Audi A4

since 1994 of release

Repair and car operation



A4 Audi
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ exhaust System
+ cooling System
+ Fuel tank and fuel pump
+ Air filter and absorption channels
- Injection system
   - System of injection of Motronic
      The major knots
      So the system of injection of 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)
      Butterfly valve cable
      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
+ ignition System
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics





So the system of injection of Motronic functions

Start of the cold engine: in addition to soaked-up air the control unit a butterfly valve lets in additional amount of air. At the same time the control unit receives from the sensor of temperature of cooling liquid information – «the engine cold». On the basis of it the control unit counts duration of opening of valves of injection for receiving the enriched mix.

Engine warming up: the sensor of temperature of cooling liquid transfers in the control unit of data on increasing heating of cooling liquid. The control unit gives team of closing of the valve of stabilization of idling, and duration of injection comes back to standard level.

Idling: on the basis of information received from a potentiometer of a butterfly valve and a measuring instrument of a stream of fresh air, the control unit learns, when the engine idles. If the number of turns falls, the control unit changes the ignition moment; at the same time the control unit a butterfly valve increases an air stream therefore the amount of injected fuel slightly raises.

Standard operation does not demand any special equipment. The provision of a butterfly valve and amount of the air passing through its measuring instrument, define duration of opening of valves of injection.

Accelerations: fast opening of a butterfly valve is distinguished by the control unit as acceleration on the signal which has arrived from a potentiometer of a butterfly valve.

Adjustment by means lambda probe: continuous change of slightly enriched and a little grown poor fuel and air mix is necessary for excellent job of the catalytic converter. In an exhaust at present the lambda probe (in the catalytic converter) transfers information on the content of residual oxygen in the control unit which gives the order to fractions of a second to injectors to extend or reduce time of injection and, therefore, intake of gasoline.

Draft shutdown: information that the foot is removed from a gas pedal, through a butterfly valve potentiometer in the block of its management again arrives in the control unit. If at the same time the sensor of temperature of cooling liquid signals about achievement of an eksplutatsionny warming up of the engine, and the Hall sensor in the distributor directs information that frequency of rotation of the engine exceeded 1500 rpm, the control unit any more does not give the order to injectors to open.

Full loading: at full loading in the conditions of completely wrung out pedal of gas the engine needs increased amount of fuel. On the basis of a signal «full gas», arrived from a butterfly valve potentiometer in a combination to the corresponding signal of a measuring instrument of a stream of fresh air, the control unit distinguishes a condition of «full gas» and forces injectors to make injection more long.

Restriction of number of turns: the control unit disconnects injectors for protection of the engine against excess of frequency of rotation if it exceeds 6500 rpm (the engine with working volume of 1,6 l) or 6800 rpm (the engine with working volume of 1,8 l).

Function of an emergency course: if from one of sensors of information does not arrive or senseless information arrives, Motronic does not fail yet. The control unit chooses so-called auxiliary size which is in a database.