Volkswagen Workshop Service and Repair Manuals

→ The residual volume screw -arrow- must not normally be altered.

The manufacturer sets the so-called residual volume via this screw on a test bench..

If the screw has nevertheless been altered, this may result in the following complaints:

• ◆ Screw turned in = residual volume too large.
  In this case the engine runs too fast and it is not possible to set idling speed.

• ◆ Screw turned out (gap at adjusting lever) = residual volume too small.
  This causes performance faults such as "flat spot" when pulling away and accelerating from low engine rpm or jerking in all gears.

If such faults occur, the following basic setting must be performed at the residual volume adjusting screw.

• ‒ → Release adjusting screw -arrow- lock nut.

Residual volume too low: (Performance faults)

• ‒ Screw adjusting screw in until idling speed increases.
• ‒ Turn adjusting screw back a half turn from the point at which the idling speed increases.

Residual volume too large: (Engine speed too high)

• ‒ Unscrew adjusting screw until engine speed no longer decreases.
• ‒ Screw in adjusting screw again until idling speed increases.
• ‒ Turn adjusting screw back a half turn from the point at which idling speed increases.
• ‒ Lock adjusting screw.