Service Infiniti QX4 since 1996 of release
1. Introduction
2. The maintenance instruction
3. Routine maintenance
4. The engine
5. Cooling and heating systems
6. Power supply systems and managements
6.1. Specifications
6.2. System of the consecutive distributed injection (SFI)
6.3. Sbrasyvanie pressure in the power supply system of petrol engines
6.4. Check of a condition and replacement of fuel lines and them choke connections
6.5. Electronic control systems - the general information
6.6. A control system of engine VG33E. Diagnostics procedures
7. Start and charge systems
8. A transmissionnaja line
9. Brake system
10. A suspension bracket and a steering
11. A body
12. An electric equipment
 












6-6-sistema-upravleniya-dvigatelem-vg33e-procedury-diagnostiki.html

6.6. A control system of engine VG33E. Diagnostics procedures

At the expense of application of a high-speed elektronno-computer (processor) the control system of the engine carries out coordination of such vital processes, as configuration of an air-fuel mix, installation and continuous adjustment of a corner of an advancing of ignition, functioning of systems рециркуляции the fulfilled gases and stabilisation of turns of idling and so forth As the corner-stone a task in view of reception of the maximum return from the engine in any road conditions at minimum the expense of fuel and concentration of the maintenance of toxic components in the fulfilled gases.


Function chart of a control system of engine VG33E

1 — the Fuel injector
2 — the Regulator of pressure of fuel
3 — the Cam of fast idling
4 — the Gauge of position throttle заслонки (TPS) and the gauge-switch of the closed position заслонки
5 — the Control lamp of refusals (MIL)
6 — the Block of management АТ (TCM)
7 — the Air cleaner
8 — the Gauge of temperature of soaked up air (IAT)
9 — the Electromagnetic valve of the gauge-switch of absolute pressure in the pipeline (MAP) / atmospheric pressure (BARO)
10 — the Gauge-switch of the permission of start (Р/N)
11 — the Gauge of absolute pressure
12 — the Gauge of speed of movement of the car (VSS)
13 — the Switch of the conditioner of air
14 — the pressure Gauge-switch in a hydraulic path of the steering amplifier (ГУР)
15 — the Gauge-switch of temperature of external air
16 — the Electronic module of engine management (ECM)
17 — the Gauge of measurement of weight of air (MAF)
18 — the Storage battery
19 — the Fuel tank
20 — the Gauge of temperature of fuel in a tank
21 — the Fuel pump
22 — the Coal adsorber of system of catching of fuel evaporations (EVAP)
23 — Perepusknoj the valve valve отсечки depression
24 — the Valve отсечки depression
25 — the Valve of management of ventilation of a coal adsorber

26 — the Gauge of pressure of a control system of purge EVAP
27 — the Valve of management of a purge of a coal adsorber
28 — the Electromagnetic operating valve of a purge of a coal adsorber
29 — the Electromagnetic valve of system рециркуляции the fulfilled gases (EGRС)
30 — Forward (предкаталитический) a warmed up ljambda-probe
31 — the One-pass valve
32 — the Volume valve of management of a purge of a coal adsorber
33 — Back (посткаталитический) a warmed up ljambda-probe
34 — Three-functional каталитический the converter
35 — the detonation Gauge (KS)
36 — the Gauge of position of a cranked shaft (CKP)
37 — Forward (предкаталитический) a warmed up ljambda-probe
38 — the Muffler
39 — Back (посткаталитический) a warmed up ljambda-probe
40 — Three-functional каталитический the converter
41 — the Spark plug
42 — Built in assemblage of the distributor the ignition coil, the powerful transistor and the gauge of position of a camshaft (CMP)
43 — the Valve of system of operated ventilation картера (PCV)
44 — the ignition Switch
45 — Valve EGRS-VRT
46 — Valve EGR
47 — the Gauge of temperature EGR
48 — the Gauge of temperature of a cooling liquid of the engine (ECT)
49 — the Electromagnetic valve-regulator of system of stabilisation of turns of idling (IACV-FICD)
50 — the Valve of additional air of system of stabilisation of turns of idling (IACV-ААС)


Design of the distributor of ignition


Site of the relay of ignition


Site of the relay of the fuel pump


The diagramme of gleams of control lamp MIL at delivery of diagnostic codes

The problem put before system on increase of efficiency of return of the engine and maintenance of the maximum comfort of movement is carried out by tracing and updating of following parametres:

  • Corner of an advancing of ignition and time перекрывания inlet and final valves in relation to positions of pistons;
  • Structure of the air-fuel mix submitted to the chambers of combustion in each working step of pistons;
  • The moment of ignition compressed in the cylinder in the end of a step of compression of an air-fuel mix;
  • Temperature of combustion of a gas mixture in cylinders, especially at engine work under loading;
  • Engine turns in any operating conditions.

