Contents: Internal components of the fuel tank ⇩ Fuel pump module ⇩ Fuel level sensors ⇩ Operating principle of the sensor ⇩ Front Fuel Level Sensor…⇩ Rear Fuel Level Sensor…⇩ Fuel pressure regulator ⇩ Receiving glass ⇩ Jet pumps ⇩ Rollover Valves (ROV) ⇩
| Item name | Spare part catalog number | Description |
| 1 | - | Fuel tank breather pipe |
| 2 | - | Fuel pump module assembly |
| 3 | - | Ventilation duct |
| 4 | - | Pump module clamp |
| 5 | - | Pump module cuff |
| 6 | - | Pump module seal |
| 7 | - | FBH pump feed line (if any) |
| 8 | - | Pipeline - Fuel Return |
| 9 | - | Pipeline - fuel supply |
| 10 | - | Frame |
| 11 | - | Fuel supply line nipple |
| 12 | - | Fuel return line nipple |
| 13 | - | Mounting bolt (6 pcs.) |
| 14 | - | FBH feed pipe nipple (if any) |
| 15 | - | Filler neck hose |
| 16 | - | Fuel tank |
| 17 | - | Heat shield |
The fuel tank is located on the right side of the vehicle body between the gearbox and the right side member. The tank rests on a frame by means of which the fuel tank assembly is attached to the vehicle body. The working volume of the fuel tank is 82.0 l.
The frame is attached to the chassis with six screws. When the frame is attached to the chassis, the fuel tank is held against the suspension crossmember by foam pads. A protective cover is attached to the right front corner of the fuel tank, which provides additional protection.
The fuel tank is made of molded plastic with a thickness of at least 3 mm. The fuel tank is a sealed unit with internal access through the flange opening of the pump module at the top of the tank.
The flange assembly consists of a cuff, a clamp, and a pump module flange, which contains all external pipe and electrical connections for the internal components of the tank. The flange is sealed with a gasket in the tank opening. To properly orient the flange, it must be positioned so that the arrow on the flange is between the two marks on the fuel tank adjacent to the pump module flange opening. The cuff is located above the flange and is secured with a clamp.
The flange has an external six-pin connector for connecting fuel level sensors and a fuel pump. This connector is divided into three connectors with a tight fit on the lower side of the flange. The supply and return fuel lines and ventilation pipes are connected using two quick-release fittings. The return fuel line fitting has a check valve that prevents fuel from leaking when the car is turned over and the pipeline is disconnected. If the car is equipped with a torch heater, the third fitting is designed to connect the fuel supply line to the torch heater.
A support structure is installed inside the tank, designed to secure the internal components of the fuel tank. The support structure contains the fuel pump module, the front fuel level sensor, the rollover valves (ROV) and the front jet pump.
The fuel pump module consists of several units. The module includes: a fuel pump, a rear fuel level sensor, a rear jet pump, a pump inlet filter and a fuel pressure regulator installed in a manifold located on the chassis. The pump module assembly and fuel level sensors are supplied only as an assembly; delivery of individual parts of these units is not possible.
Internal components of the fuel tank
| Item name | Spare part catalog number | Description |
| 1 | - | Assembled support structure |
| 2 | - | Corrugated tube of the front inversion valve |
| 3 | - | Fuel Vapor Separator (LVS) |
| 4 | - | Rear Overturn Valve (ROV) |
| 5 | - | Fuel pump module |
| 6 | - | Rear fuel level sensor |
| 7 | - | Corrugated fuel tank breather tube |
| 8 | - | Fuel tank breather nipple |
| 9 | - | Front fuel level sensor |
| 10 | - | Front ROV valve |
| 11 | - | Front jet pump |
The TdV6 engine ventilation system differs from the ventilation systems of gasoline engines. The TdV6 engine ventilation system consists of:
- two rollover valves (ROV)
- one fuel vapor separator (LVS)
- breather groove
The rear ROV valve is mounted in the right rear corner of the fuel tank. It is mounted directly to the LVS via rubber grommet and secured with a clamp.
