Fuel Supply System - Repair BMW Z4 E85/E86

Scheme 45

1. General 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.
2. 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.
3. Parts designation PARTS DESIGNATION 1. Fuel tank (plastic) 12. Non-return flap 2. Surge chamber 13. Fuel feed line 3. Electric fuel supply pump 14. Fuel rail 4. Suction jet pump 15. Carbon canister (AKF) 5. Fuel filter with pressure regulator 16. Purge air line 6. Fill level limiting valve (rollover valve) 17. Tank vent valve (TEV) 7. Overpressure safety valve 18. Intake manifold 8. Service vent valve (rollover valve) 19. Engine control unit (DME) 9. Vent line 20. Tank leakage diagnostic module (USA only) 10. Mushroom valve 21. Dust filter (USA only) 11. Fuel filler pipe A: Max. fuel tank fill height
4. Function description Fuel system The saddle-shaped fuel tank contains the surge chamber with integrated electric fuel supply pump and level sensor on its right side. The surge chamber ensures that the fuel supply pump is properly supplied in all vehicle operating states. The fuel is pumped from the right side of the fuel tank into the surge chamber via the suction jet pump integrated in the surge chamber. The fuel in the left tank half is repumped via a second suction jet pump from left to right. Return line, pressure regulator and fuel filter are located in the tank. The non-return flap prevents fuel from splashing back in the filler pipe after shutdown of the petrol/gas pump nozzle. Fuel supply to engine: M54 The fuel is routed from the electric fuel supply pump via the fuel filter and the fuel feed line to the fuel rail. Pressure regulator and fuel filter are incorporated in a single unit in the tank. This removes the need for a fuel return line. The fuel passes through the pressure regulator into the left side of the tank and thereby drives a suction jet pump. This pump repumps the fuel from the left side of the tank to the right side. The fuel rail is return-free. Venting system USA The fuel tank is vented during refueling via the vent line. Because of its large cross-section, the vent line directs the displaced volume (fuel vapors) at high speed to the carbon canister. The activated carbon retains the fuel contained in the fuel vapors. The cleaned air is discharged to atmosphere via the evaporation line, the tank leakage diagnostic module and the dust filter. During driving, the system tank is vented in the same way via the vent line. The condensed constituents of the fuel vapors remain in the tank because the tank has an integrated compensating volume. The limiting valve in the tank is closed by the rising fuel if the tank is overfilled. The residual volume thus created replaces the expansion tank. The ventilation function is maintained by a second float valve. Both valves are designed as rollover valves. This prevents fuel from escaping from the fuel tank in extreme vehicle positions (overturning, inclined position). The carbon canister is regenerated by purging with fresh air. The engine control unit opens the tank vent valve. Thus the vacuum pressure of the engine intake manifold is applied at the purge line. The carbon canister is purged in this way. The fresh air needed for this purpose is supplied via the tank leakage diagnostic module and the dust filter. The fuel constituents bound by the activated carbon are flushed out by the supplied air and directed via the purge line to the engine for combustion. This operation is only possible while the engine is running. Leakage detection for tank venting system USA The tank leakage diagnostic module serves to detect leakages for the tank venting system within the on-board diagnosis laid down by legislation. The tank venting system is pressurized and the pressure loss is detected in the event of a leak. The tank leakage diagnostic module detects the pressure loss by way of the power consumption of the integrated pump. The air required for this purpose is supplied via the dust filter. The systems is activated by the engine control unit. The mushroom valve establishes by way of the vent line the connection between the fuel tank and the filler neck. This enables a leak to be detected in the filler pipe-tank cap area. Determining fill level in fuel tank The fuel level is measured by means of lever-type sensors on both sides of the fuel tank. The right lever-type sensor is integrated in the fuel supply unit. The left lever-type sensor is located in the left sensor unit. The combination of the determined ohm values from the right and left lever-type sensors produces the actual level in the fuel tank.
5. Service data, fuel system Pressure regulator: 3.5 bar. Working pressure of suction jet pumps: 1 - 1.3 bar
6. Schematic drawings of 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.

