Stages of engine diagnostics: what determines the sequence of work

by | Apr 5, 2020 | News | 0 comments

An engine is a mechanism that turns the energy of a fuel into mechanical energy. The main node of the car, determining its most important characteristics, is the internal combustion engine. Alas, even a caring owner with a car engine will have some problems sooner or later. It is very important to locate the malfunction in time, for which there are certain stages of engine diagnostics.

Why do I need a car engine diagnostic

The car engine is built quite complicated, so its reliable operation is possible only in the case of quality care and maintenance. It is possible to verify the serviceability of all components and assemblies of the motor only with the help of its diagnostics, which is carried out in several stages. Also, this must be done in order to prevent it at certain intervals, measured either calendar or by vehicle mileage.

The psychology of most people is such that they apply for a medical examination only in case of serious problems. It often happens that for an effective treatment of the disease it is too late. They try to ignore minor ailments – tingling, slight pain – and wait until it passes by itself. However, such symptoms may be evidence of serious processes occurring in the body. And only a full examination can give a detailed picture of the state of human health.

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Similarly, the power unit of a car gradually wears out, only it can not inform its owner about this. Modern engines are equipped with advanced self-diagnosis devices. All information about the state of the car is available on the on-board computer display. However, these systems are mainly equipped with expensive cars. Also, the user is far from receiving all the information collected by the self-diagnosis. The majority of owners of budget cars are forced to carry out engine diagnostics on their own. It consists of a number of stages, each of which is important for assessing the situation.

Do not underestimate the effect of minor malfunctions on engine operation – steps must be taken already at the stage of their appearance. If you do not pay attention to them, then very soon you will have to face repair of the power unit. Repairing this unit is an expensive pleasure. We list the signs in which it is necessary to conduct a motor diagnosis:

  • Significantly increased fuel consumption. The type of fuel does not matter.
  • It is often necessary to add a lot of oil.
  • A significant cause for alarm is a drop in car power.
  • There are difficulties with shifting gears, switching on occurs jerky.
  • The appearance of unusual sounds when starting the engine.

Thanks to the diagnosis, you can find out how much repair the motor will have and what its cost will be. For diesel vehicles, it is necessary to diagnose the engine every six months. In addition, it is necessary to carry out special preparation of the engine for the winter and summer seasons. Professional auto mechanics advise to do the diagnosis of internal combustion engines not only if a malfunction is suspected, but also regularly for prevention. Often this method can prevent serious damage to the power unit.

What does a diagnostic test show on a car!

Motor diagnostics is a process that involves more than one step. However, you should not neglect each of the steps, since they are all very important for understanding the situation. We list these steps:

Check for traces of fluids.

One of the most common problems is the leakage of workers. The operation of the internal combustion engine is unthinkable without engine oil. That is why at this stage, first of all, pay attention to traces of oil on the engine. The presence of oil smudges on the engine indicates its leakage. Having determined the scale and causes of oil stains, make the necessary repairs.

Check oil.

The next step is to control the level and quality of engine oil. If the level is insufficient, then, quite possibly, the motor has significant problems. Sometimes the malfunction is eliminated by replacing the seals, but more serious repairs also occur.

Check motor operation for extraneous noise.

A working power unit during operation does not emit unnecessary noise. If the work or the start of the motor is accompanied by unusual sounds, then you can’t do without the help of professionals. The stage can be called auditory diagnosis.

Extraneous sounds emitted by a running engine indicate wear or damage to individual parts.

Carry out a vibration check.

Modern engines operate quietly, without unnecessary jerking and vibration. If the ICE suddenly began to vibrate during operation, most likely the problem is in one of the cylinders. Some more serious engine damage is also accompanied by vibration spikes. If such symptoms occur, it is necessary to resort to computer diagnostics of the unit.

Check mounting pads.

Engine mounts play a huge role. It dampens the vibration of the unit, helps to synchronize its work with the gearbox. The reliability and integrity of each engine mount pad should be checked in stages. Only serviceable fastenings can ensure the operation of the engine in nominal mode.

Check exhaust system.

Reliable engine operation is not possible without proper exhaust gas exhaust. If the integrity of the exhaust system is violated, the motor not only loses power, but also significantly increases the concentration of harmful substances in the exhaust gases, so this stage is also important from the point of view of environmental impact.

Check power system.

The speed of starting the engine depends on the quality of charging the battery. The completeness and speed of charging the battery are directly related to the health of the generator. At the stage of diagnostics of the engine power supply system, it is necessary to check the degree of tension and the condition of the generator drive belt. It is also important to check the ignition system.

If the diagnosis showed the presence of the above malfunctions, you need to conduct an in-depth study of the problem until the root causes are clarified. One of the stages of such an examination should be computer diagnostics, it is especially helpful in case of purchasing a car. As a result of this procedure, you can save time and money on engine maintenance.

The list of tools and techniques used in the diagnosis of power units is very large. Each technique consists of a strictly sequential set of steps. Some of them are available for independent use, while others are available only in professional auto repair shops. We list the main ways to diagnose the engine.

1. Visual diagnosis

Some problems are visible to the naked eye. Having examined the engine, it is already possible to draw certain conclusions about its condition.

The most common examples are:

  • Oil stains and smudges indicate wear on the gasket, poor attachment of the valve cover, and may also result from more serious problems.
  • Gasoline engines have strong vibration, engine triplets sometimes indicate a malfunction of the spark plugs. Candles unscrew and inspect. The presence of soot on the candle makes it possible to identify the culprit of the problem.
  • Mechanical damage to the sensors and a break in their wires can be detected by visual inspection of the engine compartment.

