Why does a car have trouble starting with a cold engine? Contents Carburetor Injector and problems with starting About the causes of poor starting and how to combat them Take care in advance “It doesn’t start well for me

There are many reasons for this. But among them we can distinguish those that occur in almost 90% of cases.

First of all, it is necessary to exclude the influence of low temperatures. In cold weather, the car may not start due to insufficient battery power, as well as due to the use of summer oil, which becomes very thick (these are two main reasons, but there may be others: for example, bad spark plugs or a clogged fuel pump).

Installing an automatic engine warm-up system can help here. If problems with operation occur even at positive temperatures, then it is necessary to continue troubleshooting.

1. Quite often, poor car starting is due to low fuel quality. In this case, the injectors and fuel filters may become clogged.
2. The air filter may also become dirty. Replacing it is quite simple and completely solves the problem.
3. On diesel engines, poor starting can be caused by incorrectly selected fuel. Such motors require a seasonal change in types of diesel fuel (“summer”, as well as “winter” or “arctic” - for especially cold regions).
4. Low compression in the combustion chamber. A decrease in pressure can occur due to engine wear (during its operation, the gaps are closed by an oil film, while when they cool, they reappear), as well as due to incorrect installation of the timing belt.
5. Another reason why an injection engine has difficulty starting when cold is the failure of the sensors (DPRV, DPS, DMRV).
6. It was already written above that problems with starting in winter can arise due to bad spark plugs or a clogged fuel pump. It is worth noting that these problems can also arise at positive temperatures.
7. Sometimes poor starting is caused by a lack or, on the contrary, an excess of fuel when supplied. On injection engines, spark plugs may flood in the winter (this problem usually occurs in used cars). In this case, you need to unscrew them and dry them.
8. A fairly common reason why a cold engine does not start well is contamination of the throttle valve. In this case, it does not open completely, which is why the motor does not work properly.
9. There is a fault in the electrical circuit. If the battery has a charge, but there is no spark at the spark plugs, you need to make sure that the high-voltage wires are intact, as well as the functionality of the ignition coil (checked with a multimeter). True, with such a breakdown, starting problems will arise not only on a cold engine.
10. Sometimes the cause of poor starting is a dirty idle air valve. After cleaning it, problems with engine operation should disappear.

Important! If, when you try to start the engine, smoke comes out of the exhaust pipe and the car does not start, it means that fuel is being supplied, but it is not ignited.

Identifying and eliminating engine starting problems

In most cases, problems can be identified and fixed without much difficulty. So, a sign of clogged fuel filters will be difficulties starting the engine (it may stall at idle), a decrease in power, and also the car jerking during inclines.

It is worth noting that such “symptoms” can also be the result of other faults, such as wiring problems or faulty spark plugs. In this case, it is necessary to urgently replace the filters. If this is not done in time, the motor may fail.

Fuel supply can be checked by unscrewing the spark plugs. If they are filled with gasoline, or, on the contrary, are completely dry, then it is necessary to check the sensors or adjust the carburetor.

Another problem, a sign of which may be that the engine does not start when cold, is clogged injectors. In this case, the car loses dynamics when accelerating sharply, twitches and reacts poorly to pressing the gas pedal. In addition, muffled high-frequency noises may be heard coming from the cylinder block.

If the injectors are indeed coated with deposits, they need to be cleaned. You can do this yourself. There are several main ways to restore this part:

1. The first cleaning method is rather preventive. It consists of adding special additives to the fuel that help get rid of deposits on the injector. However, many motorists try to use this method as little as possible: it is believed that additives can further worsen engine performance.
2. Some experts recommend periodically turning the engine up to high speeds. After several kilometers at a speed of 100-110 km/h, engine performance should improve somewhat.
3. If the injectors are seriously dirty, you will have to clean them manually. To do this, you need to disassemble the injector. After this, the parts are washed with high-quality fuel without impurities or kerosene and blown with compressed air.
4. There are two more ways to clean injectors. They guarantee almost 100% results, but to implement them you need to use professional equipment and have certain skills. Therefore, it is better to contact a service center here. In the first case, the parts are exposed to ultrasound, which destroys all plaque. In the second, a special liquid and a device are used that is connected to the fuel receiver. After the engine has been idling for some time, the injector will be cleaned.

