Why won't the injector start? possible causes and solutions

Why do you have to adjust the idle speed?

For proper adjustment, you need to know how to adjust idle operation. If everything is done correctly, the procedure will not take much time. However, to do this you need to understand how the carburetor works and how it works. The main trouble associated with this problem is not the lack of idle speed, but the fact that the engine cannot operate stably and stalls.

Why can't the engine hold idle?

If the engine does not hold idle, first, you need to check the solenoid valve. However, it is not installed on all types of carburetors used in the VAZ 2106. If it is, then most often the problem is hidden in it.

In its operation, the valve is similar to a starter solenoid relay, it is even designed in the same way: there is a winding, a spring, a stator, but the overall dimensions are much smaller. The solenoid valve is needed to open fuel access when the throttle valve is in the closed position (gas pedal released). When the ignition is turned off, the valve should block fuel from reaching the carburetor.

Malfunctions of the solenoid valve that cause problems with stable idle speed include the following breakdowns:

• the winding is broken, the rotor does not move, and fuel does not enter the float chamber;
• the fuel nozzle is clogged with dirt;
• the rotor is deformed and jammed.

There is no need to contact specialists to diagnose valve problems. To check, just take a piece of wire and strip it from both sides of the insulation. One end of the wire must be connected to the positive terminal of the battery, the second is connected to the contact of the solenoid valve. There should be a click when connected. If this does not happen, the valve is faulty and should be replaced. There was a click - then you need to remove the wire and turn on the ignition, and then connect the terminal block to the valve terminal. If a click is not heard, this indicates a wire break in one of the sections of the circuit.

There are three ways to solve a problem with a faulty solenoid valve.

1. If the valve is destroyed, you need to, firstly, unscrew it, and secondly, remove the fuel nozzle. This way you can get to the nearest auto parts store and buy a new valve. It costs mere pennies (no more than a hundred rubles).
2. If the wiring is broken in a section of the electrical circuit, you can connect the valve output to the positive terminal of the battery using a wire and then drive to the store.
3. The most effective temporary solution is to connect the valve contact using a suitable wire to the ignition coil contact. This way, voltage will be supplied to the valve only when the ignition is turned on. When the ignition is turned off, the valve will close.

If the problem is not the solenoid valve

Problems with idle speed can also occur due to low-quality fuel, a malfunction of the ignition system, or dirt. These factors appear both separately and together. Idle speed may become unstable or disappear completely. If you decide to diagnose the problem globally, then it is better to start troubleshooting by checking or replacing the air and fuel filters (including the fine filter on the fuel pump). If there is heavy contamination, the fuel-air mixture will flow into the carburetor intermittently.

You should also pay attention to the filter installed at the mixture inlet to the carburetor. If there is contamination, the filters must be replaced

If the problem XX still remains, it means that the search circle is expanding significantly. The next step is to check the spark plugs. If the spark plugs were last changed more than 30,000 km ago, they must be replaced. You should pay attention to the carbon deposits, or more precisely, to its color. If the service life has expired, the gap between the electrode and the spark plug will increase due to severe wear. After replacing the spark plugs, you need to check the stability of the idle speed again.

If replacing the spark plugs does not help, then you should check the ignition system. For a contact system, first of all, the breaker gap (slider) is measured and the correct ignition timing is set. In the case of a contactless system, you need to check the serviceability of the switch and Hall sensor. As a rule, these parts fail first, although nothing else can break there.

It would be a good idea to inspect high-voltage wires. If they are wet or dirty, they should be wiped down and inspected for damage, as well as checking that the insulation is intact and that there is no loss of spark. You can also inspect the distributor cover; it should not be damaged. And finally, you can measure the resistance of the resistor on the breaker; it should be within 5.5 kOhm.

Fuel system malfunction

The operating principle of the VAZ 2112 fuel system is not much different from similar vehicles with an injection system. Often the problem is purely mechanical - the fuel pump mesh becomes clogged.

