Audi A4

since 1994 release

Manual of the car

Audi A4
+ Running gear
+ Regular servicing
+ Engines
- Turbo-supercharging
   Draft switching off valve
   Check of adjustment of pressure of pressurization
   The help at malfunctions
   The turbocompressor is faulty?
   Radiator of nadduvochny air
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
+ System of injection
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
+ System of ignition
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ Body details
+ Salon
Search of malfunctions
Technical characteristics


Draft switching off valve

The valve of switching off of draft is built in a connecting hose (bypass the channel) between the soaking-up party and the party of forcing of a turbo-supercharging. Sense of the valve of shutdown of draft in the following:

  1. The high-speed pressure created by a turbo-supercharging has to decrease at the closed butterfly valve ( i.e. at the released accelerator pedal). Otherwise the congestion of air would brake the frequency of rotation of the compressor. That not to allow it, the valve opens bypass the channel. At the expense of it air leaves towards absorption, and the compressor keeps rotation frequency.
  2. If the accelerator pedal is again wrung out, the draft shutdown valve to a paste is closed. Pressurization works at whole revolutions and can give the condensed air at once. If pressurization only gained steam, then it would be impossible to gain spontaneously power – the engine would have well-known "turbodyra".

Draft switching off valve check

If in the engine noticeable delay of increase of power after a draft phase is felt, then the reason can be in the draft switching off valve. Carry out the following inspection:


  1. Dismantle the draft switching off valve.
  2. Connect the vacuum pump to the thin operating draft switching off valve hose or intensively suck it a mouth.
  3. The valve of switching off of draft has to open that it is well visible through hose junction points.
  4. Take the lowered pressure, whenever possible, during 30 with (if it is necessary, bend a hose).
  5. The valve of switching off of draft has to remain in this situation at this time.
  6. Again open a hose: the valve of switching off of draft has to be closed.
  7. The gate in the valve of shutdown of draft has to open and be closed easily and in each situation densely adjoin.
  8. Installation: the valve of shutdown of draft has to be fixed by screw collars in all points of connection of hoses.