Important! You should not take action without making sure that a specific node is indeed the cause of the poor startup. This is especially true for complex work, the incorrect execution of which can lead to even more serious damage. If in doubt, it is better to turn to professionals.

In conclusion, it is worth adding that it is better to look for the reasons for poor starting of a cold engine as they become more complex. So, you should not check the timing belt or engine compression without making sure there is fuel in the gas tank and a charge in the battery.

By methodically considering all possible fault options, you can get to the true cause of a poor start, and, in most cases, fix it yourself.

Why does my car start poorly when cold? List of reasons

Why is my car hard to start when cold? This question can often arise among drivers and car owners who just recently drove the car, and everything was fine, it sat, cooled down and does not start or starts with great difficulty.

It should be noted that there are no problems when it’s hot. Many modern cars have heating systems installed before starting, however, this does not always save.

When such problems arise, and often this happens in the morning, in front of the car with the hood open, fuss begins to warm it up and subsequent frantic attempts to start it. But, probably, every person who has a car wants to get into it, start it and drive, and not wake up with thoughts of whether it will start or not. In this article we will look into what causes the power unit to start poorly when cold.

Why is it difficult to start a car when it’s cold? It is impossible to answer this question unambiguously and accurately. The following can be taken as the main axioms of the reasons: there is nothing to ignite in the combustion chamber and there is nothing to ignite in the combustion chamber.

Of these two principles, all the rest will be only causes of a given effect. So, now let's look at each axiom separately. The concept of nothing to ignite means not only the absence of fuel, but also poor quality of its supply to the combustion chamber: too little fuel and too much fuel.

An indicator of the first reason can be a candle. We unscrew it (after turning it with the starter) from the engine and look at it: if it is flooded with gasoline, it means it is overflowing and we look further point by point, if it is dry, fuel is not delivered and again we look for the reason point by point. Also check the candle by smell - if it doesn’t smell like gasoline at all, then the cause has been found.

Let's move on to the second reason. If we checked the fuel supply and everything is as it should be, we look for the cause in the ignition device:

• First of all, we check the battery. It may be too discharged, and the starter barely turns or at different speeds;
• Malfunctions in the ignition distributor. At the same time, the machine does not try to “grab”, so to speak;
• Fracture or piercing of a high-voltage wire. In a shaded area when starting the engine, you can see a glow on these wires;
• The ignition coil is faulty. You can check with a multimeter (if there is only one ignition coil);
• The simplest thing is that the spark plugs have failed.

Naturally, when first considering the problem of cold starting, you should not look for the problem in the fuel pump, disassemble the injector, go to the timing belt, or open the cylinder block. As a rule, such reasons are rare, but they do occur, so you still need to start with the simpler ones and gradually move closer to the more complex ones.

In the article we tried to answer the question as fully as possible: why is it difficult for a car to start when it’s cold? If these problems occur, try leaving the car in cold air less often or warm it up over time.

Today you can find special devices that will maintain the engine temperature constant or turn on and warm it up at certain intervals. For example, the Tomahawk copes with this task.

For what reasons can a car have difficulty starting when cold?

It happens that you urgently need to go to work, but the car, after sitting all night, will not start. So why does a vehicle that is in good working order after the last trip suddenly refuse to start? Or does it stall as soon as you crank the engine? Let's look at the reasons why a car may have difficulty starting when cold.

First of all, it is necessary to make a reservation - your car starts perfectly if the engine has not had time to cool down, but in the case when the vehicle sits until the engine has completely cooled down, starting is difficult or completely impossible. In such a situation, even modern systems for heating and maintaining engine temperature do not always help. Let us consider in more detail the situation when a cold engine does not start well.

