A car engine may not start well when cold under various conditions. Sometimes it happens that the car has been standing in the garage or in the open air for a long time. A situation may also arise when the engine has been running, then it has cooled down, and it will not start again.

Starting problems that occur on a cold engine may not appear at all during a hot start. With a cold start, it is also important to consider the ambient temperature at which you are trying to start the car. During cold periods, some elements simply freeze, so starting the engine in such conditions is simply impossible.

The main causes of poor cold start

There are several main reasons why starting a cold engine will be difficult or even impossible. To understand the cause of the malfunction, it is necessary to conduct a thorough diagnosis and localize the breakdown. First you need to check the battery, it is possible that it is completely discharged. Next, it is necessary and rotates the motor at the same speed. If you refueled with low-quality gasoline, then this can also lead to the fact that your car engine will not start well when it is cold.

Fuel supply problems.

Cold starting problems appear when there is no combustible mixture (fuel) supply. Fuel can be supplied in very small quantities, or in very large quantities. When there is too much of it, the spark plugs will be flooded and fail. In some cases, the fuel may be supplied normally, but the ignition of the mixture in the engine cylinders themselves does not occur or does not occur in a timely manner.

Checking the fuel system must begin with an exhaust check. If, when the engine is rotated by the starter, a small amount of smoke comes out of the exhaust pipe, this indicates that ignition processes are taking place and fuel is being supplied to the corresponding engine cylinders.

After that, you need to check the spark plugs. To do this, take the appropriate key and simply unscrew them. If they are filled with fuel, then this indicates an excess of fuel in the cylinders. This can happen as a result of injector leakage or ignition failure. If the candle is completely dry, then this indicates that no fuel is supplied to the cylinders at all. It is necessary to check the performance (presence of a spark) of all candles.

Poor supply of the fuel mixture to the cylinders may be due to clogged fine and coarse filters. A kind of coating may form on the injector nozzles, which prevents the normal flow of gasoline. The fuel supply may also decrease due to breakdowns of the fuel pump. In most cases, the fuel pump simply does not create the desired pressure. To eliminate this malfunction, it will need to be completely removed and disassembled to eliminate the causes.

It will also be necessary to check all fuel lines for cracks and other damage through which air can enter the fuel system. This can be easily determined by the places of leakage.

Problems with electronic sensors.

Modern gasoline vehicles are equipped with fuel injection systems that inject fuel electronically. These systems are equipped with a variety of special sensors. If a failure occurs with one of these sensors, then the corresponding signals will not be sent to the main control unit, as a result of which the engine will no longer start normally.

First of all, it will be necessary to check the following three sensors:

• DPRV sensor, which indicates the correct location of the camshaft;
• TPS sensor. It gives signals about the main positions of the damper;
• DMRV sensor, which indicates the air flow in the system.

Ignition problems

When malfunctions appear in the ignition distributor, this can lead to the fact that the engine will not start well when cold. The essence of this malfunction is that the starter rotates the engine, but seizing does not occur and the fuel in the engine cylinders does not ignite.

It is very important to correctly set the ignition timing, for each brand of car, this angle will have its own meaning. It is also worth checking the condition of the drive and timing belt, as well as adjusting the valve timing, if any. To check you will need special tools and fixtures.

Hard start when cold :pengine compression problems

As a result of long-term operation of the engine, some of its elements may become unusable, as a result of which the compression in the cylinders will begin to fall. An engine with low compression starts very badly, because all the gaps between the main parts in the cylinders increase significantly. This leads to the fact that the necessary pressure is not formed in the combustion chamber, which is necessary for starting.

The injector device, thanks to the ECU and various sensors, is more complex, and therefore there are more vulnerable links in such an engine compared to a carburetor engine. It's harder to find the source of the problem. It happens that a car with an injector does not start well or does not start at all (if the carburetor does not start, and also if the diesel engine does not start). What, in this case, should be checked first of all?