16 00 005 Draining and filling fuel tank

The electric fuel pump must not operate without fuel!

After the repair work but before starting the engine for the first time, fill the fuel tank with min. 5 L of fuel through the fuel filler pipe.

Drawing off fuel

Start engine and allow to run. Electric fuel supply pump runs.

The fuel is thus repumped via the suction jet pump and the tank expansion line from the left to the right side of the fuel tank.

Note. Fuel can be drawn off from the left and right tank halves through the fuel filler pipe down to a small residual amount. The residual amount on left and right can continue to be drawn off after removal of the fuel filter.

Push extraction hose of suction extractor unit into fuel filler pipe. In so doing, turn slightly if necessary.

Insertion length

Approx. 90 cm

Draw off fuel with suction extractor unit as far as possible.

Follow the fuel drawing-off procedure at the fuel gauge in the instrument cluster.

Scheme 46

Drawing off residual fuel quantity

Catch dripping fuel in a suitable container.

Remove fuel filter. See 16 11 048 Removing And Installing/Replacing Fuel Filter With Pressure Regulator .

Drawing off residual fuel amount on right side

Draw off residual fuel amount in right tank half through service opening (A).

Drawing off residual fuel amount on left side

Feed extraction hose through service opening in tank above saddle into left tank half (B). Residual fuel amount can be drawn off.

Scheme 47

Fuel filling

Push extraction hose of suction extractor unit approx. 40 cm into fuel filler pipe.

Fill fuel from suction extractor unit.

Scheme 48

Drawing off after fault in suction jet pump

Draw off right tank half completely via fuel filler pipe.

Remove Fuel Filter .

Feed extraction hose through service opening in tank above saddle into left tank half (B). Fuel (also residual amount) can be drawn off.

16 00 102 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 diagnosis in accordance with faults stored. A leak test of the DM-TL module is performed when: 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

1. Content of fuel tank < 90 %
2. Reserve indicator lamp "off"
3. 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°C).
4. Do not under any circumstances fill up car with fresh fuel (strong exhalation of fresh fuel).
5. Check that tank cap is correctly seated.

Clear DME fault memory.

In the Diagnosis and Information System (DIS), go to the FUNCTION AND COMPONENT SELECTION screen.

By selecting

1. Complete vehicle
2. Drive
3. Engine management
4. Tank system test
5. Tank leakage diagnostic module (DM-TL)

Adopt test module in test schedule.

Switch to the test schedule and implement the tank leakage diagnosis module. Leakage test is carried out.

Carry out leak detection if the fault is stored again in the DME fault memory (tank leak detected). See 16 00 510 Conducting Leak Test On Fuel Tank And Tank Ventilation System .

16 00 510 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).

In the Diagnosis and Information System (DIS), go to the FUNCTION AND COMPONENT SELECTION screen.

By selecting

1. Service functions
2. Drive
3. Digital Motor Electronics
4. Activation DMTL pump

Adopt test module in test schedule.

Switch to the test schedule and implement the "Activation DMTL pump" test module.

Tank leak diagnosis pump pressurizes fuel tank and tank venting system.

Carry out leak test.

Terminate test module after completing leak test.

Note. Tank leak diagnosis pump is automatically shut down after approx. 15 minutes due to risk of overheating. Allow pump to cool down for at least 15 minutes. Then continue procedure.

The leak test can be carried out with a leak detector. Follow manufacturer's operating instructions in doing so.

Possible causes of leaks are

Scheme 49

1. Tank cap leaking.
2. Tank vent line leaking (fuel tank-carbon canister).
3. Tank vent line leaking (engine compartment).
4. Sealing ring on fuel filter leaking.

Pressurize fuel tank and tank venting system.

Note. When leak-testing with a leak tester device, follow the operation instructions of the device manufacturer.