Thus, visual inspection of the engine is the first and most affordable stage of its diagnosis. This method is also called in-place verification. Also, the operation of the engine is checked by ear – there should be no extraneous knocks, rattle or other noise. If unusual sounds accompany the operation of the internal combustion engine, then this is fraught with at least adjustment of the valve clearances, and in especially advanced cases it may result in the overhaul of the engine.

2. System self-diagnosis

Cars, currently produced, have developed diagnostic systems. These systems provide data on all errors of the electronic control unit. The analysis of these failures allows to determine the state of the engine. Errors are displayed on-board computer system or encrypted using a sequence of blinks of the Check Engine indicator.

Each car manufacturer in their own way organizes access to the engine self-diagnosis system. In one case, you need to interconnect certain contacts of the OBDII diagnostic connector and drive, in another, turn the ignition key in several stages and press the pedals. Such information on a specific car model is available on various thematic forums on the Internet.

3. Computer diagnostics

The stage of computer diagnostics requires a special scanner. This device polls the computer and reads all engine errors that have ever been fixed. Such scanners can still determine the real mileage of the car, if the mileage was twisted by an amateur. Experienced specialists know all the nuances of fixing the mileage in each particular car and will rewind kilometers so that no one can detect it.

Stages of engine diagnostics

Trading network today offers a large selection of scanners. With a limited budget, you can quite find an inexpensive model. It will allow you to perform good engine diagnostics. But such scanners still cannot detect some problems.

More expensive and high-quality autoscanners are equipped with the function of a motor tester. Using this option, the motor is diagnosed in different operating modes, which allows for a more subtle and comprehensive analysis.

Automotive oscilloscopes are also used at some stages of diagnosis. These devices, for example, the Postolovsky oscilloscope, allow you to check the signals from various sensors and by their shape reveal possible engine malfunctions.

4. Diagnostics using special tools

Instrumental engine diagnostics can be performed independently. For this, the following devices are required:

  • Strobe light It allows you to check and adjust the ignition timing.
  • Compressometer Helps determine the value of compression in each cylinder.
  • Endoscope This tool provides an opportunity to look into places hidden from the eyes. In this way, in-place diagnostics of the motor and other components and assemblies of the engine are facilitated.
  • Micrometers and probes designed to determine valve clearance.

What is the cost of engine diagnostics

There is one component necessary for the diagnosis of gasoline engines, which cannot be bought for any money. It is about the experience and abilities that qualified masters of diagnostic stations possess, professional skills are needed at each stage of the test. Indeed, not every person can determine the root cause of a malfunction by sound and appearance, and even by diagnostic errors.

This experience and qualification of the master cost some money. A listing of errors read from the computer may look like a transcript of a person’s medical tests. But just as an experienced doctor does not rely solely on the results of analyzes, studying all the nuances of the medical history, so a real professional minder approaches the process in an integrated, thoughtful and leisurely way.

Qualitative engine diagnostics cannot be completed in a couple of minutes. Computer diagnostics are not enough. Stage by stage, each engine assembly is carefully inspected, studied. Typically, diagnostic stations do not even charge a fee for simple printing of errors issued by the scanner. After all, obtaining such information is not difficult at all, highly qualified is not required. However, sometimes there are people trying to make money on it.

Comprehensive engine diagnostics consist of a number of steps. The main operation is, of course, computer scanning. Many motorists do the scan themselves. For these purposes, they buy a suitable connector, a USB converter, download a specialized program on the Internet to a laptop.

At the service station, computer scanning usually costs around 500 rubles. You can get not only a listing of all the errors, but also find out whether any operations have been performed with the computer memory. Exhaust emissions are measured using a specialized device. This action will cost 300 rubles. They ask 500 rubles for an ignition tester, and you can measure the ignition timing by breaking up with 300 rubles.

The serviceability of spark plugs, high-voltage wires and coils can be visually determined. Particular attention is paid to the inspection of the connection points of the engine with the mass. Be sure to check whether the battery holds well.

Mechanical components of the engine are checked both by inspection, and with the help of specialized tools. At the visual stage, malfunctions in the belts and their tension are detected, the level of liquids and their condition are checked, the noise level during the operation of the internal combustion engine is estimated. Cylinders must be carefully examined with an endoscope. For this service they usually ask for 600 rubles. Air pressure is measured for 400 rubles.

However, the total cost of diagnosis is usually lower than the sum of the individual steps. This is due to the accumulating discounts. The fact of competition between different service stations also affects where the main lever remains price. However, lowering the cost may be fraught with poor quality services, with the exception of certain stages of engine diagnostics at all. Usually a comprehensive check of the motor costs 4 thousand rubles. But not every car owner is ready to part with such an amount just to know the malfunctions of his power unit.

In addition to the cost of direct procedures, the price of diagnosis is affected by the speed of its implementation, the quality of customer service and additional bonuses. For a common amount of 1000 rubles. the car owner will most often receive service from 4 stages: visual diagnostics, reading errors, checking exhaust gases and ignition systems on special equipment.

Important components of the cost of diagnosis can also be: the pricing policy for the service station, the model of the vehicle, the location and prestige of the diagnostic station and the scope of the proposed work.

Dmitry Petrov

Dmitry Petrov is an engineer who specializes in materials science, and has a deep passion for all things related to automotive technology. He is a true motorhead at heart, and spends much of his free time tinkering with engines and studying vehicular dynamics.


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