Audi 80/Avant (B4)

since 1991-1995 of release

Repair and car operation

Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
+ cooling System
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
- Injection system
   + System of injection of Mono-Motronic
   + System of injection of Digifant
   - System of injection of KE-III-Jetronic
      Basic elements
      Operating procedure
      Lambda regulation
      Malfunctions and independent diagnostics
      Independent repair
      Visual check
      Check of separate elements
      Search of malfunctions
      Removal of components
      Check of a mode of idling and analysis of exhaust gases
      List of malfunctions
   + Systems of injection of MPI and MPFI
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrosystem
+ ignition System
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

Search of malfunctions

5-cylinder engine: the starting fuel valve (2) with the tip (1).

On an illustration on the right you see the proof-reader of composition of gas mixture with the locking valve (1), an air nozzle (2), the air filter (3), the batcher (4), a regulator of pressure (5) and a potentiometer of the locking valve (6).

Drawing at the left shows the correct position of the locking valve with an air nozzle. It should be exactly on and = 1,9 mm are lower than the upper edge of a narrow cylindrical part of an air nozzle. If necessary to correct by easy bending of a spring (presented in drawing in the form of "snake"). Attention: flowmeters of air of newer type are supplied with an adjusting bolt instead of a spring. In this case position of the locking valve юстируется the mentioned bolt.

The distributive valve of stabilization of idling of the 5-cylinder engine is located on the right in front at a head of the block of cylinders.

At the removed sleeve of an air inlet in the case of throttle knot both butterfly valves (3 and 4) are visible. Above on the case there is a system of driving drafts (2) which opens at first one, and by further pressing an accelerator pedal the second butterfly valve. The position (1) displays the switch of a signal of idling.

On a head of the block of cylinders in front at the left in a branch pipe of system of cooling are: the sensor of temperature of the engine of system of injection (1), and also an electronic thermoswitch (2) indicators of temperature of cooling liquid, a control bulb of cooling liquid, the conditioner, etc.

The chart below shows size of resistance of the sensor of temperature of cooling liquid depending on temperature.

In the following sections we considered those possibilities of search of malfunctions for which in house conditions no special tools or measuring devices are necessary. If you after reading of our list of malfunctions (at the end of head) or after reading of memory of the store of malfunctions suspected a certain detail, here you will find the control scheme.

Check of vpryskny nozzles


  1. To disconnect ignition system according to the scheme described in head System of ignition.
  2. To check, whether gasoline arrives in injection system, weaken bolts on bringing топливопроводе.
  3. Do not forget about a rag because in most cases from топливопровода gasoline will scatter. Otherwise ask the assistant to work as a starter.
  4. If fuel arrives, means, supply as it should be – therefore, in the second turn it is necessary to check nozzles.
  5. To remove a nozzle, the description see below in this chapter. For this purpose at first the top part of an inlet collector should be removed.
  6. To keep in readiness capacity or a rag for collecting fuel.
  7. To remove a big air line between the proof-reader of composition of gas mixture and the case of throttle knot for receiving access to the locking valve.
  8. To remove in the central switching center of the relay of the fuel pump on a shtekerny cell 10 (see head the Fuel tank and the fuel pump).
  9. On a cell 10 to connect shtekerny contacts 48 (or 30) and 52 (or 87) a wire slice. The fuel pump should earn.
  10. A few to raise a hand the locking valve of the distributor. Now the nozzle should is cone-shaped to inject gasoline. Otherwise:
  11. To lift the locking valve once against the stop. To repeat check.
  12. In the same way it is possible to check a difference in number of injected fuel between separate cylinders. However this way suits only for want of something better.
  13. To send all five nozzles to five measuring capacities, thus not to bend hoses топливопровода.
  14. A few to raise (approximately on 2 cm) the locking valve.
  15. The assistant should support the mentioned crossing point until in the first capacity 20 cm3 (ml) of fuel will not gather.
  16. To compare amount of injected fuel. The difference should not make more than 2,5 cm3.
  17. In case of big deviations to trade places nozzles with the greatest and the smallest indicators. To repeat measurement.
  18. If deviations "moved" together with nozzles, means, came to replace time nozzles with the corresponding deviations.
  19. If you received former results of measurements on cylinders with deviations, is not excluded that is made narrower топливопровод to a nozzle or the batcher is faulty.
  20. Check of tightness of nozzles: if to disconnect the fuel pump after two-minute work with the raised locking valve (to remove a crossing point), fuel from nozzles should not act.

Check of the starting fuel valve


  1. To disconnect ignition system according to the scheme described in head System of ignition.
  2. To remove the starting fuel valve, to remove a wire tip, to leave connected a tube топливопровода.
  3. A few to work as a starter that the fuel pump could create pressure.
  4. To lower a nozzle in capacity, to connect two auxiliary wires to valve contacts.
  5. To connect the free ends of wires to accumulator conclusions – one with «+», another with «-».
  6. The valve should now is cone-shaped to spray gasoline.
  7. Check on tightness: to remove auxiliary wires.
  8. Once again a few to work as a starter that the fuel pump created pressure.
  9. Absolutely to wipe the valve. Within a minute the gasoline postupaniye should not be observed.