All listed parametres are supervised and corrected by an electronic control system of the engine, providing its maximum return at minimum the expense of fuel and issue in atmosphere of toxic products of combustion practically at any service conditions of the car.


Quality management of an air-fuel mix

For maintenance of work of the petrol engine on single turns in combustion chambers the gas mixture enriched by fuel should move. At movement of the car with cruiser speed the quantity of an air component in a mix increases (pauperisation). Loading increase on the engine, work of the last on high turns also is accompanied by enrichment of an air-fuel mix. Any changes of quality of a mix should be made smoothly, whenever possible, imperceptibly for the driver. The electronic control system of engine Infiniti provides precision management of quantity of fuel injected into the engine on the basis of arriving from corresponding gauges of the analysis of the information on quantity of air soaked up in the engine, turns of a cranked shaft and position of a pedal of gas / throttle заслонки.

Measurement of the mass expense of atmospheric air arriving in the engine is carried out built in in an inlet air path of the gauge of measurement of weight of air (MAF). Gauges of the given type are capable to trace the slightest changes of the expense and density of an air stream and possess very small инерционностью, almost instantly correcting parametres given out on ECM an information signal. On the basis of the analysis of parametres of impulses of pressure ECM arriving from gauge MAF develops a command on corresponding updating of quantity of fuel injected into the engine by the most thin updatings of duration of time of opening of needle valves of injectors. As the range of changes makes milliseconds, working parametres of the engine are corrected smoothly, without throws and failures of turns.


System of the consecutive distributed injection of fuel

On models Infiniti considered in the present Management the distributed system of injection when each of combustion chambers is equipped by the individual injector placed in inlet port is used. Injectors provide тонкодисперсное fuel dispersion, under the pressure of injected directly in a stream submitted to inlet port of the chamber of combustion of an air stream. As the injection moments are co-ordinated with ignition order, it is a question of system of consecutive type. Injection of accurately dosed out quantity of fuel is carried out directly ahead of the moment of opening of the inlet valve of each of cylinders.

Functioning of injectors is defined by the fuel giving which pressure in a power supply system path is corrected depending on depth of depression in the inlet pipeline. Fuel submitted under pressure is pumped over through the filter of thin clearing established in an impellent compartment and arrives in a fuel highway with the injectors built in in it. Thus, on an input of injectors superfluous pressure that guarantees uninterrupted operation of injection at any moment at opening of needle valves is constantly supported.

At the expense of a redirection of surplus of fuel back in a fuel tank the special regulator of pressure of fuel provides on an input of injectors constant superfluous over pressure in the inlet pipeline a pressure in size in 2.4 kgs/sm 2 (235 кПа).

Such scheme allows ECM to carry out adjustment of quantity of combustion of fuel injected into chambers by simple change of duration of time of opening of injectors, — than longer needle valves of injectors remain opened, especially enriched mix moves in cylinders.


Management of a corner of an advancing of ignition

The greatest efficiency gives the chance dynamic management of ignition when the moment of ignition of an air-fuel mix is corrected depending on concrete operating conditions of the engine. As operating parametres can act loading on the engine, frequency of rotation of a cranked shaft, temperature of a cooling liquid, atmospheric pressure (height above sea level) and so forth receives All necessary data ECM from corresponding information gauges.

On models Infiniti QX4 the electronic system of ignition with the distributor is used. Distributor basic elements are built in in it the optical gauge of position of a camshaft (CMP) on a light-emitting diode (LED), the powerful transistor and the ignition coil (the Design of the distributor of ignition see an illustration).

Gauge CMP traces turns of the engine and delivers ECM the information on position of pistons.

The powerful transistor on signals ECM makes activation of the coil of ignition with delivery in the fullness of time ВВ pressure on a corresponding spark plug. A food on the coil stands out through the relay (the Site of the relay of ignition see an illustration) from the ignition switch.

At occurrence in chambers of combustion of a detonation of an air-fuel mix the raised level of vibrations is caught by the gauge of detonations (KS) and will be transformed to information signals on the basis of which analysis ECM makes corresponding displacement of a corner of an advancing of ignition towards backlog for the purpose of elimination of detonation process.


In combustion management in temperature

Photochemical загрязнителей atmospheres concern number of the most typical the oxides of nitrogen formed in products of combustion of an air-fuel mix at temperatures of burning from above 1093°С. Most obvious of ways of struggle for reduction of issue NОХ is decrease in working temperature in combustion chambers. The given purpose is reached at the expense of tap in an inlet path of a small amount of the inert fulfilled gases, corresponding process has received the process name подмешивания the fulfilled gases (EGR).