GASOLINE PUMP

From a serviceable, working fuel pump comes a characteristic sound. If there is a suspicion of its malfunction, then this suspicion can be confirmed or refuted by checking the spark plugs: if they are dry, then the problem is in the fuel pump. What went wrong in the fuel pump - wires, fuse or relay - remains to be seen. How to check the fuel pump

First, we check the integrity of the wires suitable for the fuel pump, whether they are oxidized. To do this, other new wires must be connected directly from the battery to the fuel pump. If the fuel pump works fine with them, then you need to change the regular wires.

If everything is in good condition - the fuse, relay and wires of the fuel pump, but the latter, nevertheless, does not work, it remains to be concluded that the fuel pump itself has become unusable and needs to be replaced (replacing the fuel pump with a VAZ). Again, to check the health of the fuel pump, you need to connect it to the battery directly, or, instead, connect a working fuel pump.

Video: The VAZ 2110 fuel pump (injector) does not work, we are looking for a reason

RAIL PRESSURE

It happens that the injector does not start, due to the lack of sufficient pressure in the fuel rail (normally, it should not fall below 2.8 kg / cm²). This can happen if the fuel pressure regulator is malfunctioning.

A dirty fuel filter also interferes with normal fuel rail pressure. Fuel and air filters should be changed more often.

CRANKSHAFT SENSOR

This is one single sensor, in the event of a malfunction of which the engine will not start at all. If any other sensors malfunction, the operation of the injection engine only worsens. How to check the crankshaft sensor

NOZZLES

As you know, injectors become unusable one at a time, and nothing terrible will happen to the engine if only one injector does not function. Let it be worse (there will be tripling), but the engine will work.

To calculate a faulty injector, you need to start the engine and touch the exhaust manifold pipes. The pipe that turns out to be colder than the others will indicate the cylinder that is not working. By the way, the cylinder may not work not only due to the fault of the nozzle, but also due to the fault of a candle that has failed. In this regard, if a faulty cylinder is detected, then its spark plug must be checked.

IGNITION SYSTEM

In an injection engine, check the ignition module and spark plugs.

If the injection engine does not start, the cause may be an unregulated ignition. There is a very simple way to install the ignition.

GAS DISTRIBUTION SYSTEM

Misadjusted valves, by themselves, usually do not cause the engine to not start at all. If the valve clearances are off, the engine will start, but it will just work worse from this. A serious problem for starting the engine, unadjusted valves can be, in combination with some other malfunction. If the problems are not one, but several (including incorrect valve clearances), then the engine may not start. So adjusting the valve clearances can help fix this problem (how to adjust the valves).

The engine also does not start if a mistake is made when installing the timing belt (how to set the timing marks).

Perhaps these articles can also help you solve the problem:

Video: Why an injection car does not start

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Modern cars are gradually moving from the concept of mechanisms to the concept of organisms. This is a complex system that needs to meet ideal working conditions. High engine power, squeezing everything out of technology, and other features of the modern automotive industry indicate that modern cars must receive maximum care in order to work for a long time. One of the common problems that occurs when the machine is not properly cared for is poor starting of the engine after it has warmed up. This means that if you park for a few minutes near the store, you will not be able to start the engine normally. The problem lies in two possible breakdowns, but there are also extraordinary cases. Today we will deal with the most common tasks in this case, and also talk about private options for problems.

It should be noted that the symptoms of poor hot starting can manifest themselves in different ways. One car generally refuses to start until a certain cooling of the engine. Another power unit starts only on the third or fourth attempt, and the third just has to be twisted for a long time to start. In any case, whatever happens to your car in this context, you need to find the problem and be sure to fix it. This task is a harbinger of more serious breakdowns, the elimination of which will cost you much more money. So let's see why the car does not start well when hot.

Bad fuel or additives in the fuel mixture

Poor quality gasoline or diesel fuel is one of the most common variants of such a problem. But in this case, you can conduct an experiment that will show the true problem of your car. The fact is that low-quality fuel with a poor start on a hot one will have an even more unpleasant effect when starting the engine on a cold one. Therefore, it is enough to cool the car, wait for the engine to return to normal and start it. Also, there may be the following problems with fuel:

• gasoline or diesel fuel may contain an additive that your engine does not accept;
• diesel fuel has frozen and acquired a jelly-like form, which is difficult to pump;
• solid particles are present in gasoline, the filters are clogged, and it is difficult for the pump to pump the right amount of fuel;
• the settings of the engine control system and air supply have gone astray, one of the valves may have broken;
• idle valve, as well as DMRV (mass air flow sensor) can cause such problems;
• just a functional feature of carburetor engines - a very hot unit does not start well.

