Opel Astra, Zafira
since 1998 of release
Repair and car operation
+ Opel Astra and Zafira Cars
+ Operation manual
+ Routine maintenance
+ Systems of cooling, heating
+ Power supply system and release
- Engine electric equipment
- Electronic control system of ignition (and injection) petrol engines
Checks of serviceability of functioning of system of ignition
Diagnostics of malfunctions - the general information and preliminary checks
System of onboard self-diagnostics of OBD - the general information
Oscillograph application for supervision of workers of a control system
Removal and installation of the module of ignition
Check and installation of a corner of an advancing of ignition
Removal and installation of the switch of ignition
Removal and installation of the sensor of emergency pressure of oil
Removal and installation of the sensor of level of impellent oil
Removal and installation of the sensor of temperature of impellent oil (diesel models)
+ Systems of preheat and heating of fuel of the diesel engine
+ charge and start Systems
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Onboard electric equipment
Oscillograph application for supervision of workers of a control system
Digital multimeters perfectly are suitable for check of the electric chains being in a static condition, and also for fixing of slow changes of traced parameters. At carrying out the dynamic checks which are carried out on the working engine, and also at identification of the reasons of sporadic failures by absolutely irreplaceable tool there is an oscillograph.
Some oscillographs allow to keep oscillograms in the built-in module of memory with the subsequent conclusion of results to the press or their transfer to the carrier of the personal computer already in stationary conditions.
The oscillograph allows to observe periodic signals and to measure tension, frequency, width (duration) of rectangular impulses, and also levels of slowly changing tension. The oscillograph can be used at performance of the following procedures:
Reliability and simplicity of operation of modern oscillographs do not demand any special special knowledge and experience from the operator. Interpretation of received information can be easily made by a way of elementary visual comparison of the oscillograms removed during check with the temporary dependences given below typical for various sensors and actuation mechanisms of automobile control systems.
Parameters of periodic signals
Each signal removed by means of an oscillograph (see an illustration of the Characteristic of any periodic signal), can be described by means of the following key parameters:
Usually characteristics of the faulty device strongly differ from reference that allows the skilled operator easily and quickly to reveal the refused component by the analysis of the corresponding oscillogram.
Signals of a direct current
The unique performance data of such signals is tension.
Signals of a direct current are developed by the devices presented below.
Signals of an alternating current
The main characteristics of these signals are the amplitude, frequency and a signal form.
The frequency modulated signals (WC)
Performance data of the frequency modulated signals are the amplitude, frequency, a form of a signal and width of periodic impulses.
Sources of a WC of signals are the devices presented below.
The signals modulated on width of an impulse (ShIM)
Performance data of signals of pulse-width modulation (ShIM) are the amplitude, frequency, a form of a signal and porosity of periodic impulses.
Sources of signals of ShIM are presented below the device.
The coded sequence of rectangular impulses
Performance data are the amplitude, frequency and a form of sequence of separate impulses.
This sort of signals are generated by the module of memory of self-diagnostics of ECM of a control system of the engine.
The amplitude and form of a signal remain the constants, the written-down value will stand out until memory of the module will not be cleared.
Interpretation of oscillograms
The form of a signal given out by an oscillograph depends on a set of various factors and can change considerably. In a look told before starting replacement of a suspected component in case of discrepancy of a form of the removed diagnostic signal with the reference oscillogram, it is necessary to analyse the received result carefully.
Zero level of a reference signal cannot be considered as absolute basic value, - "zero" of a real signal, depending on concrete parameters of a checked chain, it can appear shifted rather reference ( - see an illustration the Digital signal) within a certain admissible range.
The full amplitude of a signal depends on supply voltage of a checked contour and also can vary in certain limits of rather reference value ( - see an illustration the Digital signal and  - see an illustration the Analog signal).
In chains of a direct current tension of a signal is limited to supply voltage. As an example it is possible to give a chain of system of stabilization of turns of the idling (IAC) which alarm tension does not change in any way with change of turns of the engine.
In chains of an alternating current the amplitude of a signal already unequivocally depends on frequency of operation of a source of a signal, so, the amplitude of the signal which is given out by the sensor of provision of a cranked shaft (CKP) will increase with increase of turns of the engine.
In a look told if the amplitude of a signal removed by means of an oscillograph appears excessively low or high (up to trimming of top levels), it is enough to switch only a working range of the device, having passed to the corresponding scale of measurement.