System of stabilisation of turns of idling

Quantity of turns of idling influence set of various factors. So, for example, the cold engine tends to infringement of stability of turns as idling, and under loading. Inclusion of such auxiliary units as compressor K/V, the steering pump, etc. inevitably leads to decrease in turns of idling. Activation of such power-intensive equipment as head headlights heaters of glasses, fans of system of cooling conducts to increase in loading at the engine. For the purpose of stabilisation of turns of idling and maintenance of the maximum economy of the expense of fuel in any service conditions the control system of the engine provides the automatic control of turns of idling. On the basis of the analysis of data ECM arriving from corresponding information gauges calculates optimum value of turns of idling and exercises administration of quantity of air submitted to the inlet pipeline by means of the valve of the additional air IACV-AAC regulating. As the quantity of air soaked up in the engine is defined on the basis of the information arriving from gauge MAF, ECM always has possibility of corresponding updating of duration of opening of injectors for the purpose of configuration of an air-fuel mix of demanded structure.


System of onboard diagnostics OBD-II

The material resulted more low has only descriptive character and is not adhered to any concrete mark or car model.


Data on diagnostic devices

Check of serviceability of functioning of components of systems of injection and decrease in toxicity of the fulfilled gases is made by means of a universal digital measuring instrument (multimeter).

Use of a digital measuring instrument preferably for the several reasons. First, on analogue devices it is difficult enough (at times, it is impossible), to define result of the indication to within the 100-th and thousand shares while at inspection of the contours including in the structure electronic components, such accuracy takes on special significance. The second, the reason that fact is not less important that the internal contour of a digital multimeter, has high enough impedance (internal resistance of the device makes 10 million Ohm). As the voltmeter is connected to a checked chain in parallel, accuracy of measurement by that above, than the smaller parasitic current will pass through actually device. The given factor is not essential at measurement concerning high values of pressure (9-12), however there is defining at diagnostics of elements giving out low-voltage signals, such, as, for example, a ljambda-probe where it is a question of measurement of shares of volt.

The most convenient devices for diagnostics of control systems by the engine of modern models of cars are manual input readers сканерного type.

Scanners of the first generation serve for reading of codes of malfunctions of systems OBD-I. Before application the input reader should be checked up on conformity of model and year of release of the checked car. Some scanners are multipurpose at the expense of possibility of change of a cartridge depending on model of the diagnosed car (Ford, GM, Chrysler, etc.), others are adhered to requirements of the regional authorities and are intended for use in certain areas of the world (Europe, Asia, the USA etc.).

Diagnostic scanner New Generation Star (NGS) (wide application scanners FDS 2000 have received also, Bosch FSA 560 [www.bosch.de] and KTS 500 [0 684 400 500]).

With introduction in manufacture meeting the requirements of last legislations on preservation of the environment of system of onboard diagnostics of the second generation (OBD-II) input readers of a special design have started to be issued. Some manufacturers have adjusted release of the scanners intended for use by mechanics-fans in house conditions, — ask in shops of automobile accessories.

One more very convenient diagnostic device is the expensive specialised diagnostic computer of type ADC2000 of firm Launch HiTech), or the usual personal computer in the complete set with a special cable and the adapter (the complete set 1 687 001 439).

Some scanners besides usual diagnostic operations allow at connection to the personal computer to unpack stored in memory of the module of management basic schemes of an electric equipment (if those are put), to program anticreeping system, to observe signals in safety lock chains in real time. The socket site depends on mark and car model.


The free version of browser OBD-II can be downloaded from a site of composers of the present Management arus.spb.ru.

Reading written down in memory of system of self-diagnostics of codes of malfunctions can be made by means of a control lamp of refusals MIL.


The general description of system OBD

On the modules equipped with system OBD-II on established under a cowl шильде there should be a record «OBD-II compliant», and diagnostic socket DLC should be 16-contact. As a rule, system OBD-II necessarily equips the models intended for the North American market, since 1996 of release, and also the European models, since 2000 of release.

System OBD structure includes some the diagnostic devices making monitoring of separate parametres of systems of decrease of toxicity and fixing revealed refusals in memory of the onboard processor in the form of individual codes of malfunctions. The system makes also check of gauges and actuation mechanisms, supervises operational cycles of a vehicle, provides possibility of freezing of parametres and clearing of the block of memory.

All models described in the present Management are equipped by system of onboard diagnostics of the second generation (OBD-II). A system Basic element is the onboard processor, more often named the electronic module of management (ECM). ECM is a brain of a control system of the engine. The initial data arrives on the module from various information gauges and other electronic components (switches, the relay etc.). On the basis of the analysis of the data arriving from information gauges and according to put in memory of the processor in base parametres, ECM develops commands on operation of various operating relays and actuation mechanisms, carrying out thereby updating of working parametres of the engine and providing peak efficiency of its return at the minimum expense of fuel.

A.

B.

Data read-out of memory of processor OBD-II is made by means of the special scanner connected to a 16-contact diagnostic socket of reading of a database (DLC), located at the left under the panel of devices.

