Adjusting Air/Fuel Mixture for Improved Engine Performance - USA - Page 1315
a) A test socket is located on engine central electric board in engine compartment on left-hand side.
Bridge test jacks B and C with a locally made wire.
(This stops function of the idle volumetric control.)
b) Check and adjust speed with, for example, VAG tester 1367.
Turn control screw (bypass) on throttle housing until specified speed is reached.
5. Start function of idle volumetric control after completing adjustments (remove locally made wire).
6. Recheck adjustments, correcting if necessary.
