Imagine a situation. You wake up early in the morning, hurriedly go to the garage and get into the car. You turn the ignition key and ... The car does not start. Probably every car owner has faced such a situation. The problem with starting the engine is one of the most unpleasant. After all, you need to go, but the car is standing. There is panic. What to do if the diesel does not start? The reasons and methods for their solution are further in our article.

Features of the diesel engine

In gasoline units, a mixture of air and fuel is formed, which is injected into the cylinders with the help of an injector. Once in the combustion chamber, the mixture is ignited by a candle and a working stroke occurs. Next - release, compression, then the cycle repeats. Unlike petrol engines, the mixture in a diesel engine is ignited by high pressure. It enters the combustion chamber with the help of spray nozzles. In addition, a glow plug is included in the work, which heats the fuel to the desired temperature.

But when they fail, the diesel unit is not able to start normally. The glow plug greatly simplifies the process of igniting the fuel, and, accordingly, starting the engine. If the diesel does not start "cold", then the control relay has broken and the candle does not heat up the diesel fuel. The action of this element does not stop until the temperature of the coolant reaches operating values. The glow plug has often saved car owners in the winter.

We also note that, in addition to the ignition method, such motors differ in design fuel system. And if gasoline has a simple submersible pump, then there are two of them: one low and the second high pressure. Well, let's look at why the diesel does not start "cold" and "hot".

Compression

Initially, its level is twice as high as that of gasoline units. The mixture ignites from strong compression. And the drop in compression does not have the best effect on starting the engine. Since any compression process is accompanied by the release of thermal energy, the mixture does not heat up enough and is not able to ignite. If this is a car with high mileage, compression drops with wear of the cylinder walls and burnt rings. Recall that each piston has three rings. Two compression, one - oil scraper. This requires disassembly and repair of the engine. It happens that the compression drops in only one of the cylinders. In this case, the diesel is either troit. This means that one of the cylinders does not work or ignition occurs irregularly.

What is normal compression?

If for gasoline units this indicator is from 9 kg / cm², then for diesel the minimum value is 23 kg / cm². It is measured using a special device - a compression gauge.

In this case, the starter must be turned for no more than 3-4 seconds, otherwise the battery will be discharged. Already at the first "grasping" the result will be visible. With more turns crankshaft he won't change.

glow plugs

Why won't diesel start? The reasons may be hiding in the glow plugs. It is very simple to determine this breakdown - the car starts up well only on a warm engine. The starter turns "on a cold", but the engine does not start due to an unheated combustion chamber. Usually happens in winter.

Also, if the motor was able to start, it will work intermittently. If diesel is possible, several glow plugs have failed at once.

Relay

This element is controlled by a relay. Sometimes a breakdown of this element causes problems with starting the motor. How to check it? When starting the car, you should hear characteristic clicks from the spark plug relay. If not, the element is burned out and needs to be replaced. The spark plugs themselves are in perfect working order.

Fuel system

As we said earlier, its device is significantly different from gasoline counterparts. In 60 percent of cases (including on Ford cars), a diesel engine does not start due to problems in the first thing that could be a clogged injector. This is due to poor quality fuel. You cannot clean them yourself - only in a specialized service.

Filters

What are some other reasons why a diesel engine won't start? Of course, these are filters. You need to check their condition.

There are two levels of purification in the diesel engine fuel system - coarse and fine.

The latter must be given Special attention. The paper cavity of the filter, through which the fuel passes to the nozzles, is capable of retaining particles up to 10 microns in size. The resource of this element is 8-10 thousand kilometers. If you do not follow this regulation, the filter will simply become clogged. As a result, fuel will not enter the combustion chamber, although the pump produces the desired pressure. You can determine this by the nature of the movement of the car. If dips in dynamics are observed, this means that the fuel is supplied with a delay. And it is the filter clogged with dirt that delays it.
It is worth mentioning the air elements.

These filters also need to be replaced. According to the regulations, their service life is 10 thousand kilometers.

They are stored in a plastic case, you can replace them with your own hands by sliding the mounting brackets and removing the cover. The photo above shows how dirty it looks. air filter. As a result, the diesel will not start. Oxygen supply stops or decreases to the minimum level. The engine does not have enough air - it chokes on fuel.

dark smoke

If the engine is difficult to start and exhaust pipe goes black smoke, it speaks of wrong work nozzles, namely their spraying of fuel. It is produced in excess, which is why part of the fuel does not have time to burn out and flies out, as they say, “down the pipe.”

