Strong engine vibration, or why Toyota's VVTi engine is tripping

The Toyota Corolla 120 is designed without significant design flaws, so it presents virtually no problems to the owner during operation. Malfunctions begin to appear mainly due to the exhaustion of the main components of their resource or are a consequence of improper maintenance.

The power units of the Toyota Corolla 120 are famous for their reliability, but despite this they have their weaknesses. One of the main engine problems is the appearance of vibration at idle speed after the engine reaches operating temperature. The engine control program, which is stitched into the ECU, is not adapted for domestic fuel. As the mileage increases, the vibration becomes stronger and is quite difficult to eliminate.

• Another problem with the Corolla 120 power plant is its high sensitivity to oil starvation. Even short-term operation of the engine with a lubricant level slightly below o can lead to the need to repair the power unit.

The service life of oil scraper rings is extremely short, especially with a sporty driving style. Their failure leads to a significant increase in oil consumption. Subsequently, the mobility of the rings in the piston groove decreases. This impairs lubricant drainage and the piston crown is not cooled effectively.

Most car owners complain that the Corolla 120 does not start after a long period of parking in cold weather. This problem manifests itself most noticeably when the mileage exceeds 180 thousand km.

• Another reason for difficult starting is a broken starter bendix. At the same time, a buzzing noise comes from the engine compartment without cranking the engine. The owner may encounter this problem when the car’s mileage approaches 100 thousand km.

A car owner may encounter a situation where the revs fluctuate after a mileage of 50 thousand km. The cause of the problem is a malfunction of one of the sensors. Self-diagnosis helps to identify a faulty element.

Toyota Corolla engine malfunctions

During interruptions, the engine idles unstably, does not develop sufficient power, and consumes gasoline increased.
In addition, exhaust gas converters may fail. Interruptions, as a rule, are explained by a malfunction of the injectors or electric fuel pump (see “Power System”), a malfunction of the spark plug of one of the cylinders, or air leaks into one of the cylinders. You need to find the problem and fix it if possible. 1. Start the engine and let it idle. Go to the exhaust pipe and listen to the sound of the exhaust. You can bring your hand to the cut of the exhaust pipe - this way the interruptions are felt better. The sound should be even, “soft”, of the same tone. Popping noises from the exhaust pipe at regular intervals indicate that one cylinder is not working due to a failed spark plug, lack of a spark, an injector failure, a strong air leak into one cylinder or a significant decrease in compression in it. Popping noises occur at irregular intervals due to dirty injector nozzles, severe wear or dirty spark plugs. If popping noises occur at irregular intervals, you can try to replace the entire set of spark plugs yourself, regardless of mileage and appearance, but it is better to do this after contacting a car service center to diagnose and repair the engine control system.

2. If the popping sounds are regular, stop the engine and open the hood. Check the condition of the ignition system wiring harness and the fastening of the wiring harness blocks on the ignition coils.

3. Remove the spark plugs.

4. Inspect the spark plugs and compare their appearance with the photographs given in the subsection “Diagnostics of the engine condition by the appearance of the spark plugs.” If the spark plug is black and wet, it needs to be replaced.

5. If all spark plugs look good, reinstall them and connect the ignition coils. The operating order of the cylinders is 1–3–4–2, the numbering of the cylinders (1, 2, 3, 4th) is carried out from the engine crankshaft pulley.

6. Take a spare spark plug. Secure it to the engine in any way. Connect the spare spark plug to the ignition coil. Start the engine. If engine interruptions do not worsen, replace the spark plug in cylinder 1 with a known good one. Insert the spool into place. If the interruptions intensify, repeat this procedure sequentially with all cylinders to identify the faulty spark plug.

WARNINGS

Reliable contact of the spark plug body with ground is mandatory, since if an additional spark gap appears, larger than the gap between the spark plug electrodes, the ignition coil or engine control system unit may be damaged. Try to carry out the check described above in the shortest possible period of time, since if unburned gasoline enters the catalytic converters for a long time, they may fail due to overheating, since gasoline will burn in them.

