Variable Induction System: Testing and Inspection

Variable Intake Manifold, Checking

Only perform the test if there is a loss of torque. That means elasticity or engine torque is reduced.

Special tools, testers and auxiliary items required

• Hand vacuum pump (VAS 6213)





Test Conditions

• The intake manifold runner control valve (N316) was checked with the vehicle diagnosis, testing and information system (VAS 5052).

If the intake manifold runner control valve (N316) is OK, perform the following tests:

- Remove the engine cover carefully.

- Start engine and let run at idle.

- Have a 2nd person increase engine speed abruptly (press accelerator pedal). Observe the variable intake manifold vacuum actuator.

• The actuator must activate - arrow -.





If change-over does not function as specified:

- Check the vacuum system for leaks.

- Check whether the change-over mechanism moves easily. Do this by actuating the linkage by hand.

- Check whether the vacuum lines are correctly connected.

- Check that vacuum hoses are not porous.

- Remove the vacuum hose - 1 - on the intake manifold runner control valve (N316) - 2 - to the control valve actuator.





- Set the slide ring - 1 - on the hand vacuum pump (VAS 6213) to the -A- position for "vacuum".





- Connect the hand vacuum pump (VAS 6213) to the intake manifold runner control valve (N316) actuator.





- Operate hand vacuum pump (VAS 6213) several times.

The vacuum actuator must move - arrows -.

- Replace the vacuum actuator if it does not move.