Pump

The system has two mechanisms. These are high pressure fuel pump and high pressure fuel pump. Often the first element fails, since its device is more complex than that of the second. The pump cannot produce the required pressure in the fuel system, which is why the diesel engine does not start or starts with difficulty. The movement is accompanied by "sneezes" (as if the car does not have enough fuel). It should be noted that a belt is connected to the injection pump. It may break or fall off. First of all, we check the belt drive. Check the fuel system fuses (which go to the pump). One of them may burn out. Often this happens with a short circuit. Experienced motorists are advised to always carry a set of spare fuses in the glove compartment.

Fuel and winter

Especially often a diesel engine does not start well in the autumn winter period, when the air temperature drops sharply, and “Arctic” fuel has not yet appeared at gas stations. As a result, the summer "solar oil" simply freezes. At low temperatures it crystallizes and turns into paraffin, which clogs in fuel lines and filters.

Further movement with such a filter as in the photo above is simply impossible. Some vehicles have filter heating installed. But it saves only at startup. After a couple of seconds, the car turns off again. It is very difficult to heat up the entire tank with frozen fuel. Not all vehicles have preheater. What is the difference between summer and winter fuel? In the presence of additives that reduce the waxing threshold at low temperatures. To prevent the problem from taking you by surprise, before the onset of cold weather, purchase an additive in diesel fuel. Experienced motorists recommend not to leave the car in the parking lot with a half-empty tank. During the night, the liquid condenses and water forms on the walls. It also does not have the best effect on starting the engine. In winter, try to keep the level above half. Moreover, the ride empty tank often kills the pump. This applies not only to diesel, but also gasoline vehicles.

Starter

With him, the problem occurs both on gasoline and on diesel cars mobiles. It also has a relay connected to it.

And if the starter does not turn, we listen to clicks, as is the case with Perhaps this is an open circuit. Check battery charge. Of course, overnight he can not fall to such low level. Even at eight volts, it will turn the starter. Slowly, but still. A sharp decline level occurs in the event of a short to ground. Perhaps the contact has broken off and is “shorting away”.

timing belt

Why won't the diesel start? If the battery is well charged, the starter turns, but does not “grab”, the timing belt may have broken. The system is not able to select the correct phase for each cylinder. Often on 16-valve engines, this breakdown is accompanied by deformation of the intake and exhaust valves. They bend when the piston hits.

In order not to bring the car to such a state, check the condition of the belt. In the presence of tears and cracks, it must be replaced. Buy original spare parts. The belt is a very important part in a car. According to the regulations, it changes every 70 thousand kilometers. If this chain drive, the element can simply stretch or skew by one or more teeth. Manufacturers say that the circuit in the engine is designed to last the life of the engine. But after 200 thousand, it stretches - noises are heard during operation. With such symptoms, it is urgent to change it.

Conclusion

So, we found out why the diesel does not start. As you can see, there can be many reasons. But to avoid such a situation, change filters in time and fill quality fuel(in winter - necessarily arctic). If it is very cold, take the battery with you into the house. At severe frosts it loses up to 30 percent of its charge overnight. This way you will provide the system with a good starting current, and the engine - clean fuel. And problems with difficult start will not bother you anymore.

The diesel engine is considered to be unpretentious to road and weather conditions, and therefore practically "not killed". However, experienced motorists know that a diesel engine, with insufficient care, has many problems, some of which are quite specific and do not occur in gasoline engines.

Most often, owners of diesel cars have problems starting the engine in low ambient temperatures. In this article, we will figure out what to do if the diesel engine does not start cold, and, as you know, there can be quite a few reasons for this.

First, let's watch a useful video, the initial determination of the cause of a difficult start of a diesel engine:

The main reasons for the poor start of a diesel engine on a cold

One of the most common causes of diesel cold start problems is glow plugs, as they are the most likely to fail. Inspect them, replace the faulty ones.

If the problem is not in them, you should check the fuel pump, it probably produces too little pressure. In this case, the engine may stop starting immediately, as soon as the temperature "overboard" drops below zero.

It is not difficult to determine such a malfunction, if at the same time the starter is working normally, the pump starts to function, but the engine does not pick up torque, and from the exhaust pipe goes White smoke. In this case, try to loosen the injector fastening nuts a little - this is necessary so that the fuel can seep into the cylinders. If after this fraud the car started up, then the problem is most likely in the pump.

Also, if the diesel engine does not start when cold, then the cause may be a malfunction of the injectors. You should check them for the degree of fuel atomization when starting the starter. If, after checking, you find that the fuel from the injectors is simply pouring, the reason is probably in them. As a rule, with this malfunction, the car starts up hot, but the engine smokes more than usual.