A — the Diagnostic socket systems OBD II, at connection use standard cable OBD-II J1962. Appointment of conclusions — see the scheme Diagnostic sockets
B — the Site of diagnostic socket DLC


Reading written down in memory of system of self-diagnostics of codes of malfunctions can be made by means of a control lamp on a control panel.

On service of components of control systems by the engine / of decrease in toxicity of the fulfilled gases special guarantee certificates with the prolonged period of validity extend. It is not necessary to undertake attempts of independent performance of problem diagnostics ECM or replacement of components of system, to an exit of terms of the given obligations, — address to experts of firm car repair shops of company Infiniti.


Information gauges (depending on a car complete set)

Oxygen gauges (ljambda-probes). The gauge develops a signal which amplitude depends on a difference of the maintenance of oxygen (О2) in the fulfilled gases of the engine and external air.

The gauge of position of a cranked shaft (СКР). The gauge informs ECM on position of a cranked shaft and engine turns. The given information is used by the processor at definition of the moments of injection of fuel and installation of a corner of an advancing of ignition.

The gauge of position of pistons (CYP). On the basis of the analysis of signals ECM arriving from the gauge calculates position of the piston of the first cylinder and uses the given information at definition of the moments and sequence of injection of fuel in chambers of combustion of the engine.

Gauge VMT (TDC). Signals developed by the gauge are used ECM at definition of installations of a corner of an advancing of ignition at the moment of engine start.

The gauge of temperature of a cooling liquid of the engine (EATS). On the basis of information ЕСМ arriving from the gauge carries out necessary updatings of structure of an air-fuel mix and a corner of an advancing of ignition, and also supervises system EGR work.

The gauge of temperature of soaked up air (IAT). ECM uses the information arriving from gauge IAT at updatings of a stream of fuel, installations of a corner of an advancing of ignition and management of system EGR functioning.

The gauge of position throttle заслонки (TPS). The gauge is located on the case of a throttle and connected to an axis throttle заслонки. On amplitude given out TPS signal ECM defines a corner of opening throttle заслонки (copes the driver from a gas pedal) and in appropriate way corrects fuel giving in inlet ports of chambers of combustion. Gauge refusal, or easing of its fastening leads to faults of injection and infringements of stability of turns of idling.

The gauge of absolute pressure in the pipeline (МАР). The gauge supervises variations of depth of depression in the inlet pipeline, connected with changes of turns of a cranked shaft and loading on the engine and will transform the received information to a peak signal. ECM uses delivered by gauges MAR and IAT the information at thin updatings of giving of fuel.

The gauge of atmospheric pressure (BARO). The gauge develops the peak signal proportional to changes of atmospheric pressure which is used ECM at definition of duration of the moments of injection of fuel. The gauge is built in module ECM and to service in an individual order is not subject.

The detonation gauge (KS). The gauge reacts to change of level of the vibrations connected with detonations in the engine. On the basis of information ECM arriving from the gauge carries out corresponding updating of a corner of an advancing of ignition.

The gauge of speed of movement of the car (VSS). As appears from its name, the gauge informs the processor on current speed of movement of the car.

The gauge of size of opening of valve EGR. The gauge notifies ECM on displacement size плунжера valve EGR. The received information is used then the processor at management of system functioning рециркуляции the fulfilled gases.

The pressure gauge in a fuel tank. The gauge is a component of system of catching of fuel evaporations (EVAP) and serves for tracing of pressure of steams of gasoline in a tank. On the basis of information ECM arriving from the gauge gives out commands on operation of electromagnetic valves of a purge of system.

The gauge-switch of pressure of system of hydrostrengthening of a wheel (PSP). On the basis of information ECM arriving from gauge-switch PSP provides increase of turns of idling at the expense of operation of the gauge of system of stabilisation of turns of idling (IAC) for the purpose of indemnification of increasing loadings on the engine, connected with functioning of the steering hydraulic booster at fulfilment of maneuvers.

Transmissionnye gauges. In addition to the data arriving from VSS, ECM receives also the information from gauges placed in a transmission, or connected to it. Number of such gauges concern: () the gauge of turns of a secondary (radical) shaft and (b) the gauge of turns of an intermediate shaft.

The gauge-switch of management of inclusion муфты couplings of the conditioner of air. At giving of a food from the battery to the electromagnetic valve of compressor K/V the corresponding information signal arrives on ECM which regards it as the certificate of increase of loading on the engine and in appropriate way corrects turns of its idling.


Actuation mechanisms

The relay of the fuel pump. ECM makes activation of the relay of the fuel pump at поворачивании the ignition key in position START or RUN. At inclusion of ignition relay activation provides pressure lifting in the power supply system. The site of the relay of the fuel pump — see models Infiniti QX4 an illustration the Site of the relay of the fuel pump).

Injector () fuel injection. ECM provides individual inclusion of each of injectors according to the established order of ignition. Besides, the module supervises duration of opening of the injectors, defined in the width of an operating impulse measured in milliseconds and defining quantity of fuel injected into the cylinder. More detailed information by a principle of functioning of system of injection, replacement and service of injectors is resulted in the Head of the Power supply system and management.