The procedure for returning the car to “life”

Let's say you find yourself in circumstances where the injection engine starts poorly or refuses to do so at all. There is no need to hesitate in such a situation - it is advisable to immediately begin resuscitation procedures. If you don’t have time to figure out the exact reason why the car doesn’t start well, then you should quickly carry out the following algorithm of actions:

1. First of all, we check the availability of gasoline and battery charge. Is there something missing? Fill it up and light it up. Let's try to start. If there is no result, proceed to the next step;
2. Next, we quickly analyze under what circumstances the car malfunctions. If it takes a long time or is difficult to start when hot, we first check the spark plugs for overheating (light carbon deposits) and the functioning of the fuel system. Otherwise, when the car malfunctions both cold and hot, a more comprehensive approach is required. As a rule, the following procedures are sufficient: checking spark plugs, wiring the ignition system, assessing the operation of the injector and fuel system;
3. Note that most motorists manage to solve the problem, so to speak, with little loss, that is, by implementing the actions described above. If you are not one of the lucky ones and your car still takes a long time, starts poorly or refuses to work at all, you will have to act globally. Here it is better to take the car to a service station or a convenient garage and check the compression, timing adjustment, clean the injector, assess the condition of the fuel system and ignition devices. If there are any malfunctions, they must, of course, be eliminated.

Causes of problematic startup

Causes of problematic starting of a cold engine

When determining the reasons why the car has trouble starting when cold, you will first need to make sure that the battery is not discharged and that the starter is in good working order (the engine turns smoothly and smoothly). A separate reason that requires exclusion is refueling a car with low-grade gasoline. The quality of the fuel being poured greatly influences the trouble-free starting of the vehicle. If the battery is not discharged, the starter is working properly and the fuel is of appropriate quality, you can suspect the following main problems if it is difficult to start the vehicle when it is cold:

• the fuel pump has failed;
• the fuel filter is clogged (due to low-quality fuel);
• injectors are clogged (due to fuel);
• The fuel pressure regulator has malfunctioned;
• air leak;
• the spark plugs, ignition coils, and high-voltage wires have exhausted their service life;
• clogged idle valve;
• The mass air flow sensor is faulty;
• temperature sensor malfunction;
• valve clearance violations;
• the oil is out of season.

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Having considered possible malfunctions due to which the car may not start well when cold, let’s move on to studying ways to detect and eliminate them.

Troubleshooting and troubleshooting in different types of engines

A problem with spark plugs is a common cause of poor starting in a cold engine.

Different types of engines have their own trouble indicators. It happens that a gasoline engine has difficulty starting when cold, and one of the main ways to find out the cause of the problem is the spark plug. It may also be the reason why diesel engines have trouble starting in cold weather. Indications for checking spark plugs, testing the battery, checking explosive wires and the ignition coil are jumping speed, engine tripping and poor cold starting, but only when the problems go away after warming up.

If the spark plug is dry, the problem is in the fuel line, as it indicates that fuel is not being supplied to the system.

Let's examine the spark plugs. Having unscrewed the spark plug, we carefully examine it. If the spark plug is wet, this indicates an overflow of fuel. Then suspicions fall on an electrical failure. We check the high-voltage wires, then we diagnose the ignition coil and battery.

We check the performance of the spark plug itself: serviceable spark plugs have a good spark. If the spark plugs fail, it is better to replace them with new ones. High-voltage wires can be checked in a dark room - if a glow is visible in the dark, the wires have been broken and they also need to be replaced.

Diagnosis of the causes of difficult starting

When a car has difficulty starting from a cold engine to a cold one, there may be different reasons. If the indicator is a dry spark plug, this is a sign of a problem with fuel supply. This can happen due to clogged filters - fine and coarse cleaning. If the engine still has difficulty starting when cold, pay attention to the injectors.

A faulty injector may be indicated by a spark plug flooded with gasoline after an unsuccessful start.

Another characteristic feature of this malfunction is poor starting in hot weather with a warm engine, and in winter problems arise with starting a vehicle that has already cooled down. You can check whether the problem is correctly detected by reducing the pressure in the fuel system before stopping the engine for an extended period of time. The injectors may be incorrectly adjusted or leaking. Additionally, we examine the fuel system for leaks, kinks or creases. Due to damage, air can leak inside and prevent the engine from starting when cold. It happens that the starter is fine, the spark plugs and wires are normal, but the engine does not start. Then you need to look for the cause in the sensor that regulates the coolant or check the pressure in the fuel system.