The forward ROV is mounted in the left front corner of the fuel tank. It is secured with a plastic retainer to the main support structure rod. The ROV is connected to the LVS via a corrugated tube.
Both ROV valves are connected directly to the LVS. Liquid fuel separated from the vapors in the LVS is drained back to the fuel tank through the ROV forward valve.
The LVS vent outlet is connected to the bottom of the fuel tank flange. A vent line then runs from the flange to the top of the filler neck. This line maintains the pressure in the tank at atmospheric pressure during normal operation of the fuel tank. This line allows air to enter the tank as the fuel is used up.
The main purpose of the fuel tank breather nipple is to control the filled volume of the tank. When refueling, fuel vapors from the fuel tank enter the filler neck through the breather nipple and the breather tube. When the fuel in the tank reaches the upper level and fills the breather nipple, the latter closes. Due to the closure of the breather nipple, the pressure in the tank increases, which, in turn, leads to the shutdown of the pump of the filling gun.
Fuel pump module
The fuel pump is attached to the tank support structure and is located at the bottom of the receiving cup. The pump and fuel level sensors are connected to the external electrical connector via connectors on the bottom of the fuel pump module flange.
The nominal capacity of the pump module is 70 l/h at 12.3 V and the output pressure is 0.5 bar (7.25 lbf/in²).
The fuel pump is supplied with power from the fuel pump relay located in the battery junction box. The relay is controlled by the engine control module and is activated each time the ignition key is turned to position II.
The filter is installed in the inlet channel at the bottom of the pump. The filter has a "winged" part located vertically on the side of the pump so that part of the filter is away from the base of the receiving cup to avoid premature contamination of the filter. The filter consists of two parts: a regular filter and a bypass filter. The regular filter has a fine mesh (the cell size is 31 microns) area 70 cm² (10.8 in²)The bypass filter has a large mesh screen. (the cell size is 300 microns) area 4 cm² (0.62 in²). In cold weather, wax can form in the fuel, which restricts the flow of fuel through the fine-mesh filter. In this case, a bypass channel opens, allowing the fuel to pass through the coarse mesh.
There are three connections on the top of the fuel pump module. One connection is the fuel pump outlet, through which fuel is supplied to the manifold. The second connection is designed to return fuel under pressure at the pump outlet from the manifold to the rear jet pump through the pump module housing. The third connection returns fuel from the pressure regulator to the receiving cup when the regulator opens as a result of excess pressure at the pump outlet.
Fuel level sensors
The sensor is a magnetic passive position sensor (MAPPS) whose signal is a change in resistance in the ground circuit of the fuel gauge. For increased reliability, the sensor is isolated from the fuel to prevent contamination of its contacts. The front and rear fuel level sensors are connected to the external electrical connector on the flange via connectors on the bottom of the fuel pump module flange.
The front sensor is mounted on the front of the fuel tank support structure and is accessible through a hole in the fuel pump flange. The rear sensor is mounted on the side of the receiver cup and is also accessible through a hole in the flange.
NOTE: The new tank comes complete with a front fuel level sensor.
The sensor has an arc with a ceramic surface on which 51 film resistors are mounted. The resistors are connected in series by means of separate contacts. A soft magnetic foil with 51 flexible contacts is mounted at a small distance above the film resistors. A magnet is mounted under the ceramic surface and is fixed to the fuel gauge float lever. When the float lever moves, the magnet moves along an arc along the film resistors. The magnet attracts the flexible contacts to the opposite film resistors and closes the circuit.
Operating principle of the sensor
| Item name | Spare part catalog number | Description |
| 1 | - | Magnetic foil |
| 2 | - | Spacer |
| 3 | - | Ceramic surface |
| 4 | - | Magnet |
| 5 | - | Resistive film |
The resistance of the film resistors arranged in a linear arc varies in the range from 51.2 to 992.11 Ohms. The output signal is proportional to the amount of fuel in the tank and the position of the float. The measured resistance is processed in the instrument panel to eliminate the effect of fluctuations in the fuel surface in the tank. The processor monitors the sensor signal and updates the position of the pointer at certain intervals to eliminate constant changes in the position of the pointer due to fluctuations in the fuel surface during braking or turning.
