Audi A3

Since 1997 of release

Repair and car operation

Audi A3
+ The maintenance instruction
+ Current leaving and service
+ The engine
+ Systems of cooling, heating
+ The power supply system and release of the fulfilled gases
- Engine electric equipment
   - System of electronic control by ignition and injection
      Self-diagnostics of systems of electronic control of second generation OBD II
      Ignition system
      Checks of system of ignition and injection
      Spark plugs
   + Charge and start systems
+ Manual box of a gear change
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Electroschemes

Spark plugs


The spark plug consists of the central electrode, an insulator with the case and an electrode (ов)ссы. Between the central electrode and electrode Hм ссы the spark igniting fuel-air a mix slips. It is not necessary to apply the spark plugs which are distinct from the recommended. The recommended type of candles is defined among other калильным by number.

The kalilnoe number characterises degree of thermal loading of a candle. The more low калильное candle number, the above degree of its thermal loading. Thus the candle takes away heat thanks to what possibility калильного ignitions of a fuel mix is excluded is better. The candle with the high thermal characteristic has that lack that its temperature of self-cleaning lies above. It is more inclined to deposit formation, in particular when the engine in an operating time often does not reach the working temperature, for example movement in a city, short movings in the winter.

Correct калильное the candle number is defined by the manufacturer of the car. There are candles with one or several electrodes Hм ссы, with various length of a carving and its diameter. At candle replacement it is necessary to establish only the candles corresponding to instructions of the manufacturer of the car.

Average service life of a candle is distinguished. Thus a serious role plays also Hм териал electrodes. Chrome-nickel an alloy is characterised by very high heat conductivity and high corrosion firmness. The best heat-conducting path silver possesses, and platinum electrodes possess high corrosion firmness and firmness against обгорания. Service life of candles lies between 20 000 and 100 000 km of run, depending on Hм териала electrodes and their number.

Depending on a design of engines distinguish two types of consolidation between spark plugs and a head of cylinders.
Flat consolidation has an external sealing ring which is not lost and is fixed on the candle case. At конусном consolidation it is not required additional sealing elements. At the limited space for installation, candles with a flat landing surface and the small size on a turn-key basis are in most cases applied. Candles with a conic landing surface thanks to a compact design have the smaller sizes.

Spark plugs it is necessary to change each 60 000 km of run.

On appearance of a candle it is possible to draw a conclusion on work of candles, carburettor adjustment, a condition of a mix and an engine condition (pistons, piston rings etc.) (address to photographic inserts).

At ввинчивании candles watch, that they have not been drawn, as the sealing washer can be damaged. Do not exceed the moment of an inhaling specified in Specifications.

Coal adjournment

Symptoms: soot Presence specifies in reenrichment of a toplivno-air mix or weak intensity of a spark. Causes ignition admissions, complicates start and leads to instability of work of the engine.

Recommendations: whether Check up the air cleaner is hammered, whether fuel level in поплавковой to the chamber is not too high, whether is jammed air заслонка and whether contacts are not too worn out. Try to use candles with longer insulator that raises resistibility to pollution.

Candle normal state

Symptoms: Gray-brown colour and easy deterioration of electrodes. The kalilnoe number of candles corresponds to type of the engine and its general condition.

Recommendations: At replacement of candles establish candles of the same type.


Symptoms: zamaslivanie candles it is caused by deterioration Hм слоотражательных caps. Oil gets to the combustion chamber through worn out directing valves or piston rings. Causes ignition admissions, complicates start and leads to instability of work of the engine.

Recommendations: Make a mechanical recovery work and replace све


Symptoms: Soft brownish colour of adjournment on one or both electrodes of a candle. A source of their formation are applied additives to Hм слу and-or to fuel. Excessive accumulation can lead to isolation of electrodes and cause admissions of ignition and astable work of the engine at acceleration.

Recommendations: At fast accumulation of adjournment change Hм слоотражательные caps that will prevent hit Hм сла in combustion chambers. Try to replace Hм ку fuel.


Symptoms: the Porous, white insulator, erosion of electrodes and absence of any adjournment. Leads to reduction of service life of a candle.

Recommendations: whether Check up corresponds to requirements of Specifications калильное number of the established candles, whether the corner of an advancing of ignition is correctly exposed, whether too poor toplivno-air mix moves, whether there are no leaks of vacuum of the inlet pipeline and whether valves are jammed. Check up as level of a cooler and whether the radiator is corked.


Symptoms: the Rounding off of electrodes with a small congestion of adjournment on the working end. Colour normal. Leads to difficulty of start of the engine in cold damp weather and to increase of the expense of fuel.

Recommendations: Change candles on new, the same type.

Too early ignition

Symptoms: Electrodes are melted off. The insulator has white colour, but can be and is polluted owing to admissions of ignition or hit in chambers of combustion of extraneous particles. Can lead to an engine exit out of operation.

Recommendations: Check up калильное number of the established candles, a corner of an advancing of ignition, quality of a mix (whether it is not too impoverished), whether the system of cooling is corked and whether the greasing system normally functions.


Symptoms: Insulators can appear chopped off or треснутыми. The inaccurate technics of adjustment of a candle backlash can result In insulator damage also. Can lead to damage of pistons.

Electrospending luster

Symptoms: the Insulator has yellowish colour and the polished kind. Speaks about sudden rise in temperature in combustion chambers at sharp acceleration. Usual adjournment are thus melted off, taking a form of a varnish covering. Leads to ignition admissions at high speeds of movement.

Recommendations: Replace candles (colder, at preservation Hм неры drivings).


Symptoms: After admissions of ignition during a long time interval of adjournment can be loosened at preservation of working temperature in the combustion chamber. At high speeds of adjournment in flakes come off the piston and stick to a hot insulator, causing ignition admissions.

Recommendations: Replace candles or smooth out and establish into place the old.

Short circuit of electrodes

Symptoms: the Waste of products of combustion gets to interelectrode space. Firm adjournment accumulate, forming a crosspiece between electrodes. Leads to ignition refusal in the cylinder.

Recommendations: Remove adjournment from interelectrode space.

Mechanical damages

Symptoms: Can be caused hit of strangers Hм териалов in the chamber of combustion or arise at piston blow about too long candle. Lead to refusal of functioning of the cylinder and to piston damage.

Recommendations: Remove from the engine extraneous particles and-or replace

On the main page