Carburetor

The main reasons for poor starting of a carburetor engine after cooling to a cold state is the failure of the ignition distributor. Determined by cranking the starter - it turns out that the engine does not “grab.” The next reason is the ignition coil, the serviceability of which is checked with a multimeter. The switch, distributor, or carburetor settings may also be faulty. If a car with a carburetor is very difficult to start when cold, or after that it starts and stalls, this indicates a breakdown of the diaphragm in the starting device.

Ignition check

The engine may not start if the ignition distributor is faulty. This malfunction manifests itself in such a way that when the starter rotates, the so-called seizure does not occur, that is, there are no signs of single attempts to ignite the fuel-air mixture in the engine cylinders.

It is also worth paying attention to the setting of the ignition timing, timing belt and its drive. In some cases, it is worth checking the condition of the variable valve timing system (if equipped). The ignition coil can be checked using a multimeter.

Injector and starting problems

Problems starting a cold injection engine

When a car cannot start when cold (cold engine), the injector installed on it requires a special approach to finding the reasons. In this case, first of all, you can turn your attention to the sensors. As a result of their malfunction, incorrect signals are sent to the electronic control unit. The functionality of the following sensors should be checked:

• throttle valve;
• fuel consumption;
• coolant temperature;
• mass air flow;
• The operation of the fuel regulator is often disrupted.

On cars with a mechanical injector, the root cause of poor starting is the starting injector. Probably, after these actions, the question is, “Why does my car have trouble starting in the morning when it’s cold with an injector inside?” will leave the owner of the car.

The car is bad

The problem is less common, but if an already warmed up engine does not start well, this can become a big mystery for an inexperienced driver. Indeed, just now the machine was working like a clock, and suddenly, out of the blue, there was a problem.

In most cases, the engine does not start well when hot for two reasons:

• low fuel quality,
• malfunction of one or more sensors.

Poor quality fuel

If problems with starting the engine began after refueling, then with a 99.9% probability the reason is poor quality fuel. This statement is true for both gasoline and diesel engines. There are no ways to check the characteristics of fuel in artisanal conditions, so you will have to rely on indirect signs. It is often easier to drain low-quality fuel and refuel at a proven gas station. Otherwise, you will have to use various additives to bring the parameters of gasoline or diesel fuel to the desired values, but this is always a risk for the engine.

Electronic problems

If a VAZ of modern models does not start well, then the reasons may be in the electronics. However, foreign cars also suffer from this, but this mainly applies to used vehicles. Accurately diagnosing and eliminating malfunctions in the electronic components of a car is only possible with modern computer equipment.

Diesel engines

In a gasoline engine, troubleshooting should begin with the spark plugs, and when a diesel engine has trouble starting when cold, the reasons should begin with loss of compression. A loss of compression can be assumed when the car is started after acceleration by hand, and after that, blue smoke is observed from the exhaust pipe for some time. Low compression can occur if the valve clearances are set incorrectly. Another reason is that the timing belt is not installed correctly. If the compression is normal, you should pay more attention to the choice of high-quality fuel (its suitability for the season), fuel supply and the next reason - glow plugs.

Starting in cold weather

Tips for winter starting the engine

If your car has trouble starting in cold weather, following simple rules can correct this situation.

Try to keep your fuel tank full to help prevent condensation from forming and mixing water with fuel. This way the quality of the fuel will not deteriorate.

A car that runs on gas and cannot start well when cold - never start it without switching to gasoline! Is it dangerous!

• Before starting the engine, when it is frosty outside, it is advisable to turn on the high beams and turn them off after a couple of seconds. This procedure will help partially restore the battery capacity and eliminate poor starting in cold weather.
• Before starting a car with a carburetor, you need to pump up the fuel a little (be careful not to fill the spark plugs!).
• After turning the key in the ignition, if the car has an injector, do not rush to start the engine. It is worth waiting a while for the required pressure in the fuel system to rise.

Reasons why the car doesn't start well when cold

On automobile forums you can often come across the question: why does the engine start poorly when cold? It happens that a person has driven a car for some time, parked it, the engine has cooled down, and when he needs to drive again, it either does not start at all or starts, but with great difficulty. Moreover, if the engine has not yet completely cooled down, then it starts up calmly. Why is this happening?

