Mercedes S-Class W-140

In 1991-1999 editions

Repair and enterprise of the car

Mercedes S-Class
+ Mercedes Benz cars of the class S (W-140)
+ operation manual
+ Routine maintenance
+ motor
+ cooling systems, heating
+ Systems of power supply and edition
- Electric equipment of the motor
   - Systems of ignition and management of the motor - the general information
      Checks of tax system ignition and injections
      Search of defects - the general information and preliminary checks
      Check and regulation of a corner of Zuvorkommens of ignition
      Spark plugs
      Self-diagnostics of control systems of the pipe OBD
      Diagnostics of electronic system of the automatic conditioner of air (kilowatt)
      Application of an oscillograph for observation of signals of tax system
      Ignition coils - a device detail
      Removal, device and regulation of a sensor of provision of a wave of curve (CMP)
      The distributor of ignition (M119.97 motors) - a device detail
   + systems of freight and start
+ gear shifting boxes
+ Awtomatitscheckaja transmission
+ connection
+ brake system
+ Aufhängung and management
+ body
+ electric onboard equipment

Search of defects - the general information and preliminary checks

If introductions address also to diagnostics of the spoiled office

The system of ignition and system of fuel are mutually connected components of tax system the motor.

General information

The system of ignition and system of fuel have the general diagnostic system which is intended for preservation of Kodes of defects and performing diagnostics. At defect emergence the control unit in memory writes down some sequence of signals (a defect code) which can be considered special facility later (it watch office self-diagnostics of control systems of the pipe OBD).

If violations are observed in operation of the motor of the car, it is possible to find out the reason after all probability, issledowaw memory of the control unit. After reading of Kodes of defects it is possible to find out what knot is wrong and to fill, corresponding checks (either knot, or its electric leading device).

visuale check of the electric leading device and plugs is insufficient - by all means you consider information, in memory keep to the control unit.

Preliminary checks

If defect arose after service of some knot soon, first of all, carefully you check this knot and the surrounding room. Perhaps, the reason disappears in carelessly certain component or unreliably connected plug.

If you try to find the reason of a certain defect of the motor, for example, of an ambush of the power, measure in addition to following actions compression in the cylinder. Are convinced that the filter for fuel and the filter for purification of air changed according to the ordered intervals.

Think that it is necessary to delete them on memory of the control unit by means of the same diagnostic scanner after reading of Kodes of defects then to delete defect.

Open a cowl of the engine and you are convinced of reliability of the introduction of tops of lines to clips of the accumulator and lack of corrosion on them. At detection of traces of corrosion or damages you replace or you clean lines. In the same way you check all tires of grounding, there is convinced that they have to guarantee sure contact (the connected surfaces absolutely purely and without corrosion traces) with a body or the motor to be.

Then you look at all visible line attentively which is put within motor office. Are convinced of reliability of all associations. In this stage obviously damaged lines interest you. They can be cut either by pereterty about sharply or the moving motor knots, for example, of a detail of Aufhängung or priwodnoj of belts. The slope of the line can occur owing to the negligent device of some knot. The line can melt at contact with system of the edition. The most probable cause of damage of the line is a wrong transferring of its textures in motor office after execution of repair or service of some knot.

Lines can be damaged or sakorotscheny without damage of its isolation. In this case audit to what will not lead. Similar damages can arise after wytjagiwanija of lines or wrong placement of the line within motor office. If you think that similar damage is possible, check the line, the sequences the following which is given below.

It is possible to repair the damaged line, in breakage a part of the new line it is sealed. Soldering is necessary for receiving sure contact. From enough an insulating tape or termoussadotschnoj from the listener it is possible to restore isolation. If damages are considerable and the damaged line plays an essential role, the most correct exit (though from rather expensive) will be compensation of the corresponding texture on new.

After restoration of the damaged line you correctly decide it in motor office, is far from the rotating and hot knots. Do not forget to strengthen the line in mezhduzasova (if).