We watch the video, the airiness of the fuel system, as one of the reasons bad start diesel in the morning

Another reason, which is not always obvious, is motor oil. The point is that diesel Russian production contains a significant amount of sulfur, which oxidizes the oil in the engine much faster. Therefore, it should be changed much more often than indicated in the data sheet. vehicle. In addition, bad "solar oil" can lead to another problem that makes starting the engine much more difficult - this is a clogged fuel filter.

Another problem of "diesels" associated with fuel is the untimely transition from summer fuel to winter fuel, and in areas with very low temperatures - to arctic fuel. The fact is that when driving in the cold season on summer fuel during combustion, paraffin is released, which over time is deposited on the engine units. In this case, the engine will not start until the car is completely warmed up and the paraffin is removed.

If none of these reasons is the "root of evil" of the problem that has arisen, you should use not the most favorite tool in the car owner's arsenal - a compression gauge. Measure the compression in each cylinder and compare them with the optimum for this engine indicators.

If the compression level is too low, this is probably the cause of the engine failure. By the way, low compression or a large scatter in its values ​​may indicate more serious problems with the engine in this case it is recommended to visit a car service.

Another video why the diesel does not start in the summer:

How to prevent a difficult cold start

First of all, it is necessary to change the type of fuel in a timely manner in accordance with the season in which you plan to operate your car. Not for nothing in the parks military equipment, and, as you know, it is mainly equipped with diesel engines, which are transferred to winter and summer operation for about a month.

In addition to changing the fuel, the oil also changes, since in diesel cars it loses its lubricating properties extremely quickly. It is also necessary to monitor the quality of the fuel used and the tightness of the cooling system: poor diesel fuel leads to rapid clogging fuel filters, and water entering the fuel mixture can completely disable the high pressure fuel pump, which is fraught with serious repair costs.

During the seasonal Maintenance it is also worth monitoring the compression level, since due to excessively low rates, the engine may stop starting altogether. It is also recommended to change the glow plugs or, if this is not possible, at least clean them of soot and oil stains (if any). If the diesel does not start when cold, then the reasons can be very diverse, and sometimes this problem allows you to identify or even prevent some serious malfunctions.

Proper diesel start in cold weather

It is worth mentioning that sometimes the reason for the difficult start of a diesel engine is banal ignorance of how to start it correctly. given type engine in cold weather, which over time can lead to breakdown of individual engine mechanisms.

In any case, before starting the engine in cold weather, warm up the glow plugs at least twice. On some engines, this process is accompanied by certain clicks. The first click appears when the ignition key is turned, which indicates the beginning of the heating of the glow plugs, and the second (after 10 seconds) indicates that they are turned off. repeating this procedure several times you can start the engine.

Remember that pressing the gas pedal is only allowed if your car is equipped with a fuel pump with mechanical control. In engines where the injection pump is controlled electronically, this is not necessary.

In that diesel car - great car, perhaps, hardly anyone needs to be convinced. But what to do if even such a glorious engine does not start. Or it starts, but immediately stalls. And in this case, what to do - order fuel pump repair Or some other unit? Or maybe it’s easier to call in a car service so that specialists can figure it out?

Why is the motor silent

If you have no idea how to repair a car, then come to us. After all, there are plenty of reasons why a diesel engine does not start. But in any case, first of all, it is necessary to understand the design features of these motors. So. In diesel engines, air and fuel are supplied separately (in gasoline engines- their mixture). Once in the cylinder, due to high blood pressure, diesel fuel ignites.

To mix the fuel in the cylinder, nozzles are provided. They turn the fuel into fine dust, due to which it burns evenly. Before starting the engine, the air in the cylinders is heated by glow plugs.

The relay controls the spark plugs. In principle, candles only make it easier to start a diesel engine. But there are models in which candles heat the air for some time after starting.

As you can see, there are many systems in diesel engines, and therefore the reasons for the engine not starting are different.

Compression in cylinders

Most often, the engine does not start due to a drop in compression in the cylinders. Actually, in this case there is a banal underheating and undercompression of air, and the fuel entering it does not ignite. The reason for this phenomenon lies in the wear of the cylinders (or O-rings on them). If the problem is only in one cylinder, then the diesel can start, but then wait:

• engine shaking;
• shaking of the entire machine due to shock loads.

A drop in compression is an obvious reason to overhaul the engine.

Fuel system

If you understand that the efficiency of the fuel system has decreased, it is quite possible that the time has come to change or perform nozzle repair. Believe me, in this case, it is better to do it than to postpone it ... Because the diesel engine simply will not start. Why? Because starting is one of the most difficult engine operating modes.

If smoke is observed during operation, then along with malfunctions of the fuel system, a compression drop is possible.