There are two basic reasons - either it is 1) a problem in the fuel supply, or 2) a problem in the ignition system.

The following malfunctions lead to incorrect fuel supply:

1. Poor quality fuel. 2. The injectors are clogged. 3. The coarse filter is clogged. 4. The fine fuel filter is clogged. 5. The throttle valve is clogged (cleaning the throttle valve). 6. The idle jet is clogged. 7. Insufficient pressure in the fuel pump. 8. Fuel pressure is not adjusted correctly. 9. The air filter is clogged. 10. The outside temperature is too low to start the engine.

Now you need to determine whether, in your case, there is a problem with the fuel supply - the spark plug will tell you about this. You need to turn the starter, unscrew the spark plug and inspect it: if it is filled with gasoline, it means that too much fuel is entering the combustion chamber; if it is completely dry, it means that not enough fuel is entering.

Next, refer to the list of faults for fuel supply problems listed above and identify this fault.

If the engine doesn’t start well when cold, but you still haven’t found any problems with the fuel supply, then the whole point is in the second reason: there is a problem in the ignition system.

The following reasons lead to malfunctions in the ignition system:

1. The spark plugs are worn out (how to check the spark plugs). 2. The battery is discharged, and the starter turns very weakly, at an uneven speed. 3. The ignition distributor is faulty. 4. The high-voltage wire is broken or punctured (in a dark place, when starting the engine, a glow will be noticeable on this wire). 5. The ignition coil is faulty (if there is only one, you can check it with a multimeter).

If the compression pressure in the combustion chamber has sharply decreased, this will inevitably lead to problems with fuel ignition.

Reasons for decreased compression pressure: 1) engine wear; 2) incorrectly set valve clearances (VAZ valve adjustment); 3) the timing belt is installed incorrectly.

Of course, if the car engine does not start well when cold, you should not immediately rush to disassemble the injector, reinstall the timing belt or repair the fuel pump. Still, such reasons happen quite rarely. You need to start by identifying simple causes and, as they are eliminated, approach more complex ones.

Why does a car have trouble starting with a cold engine?

“It doesn’t start well when it’s cold,” such complaints can often be heard from drivers in cold weather when discussing cars. In this case, different symptoms and behavior may be described, but the problems due to which the car is difficult to start when cold are, as a rule, almost the same. The reasons for difficult starting may differ depending on the type of engine; since gasoline engines (injector or carburetor) have their own reasons, and diesel engines will, of course, have others.

Main reasons in the table

How to cold start an injection engine

Most modern cars are equipped with a fuel injection system. The system is installed only on gasoline engines. Despite the complexity of the design and high requirements for fuel quality, the injection engine has a number of advantages over the carburetor mechanism:

• automatic adjustment of the injection system depending on the load;
• quick engine start, increase in its dynamic performance;
• low emissions of harmful substances;
• saving fuel consumption due to dosed injection;
• does not require prolonged warming up during low temperature conditions;
• the ability to program the electronic control system depending on the manner and style of driving;

Carburetor

The main reasons for poor starting of a carburetor engine after cooling to a cold state is the failure of the ignition distributor. Determined by cranking the starter - it turns out that the engine does not “grab.” The next reason is the ignition coil, the serviceability of which is checked with a multimeter. The switch, distributor, or carburetor settings may also be faulty. If a car with a carburetor is very difficult to start when cold, or after that it starts and stalls, this indicates a breakdown of the diaphragm in the starting device.

The main reasons why the carburetor does not start when cold:

1. Ignition coil.
2. Switch.
3. Distributor (lid or slider).
4. Incorrectly adjusted carburetor.
5. The starter diaphragm or the fuel pump diaphragm is damaged.

Of course, if you pump up gasoline before starting and pull out the choke more, it will start better, but all these tips are relevant when the carburetor is correctly configured and there are no problems with the switch or spark plugs.

If a car with a carburetor, be it a Solex or a DAAZ (VAZ 2109, VAZ 2107), starts up when cold and then immediately stalls, flooding the spark plugs, this indicates a malfunction of the starter diaphragm.