In the case of carburetor units, everything is quite simple - the engine itself does not start very well when hot. This is due to the fact that after stopping the car with a hot engine, the temperature in the carburetor area is quite high. Gasoline under the influence of temperature quickly evaporates and fills all the chambers and tubes of the carburetor in a state of gas. But the float chamber remains empty. If you decide to start the engine within five minutes of stopping it, you will have difficulty starting because there is no liquid fuel in the chambers. Problems are solved by manual pumping or several attempts to start the power unit. However, there can be no such problem on injectors, since fuel is supplied directly from the line. Therefore, it is worth looking for other troubles in the fuel supply system.

Too rich or lean mixture - air flow sensor

Above, we mentioned that problems with starting a car can happen due to the failure of the DMRV - the mass air flow sensor. This element of the car is one of the most sensitive to environmental influences, so they often talk about its breakdown. If starting the engine on a hot one is very difficult, check the performance of this mechanism. Also, this breakdown may be accompanied by the following factors:

• dips when pressing the gas pedal, lack of traction at some points;
• power reduction or vice versa - an inexplicable increase in the potential of the unit;
• complication of starting the engine and periodic moments of flooding;
• explosions inside the exhaust system when the gas pedal is pressed sharply;
• unstable speed due to periodic changes in the enrichment of the mixture.

The fuel mixture of gasoline and air must have a certain consistency, which is formed by mass air flow sensors and some other parts of the electrical and electronic system of your car. If these parts are faulty, you will have to change them and test the car, adjust the operation of new equipment.

An overheated fuel pump is a common problem in domestic cars.

The fuel pump cools naturally by pumping cool liquid from the fuel tank. But in extreme heat, this liquid cannot be cool in any way, so the fuel pump overheats. This is an unpleasant incident, which is fraught with the inability to start the car on a hot one. The car may simply stall on the road and not start either from the pusher or by starting by turning the ignition key. There are several ways to fix this problem:

• take a wet and cold rag, attach it to the fuel pump and periodically moisten it with cold water, cooling;
• open the hood and put the car in the shade, let all parts of the power unit cool down normally;
• change the fuel pump if you have the opportunity to quickly get another part of the fuel system;
• just wait until the temperature of the fuel pump returns to normal, and continue to operate the car;
• an overheated fuel pump is unlikely to work normally, so it's better to just change it.

Such a problem can cause the failure of important parts of the fuel pump, because when it overheats, it stops working for a reason. If nothing changes after the car cools down, then you will have to replace the fuel pump. But usually the car starts up on a cold one, after which it still drives for several days without any problems.

Problems of poor starting of cars on gas in warm weather

Many drivers, after reading all the above arguments, will say that they are invalid for their car, as there is a gas installation. It became profitable to drive on gas a few years ago, so HBO settled under the hood of many motorists. If in hot weather your car stalls and does not start when hot, you will have to let it cool completely, then start it and go straight to the service station. It is better not to joke with this question for a number of reasons:

• due to high temperatures, certain seals could deteriorate and gas hoses could open;
• your vehicle's fuel system working fluid may be leaking for other reasons;
• expansion of gas in the tank at high temperature creates a certain pressure in the system;
• it is better not to fill a full tank of gas in hot weather, limiting yourself to partial refueling;
• it makes sense to consult with a specialist if such a problem began to occur on your car.