Which leads to the impossibility of supplying fuel at the required pressure to the combustion chamber. A clogged fuel pump strainer looks like this:

An important factor in the operation of a car engine is the general condition of the fuel system. If the car does not start or does not grip well, or constantly stalls, the problem may lie in the incorrect operation of the injector ramp. The check is quite simple and you can do it yourself:

• open a special plug - it is black, located at one end of the ramp;
• the presence of pressure is determined simply - just bring your hand to the hole.

It often happens that there is pressure in the ramp. But the car continues to have difficulty starting. In this case, it is worth moving on to the next step - checking the operation of the fuel pump. Sometimes the problem lies in the carburetor. It is difficult to find VAZ 2112 cars with such an injection system on sale. If starting is difficult when cold, then the problem most likely lies in the electrics.

Motorhelp.ru engine diagnostics and repair

Typical operating parameters of VAZ injection engines.

For many novice diagnosticians and ordinary car enthusiasts who are interested in the topic of diagnostics, information about typical engine parameters will be useful. Since VAZ car engines are the most common and easiest to repair, we’ll start with them

What should you pay attention to first when analyzing engine operating parameters?1. Engine stopped.1.1 Coolant and air temperature sensors (if equipped)

The temperature is checked to ensure that the readings correspond to the actual engine and air temperatures. It is better to check using a non-contact thermometer. By the way, one of the most reliable in the injection system of VAZ engines are temperature sensors.

1.2 Throttle position (except for systems with an electronic gas pedal). The gas pedal is released - 0%, the accelerator is pressed - according to the opening of the throttle valve. We played with the gas pedal, released it - it should also remain 0%, while the ADC with a dpdz of about 0.5V. If the opening angle jumps from 0 to 1-2%, then as a rule this is a sign of a worn out valve. Less common are faults in the sensor wiring. With the gas pedal fully pressed, some units will show 100% opening (such as January 5.1, January 7.2), while others such as Bosch MP 7.0 will show only 75%. This is fine.

1.3 MAF ADC channel in rest mode: 0.996/1.016 V - normal, up to 1.035 V is still acceptable, everything above is already a reason to think about replacing the mass air flow sensor. Injection systems equipped with feedback from an oxygen sensor are able to correct, to some extent, incorrect readings of the mass air flow sensor, but there is a limit to everything, so you should not delay replacing this sensor if it is already worn out.

2. The engine is idling.

2.1 Idle speed. Typically this is 800 - 850 rpm with a fully warmed up engine. The idle speed value depends on the engine temperature and is set in the engine control program.

2.2 Mass air flow. For 8-valve engines, the typical value is 8-10 kg/h, for 16-valve engines - 7-9.5 kg/h with a fully warmed-up engine at idle. For the M73 ECU these values ​​are slightly higher due to a design feature.

2.3 Length of injection time. For phased injection, the typical value is 3.3 - 4.1 ms. For simultaneous – 2.1 – 2.4 ms

Actually, the injection time itself is not as important as its correction

2.4 Injection time correction factor. Depends on many factors. This is a topic for a separate article, but it’s worth mentioning here that the closer to 1,000 the better. More than 1,000 means the mixture is further enriched, less than 1,000 means it is leaner.

2.5 Multiplicative and additive components of self-learning correction. A typical multiplicative value is 1 +/-0.2. The additive is measured as a percentage and should be no more than +/- 5% on a working system.

2.6 If there is a sign of engine operation in the adjustment zone, based on the signal from the oxygen sensor, the latter should draw a beautiful sinusoid from 0.1 to 0.8 V.

2.7 Cyclic filling and load factor. For “January” typical cyclic air consumption: 8 valve engine 90 - 100 mg/stroke, 16 valve engine 75 -90 mg/stroke. For Bosch 7.9.7 control units the typical load factor is 18 – 24%.

Now let's take a closer look at how these parameters behave in practice. Since I use the SMS Diagnostics program for diagnostics (hi to Alexey Mikheenkov and Sergey Sapelin!), all the screenshots will be from there. The parameters were taken from practically serviceable cars, with the exception of specially stated cases. All images are clickable.

VAZ 2110 8-valve engine, control unit January 5.1 Here the CO correction coefficient has been slightly adjusted due to slight wear of the mass air flow sensor.