At check of the equipment of chains with electromagnetic management (for example, IAC system) at shutdown of a food tension throws ( - see an illustration the Digital signal) which in the analysis of results of measurement can be ignored quietly can be observed.
It is not necessary to worry also at emergence of such deformations of the oscillogram, as a skashivaniye of the lower part of the forward front of rectangular impulses ( - see an illustration the Digital signal) if, of course, the fact of a vypolazhivaniye of the front is not a sign of violation of serviceability of functioning of a checked component.
Frequency of repetition of alarm impulses depends on working frequency of a source of signals.
The form of a removed signal can be edited and brought to a look convenient for the analysis by switching on an oscillograph of scale of temporary development of the image.At supervision of signals in chains of an alternating current temporary development of an oscillograph depends on frequency of a source of a signal ( - see an illustration the Analog signal), defined by engine turns.
As it was already told above, for reduction of a signal to a legible look it is enough to switch scale of temporary development of an oscillograph.
In certain cases the oscillogram of a signal appears rather reference dependence developed specularly that speaks a reversivnost of polarity of connection of the corresponding element and, in the absence of a ban on change of polarity of connection, can be ignored in the analysis.
Typical signals of components of control systems of the engine
Modern oscillographs are usually equipped only with two alarm wires together with a set various щупов, allowing to carry out device connection practically to any device.
The red wire is connected to a positive pole of an oscillograph and is usually connected to the plug of the electronic module of management (ECM). The black wire should be connected to reliably earthed point (weight).
Management of structure of an air and fuel mix in modern automobile electronic systems of injection of fuel is carried out by timely correction of duration of opening of electromagnetic valves of injectors.
Often on the oscillogram it is possible to observe also a series of the short pulsations following directly an initiating negative rectangular impulse and supporting the electromagnetic valve of an injector abroach, and also the sharp positive throw of tension accompanying the moment of closing of the valve.
Serviceability of functioning of ECM can be easily checked by means of an oscillograph by a way of visual supervision of changes of a form of an operating signal at a variation of working parameters of the engine. So, duration of impulses at an engine provorachivaniye on single turns should be slightly higher, than at operation of the unit on low turns. Increase of turns of the engine should be accompanied by respective increase in time of stay of injectors abroach. This dependence is especially well shown when opening butterfly valve by short pressing a gas pedal.
At cold start the engine needs some enrichment of an air and fuel mix that is provided with automatic increase in duration of opening of injectors. In process of warming up duration of operating impulses on the oscillogram should be reduced continuously, gradually coming nearer to value typical for single turns.
In injection systems in which the injector of cold start is not applied, at cold start of the engine the additional operating impulses which are showing on the oscillogram in the form of pulsations of variable length are used.
In the table provided below typical dependence of duration of operating impulses of opening of injectors on a working condition of the engine is presented.
The increase in turns of the engine should be accompanied by increase in amplitude of a pulse signal developed by the sensor.
Electromagnetic valve of stabilization of turns of idling (IAC)
In automotive industry electromagnetic IAC valves of a set of the various types which are giving out signals of also various form are used.
The common distinctive feature of all valves is that fact that porosity of a signal should decrease with increase of load of the engine, connected with inclusion of additional consumers of the capacity causing fall of turns of idling.
If porosity of the oscillogram changes with increase in loading, however at inclusion of consumers violation of stability of turns of idling takes place, check a condition of a chain of the electromagnetic valve, and also correctness of given-out ECM of a command signal.
Usually in chains of stabilization of turns of idling the 4-polar step-by-step electric motor which description is provided below is used. Check of 2-contact and 3-contact IAC valves is made in a similar manner, however oscillograms of alarm tension given out by them are absolutely unlike.
The step-by-step electromotor, reacting to given-out ECM a pulsing operating signal, makes step correction of turns of idling of the engine according to working temperature of cooling liquid and the current load of the engine.
Levels of operating signals can be checked by means of an oscillograph, measuring щуп which is connected serially to each of four plugs of the step-by-step motor.
Lambda probe (the oxygen sensor)
The increase in turns of the engine should be accompanied by increase of amplitude of a signal, reduction - decrease.
Sensor of a detonation (KS)
Ignition signal on an exit of the amplifier
At increase in turns of the engine frequency of a signal should increase in direct ratio.
Primary winding of the coil of ignition
Unevenness of throws can be caused by excessive resistance of a secondary winding, and also malfunction of a condition of VV of a wire of the coil or a candle wire.