To check the nozzle, you need to unscrew everything, and then check each one on the stand. If internal elements the nozzles are not completely worn out, then the nozzles can still work, and the fuel, at least partially, is sprayed. But when starting, the diesel engine will begin to puff and sneeze, and from the exhaust pipe it will fall dark smoke from unburnt fuel.

Due to improper spraying of fuel, part of it does not burn out.

A spinning starter and a dead engine mean one thing - your car needs professional help. And then it is necessary to sequentially perform diagnostics of injection pump or injectors, high pressure pump drive, serviceability of the booster pump, measure the compression in the cylinders, etc. Therefore, there can be many reasons why the engine does not start, but there is only one correct way out - contact the professionals from Diesel-PRO.

glow plugs

A malfunction in the glow plug system is a tricky thing. You may not notice it at all when it's hot outside, and the engine is already warmed up. When one candle is not working in the summer, the internal space in the cylinder is not completely warmed up, well, okay.

And when 2 (or more) candles are faulty, it will be problematic to start a diesel engine. By the way, not only candles fail, but also relays.

When it's cold outside slightest infringement in the operation of the glow plug system will lead to the fact that you can forget about the normal quick start of the engine.

Diesel engine and Russian frost

It is believed that up to minus 15 degrees, a serviceable engine will work like a clock. But if the temperature drops even lower, the fuel without special additives paraffin. The fact is that diesel fuel contains paraffin, which tends to thicken at low temperatures and, accordingly, clog fuel filter. Accordingly, do not rush to order repair of injection pump or other units, but just wait for warming.

There are other reasons why a diesel engine won't start. These are also problems with the fuel line, which not only freezes in the cold, but may well lose its tightness at the joints in the heat.

There may also be problems with the starter, when instead of engine rotation, a useless clatter is heard in the relay. In short, there are many reasons. And in order to determine exactly what the matter is, it’s easier to visit our car center one day, and then enjoy how the diesel engine starts “with half a turn”.

Owners of cars with an appropriate engine are often faced with the question: "the reasons why the diesel engine does not start." Actually, there can be many of them, but in this article we will consider only those that are directly related to the specifics of diesel engines.

To do this, their antipodes - gasoline counterparts - will be subjected to a cursory analysis, and the characteristics of the operating mode will be given. In general, understanding the reasons - at the consumer level - is guaranteed.

As for their competent identification, and even more so their elimination, everything is much more complicated here: as practice shows, amateurs are not able to fully resolve these issues.

List of reasons

Reasons why a diesel engine does not start. We list only the main:

• insufficient heating fuel mixture and as a result, the absence of its ignition;
• Excessive wear of the cylinders (or corresponding O-rings). It is possible to eliminate only during the overhaul of the engine;
• problems related to the fuel system;
• climate problems. Seasonal temperature fluctuations directly affect the course of starting the engine - first of all, this applies to winter cold. Paraffin, contained in diesel fuel in a certain concentration as an obligatory component, thickens at low temperatures. Logically, and naturally, there are problems with starting the engine;
• fuel line leak(Availability mechanical damage, leaks, etc.).

Each of the listed reasons is sufficient for the engine not to start.

The question of how to level the causes of failures in starting the engine is too extensive - in each specific case, a certain set of measures is supposed to be taken to eliminate the shortcomings. For the average user, they will probably consist of turning to professionals - in most cases self-elimination breakdowns are fraught with excessive difficulties, the fight against which is the lot of specialists.

Helpful information

The specifics of diesel engines - more precisely, their difference from gasoline "brothers" - the supply of fuel and air is separated (due to design features), in petrol cylinders, the cylinders are saturated with an air-gasoline mixture.

The fuel is subjected to additional heating from the glow plugs. So candles make it easier to start the engine, but their operation is regulated by a special relay, which is also prone to breakdowns.

The foregoing gives some idea of ​​the variety of reasons why the engine either does not start at all, or starts “once again”, or does not work correctly.

Based on the above main causes of failures in the startup process, necessary to check the relevant nodes- cylinder block, glow plug system, injectors and other elements of the fuel system, as well as a starter. Perhaps the only component on this list, available to the car owner– checking whether the fuel line is intact, i.e. whether the fuel is delivered as intended. In a positive case, we state the presence of smoke from the exhaust pipe. So the reason is different.

You can try to diagnose

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Diesel power units have been used for many years in cars. Being economical and reliable, they have become quite popular with all motorists. This motor is quite demanding on timely service oil change and quality diesel fuel, failure to comply with these conditions can disable it. Typical malfunction unit is its inability to start after some technical work or for other reasons.