The ignition distributor. The distributor operates functioning of the coil of ignition, defining a demanded base advancing on the basis of developed ECM commands.

The valve of stabilisation of turns of idling (IAC). Valve IAC carries out a dosage of quantity of air which is restarted up bypassing throttle заслонки when last is closed, or occupies idling position. Opening of the valve and formation результирующего an air stream operates ECM.

The electromagnetic valve of a purge of a coal adsorber. The valve is a component of system of catching of fuel evaporations (EVAP) and, working at the command of ECM, carries out release of steams which have accumulated in an adsorber of fuel in the inlet pipeline for the purpose of their burning in the course of normal functioning of the engine.

Electromagnet of management of a purge of a coal adsorber. The electromagnet is used ECM at check by system OBD-II of serviceability of functioning of system EVAP.


Reading of codes of malfunctions and clearing of memory of the processor

At revealing of the malfunction repeating successively on two trips, ECM gives out a command on inclusion of the control lamp built in in an instrument guard «Check up the engine», named also the indicator of refusals (MIL). Simultaneously the monitor is switched to emergency operation. The lamp will continue to burn until memory of system of self-diagnostics will not be cleared of the codes of the revealed malfunctions brought in it (see more low).


Reading of codes by means of the scanner

Reading of codes of malfunctions is made by connection of the special input reader (see above) to 16-contact diagnostic socket DLC, — operate according to instructions of the menu of the device. The list of codes is resulted in Specifications.


Reading of codes by means of a control lamp of refusals MIL

Muffle the engine and switch off ignition.

At revealing of the malfunction repeating successively on two trips, РСМ gives out a command on inclusion of the control lamp built in in an instrument guard «Check up the engine», named also the indicator of refusals. The lamp will continue to burn until then, infringement will not disappear, and will not be shown during three and more trips.

For reading of codes it is necessary to provide access to РСМ for the purpose of selector switching on высвечивание codes by means of diagnostic lamps / of a control lamp «Check up the engine». РСМ it is necessary to remove from the basic arm (without disconnecting electroconducting) and to operate according to the instructions resulted more low.

 PERFORMANCE ORDER

  1. Include ignition (without starting the engine). A control lamp «Check up the engine» on the panel of devices should remain included that confirms delivery on it of a food from РСМ and serviceability of the lamp.

Infringement of an order described below procedure can lead to casual clearing of memory РСМ!

  1. By means of a screw-driver turn the selector on wall РСМ against the stop clockwise. Diagnostic lamps should start to blink, — after three gleams turn the selector against the stop counter-clockwise;
  2. Attentively observe of functioning of a control lamp «Check up the engine». The lamp will highlight the first figure of a code a series long (approximately on 0.6) gleams, then, after a 0.9-second pause, will start to высвечиванию the second figure of a code in the form of a series short (on 0.3) gleams (address to an illustration). A pause between codes nearby 2 with. For the purpose of definition of the highlighted code write down quantity of gleams of each series so, a code 0403 (chain TPS) will look as follows: 4 long gleams, then, after a pause, three short. To absence of the infringements revealed by system testifies высвечивание a code 0505 (the list of codes of malfunctions in Specifications see);
  3. At repeated inclusion of ignition after its deenergizing in the course of reading of codes the system automatically cancels results of preceding search and reading procedure it is necessary to begin anew.

Engine start automatically blocks access to self-diagnostics system.

The highlighted code allows to define only the system chain which refusal has been fixed by self-diagnostics system. So, if the code specifies in malfunction of the gauge of temperature of a cooling liquid (ECT), the probability of infringement of functioning actually the management module is not excluded also. To establish true it is possible or gauge replacement, or by carrying out of corresponding control measurements.

At chain check, first of all, disconnect corresponding electroconducting and check up a condition of its contact connections of connection. In case of need smooth out plugs, completely having removed from them oxidation traces.

Check up reliability of fastening of a cable at a cable tip.

Check up resistance of a suspected element, — if nominal resistance of an element is insignificant, it is necessary to take into consideration such factors, as accuracy and internal resistance of the measuring device.

Check up integrity of the wires going to the module of management (be in case of need verified with schemes of electric connections).

At reading of the codes specifying in excessive understating of level of a signal, first of all, it is necessary to make sure of reliability of grounding of a corresponding component. Overestimate of level of a signal appears connected with electroconducting breakage more often.


