BMW X5: Fuel Pick-Up, Cleaning

GENERAL FUNCTION DESCRIPTION FOR FUEL SUPPLY SYSTEMS

Fuel supply systems, spark-ignition engines

Fuel system

The electric fuel pump in the fuel tank generates the pressure in the fuel system which is set by the pressure regulator to a specific level.

Tank venting system

The tank venting system is an enclosed system which is vented via a carbon canister. The carbon is incorporated in the carbon canister as granulate. The large surface of the carbon stores the fuel vapors which occur in the fuel tank. The carbon canister must be regenerated on a regular basis so as to be able to continue storing fuel vapors.

Regeneration is performed by way of purging with fresh air via the intake manifold. This process is controlled by the engine control unit.

Fuel supply systems, diesel engines

Fuel system

The electric fuel pump in the fuel tank supplies the engine with fuel. Two types of high-pressure pump are used for cylinder injection.

1. The distributor injection pump supplies each cylinder directly with fuel via the corresponding injection nozzle.

2. The high-pressure pump for the common rail systems generates in the fuel rail the necessary pressure for all the injection nozzles.

In common rail systems, a further pump (inline pump, M57/gear pump, M67) is connected between the high - pressure pump and the electric fuel pump. This pump supports the fuel pump in the fuel tank in the event of a high fuel demand.

Tank venting system

Diesel fuel is non-volatile and therefore a carbon canister is not required. The fuel tank is vented directly to atmosphere.

OVERVIEW OF FUEL SUPPLY SYSTEM (PETROL/GASOLINE)

1. Draw off fuel.
2. Dust filter with tube.
3. Leak diagnosis pump.
4. Carbon canister for DMTL (USA).
5. Fuel pump and right fuel gauge sensor.
6. Fuel filler pipe.
7. Carbon canister.
8. Control unit, electric fuel pump.
9. Left fuel gauge sensor.
10. Fuel tank.
11. Clamping bands.
12. Testing.

DRAINING AND FILLING FUEL TANK

Special tools required:

• 16 1 080

IMPORTANT: Observe country-specific safety regulations.

Do not damage non-return flap when pulling out extraction hose.

Diesel vehicles:

Before starting the engine for the first time, if the tank has been run dry or drawn off, fill with diesel fuel and turn on ignition for approx. 1 minute. The fuel circuit is thus filled and vented, which results in the engine firing more quickly.

Drawing off fuel:

Start engine and allow to run.

The electric fuel pump runs.

In this way, the fuel is repumped through the suction jet pump from the left to the right side of the fuel tank.

NOTE: Fuel can be drawn out of left and right sides of tank through filler neck, leaving only a small residue. The residual quantity is drawn off through the service opening (on right/left).

Insert special tool 16 1 080 HOSE GUIDE into filler neck.

Special tool 16 1 080 HOSE GUIDE has two different diameters for petrol/gasoline and diesel vehicles!

Slide extraction hose of extractor unit, refer to BMW Service Workshop Equipment and Planning Documentation , through special tool 16 1 080 HOSE GUIDE into the fuel filler pipe, turning in the process if necessary.

Insertion length approx. 170 cm.

Draw off fuel with suction unit (refer to BMW Service Workshop Equipment ) as far as possible.

Follow drawing off of fuel on fuel gauge in instrument cluster.

Fig. 1: Identifying Special Tool (16 1 080)

Drawing off residual fuel quantity:

IMPORTANT: Ensure car interior is adequately ventilated.

Catch dripping fuel in a suitable container.

Remove left sensor unit.

Remove right sensor unit.

Draw off residual fuel quantity through service openings.

Fuel filling:

Insert special tool 16 1 080 HOSE GUIDE into filler neck.

Special tool 16 1 080 HOSE GUIDE has two different diameters for petrol/gasoline and diesel vehicles! Slide extraction hose of extractor unit, refer to BMW Service Workshop Equipment and Planning Documentation, approx. 40 cm into fuel filler pipe.

Fill fuel from suction extractor unit.

Fig. 2: Identifying Special Tool (16 1 080)

Extracting fuel after a defect in the suction jet pump or fuel pump:

Draw off right half of tank completely through fuel filler pipe.

Remove left sensor unit.

Insert extraction hose through service opening in tank, fuel (also residual quantity) can be drawn off.

CHECKING FUEL TANK AND TANK VENTILATION SYSTEM FOR LEAKS

Special tools required:

• 13 3 010 13 3 010 HOSE CLIP
• 16 1 070 16 1 070 PLUG (CARBON CANISTER)
• 16 1 171 16 1 170 TESTER WITH TEST ADAPTER
• 16 1 174 16 1 170 TESTER WITH TEST ADAPTER

NOTE: The following procedure is only applicable to vehicles without the tank leak diagnosis module. Check tank venting system if a leak is suspected.

Observe safety instructions on raising the vehicle.