If, as a result of the measures taken, engine interruptions are not eliminated, check the compression in each of the cylinders (see “Checking compression in the cylinders”). Normal compression is more than 1.0 MPa (10 kgf/cm2), a difference of more than 0.1 MPa (1 kgf/cm2) in one cylinder indicates the need for engine repair

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Suspension failures

The main suspension problems that owners encounter are listed in the table below.

Table - List of suspension problems

Anti-roll bar link

The engine heats up and starts to stall: why does this happen?

Almost every car enthusiast sooner or later encounters such a fairly common malfunction of the internal combustion engine, when the engine stalls. As a rule, in certain situations the engine stalls when hot or only when cold, and tripping can also occur constantly (regardless of the temperature of the power unit, operating mode, load level, etc.).

In short, engine tripping means that one or more cylinders are not firing, and there can be several reasons for such a malfunction. In this article we will talk about why the engine stalls after warming up, how the malfunction can be diagnosed, and what signs help to accurately identify the problem.

The engine stalls when hot: causes and common faults

Let's start with the main features. Often, a cold engine starts quite normally, but then begins to stall after partial warming up or completely reaching operating temperatures. In this case, tripping can occur both at idle and under load (while driving).

In any case, incorrect readings or malfunctions of sensors (lambda probe, temperature sensor, mass air flow sensor, etc.) and actuators can cause a hot engine to fail. Based on incorrect readings, the ECU may well over-enrich the working fuel-air mixture and flood the spark plugs.

If the spark plug is wet and/or oily, then it is quite obvious that too much engine oil is entering the combustion chamber or the fuel is not being burned in the cylinder. In any case, a wet spark plug does not allow the cylinder to operate normally. Let us add that often both causes are often present simultaneously or are a consequence of each other.

If all the spark plugs are wet, you should check the oil level in the internal combustion engine. When the level is elevated (often as a result of overflow), the oil pressure in the lubrication system after the engine warms up exceeds the norm, excess lubricant penetrates the combustion chamber and contaminates the spark plugs. The result is a weak spark.

You also need to check the crankcase ventilation system. For example, the breather hose may become kinked, contamination may occur, etc. The main thing is that problems with this system also lead to pressure rising and excess oil entering the cylinders. If the hot vibration disappears after pumping out excess oil and cleaning the crankcase ventilation system, we can talk about a successful solution to the problem.

If this does not help, the spark plugs themselves will require increased attention. It is likely that even if the spark plugs have recently been changed, they will turn out to be incorrectly selected for the engine in terms of heat rating and will be “cold”; also, the spark plugs may simply fail or the product will be defective. To check, you need a kit that is known to be working (it is better if the spark plugs were removed from another car). If the engine does not start in these sections after warming up, then the spark plugs need to be replaced.

If it turns out that the dry spark plug in the cylinder has become wet, then it is worth checking the high-voltage ignition wire of a particular cylinder. The wire needs to be replaced with a working one. Also note that the problem may not be in the wires. For example, on carburetor internal combustion engines, a common cause of ignition problems is the distributor (ignition distributor).

On injection engines, failures can result from breakdowns of the ignition coils. In the case of a distributor, the device must be disassembled, dried, cleaned the contacts and made the necessary adjustments. If we are talking about an engine with an injector, you can swap the ignition coils and wires. This method allows you to quickly identify a faulty coil.

