11 61 730 BMW leak test for intake system (N54)

IMPORTANT: Pressure and vacuum lines can be recognized by the size of their fasteners and are color-coded blue and red respectively.

Designation:

Pressure line blue
Vacuum line red

Pressure and vacuum lines must not be mixed up.

Danger of engine damage!

Necessary preliminary work (pressure check):

Remove INTAKE FILTER HOUSING

Necessary preliminary work (vacuum check):

Remove CLEAN AIR PIPE

Necessary preliminary work (all checks):

Prepare BMW diagnosis system
Start diagnosis program
1. Drive
2. Engine electronics
3. Air supply
4. Boost pressure control system or perception of lack of power

Order numbers:

Auxiliary diagnosis unit - pressure/vacuum:
- Auxiliary diagnosis unit - pressure/vacuum, complete, Order number 81 29 0 426 464
- Sealing plug 3, N54, Order number 81 29 2 146 625

Pressure measurement:

Prepare BMW diagnosis system on BMW auxiliary diagnosis unit - pressure.

Screw in pressure sensor (1).

Insert blue pressure line (2) as far as it will go into pneumatic coupling.

NOTE: Pneumatic coupling locks automatically.

Connect stimulus leads (3) to positive and negative terminals.

Connect leads (4) to positive and negative poles of vehicle battery.

Fig 1: Connecting Leads To Positive And Negative Poles Of Vehicle Battery

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NOTE: Clean-air tube (1) and sealing stopper (3) must be free from dirt and grease to ensure an exact leak test.

Insert sealing stopper (3) with union nut (4) into clean-air tube (1).

Secure clamp (2) to 4 Nm.

Secure union nut (4) to 10 Nm.

Fig 2: Identifying Clean-Air Tube, Sealing Stopper And Union Nut

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Insert blue pressure line (3) as far as it will go into pneumatic coupling (2).

NOTE: Pneumatic coupling (2) locks automatically.

Fig 3: Identifying Lock, Pneumatic Coupling And Blue Pressure Line

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Note on removal:

Slide lock (1) of pneumatic coupling (2) in direction of arrow.

Release blue pressure line (3).

Vacuum pressure measurement:

Prepare BMW diagnosis system on BMW auxiliary diagnosis unit - vacuum.

Screw in pressure sensor (2).

Insert red vacuum line (1) as far as it will go into pneumatic coupling.

NOTE: Pneumatic coupling locks automatically.

Fig 4: Connecting Leads To Positive And Negative Poles Of Vehicle Battery

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Connect stimulus leads (3) to positive and negative terminals.

Connect leads (4) to positive and negative poles of vehicle battery.

Calibration for vacuum pressure measurement:

Seal stop cock (1) in direction of arrow.

Release lock nut (3) on regulator (2).

Adjust pressure in accordance with BMW diagnosis instruction.

Secure controller (2) hand-tight against turning.

Open stop cock (1) again.

Fig 5: Calibrating For Vacuum Pressure Measurement

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Connections on EPPC:

"VAC" connection (1) to vacuum reservoir
"OUT" connection (2) to turbocharger

Fig 6: Identifying OUT Connection And VAC Connection

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Checking vacuum unit (wastegate valve), cylinders 1-3:

Detach vacuum hose (2) from EPPC (3), cylinders 1-3 (OUT).

Fig 7: Detaching Vacuum Hose From EPPC

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Clamp off vacuum hose (1) with a suitable tool.

NOTE: For purposes of clarity, the illustration shows the red vacuum line removed.

Insert vacuum hose (2) as far as it will go into pneumatic coupling of red vacuum line of BMW auxiliary diagnosis unit (see arrow).

Checking vacuum unit (wastegate valve), cylinders 4-6:

Detach vacuum hose (1) from EPPC (3), cylinders 4-6 (OUT).

Clamp off vacuum hose (2) with a suitable tool.

NOTE: For purposes of clarity, the illustration shows the red vacuum line removed.

Insert vacuum hose (1) as far as it will go into pneumatic coupling of red vacuum line of BMW auxiliary diagnosis unit (see arrow).

Fig 8: Inserting Vacuum Hose Into Pneumatic Coupling Of Red Vacuum Line Of BMW Auxiliary Diagnosis Unit

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Starting position (1) of linkage in event of depressurization at vacuum unit (wastegate valve):

Flap of vacuum unit (wastegate valve) is open.

Fig 9: Identifying Vacuum Unit Position

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Starting position (1) of linkage in event of vacuum pressure at vacuum unit (wastegate valve):

Flap of vacuum unit (wastegate valve) is closed.

Fig 10: Identifying Position Of Wastegate Linkage With Vacuum Pressure

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Checking flap of vacuum unit (wastegate valve):

Flap (1) of vacuum unit (wastegate valve) must be open in depressurized state.

Flap (1) of vacuum unit (wastegate valve) must be closed in event of vacuum pressure.

Check shaft on turbine wheel for rotatability.

Fig 11: Identifying Wastegate Valve

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Checking pop-off valves:

Necessary preliminary tasks:

Remove both POP-OFF VALVES

NOTE: To check the function of the pop-off valves (2), it is necessary to build up vacuum pressure at the valves.
Establish vacuum pressure with the BMW auxiliary diagnosis unit - vacuum.

Fig 12: Connecting Vacuum Hose

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Connect vacuum hose (3).

Establish vacuum pressure at 500 mbar.

Plunger (1) must visibly release the opening in the direction of the arrow as far as it will go.

IMPORTANT: Plunger (1) must maintain this position while vacuum pressure is being created.

If this is not the case, replace the pop-off valve (2).

Assemble engine.

Observe BMW diagnosis instructions.