Audi A4

since 1994 release

Manual of the car

Audi A4
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
- System of injection
   - System of injection Motronic
      The major knots
      So the system of injection Motronic functions
      Violations in work and self-diagnostics
      The self-help at injection
      Visual control
      Search of malfunctions in separate knots
      Check of idling and exhaust gases
      Check of exhaust gases (AU)
      Cable of a butterfly valve
      The help at malfunctions
   + System of injection of MPI and MPFI
+ 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


Visual control

  • Whether untight sites on fuel pipes are noticeable?
  • You disconnected and then connected several times sockets of wires? Corrosion or the nonprofessional address can damage contacts.
  • Attentively examine sockets of separate knots of system of injection. Do not bend contacts, only process them spray for contacts.
  • At violations in operation of the engine in the range of idling check whether additional air soaks up the engine.

Search of the place of intake of "additional air"

Untight sites of system of absorption of air pass so-called additional air, i.e. air which does not enter calculation of the control unit and therefore noticeably breaks process of preparation of fuel and working mix. In working mix the amount of fuel uncontrollable decreases. This violation idling is the most noticeable by fluctuation of speed.


  1. Check vacuum hoses and durability of their fastening for existence of cracks. Check all hoses connected to an inlet collector (for example, from the brake amplifier, from the regulator of pressure of fuel, the electromagnetic valve of system, system of collecting/return of vapors of fuel).
  2. Warm up the engine, then, having left it to idle, open a cowl.
  3. Water from a spray of starting fuel (for example, "Startpilot") a branch pipe of a butterfly valve, laying of flanges, inlet channels and pipelines to the units operated by means of the lowered pressure. For this purpose disconnect the socket a lambda probe.
  4. If at a sbryzgivaniye of a certain place speed changes, then the untight site is found.