Audi A3

since 1997 of release

Repair and car operation

Audi A3
+ Maintenance instruction
+ Current leaving and service
+ Engine
+ Systems of cooling, heating
+ the Power supply system and production of the fulfilled gases
- Engine electric equipment
   - System of electronic control by ignition and injection
      Self-diagnostics of systems of electronic control of the second generation of OBD II
      Ignition system
      Checks of system of ignition and injection
      Spark plugs
   + charge and start Systems
+ 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


Spark plugs


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

Kalilnoye number characterizes degree of thermal loading of a candle. The kalilny number of a candle is lower, the degree of its thermal loading is higher. Thus the candle takes away heat thanks to what possibility of kalilny ignition of a fuel mix is excluded better. The candle with the high thermal characteristic has that shortcoming that its temperature of self-cleaning lies above. It is more inclined to formation of a deposit, in particular when the engine in operating time often does not reach the working temperature, for example movement in the city, short movings in the winter.

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

Average service life of a candle is various. Thus a serious role H · plays also m териал electrodes. Chrome - a nickel alloy is characterized 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 an obgoraniye. Service life of candles lies between 20 000 and 100 000 km of run, depending on H · m 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 konusny consolidation it is not required additional sealing elements. At limited space for installation, candles with a flat landing surface and the small turnkey size 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, carburetor adjustment, a condition of a mix and an engine condition (pistons, piston rings etc.) (address to photographic inserts).

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

Coal deposits

Symptoms: Availability of soot indicates reenrichment of a fuel and air mix or weak intensity of a spark. Causes ignition admissions, complicates start and results in instability of operation of the engine.

Recommendations: Whether check the air purifier is hammered, whether fuel level in the poplavkovy chamber is not too high, whether the air zaslonka is jammed and whether contacts are not too worn-out. Try to use candles with longer insulator that increases resilience to pollution.

Normal state of a candle

Symptoms: Gray-brown color and easy wear of electrodes. Kalilnoye 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: Zamaslivaniye of a candle is called by wear of H · m of slootrazhatelny caps. Oil gets to the combustion chamber through worn-out directing valves or piston rings. Causes ignition admissions, complicates start and results in instability of operation of the engine.

Recommendations: Perform mechanical recovery works and replace све


Symptoms: Soft brownish color of adjournment on one or both electrodes of a candle. A source of their education are applied additives to H · m слу and/or to fuel. Excessive accumulation can lead to isolation of electrodes and cause admissions of ignition and unstable operation of the engine at acceleration.

Recommendations: At fast accumulation of deposits change H · m slootrazhatelny caps that will prevent H hit · m сла in combustion chambers. Try to replace H · m ку fuels.


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

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


Symptoms: A rounding off of electrodes with a small congestion of deposits on the working end. Color normal. Leads to difficulty of start of the engine in cold damp weather and to fuel consumption increase.

Recommendations: Change candles on new, the same type.

Too early ignition

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

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


Symptoms: Insulators can appear chopped off or burst. Also inaccurate equipment of adjustment of a candle gap can lead to damage of an insulator. Can lead to damage of pistons.

Electrocarrying-out luster

Symptoms: The insulator has yellowish color and the polished appearance. Speaks about sudden temperature increase in combustion chambers at sharp acceleration. Usual deposits 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 H preservation · m ner of driving).


Symptoms: After ignition admissions during a long period 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: A waste of products of combustion gets to interelectrode space. Firm deposits accumulate, forming a crossing point between electrodes. Leads to ignition refusal in the cylinder.

Recommendations: Remove deposits from interelectrode space.

Mechanical damages

Symptoms: M териалов in the chamber of combustion can be caused by hit of strangers of H · or to 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