Fuel Tank and Lines

Fuel Tank and Lines

5.0L V8 FUEL TANK AND LINES COMPONENT LOCATION (All except NAS)









5.0L V8 FUEL TANK AND LINES COMPONENT LOCATION (NAS ONLY)









GENERAL
The major components of the 5.0L V8 fuel system comprises a fuel tank, a fuel delivery module, a fuel filler assembly and two fuel level sensors.
The 5.0L V8 fuel system uses a returnless fuel system which comprises a fuel pump mounted in the fuel tank to deliver fuel at a variable flow and pressure to the engine mounted high pressure fuel pumps which supply fuel to the fuel rails and to all the fuel injectors.
The fuel pump operation is regulated by a Fuel Pump Driver Module (FPDM) which is controlled by the engine management system. The driver module regulates the flow and pressure supplied by controlling the operation of the fuel pump using a Pulse Width Modulation (PWM) output.
The fuel rails and the injectors are described in Fuel Charging and Controls - 5.0L V8. For additional information, refer to Fuel Charging and Controls Fuel Charging and Controls
For additional information, refer to Turbocharger Fuel system emission control is described in Engine Emission Control - 5.0L V8 For additional information, refer to Electronic Engine Controls Description and Operation
For additional information, refer to Electronic Engine Controls

FUEL TANK
The fuel tank is located on the right hand side of the vehicle, between the transmission and the right hand chassis longitudinal. The tank is located on a mounting cradle which secures the whole fuel tank assembly to the vehicle. The tank is blow moulded from HDPE (high density polyethylene) and has a useable capacity of 86.0 liters (19 gallons).
The cradle is attached to the chassis with six screws. When the cradle is attached to the chassis, the tank is positively secured via foam pads which bear against the central chassis cross beam. A protective cover is fitted to the front right hand corner of the tank and provides additional protection.
The fuel tank is manufactured from moulded plastic which is a minimum of 3 mm thick. The tank is a sealed unit with the only internal access being via the pump module flange aperture on the top of the tank.
The flange is fitted with a locking ring and seal. The seal locates in a groove on the tank. The locking ring locates and clamps on the encapsulated ring that is moulded into the fuel tank. The flange has a tag which locates in the top of the tank to ensure correct orientation.
The flange has six pin internal and external connectors which provide for electrical connections for the level sensors and the fuel pump. A quick release connector provides for the connection of the fuel supply pipe.
A carrier within the tank provides for the mounting of the fuel suction tube, vent valve, and the front fuel level sensor.
The fuel delivery module is mounted on a bayonet lock ring which is welded inside the fuel tank. The fuel delivery module comprises the fuel pump, jet pumps, the pump inlet filter and the fuel pressure relief valve. The rear fuel level sensor is also mounted on the side of the pump module body.
The pressure relief valve assists engine starting by retaining a pre-set fuel pressure in the fuel supply pipe and the fuel rails. The valve also limits fuel rail pressure due to temporary vapor increase in hot conditions and pressure caused by sudden load changes; a fully open to closed throttle transition, for example.
Only the pump module assembly, the fuel level sensors and the flange are available as serviceable components, the individual assembly components are not available separately.

FUEL DELIVERY MODULE









The fuel delivery module is a new design for 5.0L V8 2010MY vehicles. The module is located inside the fuel tank and comprises three main components; a fuel pump, a remote fuel pick-up and a top flange assembly.

Fuel Pump
The fuel pump is a variable-speed rotary-vane type, which operates in a fuel pump module located at the rear of the fuel tank. A venturi transfer pump is also located in the rear of the tank. The fuel pump module is secured in the fuel tank with a bayonet style locking ring that is welded into the tank structure. The fuel pump module has an integral top plate for the external pipe work and electrical connectors.
The fuel pump delivers fuel at a maximum pressure of 630 kPa (6.3 bar; 91.4 lbf/in.2) to the filter bowl in the top flange.
The electric pump is located in a plastic swirl pot which collects fuel from the base of the fuel tank via a filter. The swirl pot acts as a fuel reserve, providing a constant supply of fuel to the fuel pump irrespective of fuel quantity or vehicle attitude. When the vehicle is level the swirl pot contains approximately 275 cm3 (16.8 in3) of fuel when the engine is running. The jet pump ensures that fuel is constantly supplied to the swirl pot to provide a sufficient fuel supply for the pump. A one way valve is located in the base of the swirl pot. The valve allows fuel from the tank to enter the swirl pot, but prevents it from escaping.
The fuel level sensor for the rear of the tank is attached to the outside of the swirl pot.
The fuel pump module is a serviceable component and access to the pump is by removal of the top flange.