Check of the batcher of fuel


  1. A few to work as the engine (about 10 c) or a starter that the total pressure of fuel was created.
  2. To uncover and a replaceable element of the air filter.
  3. To remove a big air line between the proof-reader of composition of gas mixture and the case of throttle knot.
  4. Now the locking valve which is necessary for extending completely upward is visible. This process should pass all the time with identical effort.
  5. By fast pressing of the locking valve resistance should not be felt. Otherwise it is necessary to replace an air flowmeter.
  6. If the locking valve manages to be extended only with great difficulty, but it very easily falls, means, in the batcher of fuel the distributive piston hanged. It is necessary to replace the fuel batcher.

Check of a flowmeter of air


  1. To warm up the engine to working temperature, or to work as the warmed-up engine during about 10 with before check.
  2. After weakening of collars it is necessary to remove an air inlet sleeve between the proof-reader of composition of gas mixture and the case of throttle knot.
  3. To check the locking valve: it should be from the party turned to the vpryskny pipeline, on 1,9 mm below the upper edge of a narrow cylindrical part of an air nozzle, the most bigger on 3 mm is deeper.
  4. If the valve is located incorrectly, it can be tightened up and to correct its situation, having bent a fixing wire bracket below in the channel of a flowmeter of air. Not to bend at all a spring!
  5. Check now, whether the locking valve of walls concerns.
  6. If it so, it is necessary to weaken the central fixing screw and anew to align the valve.
  7. After this adjustment it is necessary to recheck idling and the contents WITH.

Check of stabilization of frequency of idling


  1. To include ignition, to concern the distributive valve a hand: working vibration should be felt, otherwise is faulty either the distributive valve, or the control unit of system of injection of KE-III-Jetronic.
  2. To check the distributive valve: to remove tips. To measure resistance between shtekerny contacts of the distributive valve: it should be insignificant. Infinity value means a rupture of a winding – defect of the distributive valve.
  3. If as it should be, a source of malfunction it is possible to assume the distributive valve in a rupture of conducting or the faulty control unit. To check and, if necessary, to replace.
  4. To connect the light-emitting diode voltmeter to both poles of a free tip of a wire.
  5. To include ignition.
  6. Volmetr should flash, in this case food giving from the control unit of system of injection of KE-III-Jetronic as it should be.

Check of the sensor of angular moving of a butterfly valve

Models with a mechanical transmission

Contacts of an ohmmeter cannot be connected directly to sensors from which one is located below the case of throttle knot. Therefore separate only plug connection available from above. Measure resistance in sensor conducting:


  1. Switch of a signal of idling: to connect an ohmmeter to contacts 1 and 2 tips.
  2. Butterfly valve in the provision of a mode of idling: indicator of 0 Ohm. Slightly to slightly open a butterfly valve: the indicator should pass to Ohm.
  3. Switch of a signal of full loading: to connect an ohmmeter to contacts 2 and 3.
  4. Butterfly valve in the provision of full loading: indicator of 0 Ohm. Slightly to cover a butterfly valve: the indicator should pass to Ohm.

Check of a potentiometer of a butterfly valve

Models with an automatic transmission


  1. To separate the three-polar tip of a potentiometer of a butterfly valve.
  2. For check to connect an ohmmeter to contacts 1 and 2:
  3. The indicator should make 1,5 – 2,6 kiloohms.
  4. Now to connect an ohmmeter to contacts 2 and 3:
  5. The indicator should make 0,75 – 1,3 kiloohms.
  6. Slowly to open a butterfly valve, the ohmmeter is connected.
  7. Resistance should increase a maximum to 3,6 kiloohms.

 Help: the potentiometer of a butterfly valve can be regulated. However after that it is necessary to carry out «the main adjustment» automatic transmission – business for a workshop.

Check of sensors of temperature of the engine


  1. The Audi 80 car with system of injection of KE-III-Jetronic is supplied with the double temperature sensor for system of injection and completely electronic system of ignition. Measurements at these sensors are made from each of both contacts to "weight" (the block of cylinders).
  2. For check to connect an ohmmeter to one of both contacts and to "weight" (the bared metal of the block of cylinders).
  3. The received indicator of resistance depends on temperature.

Check lambda regulation

Though functioning check a lambda regulation can be carried out rather easily, however the soglasuyushchy wire and the ampermeter which is available for many fans of electronics are necessary for it. Or it is possible to inspect by means of a gas analyzer for contents definition WITH. The check description below is provided:


  1. Check should be carried out at the heated-up engine.
  2. To remove the tip of a regulator of pressure, to connect made by you from two suitable tips and a wire slice the measuring adapter connecting conducting and a regulator of pressure.
  3. To separate one of soglasuyushchy wires and to bring to the measuring device (a milliamperny range).
  4. To get the engine and to leave to work in an idling mode.
  5. To write down the received indicator.
  6. To extend measuring oil щуп.
  7. The current should increase in a chain of management.
  8. Otherwise one of components a lambda regulation is faulty.
  9. In this case to try to separate shtekerny connection to a lambda probe and to take a green wire to the control unit about 20 with on "weight".
  10. If now the current in a chain of management changes, means, the control unit system of injection of KE-III-Jetronc as it should be, but is faulty a lambda probe – to replace.
  11. If will occur nothing, means, the control unit injection system is faulty.

 Help: the main precondition functioning the lambda regulation is the correct main installation of idling that means that the contents WITH corresponds to norm, otherwise regulation will constantly be in one of the ends of a standard range. The same conditions are created, if the mix is strongly impoverished by unrecorded air.