The leak test can be carried out with a leak detector.

Possible causes may be

Scheme 50

1. Tank cap leaking.
2. Tank vent line leaking (fuel tank-carbon canister).
3. Tank vent line leaking (engine compartment).
4. Sealing ring on fuel filter leaking.
5. Carbon canister shut-off valve leaking.

16 11 030 Removing and installing fuel tank

Special tools required

1. 31 1 150
2. 33 4 410

1. Check resistance between metal filler bowl and wheel hub. Measured value approx. 0.6 ohm.
2. Fill fuel tank with min. 5 L fuel. After installation: Carry out wheel alignment check.

Necessary preliminary tasks

Draw off fuel from fuel tank. See 16 00 005 Draining And Filling Fuel Tank .

Remove handbrake Bowden cables. See 34 41 120 REMOVING AND INSTALLING/REPLACING BOWDEN CABLES .

Remove right wheel arch cover.

Remove right wheel arch lip.

Remove tank cap with cover.

Disconnect feed line (1) and connector (2) from fuel filter.

Unclip both lines from tank.

Note. To disconnect feed line, press ring (3) in direction of fuel filter and pull out feed line.

Scheme 51

Unfasten screws.

Installation

Tightening torque, see 16 12 11AZ in FUEL SUPPLY SYSTEM - TIGHTENING TORQUES .

Scheme 52

Unfasten nut.

Disconnect service vent lines from tank filler pipe.

Installation

Tightening torque, see 16 12 16AZ in FUEL SUPPLY SYSTEM - TIGHTENING TORQUES .

Installation

Moisten connecting pieces and seals of vent lines with lowsurface-tension water or with a soapy solution.

Facilitates installation!

Scheme 53

Disconnect cable for wear indicator and wheel speed sensor and detach from trailing arm.

Scheme 54

Release both holders for brake line.

Detach brake line completely from right trailing arm.

Tightening torque, see 34 32 3AZ in BRAKES - TIGHTENING TORQUES .

Scheme 55

Remove tension strut on final drive.

Support final drive with transmission lifter and special tool 33 4 410.

Scheme 56

Consequence: noise!

If necessary, detach cable for ride level sensor from rear axle bracket.

Replace rear screws (1) on left and right with special tool 31 1 150.

Note. Screws of E38 front axle support (part number 9 900 223) can be used instead of special tool 31 1 150.

Scheme 57

Lower rear axle bracket with special tool 33 4 410.

Clearance A=10 cm.

Installation

Damaged threads in body-side sleeves can be repaired with Helicoil thread inserts. Install Helicoil thread inserts flush with original thread.

Mark position of right bearing block to body with colored markings (1). This simplifies subsequent toe-in adjustment.

Replace screw (2) with special tool 31 1 150.

Scheme 58

Note. Screws of E38 front axle support (part number 9 900 223) can be used instead of special tool 31 1 150.

Release and lower bearing block.

Clearance A=9 cm.

Installation

Damaged threads in body-side sleeves can be repaired with Helicoil thread inserts. Install Helicoil thread inserts flush with original thread.

Scheme 59

Installation

Pay attention to top vent line (1) when installing fuel tank.

Feed vent line (1) through opening (2) into wheel arch.

Scheme 60

Support tank with lifter.

Unscrew left and right bolts (1).

Remove clamping band (2) on left and right.

Remove tank downwards with assistance of a 2nd person.

Scheme 61

Installation

Tightening torque, see 16 11 1AZ in FUEL SUPPLY SYSTEM - TIGHTENING TORQUES .

When replacing fuel tank

1. Modify fuel pump. See «16 14 010 Removing and installing/replacing fuel pump»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-14-010-removing-and-installingreplacing) .
2. Modify fuel filter. See «16 11 048 Removing And Installing/Replacing Fuel Filter With Pressure Regulator»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-11-048-removing-and-installingreplacing) .