VAZ 2107, control unit January 5.1.3

VAZ 2115 8 valve engine, control unit January 7.2

Engine VAZ 21124, control unit January 7.2

VAZ 2114 8 valve engine, Bosch control unit 7.9.7

Priora, VAZ 21126 1.6 l engine, Bosch control unit 7.9.7

Zhiguli VAZ 2107, control unit M73

Engine VAZ 21124, control unit M73

VAZ 2114 8 valve engine, M73 control unit

Kalina, 8 valve engine, M74 control unit

Niva VAZ-21214 engine, Bosch ME17.9.7 control unit

And in conclusion, let me remind you that the above screenshots were taken from real cars, but unfortunately the recorded parameters are not ideal. Although I tried to record parameters only from working cars. download dle 10.6 movies for free

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The engine does not start: injector nozzles

Every car enthusiast should know that the basis for the smooth operation of an injection engine is the condition of the injectors. The condition of the injectors is especially critical in winter, where clots of non-gasoline origin can seriously complicate, or even completely prevent, the injector engine from starting.

As a rule, injectors should be changed every 100-120 thousand kilometers, and they should be washed regularly, taking into account the quality of the gasoline being poured - the more often, the better.

If you have adapted to cleaning injectors at home, be sure to ensure that there is no depressurization of the injectors after reinstallation. If, after stopping, the injector does not start hot or starts with problems, then the most likely reason may be “airing” of the hot ramp. It's easy to check: start the engine, heat it up, press the nipple. If the stream contains bubbles, then, as a rule, poor starting of the hot injector is obvious.

Injector leaks are checked by the pressure drop across them. Moreover, it may not start even when cold if the gasoline in the injector contains air. We do the following: attach the pressure gauge, raise the pressure to 3 and turn on the ignition. If the pressure drops to 2-2.4 and is not maintained for several minutes, then the injectors or check valve are depressurized.

What to do if your VAZ-2110 (8-valve injector) doesn’t start well: reasons

There are many reasons why the fuel-injected VAZ-2110 with 8 valves does not start well after an overnight stay. A particularly common situation is when everything was fine in the evening, and in the morning an unpleasant surprise is discovered in the form of a non-working car. Next, we will consider what reasons can lead to difficulties in starting the injection VAZ-2110 and what to do to fix the problem.

To determine why a car has trouble starting, you need to know how it works. A spark is responsible for starting the engine, which, in turn, is completely dependent on the ignition system and the fuel-air mixture, supplied in precisely metered proportions.

If one component of this chain is broken, starting is problematic or completely impossible.

Possible faults

No matter how trivial it may sound, if the injector does not start, it means something has gone wrong. The success and speed of repair depends on how quickly and efficiently the problematic link in the car’s design can be identified

To better understand the essence of repair activities, it would be a good idea to pay attention to potential breakdowns. The basic list of the latter is as follows:

• Malfunctions of the injector itself. In the event of a breakdown of this kind, as a rule, the car does not start either cold or hot. On top of that, the injector indicator on the dashboard or on-board computer constantly lights up, signaling its malfunction. It is much less common for the engine to work when the indicator is on, but in this case the car starts poorly and is extremely unstable. It is worth noting that the injectors in the injector most often become clogged or the ECU burns out, so it is advisable to check these components first;
• Ignition system failures. Here the list of possible faults is quite large. Often the candles that suffer are simply flooded. In the event of such a breakdown, the car starts and immediately stalls, but in the long term it stops even “grasping.” Other components of the ignition system (coil, module, distributor, crankshaft sensor, etc.) are noticeably less likely to suffer;
• Incorrect operation of the fuel system. In this aspect, injection engines most often suffer on three fronts:
• Fuel filters are clogged (the car “picks up”, but does not start; if the engine starts, it is extremely unstable);
• The fuel pump is faulty (its characteristic operating sound is absent when you turn the ignition key, the injector itself simply does not start both cold and hot, the starter turns).
• There is insufficient pressure in the fuel system (the engine starts up reluctantly both cold and hot, but if it starts working, it functions unstable);
• Engine problems. Perhaps the widest range of possible malfunctions. Often the reason lies in weak compression or incorrectly adjusted valves. In any case, with a “motor” starting problem, high-quality engine diagnostics are required, otherwise it will be very difficult to determine the cause of the malfunction.