Are convinced of reliability and purity of all available plugs. All bolts have to be defined. If on the internal surface of the plug you erase corrosion traces (white or green deposits, and also rust traces) or you accept the increased pollution, you clean it from the corresponding clip and carefully. For this purpose you can use a special aerosol. If the plug is seriously damaged, it is necessary to replace it is necessary. Think that in several cases you have to replace a texture completely.

If you could delete corrosion traces from the plug completely, fill the preserving lubricants then into place you establish try to obtain. They can learn the Schmierens type on 100.

On all models the inductive sensor of situation kolenwala (defined with its help clears up also WMT of the first cylinder). On models of the early edition a working part of oil or dust can be polluted that can lead to violations in its work and as appropriate to documents of ignition. The sequence of actions is given at removal and the device of a sensor in the head of system of power supply and the edition.

Attentively you look at all hoses of vacuum and at listeners who are located in motor office. Are convinced of reliability of the train of collars and lack of cracks, stratifications and traces of damages on hoses. Are convinced also that any hoses not of peredawleny are not too strongly bent, i.e. do not pass air. You mark out special attention to hoses which are located near sharp edgings, and also to the ends of all hoses. It is necessary to replace all damaged hoses.

Also pollution on hoses of system of ventilation of kartera are convinced of lack of traces of damages. Are convinced also that they are not blocked from within. The quantity and a grade of installation of hoses of system depends on car model, but on all models the hose which connects the top part of the motor with a hose to air receipts or access pipelines is defined. Hoses of system connect also the block of cylinders (or maslosaliwnuju a neck) with the access pipeline. These hoses deliver oil vapors in burning cameras. At pollution or blocking of these hoses the motor will unstably work (especially at not aggravated changes).

From the tank being followed by the filter for fuel up to the highway of distribution of fuel along pipelines of fuel, you look at them attentively. At detection of traces of damages or exaggerations you replace the corresponding section. You mark out special attention to joints of listeners. On them there can be cracks which lead to a fuel vytecheniye.

Accept a filter body cover for purification of air and you look at an element. It has to be to be rather pure and is dry. Strongly polluted cleaner shows the strong resistance of current of air that leads to remarkable immersion of engine capacity. Replace the filter for purification of air if it is necessary.

Start the motor and be engaged to work at not aggravated changes.

At execution of some works in motor office at the working motor you extremely are careful.

Except high probability of receiving burns of heated details of the motor or system of the edition, you risk to receive serious violation of the rotating details (for example, the fan of the heater or priwodnogo of a belt).

Prior to work, actions seize you, first of all, and pay attention to you safety of work it is presented at the beginning of each chapter.

They follow hands, do not allow you I will meet long hair or clothes in motor office. They keep slightly further from system of the edition and other hot details.

In air receipt to the filter for purification of air is farther up to a thrush the following, are convinced of lack of a vytecheniye from air transfer hoses (inclusive nearby hoses of vacuum). It is possible to find it after characteristic whistle. If whistle does not ring, charge small amount of soap water on suspicious section of a hose. If the hose is damaged, kind of work of the motor will change, and will be on it bubbles processed a hose surface (can appear or, depending on pressure in a hose, water begin to get inside). At Ausfließens detection you, of course, tighten a collar or you replace the damaged hose.

In the same way you check all system of the edition (from a collector up to back section). Are convinced of lack of a vytecheniye of gases. For work simplification you can lift the car on the elevator to establish on transfer or about a hole. For conducting the simplest check you stop up final opening of system of the edition and you listen carefully to work of system. If you heard characteristic whistle, this vytecheniye available. At Ausfließens detection you tighten the corresponding collar, bolts or Muttern, you replace transferring or the burning-down section.

The following check exists in alternate shift of each plug on the corresponding clip at the working motor. The unreliable contact will clear up after change of kind of work of the motor. Restore reliability of the contact replaced or, the corresponding plug it is cleared. Think that it is necessary to change all textures in several cases.

If owing to preliminary checks you did not find the reason of unstable operation of the motor, it is necessary to banish it is necessary the car on the station of service for performing more careful diagnostics when using the special equipment.