Toyota Corolla E150 (2010+). Strong engine vibration

Toyota Corolla E150 (2010+). Strong engine vibration

Engine vibrations in a car (at idle) - possible causes

During normal operation, a stable idle speed, depending on the engine type, ranges from 800 to 1000 rpm. If this value is less than the lower limit, then the engine will simply stall, and if it exceeds the upper limit, this will lead to excessive fuel consumption, and the vehicle components will wear out intensively. There are main reasons why a diesel engine vibrates at idle. Most often, this phenomenon occurs when the cylinders operate unevenly. The greatest negative effect is noticeable when the engine is tripping, that is, in this situation one of the cylinders does not work. As the speed increases, the shaking may decrease, but the engine power will decrease. There is only one solution in such a situation - to urgently repair the missing cylinder, because such a defect not only creates unpleasant vibrations, but also contributes to wear of parts, since the fuel does not burn inside, but only washes away the lubricant, and also accelerates coking of the entire engine. You can solve this problem yourself, but you will have to master many operations; if a working motor is needed urgently, then it is better to contact a service station. Another fairly common cause of vibration is an improperly mounted motor. Very often this is due to wear of the cushions or too rigid fastening elements. In any case, to avoid unpleasant sensations, it is necessary to take measures, carry out repair and adjustment work. You can find out the shortcomings in the motor mount with an assistant. You need to open the hood and alternately engage neutral, reverse and forward gears, and an assistant should pay attention to the position of the engine at these moments. By doing this, you unload one by one the special cushions that hold the motor. Each time you switch, it will deviate in different directions, ideally at the same angle. If it falls to one side more than usual, it means that the pillow in that place needs to be replaced; perhaps it is completely destroyed. In addition, maybe it was not the engine that caused the vibrations, but some parts that fit it, because when the engine collapses, they come into contact with the body machines. In addition to the main reasons, vibration of a diesel engine at idle speed can be associated with other factors. Its unstable operation is often affected by components and assemblies associated with the fuel supply, which are heavily contaminated. This is caused, most often, by impurities contained in the air and gasoline, which enter through the filter mesh of these units; Water may also be introduced into the gas-liquid mixture. In addition, pollution is often caused by used engine oil and soot entering the fuel system.

Engine vibration at idle - what can be adjusted

To adjust the idle speed, several components and assemblies installed in the car are used. First of all, it is the injector or carburetor that is part of the fuel system, producing a mixture of fuel and air. In addition, the fuel pump is adjusted, mechanical or electronic sensors, the fuel pressure regulator and other engine components are checked. It should be remembered that the number of revolutions depends on the degree of opening of the throttle valve, which regulates the air supply, as well as on the action of the idle air valve, which supplies air independently of the throttle. The idle speed can be increased using the accelerator pedal. Any vibration, including at idle, is very harmful to the car. It not only causes discomfort to the driver and passengers, but also negatively affects the general condition of the car. Gradually, cracks appear in the body, characterizing structural fatigue, and spontaneous loosening of bolts and nuts may occur. Such malfunctions often lead to unpredictable consequences and cause emergency situations.

Vibration of a diesel engine - prevention of wear of components

With constant vibration, the engine wears out quickly, its spin-up will be much slower and will not reach maximum speed. The crankshaft packing deteriorates very quickly, leaving you at risk of oil leakage. It is also necessary to remember to eliminate not only the vibration itself, but also its consequences. Experts recommend constantly tightening all nuts and bolts, even if they are additionally secured with wire or cotter pins. Any connection that is tightened very tightly will loosen after a while. In some cases, the fastener can only be held in place by a cotter pin. To ensure high-quality fastening, it is recommended to use special nuts with nylon inserts. Thus, the fight against engine vibration plays a decisive role in ensuring reliable, durable and safe operation of the vehicle.

Engine vibration at idle

Idling is the operation of the engine with the clutch disengaged and set to neutral. During vehicle operation, a phenomenon such as engine vibration at idle may occur. Idle speed or revolutions can be determined with the engine on and the clutch disengaged, and while setting the gear to neutral. At this time, the engine torque is not transmitted to the driveshaft, hence the idle speed. During such operation, the working engine should not give rise to vibrations, pops or any other sounds. But if this happens, then some changes have occurred in the engine that will not have a very good effect on it. In order not to wait for expensive repairs, you need to fix problems as they arise.

What are the causes of engine vibrations in a car?

During normal operation, a stable idle speed varies from 800 to 1000 rpm, these numbers depend on what kind of engine you have installed. If the number of idle strokes is less than the lower limit, the car will simply stall, but if, on the contrary, it is higher than the upper limit, then there will be high fuel consumption and automobile components will quickly wear out.