The injector starts and stalls: spark plugs

If the injector starts up and immediately stalls, then you must take into account the fact that the electronics are trying to enrich the combustible mixture, taking into account the low temperatures. If you turn the starter for a long time, the spark plugs may fill with gasoline, and as a result, another problem will arise - the injector may malfunction and stall. Try not to get caught with this, especially in the bitter cold with hungry wolves around.

We have selected something even more interesting for you: How does direct fuel injection work and why is it better?

How to start the injector correctly in this case? The gas pedal will not help here, since when pressed, the air flow through the throttle increases, which helps to clear the spark plugs and combustion chamber from accumulated gasoline. But the fact is that when you press the gas, the electronics supply more gasoline to the engine through the injectors, as a result of which no purging will work.

Now here’s a little trick on how to start the injector in this case. You must act quickly, decisively and with knowledge of the machine's structure. We think logically: if the spark plugs are flooded with gasoline, and this is the likely reason for the injector’s inactivity, then its flow to them should be stopped, right? To do this, we take out the fuel pump fuse; as a rule, it is located in an accessible place. On cars where the fuel pump fuse is combined with the power supply to the injectors, it is better to remove the terminal from the fuel pump itself.

Next, we crank the starter. The pressure in the line should be enough for injection, and as soon as the engine starts, put the fuse or terminal back. After this, you can safely press the gas without the risk of flooding the spark plugs.

Specifics of the injection engine

Cars with the mentioned type of power unit came off the assembly line only in the last years of mass production of “sevens”. Engines with such an injection system are more advanced compared to carburetor engines, but at the same time they are noticeably more complex. However, the reluctance to launch here can be explained by very few factors.

The most basic reason is an empty gas tank. If there is sufficient quantity of fuel, then it should be assumed that its supply is somehow disrupted.

The second option is the absence of a spark or its insufficient strength.

It wouldn't hurt to find out what the pressure is in the fuel line. In a VAZ on which the injector is installed, too low sometimes prevents normal starting. Measurements are made with a pressure gauge, for which there is a special fitting.

If your car has an on-board computer, it will allow you to quickly determine the cause of the malfunction. So, often problems with startup lead to an error being displayed. In this case, most likely, the VAZ injector does not want to start due to the fact that the fuel is not ignited properly in the cylinders. Inspecting the spark plugs will help here. Make sure they spark.

Proceed like this:

• unscrew one together with the wire;
• apply to the mass of the car;
• turn on the ignition.

VAZ 2109 injector does not start

Injection Zhiguli models have their own characteristics; the differences in troubleshooting for carburetor and injection engines are very significant. Thus, the owner of a carburetor engine can, with his eyes closed, determine why his car does not start. However, if you transfer him to a fuel-injected car that does not start, then the person will not know what to do. It’s understandable: an electric fuel pump, an ECU, a bunch of sensors, injectors, an ignition module. Without knowing what and in what order to look, a situation where an injection engine does not start can quite frighten the car owner. Here, as in diagnosing any malfunction, a clear, well-thought-out sequence of actions to identify the malfunction is important. So let's start, if the engine VAZ 2108 2109 21099 injector does not start, then the old rule applies here: “Either there is nothing to burn, or there is nothing to ignite.” That is, either there is no spark, or the combustible mixture does not enter the engine cylinders. 1) Check if there is a spark. To do this, unscrew the spark plug from the cylinder, press it against the ground and turn the starter. If the spark jumps at the spark plug, then the problem is in the fuel supply system. However, we must remember that if the unscrewed spark plug is wet and there is a spark, be sure to check the timing belt marks.

