Checking and adjusting the back-up valve (K-, K-Jetronic) (Audi 80 B3)

The air flow meter's support flap rises more or less depending on the amount of air being sucked in. If the flap's initial position is too deep, the engine will not start. Because of this, if the flap's initial position is set incorrectly, difficulties may arise during hot starting and malfunctions in transient modes.

Checking the initial position

Remove the air supply casing.



The upper edge of the damper should be a = 1.9±1.1 mm below the edge of the diffuser cone.

Setting the initial position in the wire bracket version

Change the position of the retaining valve by bending the wire bracket -arrow-.

Setting the initial position in the version with an adjusting screw

Remove the top section and air filter element.

Set the position of the retaining valve using the adjusting screw -arrow-.

Note: At the end of the test, adjust the idle speed and CO content.