11 37... Fault patterns, valve gear (N20/26/N55)

WARNING: The preloading on the throttle return springs increases as the rotation on the worm gear increases. Danger of injury!
The eccentric shaft may only be twisted on the mounting flats for protection.
Risk of damage to the eccentric shaft gearing and to the servomotor worm drive.
The eccentric shaft must not spring back to the minimum stroke stop. Risk of damage!

Necessary preliminary tasks

Remove cylinder head cover.
Remove ignition coil and injector shafts.

WARNING: Heed stop installation instructions.

The eccentric shaft on the mounting flats (2) must only be turned with an open-end spanner (1) for support.

The eccentric shaft has mounting flats on both sides; if the engine is installed, the front mounting flat must be used.

Heed the following work instructions.

After the engine stops, the eccentric shaft is in the maximum stroke position.

Fig 1: Turning Eccentric Shaft Using Open-End Spanner

G09845780

Courtesy of BMW OF NORTH AMERICA, INC.

If the actuator drive is defective, the eccentric shaft is located in an undetermined position.

Check throttle return spring (2) for breakage and correct installation position on intermediate lever (1).

Check roller cam follower (3) for correct installation position.

Fig 2: Locating Throttle Return Spring

G09845781

Courtesy of BMW OF NORTH AMERICA, INC.

Check that intermediate lever (1) is correctly seated.

NOTE: Graphic does not show sliding block.

Fig 3: Identifying Intermediate Lever

G09845782

Courtesy of BMW OF NORTH AMERICA, INC.

Check wear at stop (1) - minimum lift and maximum lift.

Check that stops are securely seated.

Tightening torque: 11 37 5AZ .

Fig 4: Identifying Eccentric Shaft Minimum Stroke Stop

G09845783

Courtesy of BMW OF NORTH AMERICA, INC.

Stiff movement in eccentric shaft bearing is excluded.

Stiff movement can occur in worm gear.

Fig 5: Identifying Special Tool (11 7 170)

G09845784

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.