Audi A4, S4

since 2000 release

Repair and operation of the car



Audi A4, S4
+ Introduction
+ Governing bodies and methods of safe operation
+ Current leaving and service
+ Engine
+ Cooling systems, heating and air conditioner
+ Power supply systems, release and decrease in toxicity of the fulfilled gases
- Systems of electric equipment of the engine
   - System of ignition and engine management
      Main data and security measures
      Checks of a control system of ignition and injection
      Search of malfunctions - the general information and preliminary checks
      Check and adjustment of a corner of an advancing of ignition
      Spark plugs
   + System of preheat of the diesel engine
   + Diagnostics of systems of electronic control and diagnostic equipment
   + Systems of charging and start
+ Manual box of gear shifting
+ Automatic transmission
+ Coupling, power shafts and differential
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment






Spark plugs

General description

The spark plug consists of the central electrode, an insulator with the case and a weight electrode(s). Between the central electrode and an electrode of weight the spark igniting fuel-air mix slips. It is not necessary to apply the spark plugs other than the recommended. The recommended type of candles is defined among other things by kalilny number.

The Kalilny 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 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 the movement in the city, short trips 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 weight, with various length of a carving and its diameter. When replacing a candle it is necessary to establish only the candles conforming to requirements of the manufacturer of the car.

Average service life of a candle is various. Thus the serious role is played also by material of electrodes. A chrome-nickel alloy is characterized by very high heat conductivity and high corrosion resistance. The best heat conductivity silver possesses, and platinum electrodes possess high corrosion resistance and firmness against an obgoraniye. Service life of candles of 100000 km of run.

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 conical consolidation it is not required additional sealing elements. At limited space for installation, candles with a flat landing surface and the turnkey small 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, address to the Head the Current leaving and service.

On appearance of a candle it is possible to draw a conclusion on work of candles, quality management of mix and a condition of the engine (pistons, piston rings, etc.).

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

Coal deposits

Symptoms: Availability of soot indicates reenrichment of fuel and air mix or weak intensity of a spark. Causes admissions of ignition, complicates start and results in instability of operation of the engine.
Recommendations: Whether check the air cleaner is hammered, whether fuel level in a float-operated chamber is not too high, whether the air gate is jammed and whether contacts are not too worn-out. Try to use candles with longer insulator that increases resilience to pollution.

Oiling

Symptoms: Oiling of a candle is caused by wear of maslootrazhatelny caps. Oil gets to the combustion chamber through the worn-out directing valves or piston rings. Causes admissions of ignition, complicates start and results in instability of operation of the engine.
Recommendations: Perform mechanical recovery work and replace candles.

Overheat

Symptoms: Porous, white insulator, erosion of electrodes and lack of any deposits. Leads to reduction of service life of a candle.
Recommendations: Whether check the kalilny number of the established candles conforms to requirements of Specifications, whether the ignition advancing corner 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 also the level of a cooler and whether the radiator is corked.

Too early ignition

Symptoms: Electrodes are melted off. The insulator has white color, but maybe is polluted owing to admissions of ignition or hit in combustion chambers of foreign particles. Can lead to an engine exit out of operation.
Recommendations: Check kalilny number of the established candles, an ignition advancing corner, quality of mix (whether it is not too grown poor), whether the cooling system is corked and whether the lubrication system normally functions.

Electroconductive luster

Symptoms: The insulator has yellowish color and the polished appearance. Speaks about sudden temperature increase in combustion chambers at sharp acceleration. Usual deposits thus are melted off, taking a form of a varnish covering. Leads to admissions of ignition at high speeds of the movement.
Recommendations: Replace candles (colder, at preservation of a manner of a driving).

Short circuit of electrodes

Symptoms: Waste of products of combustion gets to interelectrode space. Firm deposits accumulate, forming a crossing point between electrodes. Leads to refusal of ignition in the cylinder.
Recommendations: Remove deposits from interelectrode space.

Normal state of a candle

Symptoms: Gray-brown color and easy wear of electrodes. The Kalilny number of candles corresponds to type of the engine and its general state.
Recommendations: When replacing candles establish candles of the same type.

Peploobrazovaniye

Symptoms: Soft brownish color of adjournment on one or both electrodes of a candle. A source of their education are the applied additives to oil and/or 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 maslootrazhatelny caps that will prevent hit of oil in combustion chambers. Try to replace fuel brand.

Wear

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.

Detonation

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

Zabryzgivaniye

Symptoms: After admissions of ignition 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 admissions of ignition.
Recommendations: Replace candles or smooth out and establish into place the old.

Mechanical damages

Symptoms: Can be caused by hit of foreign materials in the combustion chamber or arise at blow of the piston about too long candle. Lead to refusal of functioning of the cylinder and to damage of the piston.
Recommendations: Remove foreign particles from the engine and/or replace












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