There are several main reasons why the engine vibrates at idle:

The first reason is engine tripping. The most well-known reason is uneven operation of the engine cylinders, when the engine is tripping, or one of the cylinders does not work. With an increase in the number of revolutions, vibrations may decrease, but at the same time the power of the engine itself will decrease. With this problem, the load on the crankshaft will be distributed unevenly. Because of this, you can see the engine jerking from side to side. Also, when the engine revs, you can feel the vibration of the steering wheel. At idle, all these problems are more pronounced. With greater rotation of the shaft, vibration becomes less noticeable. But you will immediately notice higher fuel consumption and a decrease in vehicle power. This will be especially noticeable when driving downhill. This problem must be solved immediately, you need to repair a non-functioning cylinder, since such a defect creates not only unpleasant vibrations for you, but also parts wear out due to the fact that the fuel does not burn inside, but only washes away the lubricant, and also accelerates the coking of everything engine. You can probably solve this problem yourself, but you will need to perform many different operations, but if you need a working car urgently, then it is better to contact a service station. The second problem is an improperly secured motor.

Another equally well-known problem is an improperly secured engine. Most of all this is due to worn-out cushions or very rigid fastening elements. In such cases, in order to prevent vibrations, you need to do something, repair or adjust the engine. In order to find out that the motor is poorly secured, you need an assistant. To do this, you need to open the hood and alternately engage neutral, reverse and forward gears, and another person must monitor the engine at this time. With this technique, you take turns unloading the special cushions that hold the engine. Each time you change gears, the engine will deviate in different directions; ideally, this deviation should be at the same angle each time. If there is a greater tilt in any direction, then it is worth replacing the pillow in that place; it may be completely destroyed. The cause of engine vibration may be some parts suitable for it, and not the engine itself. So, during its operation, the parts come into contact with the walls of the body. Compared to the previous cause of engine vibration, this cause is not so bad. But in order to avoid constant shaking and unnecessary sounds, it is worth changing the supports or adjusting their position in the right direction. And other reasons that create engine vibrations

In addition to the main causes of engine vibration, there are others. Of course, these reasons appear very rarely, but you cannot ignore them. First you need to look at all parts of the fuel system. If these parts are very dirty, the air/fuel mixture will not burn as well as it should. This may result in higher fuel consumption, some strange sounds (maybe popping noises) and vibration. It is very bad when water can get into the fuel. Due to the ingress of water, not only high gasoline consumption can occur, but also coking of the engine cylinders may occur. The consequence of all this is poor engine performance. Also, soot and oil can get into the fuel system, which also has a very bad effect on engine performance. Another reason for poor engine performance is the different mass of parts in the cylinder-piston group. When operating a car, especially one with a mileage of more than two hundred thousand, increased attention to the engine is required, and in some cases, replacement of some elements in it is required. Even a small difference in weight between parts can greatly affect the performance of the motor in the future. This applies to all engine parts, such as the piston, connecting rod or skirt.

On some small cars that have an electronic throttle control system, vibrations in the cabin at idle may appear due to the heavy load on the generator. This phenomenon can most often happen in winter, when the headlights, stove, heated windows, mirrors and seats are all working at the same time. Most often, vibrations in such machines occur when stopping. When the driver releases the accelerator pedal, a signal to close the throttle to idle will appear on the on-board computer, and a load from the generator will appear on the engine, and then strong engine vibration will occur. Often it disappears in a couple of seconds. A similar phenomenon on such cars, and especially with automatic transmissions, is the norm, and this problem can be solved by changing the fuel to a higher quality one and replacing the air filter. It must be said that engine vibration may appear due to the replacement of the timing belt, especially when the balancer shaft gear rotates along with the removed part. After being displaced, it rarely returns to its former place. It is because of this that when replacing a belt, you do not need to rotate the shaft gear with your fingers, unless you want to check the condition of the bearings. But everywhere you need to be as careful as possible. Any movement of parts from their place can then create unpleasant vibrations that will cause discomfort to both you and your passengers.