The starter turns poorly on a cold VAZ 2109

This is one of the most common causes of poor fret starting. There are two sides to this: the starter is stuck or the battery is frozen. If everything is clear with the first case, then the second requires special attention.

In severe frosts, it is recommended to bring the battery into the house and charge it, then starting problems will be left behind. But if this is not done, the task may become more difficult. To start, you will need to turn on the low beam for a while - this will warm up the electrolyte. After this, you can try to turn on the starter for no more than 3 seconds. Each new attempt to start the engine must be accompanied by pauses of 30 seconds, 1 minute and 2 minutes. Otherwise, the battery will run out completely and instead of traveling you will have to wait until the battery is charged.

Injector and starting problems

When a car cannot start when cold (cold engine), the injector installed on it requires a special approach to finding the reasons. In this case, first of all, you can turn your attention to the sensors. As a result of their malfunction, incorrect signals are sent to the electronic control unit.

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The functionality of the following sensors should be checked:

On cars with a mechanical injector, the root cause of poor starting is the starting injector. Probably, after these actions, the question is, “Why does my car have trouble starting in the morning when it’s cold with an injector inside?” will leave the owner of the car.

Diesel engines

In a gasoline engine, troubleshooting should begin with the spark plugs, and when a diesel engine has trouble starting when cold, the reasons should begin with loss of compression. A loss of compression can be assumed when the car is started after acceleration by hand, and after that, blue smoke is observed from the exhaust pipe for some time. Low compression can occur if the valve clearances are set incorrectly. Another reason is that the timing belt is not installed correctly. If the compression is normal, you should pay more attention to the choice of high-quality fuel (its suitability for the season), fuel supply and the next reason - glow plugs.

If a diesel engine has trouble starting when cold, the reasons can be collected in a single list of ten points:

1. Starter or battery faulty.
2. Insufficient compression.
3. Faulty injector/injectors.
4. Incorrectly set injection timing, desynchronization with fuel injection pump operation (timing belt jumps by one tooth).
5. Air in fuel.
6. The valve clearance is incorrectly set.
7. Malfunction of the preheating system.
8. Additional resistance in the fuel supply system.
9. Additional resistance in the exhaust system.
10. Internal breakdown of the injection pump.

The main causes of problems during cold engine starts

Low quality fuel

The likelihood of refueling a car with low-quality fuel at certified gas stations in large cities is very low. It is much easier to encounter counterfeit products at little-known gas stations on the highways or when purchasing fuel second-hand. Such fuel does not pass quality control and contains a large amount of impurities that contaminate filters and fuel pipe channels. As a result, the pressure in the system decreases and the car does not start.

The use of low octane gasoline is determined by the following criteria:

In diesel engines, a problem may arise due to the fuel selected “out of season.” An owner who uses diesel fuel for the summer during the winter period of operation of the vehicle will encounter difficulties. The main reason is the discrepancy between the physical and chemical properties of the fuel and the operating conditions.

Summer diesel fuel at subzero temperatures turns into a viscous and thick mass that clogs both the fuel line and the filter. Its chemical composition is not suitable for working in such conditions. In this situation, preheating the fuel system and installing a new filter instead of the dirty old one will help.

Poor condition of spark plugs

Remove the spark plugs after an unsuccessful attempt to start the engine. The presence of strong smudges, as a rule, indicates a malfunction with the ignition system and a violation of the tightness of the injectors.

First you need to inspect the external condition of the candles. Check their integrity. You should look at the high voltage wires. There should be no defects.

A dry spark plug indicates that fuel is not getting into the cylinder.

About the causes of poor starting and how to combat them

The list of reasons why a cold engine is difficult to start is quite wide. Before starting diagnostics, it is necessary to more accurately localize the fault. Make sure the battery is charged and the starter turns the engine smoothly (at the same speed). Additionally, it is worth excluding the possibility of refueling with low-grade gasoline.

Fuel supply

Problems with starting the engine can arise both as a result of the fact that there is no fuel supply, and due to failures in the process of its ignition in the engine cylinders. As for the fuel supply, there may be too little fuel to start. It is also possible that the spark plugs are flooded with excess fuel.

