Audi A3

since 1997 of release

Repair and car operation

Audi A3
+ Maintenance instruction
+ Current leaving and service
+ Engine
+ Systems of cooling, heating
- Power supply system and production of the fulfilled gases
   + Power supply system
   + System of injection of fuel
   + System of injection of the diesel engine
   - System of production of the fulfilled gases
      Operation of the catalytic converter
      Security measures for an exception of damages of the catalytic converter
      Removal and installation of system of release
      Checking of system of release
      Replacement of the central/additional exhaust silencer
      Check of system of release on tightness
      Replacement of the sensor of oxygen
+ engine Electric equipment
+ Manual box of gear shifting
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Elektroskhema

Security measures for an exception of damages of the catalytic converter


Scheme of system of a turbokompressor

1-an adsorber with absorbent carbon
2-the ventilating pipeline from a fuel tank
3-the return valve for an adsorber with absorbent carbon
4-a turbokompressor with a drive from exhaust gases
5-regulator of pressure of fuel
6-inlet pipeline (the fuel highway)
7-ventilation of a case of the engine
8-the return valve of an adsorber with absorbent carbon
9-connection on the butterfly valve case
10-an interkuler (a cooler of forced air)
11-receiver of an interkuler
12-the otsechka valve at movement nakaty
13-the electromagnetic valve for restriction of pressure of pressurization
14-valve of restriction of pressure of system of ventilation of a case
15-electricly the operated valve of an adsorber

For an exception of damages of the sensor of oxygen and the catalytic converter it is necessary to fulfill the following requirements:

Petrol engines

– Surely apply only unleaded gasoline.
– Start of the heated-up petrol engine by pushing or towage is authorized to carry out only in one attempt and at distance no more than 50 m. Better for this purpose to apply a starting cable. Not burned down fuel at ignition can lead to an overheat of the catalytic converter and its destruction.

Start of cars with AT is for technical reasons impossible.

– At difficulty with start of the engine it is not necessary to include a starter too long. Continuous injection of fuel is thus made. It is necessary to reveal and eliminate a cause of defect.
– If there are malfunctions with ignition system, at determination of their character it is necessary to exclude fuel injection at starter inclusion. For this purpose disconnect the relay of the fuel pump.
– Never spend fuel in a fuel tank completely.
– At emergence of interruptions in ignition do not raise number of turns of the engine and immediately eliminate malfunction.
– Apply only the recommended spark plugs.
– Do not carry out spark check with the disconnected shtekerny connection of a spark plug.
– Carrying out test of operation of the cylinder by disconnection of a wire of ignition from its candle is not allowed. Thus not burned down fuel gets to the catalytic converter.
– Do not stop the car over dry foliage or a grass. The system of production of the fulfilled gases around the catalytic converter very hot also radiates heat even after an engine stop.
– Do not put on elements of system of release of means for protection of the bottom of the car.
– It is not allowed to change a design of heat-shielding screens.
– When filling engine with oil especially pay attention to exceeding at all the level designated on the index as by Max. Excess of oil owing to incomplete combustion arrives in the catalytic converter and can damage its covering from the alloyed metal or completely to destroy the catalytic converter.


Petrol engines of 1.8 l of 150 h.p. are equipped with a turbokompressor.

Turbokompressor has two turbines established on one shaft and placed in two separate cases: the driving turbine working from fulfilled gases, and the delivery turbine compressing air, arriving in the engine. Thus angular speed of rotation of a shaft of the turbine reaches 120 000 rpm. Greasing of a turbokompressor is carried out from system of greasing of the engine. In addition the turbokompressor is cooled with liquid of system of cooling of the engine.

The increase in engine capacity at the expense of a turbo-supercharging reaches 100 %. Capacity growth among other things depends on pressure of submitted air which at engines of cars makes 0.4 – 0.8 bar (pressure of air in tires makes 1.8 bar). Pressure of air is supervised by the sensor. If pressure of air exceeds the established value, the valve of adjustment of pressure opens, reducing it.

Along with capacity increase owing to application of a turbokompressor the torque increases also that, first of all, affects improvement of elasticity of the engine. A condition of reliable pressurization is turbokompressor rotation with demanded number of turns. Therefore at the engine rather small turbokompressor which starts to work already at small numbers of turns of the engine is established, and raises its torque.

Between a turbokompressor and an inlet path of the engine there is an interkuler (a cooler of submitted air). Cooling of air promotes engine capacity increase as cold air thanks to higher density has higher content of oxygen.

In the diesel engine an adjustable turbokompressor (the turbokompressor with adjustable geometry) provides increase in engine capacity. Smooth adjustment of shovels is carried out by a control system of the engine via the electromagnetic valve and a vacuum box. Thanks to it at any number of turns optimum pressure of pressurization and by that engine capacity increase is reached, in particular, at low turns of the engine.

Turbokompressor represents the precision mechanism. Therefore, as a rule, in case of malfunction it is necessary to replace a turbokompressor.

Malfunctions of a turbokompressor

If the turbokompressor works incorrectly, it is possible to determine it by decrease in capacity or impossibility of achievement of the maximum speed in the assumption that the system of injection of fuel works normally. It can be caused by leak in system or malfunction of a turbokompressor. The following sequence of checks is recommended:

Leaks in system

Check an air hose between a turbokompressor and the inlet pipeline through an interkuler on existence of breaks, the cracks, the weakened connections etc. and at their detection eliminate them. Check, whether there is no thinness between a head of cylinders and the inlet pipeline. It can occur because of defective laying or, in certain cases, because of pipeline shift.
Thinnesses can be in connecting flanges between a final collector and a head of cylinders or between a final collector and a turbokompressor.

Faulty turbokompressor

Check pressure of pressurization in a workshop. It can be either too high or too low. If pressure too high, the reason of it can be malfunction of the electromagnetic valve of restriction of pressure of pressurization or a receiver of the regulating valve of pressure of pressurization. Poll of memory of the device of diagnostics in a workshop will help to establish, where malfunction.

If pressure too low, it is possible to suspect a receiver of the device of restriction of pressure of pressurization. Otherwise the turbokompressor should be faulty.


It is known that the engine after a long trip with high speed cannot be switched off at once, it is necessary to allow for it to work a little idling. The reason of it in the following: if at once to muffle the "peregrety" engine, the bearing of a shaft of a turbokompressor will heat up so that oil for greasing of the bearing can burn out. At such address and restart the turbokompressor will soon fail.

Turbokompressor is rather sensitive to dirt or alien subjects therefore at removal and installation it is necessary to observe purity.

1. Disconnect a "weight" wire from the storage battery (do not forget about the radio receiver coding).
2. Remove an air hose from a turbokompressor.
3. Press the hose of cooling liquid going to a turbokompressor by means of a clamp or merge cooling liquid.
4. Lift and establish a forward part of the car on supports.
5. Disconnect fastening of an exhaust system from RKPP. Disconnect the catalyst from a turbokompressor (4 nuts). Disconnect bringing and taking-away oil tubes from a turbokompressor. Watch, that less oil flowed out. From the bottom party unscrew bolts of fastening of a turbokompressor from a final collector. To these bolts it is hard to reach, therefore it is necessary to use a suitable key (a cap key on 12 mm). Thus hold a turbokompressor and when all bolts will be removed, extend it up. Installation is carried out as it should be, the return to removal. Always use new nuts and bolts. Before connection of a tube of a supply of oil fill in a little oil in a turbokompressor (preliminary greasing). At first let's to the engine work at high turns.