Wastegate: Adjustments

Checking and adjusting basic charging pressure






1 Remove the bypass pipe with valve, 1 screw on the turbo intake pipe and 1 hose clip on the turbocharger delivery pipe.

NOTE: There is an O-ring at the bypass pipe's mounting on the compressor inlet.

2 Remove the exhaust manifold heat shield. The heat shield is attached with a nut and two clips on the underside.
3 Remove the operating arm's locking clip using the special tool (part No. 83 94 538).






4 Grip the pushrod with a pair of pliers (part No. 83 94 066) or the like and undo the locknut using the special tool (part No. 83 94 520) or a similar tool.
5 Hold the operating arm and remove the push-rod from it. Secure the operating arm as it might otherwise "overcentre."
6 Move the operating arm on the charging pressure control valve to the "Closed" position and adjust the end piece so that the pushrod can easily be fitted on the operating arm's pin.
7 Detach the pushrod from the operating arm's pin. Turn the end piece clockwise about 2 turns so that a prestress of 2 mm is obtained. Attach the pushrod to the operating arm's pin. Fit the retaining ring.
8 Detach the hose marked "W" from the diaphragm unit.






9 Connect the pressure/vacuum pump (part No. 30 14 883) to the diaphragm unit and pressure gauge (part No. 83 93 514).
10 Carefully pump up the pressure so that the control rod moves and regulates the charge pressure.
11 At the precise moment when the control rod begins to move, read the pressure indicated on the pressure gauge. The pressure should be at least 0.4 bar (but not abnormally high).
12 If the pressure is too low, shorten the rod additionally until 0.4 bar is obtained.






13 Remove the control rod and coat the pin on the operating arm sparingly with Molykote 1000 (part No. 30 20 271) or the equivalent.
14 Fit the control rod and clip, grip the control rod to prevent it from moving and lock the nut.
15 Remove the pressure gauge and pump.
16 Reconnect the hose to the diaphragm unit.






17 Fit the heat shield, coat its stud with Molykote 1000 (part No. 30 20 271) or the equivalent, and screw on the rut.
18 Grease the O-ring with non-acidic vaseline and fit the bypass pipe.
Tightening torque 8 Nm (5.9 lbf ft)