1. It's worth starting the check by making sure there is an exhaust. If light smoke appears from the exhaust pipe after turning the starter, then this indicates that there is fuel supply to the cylinders.
2. The next step is to remove the spark plugs. The spark plugs must be unscrewed after an unsuccessful attempt to start the engine. If the spark plug is flooded with gasoline, then this can often indicate problems with injector sealing or ignition. Check the integrity of the spark plugs themselves and the high-voltage wires, and also make sure that there is a spark at the spark plugs. A dry spark plug will indicate that fuel is not being supplied to the cylinder.
3. Clogged coarse and fine filters, as well as faulty or heavily coked injection nozzles, can also hinder the normal supply of fuel to the engine. Fuel may also not enter the engine due to a sharp decrease in the performance of the fuel pump. This means that the fuel pump is not creating the required pressure. To find out the reasons, you will need to check the fuel pressure in the rail and the fuel pump itself.

An additional nuance may be air leaks in the fuel system. It is necessary to examine the lines for damage, bends, cracks, etc. Gasoline leakage is a clear sign of loss of seal in the fuel lines.

Electronic sensors

The electronic injection system is equipped with special sensors, thanks to which interaction with the engine ECU is realized. Failure of individual electronic components can result in incorrect signals being sent to the control unit and the engine cannot be started.

If the engine does not start, then you need to check several sensors:

• camshaft position sensor (CPR);
• throttle position sensor (TPS);
• mass air flow sensor (MAF);

It is also necessary to simultaneously clean the throttle, check the air filter and the XX valve. Self-diagnosis of sensors can be done using a multimeter.

Ignition check

The engine may not start if the ignition distributor is faulty. This malfunction manifests itself in such a way that when the starter rotates, the so-called seizure does not occur, that is, there are no signs of single attempts to ignite the fuel-air mixture in the engine cylinders.

It is also worth paying attention to the setting of the ignition timing, timing belt and its drive. In some cases, it is worth checking the condition of the variable valve timing system (if equipped). The ignition coil can be checked using a multimeter.

Compression reduction

A loss of compression in one or more engine cylinders is a consequence of natural wear or damage to the power unit. A motor with low compression does not, as there is a strong increase in the gaps between the parts in the cylinder. In other words, it is not possible to achieve the required pressure in the combustion chamber to ignite the working mixture at the time of start-up.

Frequent causes of this malfunction may be piston destruction, broken or stuck piston rings, burnout of the timing valve, wear of the cylinder walls, etc. Low compression most often appears during a cold start, but can also be present constantly (when trying to start a very worn engine “hot”). An engine with such a malfunction is most difficult to start at low temperatures. For an accurate diagnosis, compression must be measured.

Engine operating principle

According to the principle of operation, injection engines are similar to diesel engines: fuel is supplied through special nozzles. After the starter begins to crank the crankshaft, control sensors send a signal to the electronic control unit, which indicates which stroke the cylinders are in.

After reading the data, the control unit sends a signal to the injector of the cylinder, which is located on the intake stroke. The injector opens for a strictly defined time, which corresponds to the readings of the mass air flow sensor.

Mass air flow sensor value table.

After the end of the intake stroke, compression occurs. The central module receives data from the DPKF and DF sensors that the piston is at top dead center. After processing the data, the signal is sent to the ignition unit, which transmits voltage to the desired cylinder. The task of correct supply of voltage is ensured by two transistors located in the housing of the control unit.

Further, when the working mixture has ignited, the cylinder stroke has begun in the combustion chamber, the ECU takes readings from the knock sensor and adjusts the ignition angle for the next cylinder.

For more efficient use of fuel energy, an oxygen sensor is installed on the exhaust system. Using the indicators received from the sensor, the control unit adjusts the mixture composition and sets the injector opening time. If there is a lack of oxygen when the throttle valve is open, the ECU slightly opens the idle speed control.

Take care in advance

In general, in cold weather, the alarm system’s already weakened battery is additionally drained. If the car is stored in a guarded parking lot, it is better to leave it unguarded, thereby increasing the chances of starting in the morning. In order to open the doors without problems, you need to keep a can of a composition called “lock defroster” in your clothing pocket all winter. It costs a penny, but it helps a lot when the key refuses to even “go” into the hole. If you don’t have a defroster at hand, you’ll have to test the old-fashioned method for yourself - warm the key with a lighter.