The information maintenance of categories of a 5-digit code of kind P0380

Category 1

 

P

The power unit

B

Body

C

The chassis

Category 2

Code source

0

Standard SAE

1

Expanded — set by the manufacturer

Category 3

System

0

System as a whole

1

Подмешивания air (Air/Fuel Induction)

2

Fuel injection

3

System of ignition / ignition Admissions

4

The additional control of release

5

Speed of the car and management of idling turns

6

Entrance and target signals of the module of management

7

Transmission

Categories 4 and 5

Serial number of a faulty component or chain

 

00-99


Clearing of memory OBD II

For clearing of memory ЕСМ switch off ignition, and disconnect the plug of the battery not less than for 60 seconds, or connect to system the scanner and choose in its menu function CLEARING CODES (Removal of codes), — further follow instructions highlighted on the device.

Clearing of memory OBD by a detachment of a negative wire from the battery, is interfaced to removal of adjusting parametres of the engine and infringement of stability of its turns for short time after primary start, and also with deleting of options of hours and a radio receiver.


If the stereosystem established on the car is equipped by a security code before to disconnect the battery make sure that have a correct combination for audiosystem input in action!


In order to avoid damage ЕСМ its switching-off and connection should be made only at the switched off ignition!


 PERFORMANCE ORDER

  1. Consider the systems written down in memory codes of malfunctions /
  2. Wait not less than two seconds, then turn the selector on wall РСМ against the stop on an hour arrow /
  3. Wait yet less than two seconds and turn the selector against the stop against an hour arrow /
  4. Switch off ignition.

The code written down in memory leaves automatically if corresponding malfunction does not appear during 20 starts of the engine following successively one after another (quantity of turns should be not more low 450 in a minute).

Track, that memory of system has been cleared before installation on the engine of new components of systems of decrease in toxicity of the fulfilled gases. If before start of system after replacement of the failed information gauge not to make clearing of memory of refusals, ECM will bring in it a new code of malfunction. Memory clearing allows the processor to make change-over on new parametres. Thus the first 15-20 minutes after primary start of the engine before the termination of adaptation ECM, some infringement of stability of its turns can take place.


Application of an oscillograph for supervision of workers of a control system


The general information

Digital multimeters perfectly approach for check of the electric chains which are in a static condition, and also for fixing of slow changes of traced parametres. At carrying out of the dynamic checks which are carried out on the working engine, and also at revealing 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 swapping to the carrier of the personal computer already in stationary conditions.

The oscillograph allows to observe periodic signals and to measure pressure, frequency, width (duration) of rectangular impulses, and also levels of slowly varying pressure. The oscillograph can be used at performance of following procedures:

  • Revealings of failures of astable character;
  • Checks of results of the made corrections;
  • Monitoring of activity of a ljambda-probe of a control system of the engine equipped каталитическим with the converter;
  • The analysis of the signals developed by a ljambda-probe which deviation of parametres from norm is unconditional the certificate of infringement of serviceability of functioning of a control system as a whole. On the other hand, correctness of the form of impulses given out by the gauge can serve as a reliable guarantee of absence of infringements in a control system.

Reliability and simplicity of operation of modern oscillographs do not demand any special special knowledge and experience from the operator. Interpretation of the received information can be easily made by elementary visual comparison of the oscillograms removed during check with the time dependences resulted more low typical for various gauges and actuation mechanisms of automobile control systems.


Parametres of periodic signals


The general information

Each signal removed by means of an oscillograph, can be described by means of the following key parametres:

  • Amplitude: the Difference of the maximum and minimum pressure () a signal within the period;
  • The period: Duration of a cycle of a signal (мс);
  • Frequency: Quantity of cycles in a second (Hz);
  • Width: Duration of a rectangular impulse (мс, мкс);
  • Porosity: the Relation of the period of repetition to width (In foreign terminology return is applied porosity parametre named a running cycle, expressed in %);
  • The signal form: Sequence of rectangular impulses, individual emissions, a sinusoid, sawtooth impulses, etc.

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.


Direct current signals

Unique performance data of such signals is pressure.

Direct current signals are developed by the devices presented more low:

The gauge of temperature of a cooling liquid of the engine (ECT)

The gauge of temperature of soaked up air (IAT)

The gauge of position throttle заслонки (TPS)

Warmed up ljambda-probe

Measuring instrument of the volume expense of a stream of air (VAF)

Measuring instrument of weight of air (MAF)


Alternating current signals

The basic characteristics of the given signals are the amplitude, frequency and the signal form.

The detonation gauge (KS)

The inductive gauge of turns of the engine


The frequency-modulated signals (ЧМ)

Performance data of the frequency-modulated signals are the amplitude, frequency, the form of a signal and width of periodic impulses.

Sources ЧМ of signals are the devices presented more low.

The inductive gauge of position of a cranked shaft (CKP)

The inductive gauge of position of a camshaft (CMP)

The inductive gauge of speed of movement of the car (VSS)

Working on effect of the Hall gauges of turns and position of shaft

Optical gauges of turns and position of shaft

Digital gauges of thermometric measurement of weight of air (MAF) and absolute pressure in the inlet pipeline (MAP)


The signals modulated on width of an impulse (ШИМ)

Performance data of signals of pulse-width modulation (ШИМ) are the amplitude, frequency, the form of a signal and porosity of periodic impulses.

