LR3/Disco 3
tank via the FLVV. The LVS is connected by a corrugated tube to the fuel pump module flange. This allows fuel vapor to
exit the tank during venting.
The main purpose of the FLVV is to control the fill volume of the tank. During filling, vapor is passed via the FLVV to the
LVS. The vapor then passes from the LVS to the fuel pump module flange vent connection via a corrugated tube. The
flange vent connection is connected to the charcoal canister which stores the fuel vapor. During filling, when the tank
reaches its full level, the FLVV closes and prevents fuel vapor passing through to the LVS. This causes the pressure in
the tank to rise which in turn causes the pump filling nozzle to turn off.
Fuel Pump Module
The fuel pump is attached to the carrier and is located in the bottom of the swirl pot. The pump and the fuel level sensors
are connected to the external electrical connector via the connectors on the underside of the fuel pump module flange.
The pump module has a rated flow of 122 litres/hour (32.2 US gallons/hour) at a voltage of 12.3V and an output pressure
of 4.5 bar (65.2 lbf/in
2
).
The fuel pump is energised by the fuel pump relay which is located in the battery junction box. The relay is controlled by
the engine control module and energises the relay at all times when the ignition switch is in ignition position II.
A pump inlet filter is attached to pump inlet port at the bottom of the pump. The filter has a 'winged' section which is
located vertically at the side of the pump to ensure that a portion of the filter is off the base of the swirl pot, to prevent
premature blocking of the filter. The filter has a 31 micron fine mesh filter with a surface area of 70 cm
2
(10.8 in
2
).
A second fine mesh filter is located around the top of the fuel pump. This provides additional filtration to the fuel before it
is passed into the manifold and onto the fuel rail. The filter has an electrical connection which is attached to ground. The
ground is required to dissipate electrostatic charges that can build up on the fine filter.
The fuel filter incorporates a non-return valve which prevents fuel returning to the pump when the engine is not running.
This ensures that system pressure is maintained in the fuel feed line to the fuel rail when the engine is not running.
Fuel Level Sensors
The sensor is a MAgnetic Passive Position Sensor (MAPPS) which provides a variable resistance to earth for the output
from the fuel gauge. The sensor is sealed from the fuel preventing contamination of the contacts, increasing reliability.
The front and rear fuel level sensors are connected to the external electrical connector on the flange via the connectors
on the underside of the fuel pump module flange.
The front sensor is attached to the front of the carrier and is accessible via the fuel pump flange aperture. The rear sensor
is attached to the side of the swirl pot and is also accessible via the flange aperture.
NOTE :
The sensor comprises a series of 51 film resistors mounted in an arc on a ceramic surface. The resistors are wired in
series with individual contacts. A soft magnetic foil with 51 flexible contacts is mounted a small distance above the film
resistors. A magnet, located below the ceramic surface, is attached to the sender unit float arm. As the float arm moves,
the magnet follows the same arc as the film resistors. The magnet pulls the flexible contacts onto the opposite film resistor
contacts forming an electrical circuit.
Sensor Operating Principle
When a service replacement tank is ordered the tank is supplied with the front level sensor fitted.