16 11 048 Removing and installing/replacing fuel filter with pressure regulator

Special tools required

1. 16 1 020

Necessary preliminary tasks

1. Draw off fuel from fuel tank. See «16 00 005 Draining and filling fuel tank»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-00-005-draining-and-filling) .
2. Remove exhaust system . See «EXHAUST SYSTEM - REPAIR INSTRUCTIONS»(/bmw/z4/e85e86-2002-2005/remont/exhaust/#exhaust-system-repair) .
3. Remove tunnel thermal insulation.

Disconnect feed line (1) and connector (2) from fuel filter.

Note. To disconnect feed line, press ring (3) in direction of fuel filter and pull out feed line (1).

Scheme 62

Release screw cap with special tool 16 1 020.

Installation

Always replace rubber seal.

Tightening torque, see 16 14 2AZ in FUEL SUPPLY SYSTEM - TIGHTENING TORQUES .

Scheme 63

Installation

After tightening to specified torque, make sure the notch (2) on the rotary catch is located between the two markings (1) on the fuel tank.

Scheme 64

Installation

The fuel filter can only be installed in one position.

When installing, make sure lug (1) of fuel filter engages in corresponding opening on fuel tank.

Always replace seal (2).

Scheme 65

Pull off plug (1).

Disconnect lines (2) and (3) from fuel filter.

Note. Lines (2) and (3) must not be switched round as they have different diameters.

Fuel filter and pressure regulator together form a single unit and can only be replaced as such.

Scheme 66

16 11 130 Checking filler cap pressure relief valve

Special tools required

1. 13 3 010
2. 16 1 171
3. 16 1 172
4. 16 1 173

Set pressure regulator on special tool 16 1 171 fully in "-" direction.

Connect special tool 16 1 171 via compressed air line (1) to workshop/garage compressed air system (8...10 bar).

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

Scheme 67

Select special tool 16 1 172 or 16 1 173 matching vehicle's filler cap and attach to quick-release coupling of special tool 16 1 171.

Install filler cap on selected special tool.

Scheme 68

Note. Only the absolute pressure is indicated in the display of the Diagnosis and Information System (DIS). The current ambient air pressure is already displayed without additional pressurization.

Check testing equipment for leaks!

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

Increase pressure by 0.2 bar with pressure regulator on special tool 16 1 171.

Using special tool 13 3 010, disconnect delivery line from special tool 16 1 171 to fuel filler neck.

Wait 60 secs.

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

Measurement evaluation

MEASUREMENT EVALUATION

Check filler cap pressure relief!

Follow same test procedure as for "Checking testing equipment for leaks". See 16 00 510 Conducting Leak Test On Fuel Tank And Tank Ventilation System .

Increase pressure by 0.3 bar with pressure regulator on special tool 16 1 171.

Measurement evaluation

MEASUREMENT EVALUATION

16 12 000 Removing and installing/replacing the sensor for the fuel level gauge (right)

Note. In the E85 only the right sensor for fuel level indication can be replaced. If the left sensor is faulty, the fuel tank must be replaced.

Sensors for fuel level indication, electric fuel pump and right suction jet pump together form a single unit and can only be replaced as such.

Necessary preliminary tasks

1. Draw off fuel from fuel tank. See «16 00 005 Draining and filling fuel tank»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-00-005-draining-and-filling) .
2. Remove fuel filter. See «16 11 048 Removing and installing/replacing fuel filter with pressure regulator»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-11-048-removing-and-installingreplacing)

Remove electric fuel pump. See 16 14 010 Removing and installing/replacing fuel pump .

16 12 010 Removing and installing/replacing carbon canister with DM-TL

DM-TL = diagnosis module-tank leakage

Necessary preliminary tasks

1. Remove rear right wheel arch cover. Unfasten plug connection (1). Unlock lines (2) to 4 and detach.
2. Scavenging air line.
3. Vent line to tank.
4. Evaporation line.

Scheme 69

Release screws and remove carbon canister with DM-TL towards bottoms.