Crankshaft balancing

It is also possible that vibration at idle may also appear when replacing the crankshaft. This arises due to the fact that this part, such as a regular wheel, must undergo a calibration process before the installation procedure. Balancing takes place on a special stand with a clutch basket and flywheel. During this procedure, the technician removes all excess from the surface of the crankshaft. If you neglect this procedure and do not calibrate, you will experience severe shaking. Vibration of a diesel engine - prevention of wear of components

If vibrations occur constantly, then the motor will wear out very quickly, its rotation will become much slower and the maximum number of revolutions will not be reached. The crankshaft packing deteriorates very quickly, which can cause oil leakage. It is important to know that eliminating vibrations is not the last thing; the damage caused by vibrations will also need to be eliminated. Experts advise constantly tightening all nuts and bolts, even those that are additionally secured with wire or cotter pins. Even the tightest connection loosens over time. Sometimes fasteners can only be supported by cotter pins. To ensure that the connections are well twisted, it is recommended to use nuts that have nylon inserts. It is because of this that solving vibration problems has an impact on ensuring reliable, long-lasting and safe operation of your vehicle.

Tips and tricks

Please note that in order to check the functionality of the ignition system, in some cases it is recommended to check the spark plugs for a spark. It is important to understand that if you simply unscrew the spark plug from the engine, the presence of a noticeable spark on the electrodes is not always a sign of complete service.

At the same time, checking the coils cannot be carried out by diagnostics or various tests, since in many cases the problem can be “floating”, and in the case of the test the readings will be normal. Finally, we note that practical operation identifies problems and malfunctions in the operation of ignition coils as one of the common causes of engine tripping after warming up.

In idle mode and at low speeds, the engine shakes: possible reasons for the unstable operation of the power unit. Self-diagnosis methods.

Why does the engine start to stall and the “check” light up on the dashboard: the main and most common reasons for the engine to stall and the “check” to light up.

For what reasons may misfire of the fuel-air mixture occur in one or more cylinders? Fault diagnosis, recommendations.

After switching to gas, the engine stalls, while running normally on gasoline: the main reasons for this malfunction. Diagnosis of problems, recommendations.

Engine trouble: symptoms. Why does tripping occur and how to find the reason why the motor starts to trip. Checking power, ignition, compression, etc.

Signs of a non-working cylinder (tribbing and vibration) of a diesel engine. Troubleshooting: compression, diesel injectors, glow plugs, injection pump and others.

Source

The main reasons for tripling

— The ignition timing is incorrectly set. — There is an air leak in the vacuum brake booster system. — Faulty spark plugs. It is worth noting that this problem is the most common, since spark plugs need to be changed after driving a car every 20,000 kilometers (this figure depends on the recommendations given by the designers of each car). — Breakdown of the high-voltage wire that goes to the spark plug. — Faulty installed capacitor. — Violation of the tightness of the system in the area of ​​the intake manifold. — Burnout of one of the piston or valve. — Breakage of piston rings, their deformation and wear also lead to this problem. — Incorrect adjustment of the gas distribution valves. — High degree of rocker wear. — Breakdown of the installed cylinder head gasket. — Any type of wear (hardening, breakdown, destruction) of the valve stem seals. — If the carburetor is adjusted incorrectly, the cylinders may also malfunction. — Condition of the installed distributor shaft and rotary plate bearing. — Air filter clogged. — Loss of tightness of the membrane of the vacuum ignition timing regulator. — Use of unsuitable spark plugs (not only the dimensions, but also other parameters of this element are taken into account) for this engine.

Engine trouble manifests itself in the form of increased vibrations of the power unit, and the engine noticeably loses power. Misfires may occur, which are accompanied by strong pops in the exhaust system. The engine can stall either occasionally or constantly, only at idle or under load, cold, hot, etc. Next, we intend to answer the question of what engine tripping is, and also consider the main reasons why the engine begins to trip.