Sources of signals ШИМ are the devices presented further.

Fuel injectors

Devices of stabilisation of turns of idling (IAC)

Primary winding of the coil of ignition

The electromagnetic valve of a purge of a coal adsorber (EVAP)

System valves рециркуляции the fulfilled gases (EGR)


The coded sequence of rectangular impulses

Performance data are the amplitude, frequency and the form of sequence of separate impulses.

This sort of signals are generated by the module of memory of self-diagnostics ECM of a control system of the engine.

By the analysis of width and the form of impulses, and also calculation of their quantity in each of groups can be считаны codes of malfunctions stored in memory (the code 1223 — see an illustration the Diagram of gleams of control lamp MIL at delivery of diagnostic codes).

The amplitude and the signal form remain the constants, the written down value will stand out until memory of the module will not be cleared.


Interpretation of oscillograms

A.

B.

The form of a signal given out by an oscillograph depends on set of various factors and can change appreciably. In a kind told before to start replacement of a suspected component in case of discrepancy of the form of the removed diagnostic signal with the reference oscillogram, it is necessary to analyse the received result carefully.

A — the Digital signal
B — the Analog signal


Pressure

Zero level of a reference signal cannot be considered as absolute basic value, — "zero" of a real signal, depending on concrete parametres of a checked chain, it can appear shifted concerning reference [1] within a certain admissible range.

The full amplitude of a signal depends on pressure of a food of a checked contour and also can vary in certain limits concerning reference value [3] and [2].

In chains of a direct current signal level is limited to pressure of a food. As an example it is possible to result a chain of system of stabilisation of turns of idling (IAC) which alarm pressure 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 gauge of position of a cranked shaft (CKP) will increase with increase of turns of the engine.

In a kind 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 a corresponding scale of measurement.

At check of the equipment of chains with electromagnetic management (for example, system IAC) at food switching-off throws of pressure [4] which at the analysis of results of measurement can be ignored easy can be observed.

It is not necessary to worry also at occurrence of such deformations of the oscillogram, as скашивание the bottom part of forward front of rectangular impulses [5] if, of course, the fact выполаживания front is not a sign of infringement of serviceability of functioning of a checked component.


Frequency

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 led to a kind convenient for the analysis by switching on an oscillograph of scale of time development of the image.

At supervision of signals in alternating current chains time development of an oscillograph depends on frequency of a source of the signal [3], defined by engine turns.

As already it was told above, for signal reduction to a legible kind it is enough to switch scale of time development of an oscillograph.

In certain cases the signal oscillogram appears developed mirror concerning reference dependence that speaks реверсивностью polarity of connection of a corresponding element and, in the absence of an interdiction for change of polarity of connection, can be ignored at the analysis.


Typical signals of components of control systems of the engine

Modern oscillographs are usually equipped only by 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 usually connected to the plug of the electronic module of management (ECM). The black wire should be connected to reliably earthed point (weight).


Injection injectors

Management of structure of an air-fuel mix in modern automobile electronic systems of injection of fuel is carried out by timely updating of duration of opening of electromagnetic valves of injectors.

Duration of stay of injectors abroach is defined by duration developed by the module of management of the electric impulses submitted on an input of electromagnetic valves. Duration of impulses is measured in milliseconds and usually does not fall outside the limits a range 1—14 мс. See the typical oscillogram of an injector of an impulse operating operation.

Often on the oscillogram it is possible to observe also a series of the short pulsations following directly behind the initiating negative rectangular impulse and supporting the electromagnetic valve of an injector abroach, and also the sharp positive throw of pressure accompanying the moment of closing of the valve.

Serviceability of functioning ECM can be checked easily up by means of an oscillograph by visual supervision of changes of the form of an operating signal at a variation of working parametres of the engine. So, duration of impulses at проворачивании the engine on single turns should be a little above, than at unit work on low turns. Increase of turns of the engine should be accompanied by respective increase in time of stay of injectors abroach. The given dependence is especially well shown at opening throttle заслонки by short pressing a gas pedal.

 PERFORMANCE ORDER

  1. By means of thin щупа from a set applied on an oscillograph connect a red wire of the device to инжекторной to plug ECM of a control system of the engine. Щуп the second alarm wire (black) oscillograph reliably earth.
  2. Analyse the form read out during time проворачивания the signal engine.
  3. Having started the engine, check up the form of an operating signal on single turns.
  4. Sharply having pressed a gas pedal, lift frequency of rotation of the engine to 3000 rpm, — duration of operating impulses at the moment of an acceleration should increase considerably, with the subsequent stabilisation at level equal, or hardly smaller peculiar to idling turns.

Fast closing throttle заслонки should lead to the flattening of the oscillogram confirming the fact перекрывания of injectors (for systems with отсеканием fuel givings).