Mark on the camshaft gear

Mark on the flywheel

If the timing belt slips one or more teeth, the valve timing will be disrupted and the engine will not start. If the spark does not jump at the spark plug, then the cause may be: the crankshaft position sensor (hereinafter referred to as DPKV), the crankshaft pulley, the ignition module, the ECU. 1a) Many people are very afraid of the fact that there are many sensors in the injector. Yes, it’s true, incorrect operation of sensors can greatly ruin the life of the owner of this car. I’ll tell you one important detail that will immediately make you feel better: the VAZ 2109 engine will not start due to a malfunction of one single sensor - the DPKV. If any other sensor is faulty, the engine will start, but its operation will be incorrect - it may stall, not develop power, increase fuel consumption, but it must start. So, we check the DPKV, the integrity of its connector and the wiring to it. Very often the DPKV connector rots, since moisture and dirt can get into it from below, although the sensor itself is very reliable. If there is a suspicion that the DPCV is faulty, it can be removed and easily checked. Apply power to it from the battery and bring metal to its working area. When the metal approaches, the output voltage of the sensor should increase; when the metal is removed, the output voltage of the DPKV should be close to zero. If the DPKV is faulty, we change it and try to start it. If it doesn’t start, we move on. 1b) Crankshaft pulley. What could be the problem here? The problem is that part of the pulley with teeth on the DPKV is rubber, and it can either fall off or spin.

Part of the pulley with teeth for DPKV fell off

Accordingly, the DPKV does not operate when the crankshaft rotates and the ECU does not issue a spark command to the spark plugs. You can simply remove the timing belt cover and visually verify that the crankshaft pulley is spinning and is in good working order. At the same time, check the integrity of the timing belt and timing marks. 1c) The reason that there is no spark may be a malfunction of the ignition module. It is also necessary to check the connector on the ignition module for its integrity. If possible, you can take the ignition module from another car and check whether the engine starts or not. 1d) If the ECU is faulty, the engine will naturally not start. 1e) Lack of contact in the electrical wiring. All devices may be intact: the ECU, the ignition module and all the sensors. But there will be no contact between them in the wiring, for example, a wire is torn off or the connector is oxidized. 2) If there is a spark, but the engine does not start, it is necessary to check the engine power system. We check whether fuel is supplied to the injectors: 2a) Is the fuel pump pumping?

The VAZ 2109 with an injector has an electric fuel pump

The fuel pump on the injector is electric, it is immersed in the car’s gas tank. When the ignition is turned on, its operation should be heard. To check whether it is pumping fuel or not, you can loosen one of the fuel supply pipes, place a container under it and turn on the ignition - gasoline should flow from the pipe. The pressure in the fuel rail of a car with an injector can also be measured using a conventional pressure gauge. The pressure regulator installed on the fuel rail has a special outlet for connecting a pressure gauge. We connect the pressure gauge and look at the pressure in the fuel line. It should be about 4 atmospheres. If the pressure gauge does not show pressure, then the fuel pump is not working. 2b) If the fuel filter is clogged, the pump will not be able to provide the required fuel supply to the vehicle injectors.

Fuel filter

Again, you can tell whether the filter is clogged or not using a pressure gauge connected to the tap of the pressure regulator on the car’s fuel rail. 2c) Clogged injectors.

Dirty injection engine injectors

When the injectors become clogged, they either do not allow fuel to pass through at all, or the fuel flows in in smaller quantities and does not spray, but drips. Due to clogged injectors, it may be difficult to start the engine in cold weather. Such a car usually does not develop full power while driving. 2d) Fuel may not be sprayed by the injectors if they do not receive opening signals from the ECU. You need to make sure that the chips are installed on the injectors and that all wires are intact. 3) When starting a cold engine in cold weather, especially on VAZ injection engines, a phenomenon such as slipping or shearing of the timing belt teeth often occurs. In this case, the valve timing of the engine is disrupted and it cannot start. To make sure that the timing belt has not slipped, you need to remove the belt cover and check the marks on the camshaft wheel and on the flywheel shaft. If everything is in order, we move on. 4) If the candles are flooded, they need to be dried. A spark does not form on a flooded spark plug. If you unscrew a spark plug and it is all wet, then you need to unscrew all the others and calcine them on gas. If they are flooded again, you need to look for the cause elsewhere. 5) Some engines with an injection system cannot start in cold weather with an engine temperature sensor connected. This is probably a feature of the firmware or something else. You remove the temperature sensor chip, the engine starts with difficulty, but it starts. When connected - no. This feature can confuse anyone: there is a spark, and the spark plugs are wet, and the belt has not slipped, but the car will not start. I removed the temperature sensor and it started. This situation is, of course, the exception rather than the rule, but it is better for the owner of the nine to know about it. 6) Also a rare situation, but it happens. Shedding of the catalyst in the car muffler. In accordance with environmental requirements, a catalyst is installed in the Lada muffler with an injector, which reduces emissions of harmful gases into the atmosphere. If this catalyst crumbles inside the muffler, then the exhaust gases will be difficult to exhaust and the engine will either not start at all or will stall. To eliminate this point, you simply need to loosen the fastening clamp between the catalyst and the muffler so that the exhaust gases exit after the resonator.

