Diesel does not start: possible causes and solutions

Imagine the situation. Early in the morning you wake up, hastily go to the garage and get into the car. Turn the ignition key and ... The car does not start. With this situation, perhaps, every car owner. The problem with starting the engine is one of the most unpleasant. After all, you need to go, but the car is worth it. There is a panic. What can I do if the diesel does not start? The reasons and methods for their solution are discussed later in this article.

Features of the diesel engine

In gasoline units, a mixture of air and fuel is formed, which is injected into the cylinders by means of an injector. Getting into the combustion chamber, the mixture is ignited by a candle and a working stroke occurs. Next - release, compression, then the cycle repeats. Unlike gasoline, the diesel engine ignites the mixture from high pressure. Inside the combustion chamber, it will fall with the help of spray nozzles. In addition, the work includes a glow plug, which heats the fuel to the desired temperature.

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

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

Compression

Initially, its level is twice as high as that of gasoline units. The mixture is ignited by 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 is not heated enough and is not able to ignite. If it is a car with a high mileage, the compression decreases when the walls of the cylinders and the burnt rings are worn. Recall that each piston has three rings. Two compression, one - oil-removable. Here you need to disassemble and repair the engine. It happens that compression falls only in one of the cylinders. In this case, the diesel starts and stalls or trips. This means that one of the cylinders does not work or the ignition occurs irregularly.

What is normal compression?

If for gasoline aggregates this figure is from 9 kg / cm², then for diesel engines the minimum value is 23 kg / cm². Measured with a special device - compressometer. The starter should not be turned more than 3-4 seconds, otherwise discharge the battery. Even with the first "grasping" the result will be seen. With further rotation of the crankshaft, it will not change.

Candles for incandescence

Why not start a diesel engine? The reasons can be hidden in candles of incandescence. To determine this breakdown is very simple - the car starts well only on the warmed-up engine. "On a cold" starter turns, but the engine does not start because of the unheated combustion chamber. Usually happens in winter. Also, if the motor was able to start, it will work intermittently. If the diesel is badly started "on hot", several incandescent plugs may have failed.

Relay

This element is controlled by a relay. Sometimes the failure of this element causes problems with starting the engine. How can this be checked? When you start the car, you should hear the characteristic clicks from the candle relay. If they are not present, the element is blown and needs to be replaced. The candles themselves are in perfect working order.

Fuel system

As we said earlier, its device differs significantly from gasoline analogues. In 60 percent of the cases (including Ford cars) the diesel does not start because of malfunctions in the fuel system. The first thing that can be, is the clogging of the injectors. This is due to low-quality fuel. It is impossible to clean them independently - only in a specialized service.

Filters

What other reasons does the diesel not start? Of course, these are filters. It is necessary to check their condition.

In the fuel system of the diesel engine there are two levels of purification - coarse and fine.

The latter should be given special attention. The paper filter cavity, through which the fuel passes to the nozzles, is able to hold particles up to 10 microns in size. The resource of this element is 8-10 thousand kilometers. If you do not follow these rules, the filter will simply clog. As a result, fuel will not flow into the combustion chamber, although the pump produces the required pressure. You can determine this by the nature of the car. If there are dips in the dynamics, it means that the fuel is supplied with a delay. And it's the dirt-clogged filter that delays it.
It is worth mentioning about air elements. Such filters also require replacement. According to the regulations, their service life is 10 thousand kilometers.

They are stored in a plastic casing, you can replace them with your own hands, moving the mounting brackets and removing the lid. The photo above shows what a dirty air filter looks like. Because of it, the diesel does not start. The oxygen supply stops or decreases to the minimum level. The engine does not have enough air - it chokes with fuel.

Dark Smoke

If the engine is hard to start, and the exhaust pipe is black smoke, this indicates the mishandling of the injectors, namely, their spraying of fuel. It is produced in excess, because of which a part of the fuel does not have time to burn out and crashes, as they say "into the pipe."

Pump

There are two mechanisms in the system. This injection pump and the TNS. Often the first element fails, since its device is more complex than the second one. The pump can not give out the right pressure in the fuel system, because of which the diesel does not start or starts with difficulty. Movement is accompanied by "sneezing" (as if the car does not have enough fuel). It should be noted that the belt is supplied to the injection pump. It can tear or fly off. First of all, we check the belt drive. Check the fuel system fuses (which go to the pump). One of them can burn out. Often this happens with a short circuit. Experienced motorists advise to always carry a set of spare fuses in the glove box.

Fuel and winter

Especially often the diesel is badly started in the autumn-winter period, when the air temperature drops sharply, and the "petrol" has not yet appeared on the gas stations. As a result, the summer "diesel" simply freezes. At low temperatures it crystallizes and turns into paraffin, which is clogged in fuel lines and filters. Further movement with such a filter, as in the photo above, is simply impossible. On some vehicles, the filter is heated. But it only saves on startup. After a couple of seconds the car again stalls. It is very difficult to warm up the entire tank with frozen fuel. Not all cars have pre-heater. What is the difference between summer and winter fuel? In the presence of additives, which reduce the threshold of paraffinization at low temperatures. So that the problem does not catch you unawares, before the onset of cold weather get an additive in diesel fuel. Experienced motorists recommend not to leave the car in the parking lot with a semi-empty tank. Overnight, 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 maintain a level of more than half. Moreover, riding an empty tank often kills the pump. This applies not only diesel, but also gasoline cars.

Starter

With it, the problem arises both in gasoline and diesel vehicles. To him, too, is relayed. And if the starter does not twist, listen to the clicks, as in the case of the glow plug relay. Perhaps this is a break in the chain. Check the battery charge. Of course, overnight he will not be able to fall to such a low level. Even at eight volts he will turn the starter. Slowly, but still. A sharp decrease in the level arises in the case of a "close-to-earth" closure. Perhaps, the contact is "cut off" and "short".

Timing Belt

Why else does the diesel start? If the battery is well charged, the starter turns, but does not "grasp", perhaps, the belt of the gas distribution mechanism has broken. The system is not able to select the desired phase for each cylinder. Often on 16-valve engines, this failure is accompanied by deformation of the intake and exhaust valves. They are bent when the piston strikes. In order not to bring the car to such a state, check the serviceability of the belt. In the presence of tears and cracks, it is necessary to replace it. Buy original spare parts. The belt is a very important part in the car. According to the regulations, it changes every 70 thousand kilometers. If it is a chain drive, the element can simply be stretched or bent to one or more teeth. Manufacturers say that the chain in the engine is designed for the entire life of the engine. But after 200 thousand it stretches - you can hear the noise when you work. With such symptoms, you need to change it urgently.

Conclusion

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