At cold start the engine requires some enrichment of an air-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 shown on the oscillogram in the form of pulsations of variable length are used.

In the table resulted more low typical dependence of duration of operating impulses of opening of injectors on a working condition of the engine is presented.


Inductive gauges

 PERFORMANCE ORDER

  1. Start the engine and compare the oscillogram removed from an exit of the inductive gauge from resulted (reference).

Engine condition

Duration of an operating impulse, мс

Single turns

1.5—5

2000—3000 rpm

1.1—3.5

Full gas

8.2—3.5

  1. The increase in turns of the engine should be accompanied by increase in amplitude of a pulse signal developed by the gauge.


The electromagnetic valve of stabilisation of turns of idling (IAC)

In motor industry electromagnetic valves IAC of set of the various types which are giving out signals also of the various form are used.

The general distinctive feature of all valves is that fact that porosity of a signal should decrease with loading increase for the engine, connected with inclusion of additional consumers of the capacity causing fall of turns of idling.

If porosity of the oscillogram changes with loading increase, however at inclusion of consumers infringement of stability of turns of idling takes place, check up a condition of a chain of the electromagnetic valve, and also correctness given out ECM a command signal.

Usually in chains of stabilisation of turns of idling the 4-polar step-by-step electric motor which description is resulted more low is used. Check of 2-contact and 3-contact valves IAC is made in a similar manner, however oscillograms of alarm pressure given out by them are absolutely unlike.

The step-by-step electromotor, reacting on given out ECM a pulsing operating signal, makes step updating of turns of idling of the engine according to working temperature of a cooling liquid and current loading on the engine.

Levels of operating signals can be checked up by means of an oscillograph, measuring щуп which is connected serially to each of four plugs of the step-by-step motor.

 PERFORMANCE ORDER

  1. Warm up the engine to normal working temperature and leave its working on single turns.
  2. For increase in loading at the engine include head headlights, air conditioner, or, — on models with the wheel hydraulic booster, — turn a steering wheel. Idling turns should fall to short time, however there and then again to be stabilised at the expense of valve IAC operation.
  1. Compare the removed oscillogram to resulted (reference).


Ljambda-probe (the oxygen gauge)

In the given section the oscillograms typical for ljambda-probes most often applied on cars циркониевого of type in which basic pressure 0.5В is not used are resulted. Recently the increasing popularity is got by titanic gauges, the working which range of a signal makes 0—5 In, and high level of pressure stands out at combustion of the impoverished mix, low — at combustion enriched.


 PERFORMANCE ORDER

  1. Connect an oscillograph between the ljambda-probe plug on ECM and weight.
  2. Make sure that the engine is heated-up to normal working temperature.
  1. Compare the oscillogram displayed a measuring instrument to the resulted (reference) dependence.
  1. If the removed signal is not wavy, and represents linear dependence, that, depending on pressure level, it testifies to excessive repauperization (0-0.15), or reenrichment (0.6-1) air-fuel mixes.
  2. If on single turns of the engine the normal wavy signal takes place, try to squeeze out sharply some times педель gas, — signal fluctuations should not fall outside the limits a range 0—1 Century
  3. The increase in turns of the engine should be accompanied by increase of amplitude of a signal, reduction — decrease.


The detonation gauge (KS)

 PERFORMANCE ORDER

  1. Connect an oscillograph between the plug of the gauge of detonation ECM and weight.
  2. Make sure that the engine is heated-up to normal working temperature.
  1. Sharply squeeze out a pedal of gas and compare the form of a removed signal of an alternating current to the resulted (reference) oscillogram.
  1. At insufficient image sharpness slightly knock on the block of cylinders around placing of the gauge of a detonation.
  2. If to achieve unambiguity of the form of a signal it is not possible, replace gauge KS, or check up a condition of electroconducting of its chain.


Ignition signal on an amplifier exit

 PERFORMANCE ORDER

  1. Connect an oscillograph between the plug of the amplifier of ignition ECM and weight.
  2. Warm up the engine to normal working temperature and leave its working on single turns.
  1. On the oscillograph screen the sequence of rectangular impulses of a direct current should stand out. Compare the form of an accepted signal to the resulted (reference) oscillogram, paying steadfast attention to coincidence of such parametres, as amplitude, frequency and the form of impulses.
  1. At increase in turns of the engine frequency of a signal should increase in direct ratio.


Primary winding of the coil of ignition

 PERFORMANCE ORDER

  1. Connect an oscillograph between the plug of the coil of ignition ECM and weight.
  2. Warm up the engine to normal working temperature and leave its working on single turns.
  1. Compare the form of an accepted signal to the resulted (reference) oscillogram, — positive throws of pressure should have constant amplitude.
  1. Non-uniformity of throws can be caused excessive resistance of a secondary winding, and also malfunction of condition ВВ of a wire of the coil or a candle wire.


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7. Start and charge systems