Skoda Felicia

since 1994 release

Repair and operation of the car



Skoda Felicia
+ Cars of the Skoda Felicia brand
+ Maintenance instruction
+ Routine maintenance
+ Repair of the engine
+ Cooling systems, heating
+ Power supply system
- Engine electric equipment
   + Systems of a charge and start
   - System of ignition of petrol engines
      General information
      Diagnostics of malfunctions of system of ignition and check of a condition of its components
      Removal and installation of the coil of ignition
      Removal and installation of the distributor of ignition
      Check and correction of a corner of an advancing of ignition
      Removal and installation of information sensors of system of ignition
   + System of preheat of diesel engines
+ Coupling
+ Transmission
+ Power shafts
+ Brake system
+ Suspension bracket and steering
+ Body and finishing of salon
+ Onboard electric equipment





System of ignition of petrol engines

General information

The scheme of system of ignition with the contactless sensor distributor

1 — Spark plugs
2 — the ignition Distributor
3 — the Switchboard

4 — the ignition Coil
5 — the ignition Switch
6 — the Battery


The systems Bosch Mono-Motronic, Simos 2P and Magneti-Marelli 1AV are subsystems of the uniform control system of the engine controlling giving of food and an order of ignition of fuel. The real Part of the Head is devoted only to the components concerning ignition.


Carburetor models


The system of ignition is intended for transformation of current of the low voltage arriving from the rechargeable battery or the generator to a high-tension current, and also for giving of this VV of tension at the corresponding moments on the spark plugs which are setting fire air-fuel mix in engine cylinders.

On carburetor models of the considered cars the system of ignition with the contactless sensor distributor and the switchboard is used. The scheme of such system of ignition is submitted on an illustration.

In NV a contour of system of ignition current proceeds through contacts of the switch of ignition to the ignition coil 15 plug, and then - from the coil 1 plug to the switchboard.

Contour induced in a secondary winding of the coil of ignition (it is created at the moments of interruption of current in primary winding of the coil) current comes to VV on the central plug of a cover of the distributor and, further - via the runner and VV of a wire - on spark plugs.

Bosch Mono-Motronic and Magneti-Marelli 1AV

Four spark plugs, five VV of wires, the ignition distributor, the electronic coil of ignition, electronic control unit (ECU), and also set of information sensors, actuation mechanisms and connecting electrical wiring are a part of both systems. Schemes of placement of components of systems are a little various, however by the principle of functioning of system are almost identical.

ECU gives basic tension on an entrance step of the coil of ignition, exciting primary winding of the coil. Periodically basic tension is interrupted by ECU that leads to turning of magnetic field of primary winding and production of VV of tension in secondary. Further, the high voltage created in the coil via the distributor on VV to wires moves on the spark plugs generating a powerful spark on a step of ignition of the piston of each of cylinders. The spark is formed between candle electrodes at the time of giving of tension VV on it and provides the guaranteed ignition of the air-fuel mix injected into the cylinder. The corner of an advancing of ignition and duration of the closed condition of contacts of the breaker is defined and controlled by ECU, proceeding from the control system of the engine of information on engine turns, the provision of a bent shaft arriving from sensors and depth of depression in the inlet pipeline. Situation and speed of opening of a butterfly valve, temperature of the soaked-up air and cooling liquid, and in the Magneti-Marelli system belong to number of the other parameters exerting impact on the choice of a corner of an advancing of ignition, - also a detonation of air-fuel mix (information arrives on ECU from the corresponding sensors).

Control of a detonation of air-fuel mix is provided on models of 1.6 l equipped with system of injection Magneti-Marelli 1AV. The sensor of a detonation is installed on the block of cylinders and on increase of vibrations reveals the moment when ignition becomes too early. Having in due time obtained information from the sensor, ECU makes delay of ignition, preventing emergence of the sound effects connected with a detonation. Further ECU in several stages returns an ignition advancing corner to normal value. In case of repeated emergence of a detonation the cycle is repeated.

Control of turns of idling is exercised partly by means of the electronic module of the provision of a butterfly valve established to a throttle case wall, and partly - system of ignition by timely correction of a corner of an advancing of ignition. In view of told, need for manual adjustment of turns disappears, and the possibility of its performance by a design of system is not provided.

In some ECU systems it is capable to organize reusable ignition at start of the cold engine. At the time of an engine provorachivaniye a starter of a spark plug develop a spark on each step repeatedly that significantly increases efficiency ignition of mix and facilitates start of the engine.

It should be noted that diagnostics of malfunctions of system described in the present Chapter is possible only with use of the special electronic equipment. If it is not possible to establish a cause of failure during performance listed in the Section Diagnostics of Malfunctions of System of Ignition and Check of a Condition of Its Components of the Present Chapter of Checks, the car should be driven away on car repair shop. Descriptions of procedures of removal and installation of the failed components are provided in appropriate sections of the Head.

Simos 2P

In the Simos 2P system static ignition is used (without distributor). Also ignition coils, united in the uniform module, are a part of system of ignition two put in casings. The model is established directly over spark plugs, and therefore no VV of wires are provided.

Each of coils of the module serves two cylinders (one - the 1st and 4th, second - the 2nd and 3rd).

On the given ECU teams of the coil generate in cylinders two sparks of ignition - one on a step of compression and one on a final step. Tension of breakdown of a candle on a compression step as a result of increase in pressure is very considerable. On a release step when the compression is insignificant, very weak spark which is not making any impact on the fulfilled gases produced from the cylinder and called single is generated. Such scheme of ignition allows to avoid need of installation of the separate coil on each of candles.

ECU operates functioning of system on the basis of the signals received from various information sensors. On the basis of the arriving information on engine temperature, the current loading and turnover of ECU determines parameters for correction of the moment of ignition and time of a charge of coils. idling ECU, correcting as appropriate an ignition advancing corner, changes torque of the engine for the purpose of maintenance of stability of turns. The system functions in close contact with a potentiometer of provision of a butterfly valve.

Also the detonation sensor is a part of system of ignition. Established in a back part of the block of cylinders, the sensor reacts to change of frequency of vibrations of the engine and defines the moment of the beginning of emergence of a detonation of mix in cylinders. On the basis of information obtained from the sensor, ECU in due time makes step-by-step correction of a corner of an advancing of ignition, preventing further development of a detonation.