Mercedes S-Class W-140
1991-1999 of release
Repair and operation of the car
+ Mercedes-Benz cars of the class S (W-140)
+ Operation manual
+ Routine maintenance
+ Cooling systems, heating
+ Power supply system and release
- Engine electric equipment
- Systems of ignition and engine management - the general information
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
Self-diagnostics of systems of electronic control of OBD
Diagnostics of electronic system of the automatic air conditioner (AC)
Application of an oscillograph for observation of signals of a control system
Ignition coils - installation details
Removal, installation and adjustment of the sensor of position of the camshaft (CMP)
The distributor of ignition (M119.97 engines) - installation details
+ Systems of a charge and start
+ Gear shifting box
+ Automatic transmission
+ Brake system
+ Suspension bracket and steering
+ Onboard electric equipment
General descriptionThe spark plug consists of the central electrode, the 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 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. At the same time the candle takes away heat better thanks to what the possibility of kalilny ignition of fuel mix is excluded. 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 movements by 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 corresponding to instructions of the manufacturer of the car.
Middle service life of a candle is various. At the same time a serious role is played also by material of electrodes. Chrome-nickel alloy is characterized by very high heat conductivity and high corrosion resistance. Silver possesses the best heat sink, and platinum electrodes have high corrosion resistance and firmness against an obgoraniye. Service life of candles lies between 20 000 and 100 000 km of a run, depending on material of 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 conical consolidation additional sealing elements are not required. 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 a run (see the Head Routine maintenance).
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.)
Normal state of a candle
Too early ignition
Short circuit of electrodes
At a vvinchivaniye of candles you watch that they were not drawn as the sealing washer can be damaged. Do not exceed the inhaling moment specified in Specifications.