You shouldn’t joke with gas-powered cars at all - even the latest generation of HBO carries a certain danger. If your car on gas does not start hot, you should involve a specialist in solving this problem. So you can easily get the necessary features of the operation of the power unit, and you will not expose yourself to the danger of incorrect operation of the fuel supply system. We offer a look at the explanations of experts about a poor start in the hot season:

Summing up

High-quality fuel supply systems rarely fail, so even in the hottest weather, hot cars start up without problems. But in the event of such a nuisance, the driver is unlikely to be able to fix it on his own. There are too many factors of possible breakdowns that are difficult to check without special knowledge and certain tools. Therefore, it is best to show the car to specialists and get a very specific answer to your problem. Most likely, the repair of this problem will involve minor sensor replacements and not too expensive procedures.

Therefore, in most cases, it is the appeal to the masters that will be the key to a successful trip on your car in any weather. You need to contact the service station as soon as the manifestations of poor starting of the car began to appear in your case. The sooner you arrive at the master, the easier it will be for him to help you. Yes, and the cost of repairs increases with the delay of the visit to the master. Have you had a similar situation in the practice of driving a car?

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 start of the engine, increase in its dynamic performance;
• low emission of harmful substances;
• saving fuel consumption due to metered injection;
• does not need prolonged warming up during low temperature conditions;
• the possibility of programming the electronic control system depending on the manner and style of driving;

The principle of the engine

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

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

DMRV 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 voltage supply is provided by two transistors located in the control unit housing.

Further, when the ignition of the working mixture occurred, the stroke of the cylinder began 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 composition of the mixture, sets the nozzle opening time. If there is a lack of oxygen at open throttle, the ECU opens the idle speed control slightly.

Causes of improper operation of the injection engine

The reason that the injection engine does not start well on a cold one can be several. The main one is a malfunction of the sensors.. If one of the modules fails, the electronic control unit receives incorrect data, from which the engine starts poorly and runs intermittently.

Common causes of poor starting of an injection engine.

Air leak

Occurs when there is a leak in the parts of the air supply system. The mass flow sensor cannot capture some of the air entering the engine, which is why a lean mixture is supplied to the combustion chamber. This results in erratic idling and a cold start problem for the injection engine.

During warm-up or choke operation, this problem is almost not noticeable, but when the engine warms up to operating temperature, interruptions in idling become more noticeable.

Air leakage can occur for the following reasons:

• violation of the tight connection in the vacuum amplifier;
• mechanical damage to the fasteners and air supply hose to the intake manifold, pipelines of the pressure regulator and the crankcase ventilation system;
• damage to the gaskets between the cylinder block and the intake manifold.

The cause of air leakage can be determined by visual inspection. If the fault significantly affects idling and starting a cold injection engine, before repair is carried out, you can increase the speed by disconnecting the plug from the mass flow sensor. Such an action will lead to a significant increase in fuel consumption, so it is not recommended to delay the repair.

With a slight suction, it is enough to adjust the fuel supply using the L-probe device.

The main indicators of the fuel and air mixture

Mass of fuel, kg.	Air mass, kg	Excess air coefficient	Mixture names	combustion rate	Engine power	Application mode
>1:6			The mixture is not flammable
1:6	1:11	0,41 - 0,75	rich	reduced	reduced	Cold start
1:11	1:13,7	0,75 - 0,92	Enriched	Maximum	Maximum
1:13,7	1:15,4	0,92 - 1,05	Normal	Medium	Medium	Used with exhaust gas converter
1:14,7		1	Stoichiometric	Medium	Medium	Used with a neutralizer
1:15,4	1:17,7	1,05 - 1,2	depleted	reduced
1:17,7	1:20	1,2 - 1,36	poor	Dramatically reduced	Loss of power	Not applicable
		>1,36	The mixture is not flammable

Mass flow sensor failure

Incorrect operation or breakdown of the sensor leads to an instant stop of the motor after starting. When this happens, you need to disconnect the sensor and restart the car. If the engine runs without interruption, then the flow sensor needs to be replaced.

Faulty temperature sensor

When the central control unit does not receive signals from the coolant temperature module, it takes a value of zero. The built-in program prepares the working mixture according to this temperature, which leads to the following consequences:

• the injector engine does not start well on a cold one;
• detonation at low speeds.

The module is not repairable, so the defective part is replaced with a new one.

Faulty ignition

You can fix the problem by setting the spark timing, adjusting the position of the timing belt and replacing damaged parts.