By the way, if you inject the same defroster or WD-40 into the lock in advance of frost, practically no water gets there. Do not use brake fluid to dissolve ice or treat locks. The lock may open, but by the evening it will freeze again, because, unlike special fluids, the brake fluid does not repel water, displacing it from the lock. In addition, it easily damages car paint.

Also, in severe frosts at night you can go out to warm the engine. Or pay parking attendants to warm up your car overnight. If possible, place it in the garage. Even in an unheated room, the temperature is 5-7 degrees higher than outside. And these are “two big differences” – minus 27 or minus 20.

If you still can’t start, and you have enough time, then you can try to determine the composition of the fuel mixture. To do this, simply remove one of the spark plugs from the engine and inspect it. If there are black (or very dark) deposits, the fuel mixture is quite rich, which means that there is something wrong with the car’s ignition system. Most often, in such cases, it is enough to replace the spark plugs, and engine starting returns to normal.

If there is no dark carbon deposit on the removed spark plug or it is white, we are talking about a lean fuel mixture. In this case, the culprit of the problem is often the coolant temperature sensor. You will always have problems with this - you will have to replace it.

When the fuel mixture is lean, some car owners try to start the engine using various additives that increase the octane number of the fuel. Sometimes they succeed. Another method that is often used in this situation is the injection of ether compounds to start carburetor engines. However, dealing with depressurization of the intake tract in the cold, and then doing all this in the reverse order, is not a pleasant task.

Another reason for a lean fuel mixture can be insufficient fuel pressure in the system. There are mainly two reasons here. This is either a dying fuel pump or a fuel pressure regulator. If there is a problem with the fuel pump, it may be impossible to start the engine. But sometimes the fuel pressure in the system can be raised to the optimal level by plugging the drain hose by squeezing it. This must be done carefully, as it may burst in severe frost. After starting the engine, you should not continue to pinch the hose. Otherwise, there is a high probability that the spark plugs will be splashed with too rich a fuel mixture. If this happens and the engine stalls, allow the mixture to evaporate by waiting 5-10 minutes. Or clean the spark plugs.

The most common cause of problems starting a cold engine can be the usual depressurization of the intake tract. Most often we are talking about a slipped (sometimes burst) tube that connects the fuel pressure regulator in the system to the intake manifold. Carefully inspect the connections of all tubes (hoses, etc.) that go from the intake tract to other systems or elements (brake system, adsorber, crankcase ventilation, etc.), and if there are serviceable elements of the injection system, problems with cold starting on your car will not.

Tips for starting the engine in cold weather:

1. Keep the tank full - this will prevent condensation from forming and water will not get into the fuel.
2. Turning on the high beams for a couple of seconds before starting will restore some of the battery capacity on frosty days.
3. After turning the key in the ignition switch (on an injection car), wait a few seconds until normal pressure is created in the fuel system, and only then start the engine.
4. Pump up gasoline manually (on a carburetor car), but you must not overdo it, otherwise the spark plugs will flood.
5. Cars run on gas, under no circumstances should you start them cold, switch to gasoline first!

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Incorrect engine start of VAZ 2109

Before drawing any conclusions, it is necessary to ensure that the driver correctly follows the requirements for starting a cold engine. For these purposes, carburetor engines have a manual throttle control drive. Without using this mechanism, starting the car, especially in cold weather, is quite problematic.

You need to start the engine in the following sequence:

• Open the hood and pump up fuel using the manual fuel pump pedal
• Pull the choke control handle towards you
• Pump gasoline into the manifold using the accelerator pedal
• Without pressing the gas pedal, start the engine

You may not be able to start the engine the first time. But the second time it should. You also need to pay attention to pumping gasoline with the gas pedal. The main thing here is not to overdo it, otherwise you can fill the spark plugs and then the engine will definitely not start. If this does happen and the car does not start, then press the pedal all the way, turn on the starter and, while it rotates, slowly release the gas pedal.