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
      Operating procedure
      Malfunctions and independent diagnostics
      Independent repair
      Visual check
      Check of separate elements
      Check of a mode of idling and the analysis of exhaust gases
      Check каталитического neutralizer and a ljambda-probe
      Trosovyj drive of "gas"
      The list of malfunctions
   + System of injection Digifant
   + 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



Operating procedure

Start-up of the cold engine: from the gauge of temperature of a cooling liquid the management block receives the information on engine temperature. Than more coldly the engine, especially long is the period of injection for creation of the starting mix enriched by fuel.

Warming up phase: the temperature gauge informs on gradual warming of a cooling liquid by means of changing indicators of resistance to the management block.

Idling: the switch of a signal of idling informs the management block on this operating mode. The regulator of position throttle заслонки regulates turns of idling and counterbalances thus decrease in frequency of the rotation, arising because of inclusion powerful потребителй the current which completely has been turned out in one party of the amplifier of the steering mechanism, the included working position of an automatic transmission or the included conditioner. It occurs by means of change of the moment of ignition.

Normal operation: the management block receives the information on engine work thanks to impulses of frequency of the rotation, proceeding from the Hall gauge, and to indicators of resistance from a potentiometer throttle заслонки (position throttle заслонки). From this the management block does conclusions about a loading condition on the engine and measures through впрыскную an atomizer necessary quantity of fuel to arriving air.

Ljambda-regulation: at fuel dispensing the fuel/air parity l = 1 is considered. Constant change of the enriched and impoverished mix does possible optimum work каталитического neutralizer.

Acceleration: thanks to signals from a potentiometer the management block distinguishes sharp pressing an accelerator pedal as acceleration process owing to what the mix "is immediately enriched".

Full loading: in position of full "gas", or to tell more precisely, at position throttle заслонки nearby 72,5 the management block provides gas mixture enrichment in a mode of full loading. Therefore at a mix is present proportionally more fuel. On position throttle заслонки informs a potentiometer. However at gas mixture enrichment in a mode of full loading the ljambda-probe signal is ignored.

Mode of compulsory idling (movement накатом): at movement under a hill with the released pedal of "gas" the system of injection Mono-Motronic saves fuel and disconnects fuel access as soon as the engine has reached working temperature. The management block distinguishes this operational condition on the released pedal of "gas" (a potentiometer throttle заслонки), to messages from the gauge of temperature of a cooling liquid and frequency of rotation of the engine from above 1500 – 1900 rpm (the Hall gauge).

Restriction of frequency of rotation of the engine: in case of excess of the maximum frequency of rotation the management block disconnects access of fuel for maintenance of protection of the engine. Restriction of frequency of rotation cannot occur by ignition switching-off because in this case not burnt down fuel will get in каталитический neutralizer. It can lead to dangerous rises in temperature and, thereby, to long damages каталитического neutralizer.

Work in emergency situations:
if the signal from one of suppliers of the information does not come absolutely or has senseless size the system of injection Mono-Motronic still continues to work normally. At the disposal of the management block there are the so-called spare indicators which have been already written down in memory. The similar spare indicator, of course, cannot consider many service conditions, but the car all the same remains mobile. The driver can distinguish absence of a signal from the gauge on insufficient capacity or bad starting properties.