Table of indicators of resistance of the temperature sensor from the temperature of the cooling medium.

A failure in the fuel regulator causes fuel to leak into the combustion chamber through the intake manifold pipes. As a result, an enriched mixture enters the engine, which leads to severe clogging of the spark plugs. This malfunction significantly affects the cold start of the injection type engine.

Camshaft phase sensor

The breakdown leads to the transition of the fuel supply mechanism in emergency mode, in which the nozzle supplies fuel twice as much as necessary.

Reasons for replacing the module:

• difficult start;
• interruptions in the vehicle self-diagnosis system;
• significant increase in fuel consumption;
• smoke in the exhaust mechanism.
• difficult cold start of the injection engine

You can fix the problem by self-adjusting the position of the sensor or contact the service center.

Stepper motor. A malfunction of this element does not allow idling (the engine does not have enough air). The vehicle can be driven if the throttle pedal is kept idling when the load is removed. If you have a DST-2M or DST-8 tester, set the idle speed on a warm engine to 900 - 1000 rpm using a stepper motor (if it is still controlled). Remove the connector from the stepper motor.

In this state, you can safely drive a car without experiencing difficulties if the outside temperature is up to -5˚. In cold weather down to -15˚, starting a cold engine will be difficult, but using the same throttle pedal, you can warm up the engine (using the pedal like a choke in a carburetor). After -18˚, starting the engine will become problematic - it will be difficult to provide a given air flow when the system switches from starting mode to warm-up mode. The engine will stall, and after 2-3 such attempts, the candles will flood.

Air suction. A leak in the air intake system downstream of the mass flow sensor causes erratic idling. The mass flow sensor "does not see" part of the air entering the engine, so the system incorrectly calculates the fuel supply (low fuel - lean mixture). On a cold engine and slight suction, this effect may not be noticeable, but as it warms up, idling instability becomes more pronounced and can lead to engine stalling. The reasons for suction can be:

Rupture (violation of fasteners) of any of the hoses that have access to the intake manifold (from a small tube to the pressure regulator to large crankcase ventilation tubes);

Violation of the tightness of the vacuum amplifier;

Damage to the gasket between intake manifold and engine, etc. Basically, the causes of air leakage can be established visually. If air leaks prevent the engine from idling, remove the connector from the mass air flow sensor. At the same time, the idle speed will increase, but the car will be able to reach the destination. If, at the same time, the stepper motor is set to an acceptable idle position, then there will be less inconvenience in driving the car. A small leak in the air supply system may not lead to noticeable changes in the driving characteristics of a vehicle equipped with L-probe fuel control systems, but engine efficiency will drop.

Mass flow sensor failure. This defect leads to the stalling of the car after starting. If the engine stalls after starting and you don't know what's wrong, try starting the engine with the mass flow sensor connector removed. If the engine runs after that, then it is likely that the sensor is out of order.

The temperature sensor is defective. At temperatures below -8°C, the engine will not start. In warm weather, you can maintain idling after starting by slightly depressing the throttle pedal. In the standby mode of the system, if the temperature sensor fails, the value of the coolant temperature is set according to the time the engine is running. Starting a hot engine with a temperature sensor failure will have its own difficulties.

Faulty throttle assembly. A hot engine stalls after starting - there is no transition to idle mode. Helps pressing the throttle immediately after starting the engine. You can bend the tongue-limiter of the closed position of the throttle, but so that the throttle position sensor reads 0 when the pedal is released (checked by a tester).

Faulty ignition. There are no recipes here, except to replace all the faulty elements of the ignition system.

Faulty fuel regulator. The fuel regulator is leaking, additional fuel enters the intake manifold through the air tube, the engine floods. In this situation, you should remove the tube from the intake manifold, the engine should run stably.

In this article, we will try to find out: why the car does not start when cold, hot, or simply stalls after it warms up. What needs to be done to fix these problems, as well as discuss other options for improper engine operation.

Cold engine won't start

As a rule, such a nuisance occurs in the winter, when you absolutely do not expect trouble from your car.