Why does the engine start to stall?

Engine tripping is a violation of the combustion of the mixture in the cylinders, which is accompanied by a clear increase in vibration. Please note that the appearance of internal combustion engine vibrations is not necessarily a tripping, since there are a number of other reasons why the engine vibrates strongly. The list of main faults that cause the engine to stall includes:

supply of insufficient or excess fuel to the cylinder; supply of insufficient or excess air; malfunction of the ignition system, early or late ignition; wear or breakdown of the motor, which is accompanied by a decrease in compression; In other words, the engine begins to stall as a result of an inappropriate composition of the fuel-air mixture, untimely ignition of the mixture or inability to ignite the charge, as well as violation of the conditions for normal combustion of the mixture as a result of mechanical wear or breakdown of the engine itself. Based on this data, you can narrow your search and the number of systems for diagnosis. The check should begin with the fuel system and injector, then the intake air supply and the ignition system are checked. In some cases, engine stalling may also be the result of a failure of one of the ECM sensors.

Engine troubles: ignition of fuel-air mixture is disrupted

The most common reason that causes the engine to misfire is late or early ignition, as well as a weak spark plug. At the initial stage, you should unscrew the spark plugs for a detailed inspection. If damage to the insulator or other defects is noticeable, then the spark plug should be replaced.

In the case of a damaged insulator, the place of damage is clearly visible, since this area turns black. You should also pay attention to the condition of the central electrode and evaluate the gap of the side electrode. Next you need to check the spark plug wires. An indirect sign indicating this element is the occasional tripping of the engine in conditions of high humidity (rain, dampness, etc.). After the engine warms up and reaches operating temperature, the symptoms may disappear completely.

You should start by inspecting the spark plug cap and the highest voltage wire. These elements have rubber insulation, which tends to dry out and crack over time, as a result of which the wire begins to break through. Also, the high-voltage wire or cap is often damaged during service or repair work in the engine compartment. Let us add that the location of the breakdown may not be visually detectable. In this case, it is better to check this element of the ignition system using one of the available methods. If everything is in order with the spark plugs and wires, then the ignition coil may be the culprit for the engine misfiring. On engines with separate coils for each spark plug, this phenomenon is especially widespread. To check the ignition coil, you need to unscrew the spark plug, apply it to ground and start the engine. Please note that the thread of the candle must tightly touch the mass, the cap must be tightly placed on the candle. Ignoring these rules may result in burnout of the coil or commutator. A good spark with a characteristic crackling sound will indicate the serviceability of the coil; the absence of a spark will indicate the need to replace the coil.

As for the electronic ignition distributor (switch), this element does not break down often. To check, the spark plugs are securely attached to ground, then the caps are connected to them, after which one person turns the engine with the starter, and the other evaluates the strength of the spark on the spark plugs.

Motor tripping: air supply problems

Inadequate or excessive intake air can also cause cylinder misfire. The air supply system may lose its tightness and the engine begins to suck in excess air. The ECU does not take this leak into account, and as a result, the stability of operation is disrupted.

Malfunctions in the ignition system

Original spark plugs rarely cause trouble for the owner. Their resource exceeds 70 thousand km. Installing low-quality spark plugs or delaying their replacement leads to gaps in the ignition of the fuel-air mixture. As a result, the engine suffers, fuel consumption increases, and dynamics deteriorate.

A set of spark plugs removed from the engine

Coils also present problems in the ignition system. When driven under 80 thousand km, cracks form on the tips. It is impossible to eliminate them using heat shrink or electrical tape, due to the discrepancy between the breakdown voltage.

Crack formation at the tip

A visual inspection of the coils shows the location of the breakdown that prevents sparking. Damage to the coil body occurs mainly during runs of 100-120 thousand km. Frequent overheating of the power plant can provoke earlier failure of the coil.