Remote Fuel Suction Jet and Level Sensor Assembly
The remote fuel suction jet is located in the front of the fuel tank. The fuel suction jet is attached to the internal carrier which is secured inside the fuel tank.
The fuel system incorporates 2 jet pumps. The jet pumps are integrated into the fuel pump module and draw fuel from the front and rear of the fuel tank. A suction pipe is connected to the fuel suction jet that is located in the front of the tank that allows fuel to be drawn from the front of the tank, delivering fuel into the swirl pot via the suction pipe connection on the pump body. The jet pump operates on a venturi effect created by the fuel at pump output pressure passing through the jet pump.
The fuel level sensor for the front of the fuel tank is attached to the carrier frame. The fuel suction jet and the level sensor are serviceable components and access is by removal of the flange cover on the top rear of the fuel tank.

Top Flange Assembly
The top flange is located on the top of the fuel tank. The flange assembly is sealed in the tank with a with a sealing ring. A locking ring secures the flange assembly in the tank and requires a special tool for removal.
The outer surface of the flange has 1 fuel feed outlet with a quick-fit connection. The connection is for the fuel supply pressure outlet to the engine mounted fuel pumps. An electrical connector is located adjacent to the pipe connections and provides the electrical interface to the fuel pump and the level sensors. A breather connection allows the fuel tank to breathe and connects the fuel tank to the fuel filler and charcoal canister systems.
On the underside of the flange, inside the tank, is a moulded housing which contains the non-serviceable fuel filter. Fuel from the fuel pump enters the base of the housing and passes through the filter before exiting the tank to the engine mounted fuel pumps. An electrical connection on the base of the filter housing provides a ground for the filter.

FUEL PUMP DRIVER MODULE (FPDM)









The FPDM is located in the LH side of the luggage compartment, above the LH wheel arch, behind the trim panel. The FPDM is located on a bracket and secured with 2 bolts and nuts.
The fuel pump operation is regulated by the FPDM which is controlled by the Engine Control Module (ECM). The FPDM regulates the flow and pressure supplied by controlling the operation of the fuel pump using a PWM output.
The FPDM is powered by a supply from the fuel pump relay in the Engine Junction Box (EJB). The fuel pump relay is energized on opening the driver's door or when power mode 9 engine crank is initiated using the stop/start button. The FPDM supplies power to the fuel pump, and adjusts the power to control the speed of the fuel pump and thus the pressure and flow in the fuel delivery line.
A Pulse Width Modulation (PWM) signal from the ECM tells the FPDM the required speed for the fuel pump. The on time of the PWM signal represents half the fuel pump speed, e.g. if the PWM signal has an on time of 50%, the FPDM drives the pump at 100%.
The FPDM will only energize the fuel pump if it receives a valid PWM signal, with an on time of between 4% and 50%. To switch the fuel pump off, the ECM transmits a PWM signal with an on time of 75%.
The output pressure from the fuel pump will change with changes of engine demand and fuel temperature. The ECM monitors the input from the Low Pressure (LP) fuel sensor and the fuel rail pressure sensor and adjusts the speed of the fuel pump as necessary to maintain a nominal output pressure of 450 kPa (4.5 bar; 65.3 lbf/in.2), except during engine start-up. At engine start-up the target pressure for the fuel delivery line is 630 kPa (6.3 bar; 91.4 lbf/in.2).
If the Supplemental Restraint System (SRS) outputs a crash signal on the high speed Controller Area Network (CAN) bus, the ECM de-energizes the fuel pump relay to prevent any further fuel being pumped to the engine.
If the ECM does not detect pressure in the fuel delivery line, it stops, or refuses to start the engine and stores the appropriate Diagnostic Trouble Code (DTC).
The ECM receives a monitoring signal from the FPDM. Any DTC's produced by the FPDM are stored by the ECM.
DTC's can be retrieved from the ECM using an approved Land Rover diagnostic system. The FPDM itself cannot be interrogated by the approved Land Rover diagnostic system.

FUEL LEVEL SENSORS
Two fuel level sensors are used in the fuel tank to measure the amount of remaining fuel in the front and rear of the fuel tank. The front level sensor is attached to the internal carrier and the rear level sensor is attached to the fuel pump swirl pot. The sensors are connected to the vehicle wiring harness via a connector on the outer face of the top flange assembly.
The sensors are a Magnetic Passive Position Sensor (MAPPS) which provides a variable resistance to ground for the output from the fuel gauge. The sensor is sealed from the fuel preventing contamination of the contacts and 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 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









The film resistors are arranged in a linear arc with resistance ranging from 51.2 to 992.11 Ohms. The electrical output signal output is proportional to the amount of fuel in each side of the tank and the position of the float arms. The measured resistance is processed by the instrument cluster to implement an anti-slosh function. This monitors the signal and updates the fuel gauge pointer position at regular intervals, preventing constant pointer movement caused by fuel movement in the tank due to cornering or braking.
A warning indicator is incorporated in the instrument cluster and illuminates when the fuel level is at or below 10 liters (2.64 US gallons).
The fuel level sender signals are converted into a CAN bus message by the instrument cluster as a direct interpretation of the fuel tank contents in liters. The ECM uses the CAN bus message to store additional On-Board Diagnostic (OBD) P Codes for misfire detection when the fuel level is below a predetermined capacity.