Comply with the following conditions in order to obtain plausible test results:

• Content of fuel tank:
  1. Max. 90% (approx. 79 l)
  2. Min. 13% (approx. 11 l, reserve warning lamp must not light up).
• Park the car in the workshop at least 2 hours before the test so that the fuel temperature is approximately that of the workshop temperature (ideal fuel temperature approx. 10...20ºC).
• Never refuel the vehicle directly prior to the leak test due to the strong emission of gas by the fresh fuel.

Remove rear right wheel arch trim.

Fold strainer in insect strainer to one side.

Using special tool 16 1 070 PLUG (CARBON CANISTER), seal opening for insect strainer on carbon canister.

Remove fuel filler cap and connect special tool 16 1 170 TESTER WITH TEST ADAPTER to fuel filler neck.

Clamp special tool.

IMPORTANT: Set pressure regulator on special tool 16 1 171.

Connect special tool.

Connect pressure sensor (2) from Diagnosis and Information System with a measuring range of 0...3.5 bar.

IMPORTANT: Do not connect fast-release coupling (3) of special tool 16 1 171 16 1 170 TESTER WITH TEST ADAPTER yet.

Select "Measurement" function on Diagnosis and Information System (DIS).

Set measuring range according to pressure sensor to 0...3.5 bar.

Using pressure regulator on special tool 16 1 171 16 1 170 TESTER WITH TEST ADAPTER, increase pressure by 0.050 bar.

Connect special tool 16 1 174 16 1 170 TESTER WITH TEST ADAPTER to fast-release coupling of special tool 16 1 171 16 1 170 TESTER WITH TEST ADAPTER.

Using pressure regulator on special tool 16 1 171 16 1 170 TESTER WITH TEST ADAPTER, reset gauge pressure in fuel tank to 0.050 bar.

IMPORTANT: Do not under any circumstances increase pressure by more than 0.100 bar as this would result in damage to the fuel tank and venting system.

Using special tool 13 3 010 13 3 010 HOSE CLIP , disconnect supply line from special tool 16 1 171 16 1 170 TESTER WITH TEST ADAPTER to tank filler neck.

Allow a rest period of approx. 20 secs.

Read off and note down starting pressure value. Wait approx. 60 secs.

Read off final pressure value and compare with starting pressure value.

Measurement Evaluation

CHECKING FUEL TANK AND TANK VENTING SYSTEM FOR LEAKS WITH TANK LEAKAGE DIAGNOSIS MODULE (DM-TL)

NOTE: An OBD fault is indicated by the "Check Engine" indicator lamp in the instrument cluster lighting up. This may indicate a leak in the tank venting system. Information on this is provided by the fault memory of the DME control unit.

• Read out fault memory of DME control unit and carry out a diagnosis in accordance with faults stored.
• A leak test with the DM-TL module is then carried out if:
  • The components of the DM-TL module are O.K.
  • A fault is stored in the DME fault memory (tank leak detected).

Adhere to following conditions in order to carry out a correct leak test:

• Content of fuel tank < 90 %
• Reserve indicator lamp "off"
• Leave car in workshop for at least 2 hours so that fuel temperature comes into line with workshop temperature (ideal fuel temperature approx. 10...20 ºC).
• Do not under any circumstances fill up car with fresh fuel (strong exhalation of fresh fuel).
• Check that fuel tank cap is correctly seated.

WARNING: Check that fuel tank cap is correctly seated.

Clear DME fault memory.

In the Diagnosis and Information System (DIS), go to the "Function and component selection" page.

Work through tank leakage diagnosis module. Leakage test is carried out.

If fault is recorded again in DME fault memory (tank leak detected), carry out leak test.

CONDUCTING LEAK TEST ON FUEL TANK AND TANK VENTILATION SYSTEM

NOTE: The following procedure is only applicable to vehicles with the tank leak diagnosis module (DM-TL).

Select "Tank leak diagnosis module (DM-TL)" on Diagnosis and Information System (DIS).

• The leak diagnosis pump pressurizes the fuel tank and tank venting system for 30 secs.
• If pressure is required for more than 30 secs., reactivate the "Activate" button after 30 secs. in each case.

For vehicles without tank leak diagnosis module:

Pressures fuel tank and tank venting system.

When leak-testing with a leak detector: follow manufacturer's operating instructions.

IMPORTANT: On vehicles with tank leak diagnosis modules (DM-TL), do not work with external pressurization as the tank venting system will leak under this condition. Or use a suitable extractor system.

Observe country-specific accident prevention and occupational safety regulations.

The leak test can be carried out with a leak detector. Possible causes may be:

• Fuel tank cap leaking (check fuel cap pressure relief valve.
• Tank venting lines leaking (fuel tank carbon canister - tank venting valve).
• Tank venting valve leaking (engine compartment).
• Fuel level sensor flange on tank leaking.

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