Audi A4

since 1994 release

Repair and operation of the car

A4 Audi
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
+ System of injection
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
- System of ignition
   That provides ignition
   When there is an ignition of fuel and air mix?
   Different systems of ignition
   So there is an ignition spark
   Executive body
   Brain of system
   The signals coming to the control unit
   Adjustment of a detonation
   Be careful in the address with ignition
   Works on system of ignition
   Search of malfunctions in ignition
   Ignition distributor
   Knot of a high voltage
   Replacement of spark plugs
   Right choice of spark plugs
   Check of the moment of ignition
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics

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Replacement of spark plugs

For replacement of spark plugs in the 92 kW engine it is necessary to disconnect the socket (1) on the terminal cascade of power and to unscrew the terminal cascade together with ignition coils. Shooters showed screws. At installation consider an order of laying of a wire: the wire from the back coil (2) goes to the 2nd cylinder (4); a wire from the forward coil (3) – to the 1st cylinder (5).

The plan of maintenance provides replacement of candles through each 60 000 km or every three years – that comes earlier. The time interval prevents emergence of defect due to aging at small run.

Audi provides very big interval in maintenance which can be observed only in case of use of admissible types of candles. Therefore there is no occasion to extend it even more. On a working condition of system of ignition it is necessary to pay special attention in case in cars there is a catalytic converter – we already spoke about it.

It is worth examining critically dismantled candles: further you will read about what tells "a face of a candle".

If sometimes candles are unscrewed for check: it is desirable not to clean candles a hand. It harms to an insulating layer of an intermediate electrode of a spark plug (steatite).

Dismantle of spark plugs


  1. Engine of 1,8 l and six-cylinder engine: dismantle an engine cover.
  2. 92 kW engine of 1,8 l: unscrew and take out ignition coils with the terminal cascade of power; remove sockets of candles.
  3. 110 kW engine of 1,8 l: unscrew and remove separate coils of ignition.
  4. At dismantle of sockets of coils of ignition do not pull a wire, and undertake the socket.
  5. Unscrew spark plugs and put them in sequence of cylinders in order that it was possible to draw conclusions on a condition of a candle of the corresponding cylinder.
  6. If candles sit very strongly, do not use force, differently it is possible to strip a thread of candles in the head of the block of cylinders made of light metal.
  7. Warm the engine and now unscrew candles.
  8. At installation do not screw up densely cold candles in the warmed head of the block of cylinders, differently they will sit then, as riveted.
  9. Spark plugs have to be screwed up on 30 Nanometers. If there is no dinamometrichesky key near at hand:
  10. Screw up a candle so that the sealing ring adjoined – it cannot already be turned without application of force a hand, a key for candles.
  11. Now the new I shine Dovintita with a special key precisely quarter turns more strongly.
  12. The candle which was in the use can be dovinchivat only approximately on 15 °.

Spark plugs have to be tightened on 30 Nanometers. If near at hand there is no dinamometrichesky key: screw up a candle so that the sealing ring (shooter) adjoined – in this case it cannot be tightened a hand or a key without application of force. Now, if a candle new, tighten it a key precisely on a quarter of a turn. If the candle was in the use, turn it a key only approximately on 15 °, it is enough of it.

 Councils: To increase sliding of a carving of a spark plug, you can scrape up in rounds a little graphite from a soft simple pencil or grease them with copper-bearing greasing a little. Oil or greasing "will bake" a spark plug in a carving of a head of the block of cylinders.

"Person of a spark plug"

Spark plugs in a certain degree are witnesses of process of combustion in the engine. It is possible to determine by appearance of a top of a candle ("the person of a candle"), the engine how optimum works. It is previously necessary to warm up thoroughly the car on the rural road or on the highway. Check after the movement on short distance can lead to the wrong conclusion. Look at an insulator top with an average electrode and at lateral electrodes:

  • Top of an insulator of light gray or brownish color: the correct installation of system of injection, the engine works economically.
  • Strong deposits: the reason can be in additives in engine oil, either in fuel, or in the raised oil consumption. Change brand of oil or fuel.
  • Deposits of black color similar to soot: due to the frequent movement on short distances the candle does not reach self-cleaning temperature, the wrong kalilny number.
  • Top of an insulator of whitish color: the moment of ignition is too strongly shifted towards "advancing", electronic adjustment of the moment of ignition or a sensor of a detonation does not work.
  • The melted-off sites on an average and lateral electrodes: filament ignition as a result of a deposit in the combustion chamber, superheated valves, incorrectly established ignition point, defective adjustment of a point of ignition or stagnation of heat as a result of insufficient cooling.
  • Destruction of a top of an insulator, at an initial stage noticeable in the form of hair cracks: detonation combustion because of fuel of poor quality, the wrong installation of ignition, defective adjustment of a point of ignition, a defective sensor of a detonation, insufficient cooling of the engine or impoverishment of fuel and air mix at the expense of collateral air.
  • Yellowish brilliant layer on an insulator top: deposits at the expense of additives in gasoline and engine oil which at sharp full load of the engine passed into a liquid state were formed and became electrowire and as a result – interruptions in ignition. At trips on short distances week you should not subject the engine to full loading at once.
  • Butter layer on electrodes and an internal surface of candles: defect of rings of pistons, the directing valves or laying of cores of valves.
  • If in appearance of a spark plug any features are not noticeable, but the engine badly is started or twitches, nevertheless the reason can be in candles. During start of the cold engine invisible cracks in a ceramic insulator can be filled with fuel condensate which takes away an ignition spark. Under pressure of a candle too can refuse though in the dismantled state it is visible as the spark slips. In a doubtful case replace.

Distance between electrodes

Fuel and air mix and exhaust gases promote corrosion of metal electrodes of spark plugs. And the high voltage at a proskakivaniye of a spark tears off from them the smallest particles of metal therefore over time the distance between electrodes of spark plugs increases. In the presence of candles with three electrodes the spark of ignition can "find" the shortest way. Therefore it is almost not required to turn in electrodes.