The most common reason is the battery. Many car owners know that batteries cannot be repaired and their life is limited, but it is unlikely that anyone will think about it until a spent battery makes itself felt. Most often this happens in cold weather.

But the reason why the engine does not start on a cold one may be other reasons:

• the fuel pump has worn out, and for this reason it is not able to create the necessary pressure in the fuel system in order to start the engine on a cold one;
• the air mixture purification filter is so dirty that it does not pass the required amount of air;
• poor quality fuel that can lead to clogging of the vehicle's fuel system. Do not pour everything into the tank;
• the cause may be a carburetor in which the throttle has stopped working correctly or the idle speed valve has failed;
• overcooling of the engine in frosty weather.

In order to ensure the free start of the engine in cold weather, experts recommend adhering to the following rules:

• maintain all electrical circuits in good condition;
• the battery must be in good condition, charged, and have the appropriate capacity;
• refuel with fuel appropriate for the season at proven gas stations that have fuel quality certificates;
• there must always be a certain level of fuel in the tank;
• the ideal option is to keep the car in a warm garage;
• the engine must have the “correct” oil for the season;
• there should be a cable in the trunk of the car, it is also desirable to have cables to start the engine from a donor battery, so that at the right time you can “light up from a neighbor”;
• equip the car with an autostart system.

Hot engine won't start?

Another common problem, and the happy owners of domestic models know firsthand about it - the car does not start hot. Much has already been said about the poor performance of the fuel pump on VAZ models. This happens especially often in extreme heat and when standing in traffic for a long time.

But owners of cars with diesel and injection gasoline engines may also face trouble when the car does not start. The reasons why the engine does not start well are just as varied:

1. From the sensor that monitors the temperature of the coolant, distorted information is received, which leads to an incorrect supply of the combustible mixture.
2. The tightness of the fuel injectors is broken, as a result of which the fuel mixture is re-enriched and the engine does not start.
3. In diesel engines, the injection pump (high pressure fuel pump) does not work properly. It is worth thinking about replacing the plunger pair or bushings.
4. It is recommended to check the operation of the crankshaft position and air flow sensors.
5. Check idle air and fuel line pressure regulators.
6. Poor condition of armored wires.
7. Incorrect operation of the ignition module.

Hot engine stalls

The car started up, it works normally, but as soon as the sensor registers the operating temperature, the engine stalls when heated. Of course, this is bad and incomprehensible.

Here are a few reasons for this strange behavior of the motor, as well as ways to solve the problem:

1. The car worked fine, but as soon as we drove away from the gas station, it began to twitch when the gas pedal was pressed, the engine stalled or started poorly. Everything is simple - low-quality fuel. Drain the defective fuel, purge the fuel system, replace the fuel filter. In addition, the spark plugs should also be replaced (by the way, this is another strong argument in favor of always taking a check at the gas station, then there will be someone to file a claim with).
2. The fuel is normal, the car used to work, but it stopped on a hot engine, stalls - it's time to replace the fuel filter.
3. The same thing can happen if the air filter is clogged - the engine simply has nothing to "breathe" when heated, the air mixture is enriched with fuel and the engine stalls. Change the air filter.
4. We return to the fuel pump - a typical picture for VAZ engines: the engine stalls when hot. It can be repaired, but it is better to replace it with a new one.
5. The alternator stopped charging the battery. In the best case, you can get by with tightening the alternator drive belt. Did not help? So the generator is out of order. But with such a breakdown, it will no longer be possible to start the car again - the battery will be landed.

Conclusion

On modern cars, numerous sensors are responsible for the correct operation of the engine in any weather. And if you don’t know where they are, then it’s time to contact the specialists at the service center.

The engine is considered cold until it is first started.

Starting the engine when it is cold is difficult due to the fact that it needs an enriched mixture to start it, which will be difficult to ignite if there are any problems with the power plant.

If the above sensors fail, the engine ECU receives incorrect commands, which also affects the poor start of a cold engine.

Replace faulty sensors, after making sure that there are no problems in their power circuit.

