Audi 80/Avant (B4)

Since 1991-1995 of release

Repair and car operation

Audi 80/Avant
+ The description
+ Engines
+ System of release of the fulfilled gases
+ Cooling system
+ Fuel tank and the fuel pump
+ The air filter and воздухозаборные channels
- Injection system
   + System of injection Mono-Motronic
   - System of injection Digifant
      Operating procedure
      Malfunctions and independent diagnostics
      Independent repair
      Visual check
      Check of separate elements
      Removal впрыскных atomizers
      Check of a mode of idling and the analysis of exhaust gases
      The list of malfunctions
   + System of injection KE-III-Jetronic
   + Systems of injection MPI and MPFI
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Antiblocking system of brakes
+ Wheels and tyres
+ Kuzovnaja electrosystem
+ Ignition system
+ Illumination
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ Body elements
+ Search of malfunctions
+ Specifications


Check of separate elements

Pressure regulator

At the left: the regulator of pressure of giving of fuel (marksman) is connected with the case of throttle knot a vacuum hose. It regulates pressure in system by means of the increased or reduced outflow of gasoline back in a fuel tank.

On the right: position throttle заслонки is informed the block of management by a potentiometer throttle заслонки (3). Above on the case of throttle knot (2) the lever throttle заслонки (1) in which the cable of a drive of "gas" is strengthened is located.

Measurements of pressure demand presence of a corresponding manometre V. A. G 1318) with запорным the crane and the adapter. In a mode of idling pressure of giving of fuel should make about 2,5 bar, at removed from a pressure regulator a vacuum hose it should raise to 3 bar.

Check of a potentiometer throttle заслонки


    To disconnect the tip of a potentiometer throttle заслонки. To connect an ohmmeter on contacts 1 and 2. To move throttle заслонкой, thus to watch an ohmmeter. Resistance should change in regular intervals. At the left: впрыскные atomizers (arrow) are located on right in a direction of movement to the party of a head of the block of cylinders in an inlet collector.

Check впрыскных atomizers

On the right: on an illustration the connecting tip (1) with впрыскной atomizers (2) is removed. With the light-emitting diode voltmeter it is possible to check up, whether power supplies впрыскных atomizers are perfectly in order.

For electric checks it is required to you light-emitting diode вольметр.


    Power supplies check: one after another to remove tips on впрыскных atomizers. To connect the voltmeter to contacts of the removed tip. The assistant should get the engine. Light-emitting diodes should замерцать, otherwise there is a defect in conducting to atomizers or the block of management is faulty. Check of atomizers: to remove all tips on впрыскных atomizers. To connect an ohmmeter to both plug contacts of the first впрыскной atomizers. Standard indicator: 15—20 Ohm. To repeat check on other atomizers. More detailed check (tightness/kind of a stream) To remove впрыскные atomizers together with a distributor pipe – the description of works see more low in this chapter. However tips of wires should remain put on, and топливопроводные hoses connected. At the left in a branch pipe of system of cooling to remove tips of the starting valve and the temperature gauge.
    To direct впрыскные atomizers to four measuring capacities. Now the assistant should scroll a starter within several seconds: впрыскная the stream should be identical at all four atomizers. In this case the stream kind is perfectly in order. To remove the central tip впрыскных atomizers in cable mine. To switch off ignition and to include on 5 with: from each atomizer should act no more than two drops. In this case tightness of atomizers is perfectly in order.

Check of gauges of temperature

On this diagramme indicators of the gauge of temperature охладающей liquids and indicators of the gauge of temperature of arriving air are represented.


    The gauge of temperature of inlet air: to separate the 4-contact tip from above on air flowmeter. To connect an ohmmeter to both external штекерным to contacts. The gauge of temperature of a cooling liquid: to disconnect the dark blue tip from the gauge in a bulk branch pipe of system of cooling. To connect to plug contacts of the gauge an ohmmeter. Both gauges: to remove resistance indicators. Under the diagramme below on the right to check up, whether there is data for resistance of gauges, and also temperature of air and a cooling liquid at the moment of measurement within a curve. If it so, means, gauges are perfectly in order.