It is not uncommon for the owner of a car with such an engine to mercilessly operate it without proper maintenance, after which the diesel engine will not start. The device itself of this power unit is quite simple, and the reasons why the diesel engine does not start can be determined quickly and accurately. To do this, you need to understand how it works.

Working principle of diesel engine

The main difference between a diesel power unit and a gasoline one is that the diesel fuel entering the combustion chambers is not pre-mixed with air. Air enters its cylinders first, heating from increased compression, and only after that diesel fuel is supplied, which ignites as a result of strong heating of the air. V petrol engine air is mixed with fuel before entering the cylinders, and already there this mixture is ignited with the help of spark plugs.

Provide the flow of diesel fuel into the combustion chambers of the device, which are called injectors. They inject fuel under high pressure, this allows it to be evenly distributed in the combustion chamber and completely ignite. To facilitate the start of the power unit, glow plugs are placed in the cylinder head. When the ignition is switched on, they heat up within a few seconds and help ignite the cold fuel.

On the correct work this motor two factors influence:

• fuel supply;
• increased compression in the cylinders.

If any of these factors are violated, the engine starts poorly or stops working altogether.

Fuel supply problems

Determining whether diesel fuel is supplied to the combustion chamber or not is quite simple. To do this, you need to see if blue smoke comes out of the exhaust pipe while the engine is cranking with a starter.

If it is, it means that the diesel fuel is working properly, and the problem is not in the supply, but if not, then the whole trouble is in the fuel system.

The main elements of this system are:

• HPFP - high pressure pump;
• high pressure nozzles;
• filter;
• low pressure booster pump.

Each of these nodes performs important function, and the failure of any of them will contribute to the fact that the engine does not work. Their condition is strongly influenced by the quality of diesel fuel, which, in addition to the main function, carries a load in the form of a lubricating fluid for all parts of the fuel supply system. Poor quality will lead to rapid clogging of filter elements, nozzles and wear of the injection pump plunger valve.

These problems are as follows:

• filter clogging will result in insufficient bandwidth, at which the engine will lack the amount of diesel fuel, and, accordingly, it will start badly;
• faulty injectors will spray fuel poorly, which will lead to interruptions in the operation of the engine, and the exhaust from the pipe will be thick black;
• a failed injection pump will not be able to create the proper pressure in the system, which will lead to the impossibility of the power unit to work.

Reasons for poor fuel supply power unit, are quite varied, and hold self-diagnosis almost impossible, many components are subject to verification exclusively on specially equipped stands.

In order to avoid problems with the fuel supply, it is worth constantly inspecting all elements, including the fuel line, the condition of which can lead to leakage of diesel fuel or air leakage. Education air lock will not allow the engine to start.

Power unit malfunctions

Diesel engines are very demanding timely replacement oils, this is due to the specifics of their work. It lies in the production of a large amount of sulfur, which settles in the oil.

If you do not comply this regulation, the oil will lose its lubricating characteristics and will disable many internal details. It will be the main culprit for the reason why.

Main fault diesel engine is low compression. It is formed as a result of excessive wear of compression rings and cylinder walls. piston group. The reasons for this lie in poorly lubricating oil, which does not provide the formation of a film on the walls of metal parts rubbing against each other.

Measure compression with special device on a motor warmed up to 80 ° C, which is called a compression gauge. To measure, it is necessary to unscrew the nozzles or glow plugs and connect a compression gauge to their location. Next, the diesel fuel supply is turned off, this is done by pressing a special lever located on the injection pump. After that, it is necessary to scroll the engine for ten seconds, waiting for the maximum value of the compression gauge. It should be at least 28 atmospheres, if the engine is old-style, modern should be 45 atmospheres. All cylinders are checked sequentially, which should show the same value. Lack of proper compression will mean more cylinder wear or coking piston rings, which will lead to overhaul unit.

When this breakdown happened on the road, and there is no way to tow the car to the place of repair, you can fill the cylinders with oil, which will raise the compression for a while and allow the car to drive a few tens of kilometers to the nearest service station.

Other types of faults

Problems in which the engine does not start well can also be in glow plugs. Their inadequate quality will not allow the car to start in the frosty season or after long downtime. To check, they must be unscrewed and, using the wires, connected to battery cars. Place the negative wire on the body of the candle, and the positive wire on its contact. The candle should heat up quickly. This is how all glow plugs are tested. This breakdown has a bad effect on the start of a cold engine when it is in operating temperature She has no effect on him.

Another common cause the fact that the car does not start well is the use of off-season diesel fuel.

V winter time it is necessary to fill in frost-resistant diesel fuel, otherwise it will simply freeze and thicken too much.