The fuel gauge sensor consists of a float and a potentiometer.
When the fuel level drops, the sensor float also drops.
In this case, the potentiometer on the float increases the electrical resistance of the sensor. As a result, the voltage supplied to the indicator on the instrument panel decreases, and the arrow of the fuel gauge on the instrument panel deviates in the direction «leer» («empty»).
Attention! On vehicles with a direct injection petrol engine, the fuel pump control unit is located directly on the unit «pump and sensor».
Attention! When dismantling the fuel pump, some fuel may escape. Fuel vapors are poisonous and highly flammable, so keep the room and work area well ventilated. Avoid skin contact with fuel. Wear protective gloves. Avoid open flames and keep a fire extinguisher ready.
When dismantling the fuel pump and sensor, there should be no fuel in the fuel tank. If possible, use it. As an exception, it is allowed to perform work if the tank of a car with a gasoline engine is only 1/2 full, with a diesel engine - 3/4. To ventilate the workplace, you can use a centrifugal fan, the electric motor of which is outside the air flow, with a capacity of 15 mW/hour.
Removing
1. Disconnect the wire terminal with the ignition off «masses» (-) from the negative pole of the battery.
2. Tilt the rear seat forward or, if required, remove the rear seat or right rear seat (Golf Plus vehicles), see the relevant chapter.
3. Release and move back, if necessary, the floor covering under the rear seat.
4. Unscrew the bolts (see arrows in illustration) and remove, if installed, the protective cover 1 above the block «fuel pump - sensor».
5. Remove, prying with a screwdriver, cover 1 above the fuel pump and fuel gauge sensor (see illustration).
Attention! Vehicles with gasoline engines with direct fuel injection (FSI) fuel pump control unit 2 is mounted on cover 1 (see illustration 2.5). The power plug of the unit does not need to be disconnected.
6. Disconnect, being careful, a plug of the gauge of the gauge of a stock of fuel and the fuel pump a hand or having released it from fastening by a small screw-driver.
Attention! The fuel supply line is under pressure. Before disconnecting the fuel hoses, cover the joint with a rag. Disconnect the fuel hose slowly to relieve pressure in the system. Wear protective goggles when performing work.
7. Mark the fuel hoses 1 and 2 before disconnecting them with a felt-tip pen (see illustration).
Disconnect the supply 2 and return 1 fuel lines by squeezing the clamps on the connecting joints (see illustration 2.7). Plug the openings of the pipelines with suitable plugs or wrap them with adhesive tape.
8. Golf cars. Loosen the tightness, and then unscrew the union nut (see illustration). A special wrench is required to loosen the tightening.
For vehicles with 1.4 liter engine and 1.4-/1.6 liter FSI, the VW-3087 key is used, and for all others, VW-10202.
9. Touran cars. Unscrew the flare nut by installing a special wrench VW-3217 on the three rounded tabs of the flare nut (see illustration).
Attention! When turning the wrench, press it from above to ensure a tight fit on the nut (see arrow in illustration 2.9).
Attention! In the absence of the mentioned special wrenches, the union nut can be unscrewed with a wooden drift by hitting it with a hammer. In this case, sparking is not allowed.
10. All-wheel drive vehicles with 2.0 liter FSI engine.
Disconnect the feed pump piping secured by coupling A (see illustration). To do this, press on the coupling driver B and disconnect the hoses.
11. Carefully remove the feed pump and fuel gauge sensor and seal from the fuel tank.
12. Drain the fuel from the pump back into the tank or into a separate suitable container.
13. Inspect the gasket and if damaged or porous, replace it with a new one.
Installation
14. Install the flange o-ring into the hole on the fuel tank. At the same time, do not wet the sealing ring with fuel. Wetting the mating surface of the ring is only necessary when installing the fuel pump together with the fuel gauge sensor.
15. Reinstall the fuel pump, being careful not to bend the fuel gauge sensor lever.
Attention! Observe the correct installation position of the fuel pump. Depending on the model, the reference marks on the pump flange may be placed differently.
16. Golf vehicles with petrol and 2.0 liter BDK diesel engines. Marking on the sealing flange 3 (see illustration 2.6) should be, when viewed in the direction of movement of the car, facing back. The flange can only be installed in this position. If necessary, carefully rotate the fuel pump.
17. Golf cars with 1.9-/2.0-liter AVZ/BKD and Touran diesel engines. Marking on the sealing flange (see arrow in illustration) should be installed opposite the mark on the fuel tank. If necessary, carefully tighten the fuel pump. The label is hard to see.
18. Screw on and tighten the union nut of the fuel tank opening using a special wrench.
Nut tightening torques:
- Golf cars - 110 Nm
- Touran cars - 80 Nm
Attention! In the absence of the mentioned special wrenches, the union nut can be tightened with a wooden drift by hitting it with a hammer. In this case, sparking is not allowed. Make sure the union nut is tight.
19. Connect the return 1 and supply 2 hoses, guided by the marks made before their separation. The hoses have clips that should lock into place. Arrows on the connecting flanges of the hoses indicate the direction of fuel flow (see also illustrations 2.6 and 2.16).
Attention! Do not confuse return and supply hoses. They differ in color. The return hose is blue and the supply hose black.
20. Connect the multi-pin plug and secure it.
21. Be convinced that fuel and vent hoses are fixed in clamps on a tank. Fasten them if necessary.
22. Replace the fuel tank opening cap.
23. Bolt, if present, the protective cover over the tank.
24. Replace the floor covering under the rear seat.
25. Reinstall the rear seat, see the relevant chapter.
26. Connect the battery.
Attention! If the engine does not start after replacing the fuel pump, the fuel system must be bled through the vent hose fitting.
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