Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

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
   Removal of a replaceable element of the air filter
   Purge of a replaceable element of the air filter
   Replacement of a replaceable element of the air filter
   Heating of inlet air
   Heating of an inlet collector
   Inlet collector with a changeable length of a path
+ System of injection
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

Heating of an inlet collector

With 4-tsit models. engines and Mono-Motronic system

From the block of preparation of gas mixture of Mono-Motronic system mix of air and fuel through an inlet collector gets to cylinders.

If the inlet collector cold, considerable part of mix is condensed on internal walls of a collector and gets to combustion chambers any more not absolutely in the form of vapors. Losses and, thereby, the increased fuel consumption are so formed. This misfortune can be helped double heating of an inlet collector.

  • On the cold engine the electric heating of an inlet collector comes into effect. It consists from electrically warmed-up "hedgehog" who is screwed in in an inlet collector below the block of preparation of gas mixture. At our "hedgehog" with a natural small animal only the general needles. They serve in Audi 80 not so much to passive self-defense, how many increase in a surface of a heating element. Such "echinoid" heating works only approximately up to the temperature of cooling liquid of 65 °C. Then current is disconnected.
  • The thermoswitch (on electric circuits the sensor of temperature of cooling liquid – G62" is designated as ") includes "hedgehog" not directly. G62 supplies the Mono-Motronic control unit of information on temperature more likely, and this the last via the relay in the additional block of the relay under the dashboard makes the order to give food to "hedgehog".
  • At more high temperatures heating of an inlet collector is assumed by cooling liquid. For this purpose via the special channel in an inlet collector the additional quantity from the general stream of cooling liquid goes.

Check of heating of an inlet collector


  1. Check of "hedgehog": on the cold engine to disconnect the wire conducting to "hedgehog" under an inlet collector on plug connection (it is established sideways on the block of preparation of gas mixture).
  2. On a cable and to "weight" to connect an ohmmeter to "hedgehog": if it shows 0,25 – 0,50 Ohms, so "hedgehog" as it should be.
  3. Who has no ohmmeter, that has to remove the block of preparation of gas mixture at the cold engine, include ignition and check a wet finger, whether needles of "hedgehog" heat up.
  4. If "hedgehog" is not heated, despite right indicators of resistance, the reason can be in the defective relay.
  5. Check of a thermoswitch: (see the section System of Injection of Mono-Motronic).
  6. Check of the relay – see the head the Body electrical system.

The case of the filter of the engine with a power of 66 kW with system of injection of Mono-Motronic:

1 – intake of warm air;
2 – intake of cold air;
3 – membrane mechanism;
4 – draft of the drive of the air gate;
5 – temperature regulator.

"Hedgehog" (3) in an inlet collector (4) with a connecting wire (5).