Throttle assembly

Since the throttle valve is involved in the correct formation of the fuel mixture, if it malfunctions, starting the engine is difficult, as the ratio of air and fuel components changes relative to what is necessary for stable ignition of the mixture.

Dismantle, clean and flush the assembly, not forgetting to “register” it after installation.

Air leak

When air leaks appear in the starting system, the mixture becomes leaner and starting a cold engine becomes problematic, since this requires the richest possible mixture composition.

Find and fix the air leak.

Carburetor

Poor starting of a cold engine equipped with a carburetor is caused by a misalignment of its starting system or a violation of the level in the float chamber. Make the necessary adjustments to the carburetor.

nozzles

On motors with an injector, a poor start can be caused by a malfunction when they are either clogged with dirt, the spray pattern is broken, or they "pour". Also, the cause of a poor start may lie in insufficient pressure in the fuel rail.

The nozzles need to be dismantled and checked on a special stand.

Fuel

Often the reason may be the low quality of the fuel or the presence of a large number of various additives in it to raise its octane number, which adversely affects the condition of the spark plugs.

For diesel engines, the quality of fuel is generally critical, especially in winter, when the solarium turns into a gel or porridge, which makes it impossible to ignite.

Refuel the car only at proven gas stations.

Fuel system

The condition of the fuel supply system directly affects the start of a cold engine, where the following malfunctions may be present:

Low performance of the fuel pump or its failure;

Unadjusted fuel injectors;

Failure in the operation of the injection pump;

Glow plug failure.

For a stable start of a cold engine, it is recommended to periodically undergo a comprehensive diagnosis of the engine and all its systems.

VW vehicles are mainly equipped with Bosch Motronic engine management systems versions 2 7 and 2 9. Mono-Jetronic, Mono-Motronic121,123 13 KE-Motronic11, 12 and KE-Jetronic

Driving a road train under various road conditions

General rules for driving a road train

It is much more difficult to transport goods on road trains than on conventional trucks, therefore, in order to work on a road train, the driver must carefully study the device of this vehicle, its purpose, the nature of possible malfunctions and methods for their elimination, as well as know the overall dimensions and minimum turning radius of the road train.

Checking the operation of the fuel pump of injection engines

When the ignition key is turned on, the main ECM relay and the fuel pump relay are turned on.

The characteristic sound of a running pump can be the first sign of its operation.

Bad start of the injection engine

stepper motor

A malfunction of this element does not allow idling (the engine does not have enough air).

The vehicle can be driven if the throttle pedal is kept idling when the load is removed.

Idling injection engine

The idling mode is determined by the engine management system with the following:

Throttle closed

Increased fuel consumption in injection engines

High fuel consumption during the operation of a vehicle equipped with an ECM is usually attributed to electronic malfunctions.

Especially if the exact same car consumes fuel very economically.

Diagnostics of injection engines with malfunctions

Consider the main faults:

1 - when the engine does not start;

2 - when the operation of the engine does not meet operational requirements.

Diagnostics of injection cars VAZ without malfunctions

To diagnose the control system of the ECU of such cars, only a diagnostic tester and a gas analyzer are enough.

We check the errors on the tester, which were memorized during the operation of cars. For ECU Mikas, if there were fault codes:

Once again about the diagnosis of VAZ using instruments

Some subtleties that you should pay attention to when carrying out diagnostics in order to exclude the search for a faulty part by trial replacement

ECU VAZ and GAZ with 55-pin connectors. Contact Description

The car pulls poorly;

Interruptions in work

The immobilizer does not work well (it is not always possible to start the engine)

Along with high efficiency and relative reliability, injection cars have one unpleasant minus - the complexity of repair. It happens that the injector stops starting in an instant, and it becomes difficult to do something with it. Well, if it is possible to call a tow truck or show the car to a professional, but what about those motorists who are left alone with the problem? Let's figure it out, having examined in detail all the reasons why the injector does not start well or refuses to do it at all, as well as how to "cure" such a malfunction.