Scheme 70

Tightening torque, see 16 13 2AZ in FUEL SUPPLY SYSTEM - TIGHTENING TORQUES .

16 13 015 Removing and installing/replacing tank leak diagnostic module (DM-TL)

Necessary preliminary tasks

1. Remove rear right wheel. See «36 10 300 REMOVING OR INSTALLING FRONT OR REAR WHEEL»(/bmw/z4/e85e86-2002-2005/remont/wheel-tire-system/#wheel-and-tires-repair__36-10-300-removing-or-installing) .
2. Remove rear right wheel arch cover.

Unfasten line (1) and detach.

Remove hose (2).

Scheme 71

Release screws (1).

Tightening torque, see 16 13 3AZ in FUEL SUPPLY SYSTEM - TIGHTENING TORQUES .

Release lugs (2).

Detach DM-TL from carbon canister.

Scheme 72

16 14 010 Removing and installing/replacing fuel pump

Note. Fuel pump, right suction jet pump and right sensors for fuel level indication together form a single unit and can only be replaced as such.

Necessary preliminary tasks

1. Remove fuel filter. See «16 11 048 Removing And Installing/Replacing Fuel Filter With Pressure Regulator»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-11-048-removing-and-installingreplacing) .

Disconnect plug.

To do so, bend lug (1) on both sides outwards and pull plug apart.

Scheme 73

Disconnect line (2) from fuel pump.

Unlock fuel pump by pressing lug (1). Release fuel pump upwards from catch.

Remove fuel pump with sensor through service aperture. See 16 14 010 Removing And Installing/Replacing Fuel Pump .

Installation

When installed, fuel pump must clearly be heard to snap into place.

Do not bend sensor arm during installation.

Line (2) must not be kinked!

Scheme 74

16 14 030 Replacing suction jet pump (right)

Note. In the E85 only the right suction jet pump can be replaced. If the left suction jet pump is faulty, the fuel tank must be replaced.

Sensors for fuel level indication, electric fuel pump and right suction jet pump together form a single unit and can only be replaced as such.

Necessary preliminary tasks

1. Draw off fuel from fuel tank. See «16 00 005 Draining And Filling Fuel Tank»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-00-005-draining-and-filling) .
2. Remove fuel filter. See «16 11 048 Removing And Installing/Replacing Fuel Filter With Pressure Regulator»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-11-048-removing-and-installingreplacing) .

Remove electric fuel pump. See 16 14 010 Removing And Installing/Replacing Fuel Pump .

16 14 060 Removing and installing/replacing dust filter for tank leakage diagnosis module (DM-TL)

Necessary preliminary tasks

1. Remove rear right wheel arch cover .
2. Remove carbon canister. See «16 12 010 Removing And Installing/Replacing Carbon Canister With DM-TL»(/bmw/z4/e85e86-2002-2005/remont/fuel-system/#fuel-supply-system-repair__16-12-010-removing-and-installingreplacing) .

Detach line (2) from carbon canister.

Unfasten screws.

Tightening torque, see 16 13 4AZ in FUEL SUPPLY SYSTEM - TIGHTENING TORQUES .

Remove dust filter (1) with line (2).

Scheme 75

See also:
• FUEL SUPPLY SYSTEM - TIGHTENING TORQUES
• BRAKES - TIGHTENING TORQUES
• EXHAUST SYSTEM - REPAIR INSTRUCTIONS
• 36 10 300 REMOVING OR INSTALLING FRONT OR REAR WHEEL
• 16 11 048 Removing And Installing/Replacing Fuel Filter With Pressure Regulator
• 16 00 510 Conducting Leak Test On Fuel Tank And Tank Ventilation System
• 16 00 005 Draining And Filling Fuel Tank
• 16 14 010 Removing and installing/replacing fuel pump
• 16 00 510 Conducting Leak Test On Fuel Tank And Tank Ventilation System
• 16 12 010 Removing And Installing/Replacing Carbon Canister With DM-TL