Diesel badly starts "on the cold": reasons. Maintenance and repair of diesel cars

Sooner or later, each car owner is faced with the problem of a difficult engine start. And this happens both on gasoline and diesel engines. The latter especially often refuse to start up in the winter. And all because of the properties of diesel fuel. After all, unlike gasoline, there are no spark plugs that would ignite the mixture. Fuel is ignited by compression force. Plus, the diesel is thickening at low temperatures. But we will not run ahead of time. So, let's look at why the diesel engine starts badly in the morning. The main reasons and methods of elimination, see our today's article.

Starter and battery

Most problems with starting arise because of the wear and tear of these two elements. After all, it is up to them to start the engine "to cold" and "hot". If your diesel is badly put "on cold", the reasons can be in the discharged accumulator. The latter, like the diesel, is also afraid of low temperatures. Over night it can lose up to 20 percent of its capacity. This is already a critical indicator. As a result, even the new Renault Duster will not be able to start. What is the solution to the problem? There is only one way out - charging the "planted" battery. There are several ways to do this. The fastest option is "smoking". With the help of "crocodiles" you connect to the battery terminals of a working vehicle and start the engine start. However, the method is quite dangerous, primarily for the battery itself.

The second, safer way is to use so-called boosters. Recently, they have become very popular among motorists. Booster is a small battery (comparable to the size of Power Bank for mobile phones), which within 30 seconds can produce a high starting current in the "Bust" mode (hence the name). This battery is 12-volt and is suitable for most cars and minibuses with an engine capacity of up to 4 liters. However, practice shows that a high-quality "booster" is able to launch even a truck motor. The only drawback of this battery is the price. It is comparable to the cost of three good lead-acid batteries.

The third method is charging on a stationary storage. This is the safest, but slowest way. After all, to restore lost by 20 percent charge, the device will need at least 30 minutes of time.

As for the starters, they also fail. The terminal may be loose on the device, or the drive gear may be worn, which engages the flywheel ring. In any case, you can determine the malfunction "by ear". The starter will make other sounds when working.

Low compression of the diesel engine

This problem is relevant for cars older than 20 years. Compression on a diesel engine differs significantly from gasoline, at least 2 times. Since the fuel is ignited by the compression force, this indicator should be at least 20 atmospheres. Petrol engines are also successfully launched at 8 atmospheres. This must be taken into account. What could be the cause of low compression? First of all, it is the wear of the piston group, the rings. The latter can lie, which forms an ellipse in the walls of the cylinders. This problem is accompanied by a large choke of oil. By the way, compression can disappear in several, and in one cylinder. In the latter case, the problem with starting is accompanied by vibrations at idle . To diagnose the motor, compression measurement is required. And already from the received results conclusions are made - to repair the engine or to change to the new one. With your own hands, nothing can be done here - this is the work of the minder. Those who are going to buy an old diesel, advice - check the compression in each cylinder. This small operation will save you from unforeseen problems and monetary expenses.

Frozen Fuel

This is another common reason that the diesel is badly started "on the cold." Causes in the crystallization of a liquid. With each drop in temperature, a paraffin precipitate forms in the fuel. The fuel becomes cloudy and thick, like a jelly. But how do they operate cars in the northern regions? In order not to experience problems with start-up, in winter, winter diesel fuel is needed. How is it different from the usual? In contrast to the summer, winter diesel oil contains additives that prevent the formation of paraffins and the crystallization of the liquid. After all, thick fuel is unable to penetrate the pores of the filter and the main line, do not talk about the nozzles.

Where can I buy winter diesel? Such fuel is sold at all gas stations in the cold season. The gas stations are prepared in advance for the winter season, diluting the fuel with an antigel additive. Harm the engine, it does not bring - it is tested by many motorists. However, some gas stations can sell the remains of summer fuel in the winter. In order not to become a victim of the circumstances, experienced motorists recommend carrying an anti-gel bottle and adding it to the tank. Especially if a strong cooling is expected. Proportions are indicated in the instructions. What is the freezing temperature of summer diesel fuel? The fuel is paraffinized already at -5 degrees Celsius. Therefore, always ask at gas stations, the Arctic is fuel or not.

Alternative to antigel

If there is no special tool at hand, the brake fluid will prevent the crystallization of the fuel. Some craftsmen use alcohol, adding it to the tank. However, the brake fluid works more gently with the fuel system. But henceforth we recommend using additives specially designed for this. One liter of money costs about 500 rubles. Total volume is enough for 1000 liters of fuel. The additive is capable of reducing the crystallization temperature to -40 degrees.