Possible malfunctions

No matter how trite it may sound, but if the injector does not start, then something is out of order. The success and speed of repair depends on how quickly and efficiently it will be possible to identify the problem link in the car design. For a better understanding of the whole essence of repair measures, it will not be superfluous to pay attention to potential breakdowns. The basic list of the latter is as follows:

• Malfunctions directly injector. In the event of a breakdown of this kind, as a rule, the car will not start both cold and hot. On top of that, the injector indicator is constantly on on the dashboard or on-board computer, signaling a malfunction. Much less often, when the indicator is on, the engine runs, but in this case, the car does not start well and is extremely unstable. It is worth noting that nozzles are most often clogged in the injector or the computer burns out, so it is these nodes that it is advisable to check first;
• Breakdown of the ignition system. Here the list of possible faults is quite large. Often candles suffer, which are simply flooded. With such a breakdown, the car starts and immediately stalls, but in the future it even stops “grabbing”. Other components of the ignition system suffer much less frequently (coil, module, distributor, crankshaft sensor, etc.);
• Incorrect operation of the fuel system. In this aspect, injection engines most often suffer on three fronts:
  1. The fuel filters are clogged (the car “picks up”, but does not start, if the engine is running, it is extremely unstable);
  2. The fuel pump is faulty (its characteristic sound of operation is absent when the ignition key is turned, the injector itself simply does not start both cold and hot, the starter turns).
• There is insufficient pressure in the fuel system (the engine is reluctant to start both cold and hot, but if it works, it functions unstably);
• Engine problems. Perhaps the widest range of possible faults. Often the cause lies in weak compression or improperly adjusted valves. In any case, with a “motor” start-up problem, high-quality engine diagnostics are required, otherwise it will be very difficult to determine the cause of the malfunction.

In addition to the breakdowns described above that can break the operation of the injector, the problem may lie in more banal things. An example of this is a weak battery or lack of fuel in the tank. Considering just such incidents, before repairing a car, it is extremely important to exclude the possibility of their manifestation, so as not to waste extra time and nerves.

The procedure for returning the car to "life"

Let's say that you specifically found yourself in circumstances where the injection engine does not start well or refuses to do it at all. There is no need to delay in such a situation - it is advisable to immediately begin resuscitation procedures. If you deal with the exact reason why the car does not start well, there is no time, then you should quickly carry out the following algorithm of actions:

1. First of all, we check the presence of gasoline and battery charge. Is there something missing? We pour, we smoke. Let's try to start. If there is no result, proceed to the next step;
2. Next, we quickly analyze the circumstances under which the car malfunctions. If it starts up hot for a long time or poorly, first of all we check the spark plugs for overheating (light soot) and the functioning of the fuel system. Otherwise, when the machine fails both cold and hot, a more integrated approach is required. As a rule, the following procedures are enough: checking candles, wiring the ignition system, evaluating the operation of the injector and fuel system;
3. Note that most motorists manage to solve the problem, so to speak, with little bloodshed, that is, through the implementation of the actions described above. If it was you who were not among 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 drive 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, ignition devices. If there are any malfunctions, they must, of course, be eliminated.

In general, there are no particular difficulties in repairing a non-starting injector. The main thing in the process of such work is to act competently, in accordance with the procedure described above and possible malfunctions of the car.

Injector failure prevention

Why the injection engine does not start and how to fix possible problems is now known to all readers of our resource. However, it is better to avoid such breakdowns, so let's pay attention to ordinary procedures that, if carried out systematically, will help minimize the risks of all malfunctions. The most simple but effective prevention consists of the following measures:

• First, refuel exclusively at proven gas stations and only with high-quality fuel. Remember that most fuel system and engine malfunctions are provoked by dirty gasoline;
• Secondly, change all consumables on time and only with quality products. The most important are periodic replacements of various filters and engine oil;
• Thirdly, periodically check the main components of the machine for stability. The list of the latter, of course, includes an injector, elements of the fuel system, ignition and engine;
• Fourth, never neglect the scheduled diagnostics of the machine at the service station. Surprisingly, even a delay of a couple of hundred kilometers can cause serious damage, which before that could be eliminated with very simple actions;
• And fifth, always properly operate the car. That is, you do not need to overheat, excessively load and adversely affect your car in any other way.