FUEL FILLER PIPE AND TANK BREATHER ASSEMBLY

Fuel Filler Pipe Assembly (All Except NAS)









Fuel Filler Pipe Assembly (NAS Only)









The fuel filler head is positioned at the rear of the vehicle, above the right hand rear wheel. The filler head and cap is covered by a moulded plastic cover which is electrically locked when the vehicle is locked.
The filler cap is a conventional screw in type which is secured to the vehicle with a lanyard. The filler cap must be securely fitted to ensure that the tank venting system is sealed. The cap has a locking mechanism which gives an audible click when the cap is correctly tightened.
Failure to correctly secure the filler cap will result in vapor being lost from the system. On NAS Vehicles, if the cap is incorrectly secured when the engine management system operates the Diagnostic Monitoring Tank Leakage (DMTL) system, the loss of vapor will be detected as a leak and the MIL lamp will be illuminated.
The filler head is a stainless steel fabrication. A bracket provides for the attachment of the filler head to the vehicle body.
A connection on the rear of the filler head allows for the connection of the fuel tank breather pipe from the vapor separator on ROW vehicles and from the roll over valves on NAS vehicles.
The fuel filler pipe locates in the tank and incorporates a spitback flap in the tank end of the pipe. The flap is a spring loaded cover which acts as a 1-way valve, allowing the tank to be filled but preventing fuel leaving the tank into the filler pipe.
All vehicles have a charcoal canister breather pipe which is connected from the charcoal canister and is routed alongside the fuel filler pipe to the filler head. The filler head end of this pipe is connected differently depending on market as follows:
- On ROW vehicles the breather pipe is fitted with a mesh and allows fresh air to be drawn into the charcoal canister when fuel vapor is being purged from the system.
- On NAS vehicles the breather pipe is connected to the DMTL pump. Fresh air is drawn into the pipe via a DMTL filter integral with the pump when fuel vapor is being purged from the system. When the DMTL system is active, the breather pipe is closed by the pump, sealing the system and allowing the system to be pressure checked for leakage.
For information on the charcoal canister and purging system refer to the evaporative emissions section. For additional information, refer to Evaporative Emissions
A second pipe is routed alongside the charcoal canister breather pipe. On ROW vehicles, this pipe is the fuel tank breather pipe from the vapor separator and is connected into the fuel filler pipe near to the filler head. On NAS vehicles, this pipe is smaller in diameter and also serves as the fuel tank breather pipe. The pipe is not connected to the vapor separator but allows fuel vapor from the right hand roll over valve to vent into the connection with the fuel filler pipe near to the filler head.
A pipe is routed across the top of the tank in front of the vapor separator. This pipe connects the charcoal canister to the purge valve located in the engine compartment.

FUEL LOW PRESSURE (LP) SENSOR





The fuel LP sensor supplies a pressure signal to the Engine Control Module (ECM) to enable closed loop control of the fuel pump. The fuel LP sensor is installed in a manifold in the fuel supply line. The manifold is located in the rear of the front Right Hand (RH) wheelarch, behind the splash shield.

OPERATION
The fuel pump is a variable-speed rotary-vane type, which operates in a fuel delivery module located in the fuel tank. The fuel delivery module is secured in the fuel tank with a bayonet style locking ring that is welded into the tank structure. The fuel pump module has an integral top plate for the external pipe work and electrical connectors.
Fuel level is biased towards the rear of the fuel tank by drawing fuel from the front of the tank via the jet pump, which serves to deliver a constant supply of fuel to the swirl pot. High pressure fuel from the fuel pump is directed through the jet pump's orifice, creating a low pressure area to be formed in the cross over pipe. The fuel is drawn into this low pressure area in the cross over pipe and directed into the swirl pot delivery pipe.
Fuel is pumped from the fuel pump to the to the two engine mounted HP fuel pumps via the integral filter and pressure relief valve.
The pressure relief valve assists engine starting by retaining a pre-set fuel pressure in the supply pipe and fuel rail. The pressure relief valve also limits fuel rail pressure due to temporary vapor increase in hot conditions and pressure caused by sudden load changes, for example, a fully open to closed throttle transition.
To meet emission requirements, the fuel tank and associated components are designed to minimize fuel vapor loss during refueling. This is achieved by preventing fuel vapor from the fuel tank venting directly to the atmosphere. Instead fuel vapor is directed into the charcoal canister where it is stored before being purged at intervals to the engine's intake manifold.
North American Specification (NAS) vehicles feature additional connections and pipes at the rear of the filler head and also incorporates a Diagnostic Monitoring Tank Leakage (DMTL) pump for leak detection requirements.

Fuel System Schematic Diagram