the fuel evaporation system integrity. A hose is
connected to the sensor and is routed across the top of the fuel tank and terminates at the top of the fuel filler tube.
The pipe is open to atmosphere and provides atmospheric pressure for the sensor operation.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.

FUEL DELIVERY SYSTEM - V8
19-2-8 DESCRIPTION AND OPERATION
Fuel pressure regulator
The fuel pressure regulator is located in the underside of the top cover. The regulator is sealed with two 'O' rings and
retained with a clip.
The regulator is connected to the fuel feed pipe at the top of the pump housing and maintains the fuel pump delivery
pressure to 3.5 bar (50 lbf.in
2). When the fuel delivery pressure exceeds 3.5 bar (50 lbf.in2), the regulator opens and
relieves excess pressure back to the swirl pot via a return pipe. The regulator ensures that the fuel rails and injectors
are supplied with a constant pressure.
The fuel pump delivery pressure and pressure regulator operating pressure can be checked using a Schraeder type
valve located at the rear of the engine on the fuel rail. The valve allows the pump delivery pressure to be measured
using a suitable gauge and an adaptor and hose which are special tools.
Fuel gauge sender
The fuel gauge sender unit comprises a rotary potentiometer operated by a float. The float rises and falls with the fuel
level in the tank and moves the potentiometer accordingly.
Battery voltage is supplied to the potentiometer. The output voltage from the potentiometer varies according to the
resistance through the potentiometer in relation to the fuel level. The output voltage is connected to the fuel gauge in
the instrument pack. The fuel gauge receives a battery voltage input and this is compared with the output voltage from
the potentiometer. The difference between the two voltages determines the deflection of the fuel gauge pointer.
Fuel gauge reading Tank volume litres (US Gallons) * Sender unit resistance
ohms Ω
FULL 95 (25) 15
3/4 71 (18.8) 36
1/2 48 (12.7) 64
1/4 24 (6.4) 110
RESERVE (fuel light ON) 11 (2.9) 158
EMPTY 0 (0) 245
*Tank volumes are approximate.

FUEL DELIVERY SYSTEM - V8
DESCRIPTION AND OPERATION 19-2-9
Injectors
1'O' ring 2 off
2Electrical connector
3Steel housing
4Filter strainer
5Spring6Valve needle and armature
7Valve seat/spray orifice
8Plastic housing
9Solenoid winding
An injector for each cylinder is mounted externally in the lower inlet manifold on the engine. The injector protrudes
into the inlet manifold tract, where it releases a controlled delivery of fuel into the manifold air inlet.
Each injector is sealed to the fuel rail and the inlet manifold with 'O' rings. Spring clips retain each injector to the fuel
rail and the attachment of the fuel rail clamps the injectors in the lower manifold.
The injector housing is manufactured from plastic which encapsulates a high-alloy steel housing. The steel housing
contains all components which come into contact with fuel. The plastic housing also provides the attachment for the
engine harness connector for the injector. A solenoid is located between the two housings and moves a valve needle
via an armature. The valve needle seats on a valve seat which incorporates a spray orifice plate. A filter strainer is
fitted at the connection with the fuel rail to remove any particulate matter from the fuel before it enters the injector.
When the ECM energises the solenoid, the armature moves lifting the valve needle off its seat. This allows
pressurised fuel from the fuel rail to pass through the injector housing and needle to the spray orifice. The spray orifice
controls the spray shape and fuel metering. When the solenoid is de-energised, the valve needle returns to the valve
seat, aided by a spring, closing off the injection of fuel into the inlet.
Each injector receives a battery supply voltage via a fuse in the engine compartment fusebox. The fuel delivery timing
is controlled by the ECM, which, at a precisely timed interval, provides a ground path for the injector. The completion
of the ground path operates the injector to allow fuel at pump pressure to be delivered from the fuel rail to the injector
nozzle. Each injector sprays a finely atomized spray of fuel into the inlet, where it is mixed with the intake air prior to
combustion.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.
Faults for each injector are stored in the ECM and can be retrieved using TestBook. Each injector can be checked
across the two connector pins. For a correctly functioning injector a resistance of between 13.8 and 15.2 ohms at a
temperature of 20
°C (65°F) should be read across the pins.