The problems described above are the most common reasons why the VAZ 2108 2109 21099 injector engine does not start, but you should remember that there are special cases in which only a service station can help.

HBO for cars

A hot engine can also cause a breakdown in the case of an installed gas system. Since driving on gas has recently become profitable, many drivers switched to this type of fuel, however, they did not take into account some of the nuances of the new system. In hot weather, gas expands more, which leads to increased pressure inside the system and often causes damage. This is why it is bad to drive on gas in the heat.

The result is an extremely dangerous situation. To avoid this, try not to fill the tank to full gas in the summer, this will reduce the pressure in the system and the risk of breakdown. If a similar problem occurs, it is recommended to let the car cool down and then visit a service station. You should not repair the gas system yourself; the equipment should be adjusted by a specialist.

How to quickly resolve problems that have arisen?

Lack of gasoline in the carburetor

When the carburetor is hot, the VAZ 2107 carburetor does not start well, and difficulties arise in the flow of gasoline into the carburetor. To check this version, remove the hose from the fuel outlet fitting on the carburetor, press the fuel supply lever in the fuel pump. There will be a significant amount of fuel coming out of the hose.

When hot, the VAZ 2107 carburetor does not start well; if you get a small stream of fuel or it is missing, then there is a malfunction of the fuel pump or another power component. As a result, we get a cessation of movement of the fuel liquid.

Fuel system filter clogged

We remove the special filter, unscrew the plug, completely clean it and install it in place. We also clean the seat for the filter system in the carburetor cover.

The valve or EPH system is not functioning

The VAZ 2107 carburetor does not start well when it is hot, with the engine turned off, try to start the ignition and try to remove and fix the tip of the wire from the valve passage. You will hear a beep. If it does not occur, then fasten the parts of the wire plus the battery and the valve passage. The sound signal does not occur, then change the valve. If it occurs, check the EPH system. You also need to monitor the actual presence and performance of the dense rubber ring located on the valve.

The VAZ 2107 carburetor does not start well when hot on carburetors with an idle fuel jet holder - remove the holder and release the jet from it. We thoroughly clean the part and completely fix it in place.

“Leaking” air into the carburetor

The carburetor does not start on a hot VAZ 2107, inspect all the elements attached to the carburetor. They sometimes come off the fittings or are damaged.

Contamination of two types of jets has occurred - the central system for distributing flammable liquid in the carburetor.

The carburetor will not start on a hot VAZ 2107, so there will be no valuable elements in the flammable liquid. On carburetors 2105-07, you need to remove the carburetor cover, completely remove the fuel nozzle of the first chamber, and clean it with a thin metal object. Then clean it using an air stream and return it to its place.

Also try to clean other components of the main carburetor metering systems. On carburetors 2108-21083, remove the cover and unscrew the air jet together with the emulsion tube. Using a slotted screwdriver, remove the fuel nozzle located at the bottom of the emulsion well. We clean and dry it, not forgetting about the emulsion tube and emulsion well.

The carburetor needle valve has become unusable

The carburetor overflows and moisture forms on the spark plugs. Replace the bad unit, as a small fuel leak can cause severe obstructions. You can see streaks of gasoline on the carburetor and smell its strong aroma. Remove the carburetor cover, determine whether the bracket is jamming into the float on its axis, whether the functioning of the float behind the walls of the float space is being disrupted, or whether the body is turning away from the needle valve. You can start the engine, so you need to turn it with the starter for a long time with a strong influence on the gas pedal. After a strong intake of air into the special combustion chambers, the candles will dry out and the fuel can be used for its intended purpose.