The indicator lamp in the instrument panel comes on when the fuel level in the tank is 10 liters or less.
In the instrument cluster, the signal from the fuel level sensor is converted into a CAN message as a direct interpretation of the fuel tank contents in litres.
Front Fuel Level Sensor Resistance/Fuel Level Gauge Table
NOTE: These values are valid when the vehicle is on a level surface. The fuel gauge readings will change depending on the vehicle tilt.
| Fuel level sensor resistance, Ohm | Nominal reading of the pointer |
| 51,2 | Empty tank |
| 67 | Low fuel alarm (17 l) |
| 281 | Half full |
| 872 | Full |
Rear Fuel Level Sensor Resistance/Fuel Level Gauge Table
NOTE: These values are valid when the vehicle is on a level surface. The fuel gauge readings will change depending on the vehicle tilt.
| Fuel level sensor resistance, Ohm | Nominal reading of the pointer |
| 75 | Empty tank |
| 150 | Low fuel alarm (17 l) |
| 267 | Half full |
| 768 | Full |
Fuel pressure regulator
The fuel pressure regulator is located in the manifold inside the fuel tank. The regulator controls the fuel pressure in the fuel supply line of the high-pressure fuel pump. If the pressure at the pump outlet becomes excessive, the regulator directs some of the fuel back into the receiving cup.
The regulator maintains the fuel pressure at the inlet of the high-pressure fuel pump at a maximum of 0.5 bar. (7.25 lbf/in²), and the operation of the regulator depends on the pressure at the pump outlet. If the pressure exceeds the specified value, the regulator opens, reducing the pressure at the inlet of the high-pressure fuel pump by bypassing part of the fuel into the receiving cup. The main purpose of the regulator is to protect the high-pressure fuel pump from the action of high fuel pressure pumped by the low-pressure fuel pump when high voltage is applied to it.
Receiving glass
The pickup cup is located at the rear of the fuel tank and carries most of the fuel pump assembly components.
The receiver cup serves as a fuel reservoir that ensures a constant supply of fuel to the fuel pump, regardless of the amount of fuel or the tilt of the car. When the car is on a level surface and the engine is running, there is approximately 400 cm³ in the receiver cup. (24.4 in³). Two jet pumps continuously supply the receiving cup with fuel, ensuring the supply of fuel to the pump.
There is a check valve at the base of the receiving cup. The valve allows fuel from the tank to flow into the receiving cup, but does not release it back into the tank.
Jet pumps
The fuel system has two jet pumps. The front jet pump is located on the support structure at the front of the fuel tank. The rear jet pump is located in the receiving cup under the fuel pump. Both pumps operate based on the Venturi effect, which is created by fuel under pressure equal to the pressure at the outlet of the fuel pump, when passing through the jet pump. As a result, an additional amount of fuel comes from the fuel tank into the receiving cup through holes in the body of the jet pump.
The front jet pump is used mainly when driving the car downhill. The jet pump is connected to the fuel manifold by a pipeline through which fuel is supplied under pressure equal to the pressure at the outlet of the fuel pump. Due to its location at the front of the fuel tank, it accumulates fuel from the front of the tank and pumps it into the receiving cup, ensuring a continuous supply of fuel to the pump. The jet pump has a nozzle with a diameter of 1 mm.
The rear jet pump operates at a pressure equal to the outlet pressure of the fuel pump and pumps some fuel from the rear of the fuel tank back into the pickup bowl.
Rollover Valves (ROV)
Two ROVs are located on the fuel tank support structure and are connected by tubing to a fuel vapor separator. The separator, also mounted on the support structure, is connected by tubing to the fuel tank breather outlet on the pump module flange. The ROVs use check valves that close when the vehicle is overturned, preventing fuel from leaking out of the tank through the breather tube.
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