Detecting a crack in the body

The engine stalls when hot: reasons

Even experienced car owners, when faced with the fact that the engine is running hot, without showing signs of a major malfunction until it warms up completely, first of all blame the fuel or spark plugs. In addition to these options, there are several more less obvious reasons why the car runs smoothly when cold, but when the engine warms up it starts to throttle: low compression, electronic failure, fuel shortage due to wear of one or more injectors. To find out where to look for a specific source of the problem, you need to carry out a series of manipulations.

Typical reasons why a warm engine stalls

For a gasoline engine, there are usually three reasons leading to disruption of the cycle of a cylinder (or several):

For a diesel engine, this list is even shorter: insufficient compression, deficiency or ineffective fuel atomization.

Reasons for hot tripping in the internal combustion engine of a car:

The reason that engine problems begin when the engine is hot is often a malfunction of electronic components. Pressure, position, temperature, lambda sensors - their connectors, wires and fastenings - after spark plugs and ignition coils in a gasoline engine, in case of unstable engine operation - these are the first candidates for testing.

Engine control system components

For a chipped car, a malfunction can arise out of nowhere, due to a broken firmware. For most cars with distributed injection controlled by an ECU, resetting the firmware to factory settings or physically replacing the chip can get rid of the problem when the engine only stalls when hot.

How to find a fault

First of all, you need to find the cylinder that is interfering with the smooth operation of the engine. You can isolate a non-working cylinder on a gasoline engine by simply disconnecting the high-voltage wires, or “chips,” from the ignition control module. This is done while the engine is running, one at a time (one at a time, after returning the wire to its place). If after shutdown the general symptoms of the malfunction have not changed, it means that this cylinder is faulty. If it gets worse, it means this one works, look further.

For a diesel engine, the spark plugs of which play a role only during start-up and do not control the ignition, a “map” of working and non-working cylinders can be created by turning off the power to the piezo injectors. In the case of a mechanical fuel injection drive, the changed nature of the operation can be determined by noise - with a stethoscope, or by vibration, by touch, with a screwdriver.

Sensors and contacts

In modern engines (whether gasoline or diesel), the cycle is controlled by electronics: it changes the ratio in the fuel-air mixture, selects the ignition timing, and on some engines, the timing and angle of valve opening. All changes are based on the readings of numerous sensors. In addition to the serviceability of the device itself, the reliability of these readings is affected by the quality of the contact in the connector (chip), the integrity of the wires, the battery charge level and the voltage in the on-board network.

Indicators, due to malfunction of which the engine may start to stall when hot:

It often happens that a car’s engine starts to misfire because of one magnet and a piece of wire, and before the source of the problem was discovered, the car owner had already changed the spark plugs, injectors, or even the fuel pump.

If the car often starts when hot, in order to exclude a malfunction of one or more sensors, you need to carry out detailed computer diagnostics, or, if the car is “old” and is not equipped with a BC with a self-diagnosis system, sequentially remove the parts that are “in question” and check their connections , power supply, ring with an autotester.

Malfunctions that cause a diesel engine to stall when hot

If you do not have the opportunity to do a detailed engine diagnostics, the main task is to understand whether the engine is trembling, or whether the engine is simply shaking from vibration. Make sure that the engine actually misfires by listening to the exhaust sound (uniform or not). Then, also by ear, determine the cylinder that is leaking. Swap its injector with the neighboring one. If another cylinder starts to fire, the problem is in the injector.

Checking diesel engine injectors

The smooth operation of a diesel engine mainly depends on the quality of the settings of the fuel equipment, therefore, first of all, on a diesel engine they check:

Another implicit reason is when the engine starts running after quite a long time of operation (an hour or more), vibration and “misfires” appear after start-up, as if the car does not have enough fuel - this is the incorrect operation of the USR system, which returns exhaust gases to the cylinders in the wrong way the volume that the motor is able to “digest”.

The most common breakdowns that cause a diesel engine to run hot:

Air leak in the fuel line (before the injection pump).

When starting, it works normally, but after that, the engine stutters and does not develop speed.

Replacement of fuel pipes.