Try to monitor the integrity of the needle valve of the special chamber.

Obstacles have appeared in controlling the level of flammable liquid in a specific carburetor chamber.

Under the circumstances presented, the flammable liquid is saturated. As a result, the level of the fuel mixture in a special chamber increases. Try to adjust it.

Before you begin to find out the source of the problem that provokes the situation that a hot carburetor engine does not function, try to control the ignition, since the signs of its failure are similar to the signs of ignition failure.

I sincerely recommend using this information to eliminate the cause of deficiencies in the carburetor for its normal operation.

Engines with carburetor

A warm carburetor engine may have difficulty starting due to a number of design features of the carburetor itself. Also, if you have this device, you must take into account the fact that gasoline has certain properties that additionally affect the start of a hot engine with a carburetor.

A carburetor car may not start hot due to the fact that when the internal combustion engine is running, the carburetor is cooled by air that passes through this mixture formation device. It turns out that while the engine is running, the carburetor does not heat up as much as the engine. After stopping the engine, cooling stops, and the carburetor heats up more in the engine compartment.

With such heating, gasoline, which tends to evaporate under the influence of high temperature, simply evaporates from the float chamber. The result is the formation of air pockets in the fuel supply system, which complicate the subsequent “hot” start of the engine. Also, after an unsuccessful attempt to start a hot engine, it is necessary to pause, since during repeated tests, too rich a mixture enters the cylinders. In other words, the spark plugs are flooded with gasoline.

To avoid flooding of spark plugs when trying to start a hot engine, it is necessary to deplete the fuel-air mixture (bleed the cylinders for 5 to 10 seconds).

To do this, the gas pedal is depressed by ½ stroke or to the floor on some internal combustion engines. The pedal is pressed only once. With several presses of the accelerator, the risk of completely filling the spark plugs increases even more. As for AvtoVAZ products, the fuel pump is also a common reason why a hot engine will not start. The fact is that simple overheating causes malfunctions of the device.

Kalina won't start, the starter turns

Possible malfunction

Injection petrol and diesel engine

Electronic injection systems have a number of components. A malfunction of any element can result in injection gasoline and diesel engines having difficulty starting when hot. The list of possible causes of difficulty starting a hot engine includes:

• coolant temperature sensor;
• mass air flow sensor (MAF, flow meter);
• fuel rail pressure regulator;
• crankshaft position sensor;
• idle air control (IAC);
• problems with the fuel pump;
• fuel injection pump malfunctions in a diesel engine;
• injection nozzles;
• high-voltage armored wires;
• ignition coil, etc.

Sensor malfunctions must be identified using diagnostic equipment. The simplest solutions include a multimeter, which measures the resistance of an electronic device.

We also recommend reading the article about why gears are difficult to engage when the engine is running. From this article you will learn about the main reasons causing difficulty in switching on speeds.

Failure of the coolant temperature sensor will mean that an incorrect signal is sent to the engine ECU, as a result of which the optimal fuel supply for starting a hot engine is disrupted. Violation of the tightness of the injection nozzles leads to the fact that the injectors pass gasoline not at the time of fuel injection, but when the nozzle is closed. The result is a strong enrichment of the fuel-air mixture, flooded spark plugs, etc. The problem is partially reminiscent of the situation with the carburetor. To start a hot engine in this case, it is also necessary to purge by partially or fully opening the throttle. Additionally, it is necessary to check the injector O-rings for integrity and tightness.

Malfunctions of the power system that prevent the VAZ 2107 engine from starting

1. Gasoline pump

Experts believe that the main defects affecting the performance of the fuel pump are:

• Formation of a vacuum “plug” in the gas tank.
• Blockages, including due to damage to the diaphragm.
• Icing of the filter mesh and the formation of an ice plug from condensate (when operating at low temperatures).

Measures to eliminate the above reasons are as follows:

• Blowing out individual sections of the supply lines (for example, between the fuel filter and the tank) with compressed air.
• Warming up frozen areas and removing condensate from the fuel supply system.
• Cleaning the fuel pump valve and filter mesh from dirt.
• Replacing the diaphragm.