The starting valve

The starting valve (arrow) is located in well accessible place behind on the right on a final collector.


    To disconnect tips from all впрыскных atomizers. Power supplies: to remove a wire tip on the starting valve. To connect to the tip the light-emitting diode voltmeter with auxiliary conducting. To disconnect the tip from the gauge of temperature of a cooling liquid. The assistant should turn a starter the engine, thus a light-emitting diode should flash on 1–4 with. If it does not occur, means, conducting is interrupted, or the block of management of system of injection Digifant is faulty. Action check: tips of atomizers remain still disconnected. To turn off the starting valve, tips of wires and a tube топливопровода remain connected. To disconnect the tip from the gauge of temperature of a cooling liquid. To direct the starting valve to any capacity. Ask the assistant to turn the engine a starter. During 1–4 about the valve should inject gasoline a uniform stream. Clean to wipe the valve for tightness check. Within a minute from it gasoline should not act, the starting valve outwardly also should not make impression wet from fuel.


The arrow specifies in plug connection to a ljambda-probe.

For this check the device is necessary for measurement of the maintenance WITH so it is possible, it is necessary to visit a workshop. For the correct control the system of release of the fulfilled gases should be serviceable, and the ljambda-probe should receive power supplies (whether as it should be safety locks?).


    To warm up the engine. To connect the device for measurement of the maintenance WITH. To get the engine and to leave to idle within at least 2 minutes To increase frequency of rotation to 2000 rpm. To write down the maintenance WITH. On the case of throttle knot to remove a vacuum hose of a regulator of pressure and to close a tubule a finger. The maintenance WITH for short time should raise, and then again fall to already measured size. If value WITH does not change, to separate штекерное connection to a ljambda-probe. To connect a wire contact on the tip (to the management block) by turns to the positive and negative plug of the accumulator. If at this check the indicator WITH changes, means, the ljambda-probe is faulty. If value of the maintenance WITH remains invariable it is necessary to check up conducting to the management block. If here there are no malfunctions, means, the management block is faulty.

Air flowmeter

The zapornyj valve (arrow), visible in an air aperture of a flowmeter of air, should move slightly. Electric check расходометра air is carried out on connecting contacts which on this illustration are visible above on the case of a flowmeter of air.

On an illustration the air line (2) which have been removed in the case of the air filter is shown to make more appreciable the gauge of temperature of air (1). It is located a bit further behind in the case of a flowmeter of air screwed here.


    To remove a wire tip on air flowmeter. Numbering of uvulas of contacts at the sight of from above goes from left to right from 1 to 4. Potentiometer: to connect an ohmmeter between average contacts 2 and 3. To move запорным the valve, observing thus of an ohmmeter. Resistance should change. To connect an ohmmeter between contacts 3 and 4. Value of resistance should be between 0,5 and 1 clod. If you at measurement have received other indicators, it is necessary to replace air flowmeter.

Idling stabilisation


    To include ignition – the valve should make an easy hooting sound. Besides, you can feel its easy vibration. Otherwise it is necessary to check up safety locks. If all safety locks are perfectly in order, to remove the tip on the valve of stabilisation of frequency of rotation of a shaft of the engine in an idling mode. With диодной a control bulb to check up food presence in the tip on contact of a black-dark blue wire (at the included ignition). For this purpose other contact диодной a control bulb to bring to "weight". If the bulb has flashed, means, valve power supplies are perfectly in order. Hence, it is necessary to check up the valve: To connect an ohmmeter and to check up resistance on plug contacts of the valve. If the valve is serviceable, the resistance indicator should make 2—10 Ohm. If the standard size is not reached, to replace the valve. At correct resistance it is necessary to search for a cause of defect in rupture of conducting or defect of the block of management of system of injection Digifant. For regulation check the operating current is measured. For this purpose the workshop applies the device to interrogation of memory of the store V. A. G 1551, measurement by make-shifts is not meaningful.