Excessive fuel pressure in the injector.

After starting, the engine shakes at all speeds, there is obvious strong vibration, a knock or clatter is heard from the side of the CPG.

Injection pump repair, pressure valve replacement.

Insufficient fuel spray from the injector.

The car jerks while driving, stalls after heating, at speeds above 1000.

Checking the quality of injectors, cleaning, or replacing.

The pressure in the fuel rail drops.

The pressure sensor is faulty - the fuel drain valve (return) opens earlier than necessary.

Inspection of contacts, replacement of pressure release sensor.

One or more valves are pressed (not completely closed).

It starts to burn at idle, or low, after warming up - the combustion of the mixture is uneven. If you add speed, the problem disappears.

Adjusting the valve clearance.

The crankshaft position sensor has come off (failed).

Unstable idle, problems with starting, troits during startup and after heating.

Diesel shakes and smokes: problems with fuel supply

If there are problems with the fuel supply, then the diesel engine starts to stall for the following reasons:

• the fuel pump does not create optimal pressure in the fuel supply system;
• the injection intensity is disrupted as a result of a malfunction of the diesel injector;

In both cases, fuel atomization deteriorates and the mixture does not burn completely. The fuel injection pump can create normal pressure, but the fuel injectors deliver different amounts of fuel to the cylinders. In such conditions, fuel is distributed unevenly among the cylinders, the engine shakes in different operating modes. If it is completely impossible to pump a portion of diesel fuel through the nozzle, the diesel engine begins to stall. Cleaning, repairing, or replacing injectors must be accompanied by adjustment of the injectors before installation on the engine.

We also recommend reading the article on how to clean and adjust diesel injectors. From this article you will learn about what malfunctions occur during the operation of injectors, as well as methods for diagnosing and eliminating problems.

At the same time, it is necessary to regulate the fuel injection pump. The pump may be worn out and/or incorrectly adjusted, resulting in insufficient pressure to deliver the required amount of diesel fuel through the rebuilt or replaced injectors. The diesel engine may start to run rough, with detonation. Replacing injectors is necessarily accompanied by checking the performance of the fuel injection pump.

If there are problems with both the fuel pump and the injectors, the parts must be adjusted, repaired or replaced immediately. Detonation on a diesel engine will quickly damage the engine.

Compression in cylinders

When a car stalls when starting hot - while the engine has not yet cooled down - this may indicate a low compression ratio in one or more cylinders. Triple, if, for example, we take 11–12 units as the norm, it will occur already at 9 or 8. As the cylinder warms up, air will begin to be sucked in from the outside, the mixture will become lean, and this cylinder will begin to heat up more than the others. In a diesel engine, a low compression ratio simply will not allow the mixture to ignite - and it will fly out into the exhaust manifold.

Reasons for low engine compression:

The engine will only start if most of the cylinders still work adequately, otherwise the car simply won’t start, or will start with great difficulty. The main sign that a cylinder is leaking is a lower temperature in its part of the exhaust manifold. It is difficult to check this symptom - on most cars, this requires removing the heat shield.

Measuring compression in cylinders with a compression gauge

To find out without disassembling the engine what malfunction is causing it (the reason is in the piston and rings, or in the valves), you need to measure the compression in each cylinder, then pour 1 ml of engine oil into each and measure it again. If the values ​​are the same as the first time, the problem is in the engine “head” (valves, seats, gasket). If the compression increases, the problem is in the CPG.

Steering problems

The weak part of the steering is its rack. It causes trouble when the car's mileage reaches 120-140 thousand km. The unit has a high cost, which can reach 30-45 thousand rubles. Repairing a rack is a labor-intensive process. Its weak link is the bushing. To replace it, you need to completely disassemble the unit.

New and failed bushings

The appearance of problems in the steering is accompanied by knocking and crunching noises when turning the steering wheel or while overcoming uneven road surfaces. In more advanced cases, the steering wheel becomes jammed, controllability deteriorates, and significant vibration is transmitted to the column.