Water in the system

Where does it come from? This can be condensate from the tank. And this problem is faced by the owners of not only trucks, but also cars, including the Renault Duster. The most active condensate is formed in cold weather. Also, water enters the tank from the pistol. Nobody canceled the laws of physics - condensate can be formed in the reservoirs of the gas stations themselves, even though they are hidden underground. As a result, water enters the tank and settles in the mains. And as you know, this liquid does not mix with diesel fuel. Penetrating water can disable a high-pressure pump.

How to deal with this problem? On trucks, additional separator filters are often installed. Fuel, passing through them, is cleaned of impurities. Including the separator absorbs condensate. From time to time it is drained off by unscrewing the special valve at the bottom. If it is a car that is used in the northern region, it will not be hampered by the installation of the separator. The advantages of this filter are appreciated by many drivers. This is really an effective device that can protect the engine from a water hammer, and the tank from internal corrosion. Some devices are heated. This gives a guarantee for a successful start-up at a temperature of -50 degrees Celsius. However, the cost of such units is 30 thousand rubles. Separators without heating can be bought for 7-9 thousand.

Air in the fuel

Strangely enough, but because of this, the diesel is badly started "on the cold." Causes - the presence of an airlock. As you know, the cylinders of the diesel engine air and fuel are fed separately. And if there is a "cork" in the system, the proportions of the preparation of the mixture will be violated. The motor will grasp and immediately go deaf.

Oxygen in the fuel pump is due to damage in the fuel line. Inspect the attachment points and the condition of the tubes themselves. It is unacceptable to have cracks and streaks of fuel on them. This can cause excessive air sucking. Because of this, the diesel engine is not able to operate normally. How to fix the problem? The air plug is removed by opening a special settling valve on the filter.

Too thick oil

As is known, for diesel engines a different lubricant is used, rather than for gasoline engines. However, this does not insure the car from difficult starts, especially in the winter. With a decrease in temperature, the oil in the engine begins to thicken. Starter, even with a charged battery, it will be difficult to crank the flywheel, and with it the crankshaft. Typically, diesel engines use engine oil with a viscosity of 15W-40. When operating under extreme conditions, experts recommend lowering the bar to 5W-30. A more fluid oil facilitates easy rotation of the crankshaft, which is especially true for the engine with lower temperatures.

Ignition angle

In diesel engines, too, there is such a parameter. If it does not match the norm, the motor will run intermittently. Noticeable excessive vibration, diesel is badly started "on the cold." The reasons for the wrong angle of ignition advance. Also this parameter can be "shot down". How to set the ignition correctly? This procedure requires certain skills. Setting the advance angle involves adjusting the fuel injection, which is delivered at a specific time at the end of the compression stroke. In the event of a deviation from the normal parameters, the combustion of fuel in the cylinders is inadequate. Because of this, detonation and jolting at idle are possible. How to set the ignition correctly? The parameter is set by turning the fuel pump around the axis. Also, the angle is set by turning the camshaft pulley. To go to the tuning, you need to get to the flywheel of the engine, after removing the cover from it. It is necessary to find a stopper on the flywheel that goes down into the slot, and scroll the element with a key.

So we put the crankshaft into motion. The flywheel must be rotated clockwise before the locking stop. Next, we find the drive shaft of the injection pump. Diesel on it should not flow. We combine marks on the pump flange and on the drive coupling. Further we roll the crankshaft one more turn and see if the marks coincide. Then we control the position of the scale. After tightening the drive clutch, raise the stopper on the flywheel. The shaft is rotated 90 degrees. Place the stopper in the groove.

At the final stage, the flywheel housing is installed and the fastening bolts are tightened. We start the engine and check its operation. At idle, the motor should not emit excessive vibrations, and the motion should be without failures and jerks.

Candles, relays

Yes, the diesel engine also has a candle. However, unlike gasoline, they are responsible not for burning the mixture, but for its incandescence. In other words, the engine is heated. The diesel becomes less cold due to the glow plugs. They are especially relevant in the winter. Therefore, if the motor starts up badly, you should inspect the candles. Perhaps they do not produce a normal fuel preheat for the diesel. These elements are powered from the relay and equipped with its own control unit. The latter controls the heating of the candles in accordance with a specified amount of time. After a certain time of work, the supply of voltage to the spark plug stops. The relay does not work anymore, because the fuel for the diesel has already been heated. But this does not always happen. It happens that the candle stops working at the initial stage. And here the problem is in electronics. It is worth checking the operation of the relay and the electronic unit. The mechanism should make a characteristic click. If the system has a fuse, check it. Probably, the element was blown out at a voltage jump, and there was an automatic open circuit. With the fuse replaced, the operation of the elements resumes.

It would be superfluous to measure the resistance of the candles themselves. This is done with a multimeter. The same tester diagnoses the operation of the relay. But the surest way is to try to start the engine on a well-functioning unit and relay. This method will allow you to quickly determine the reason why the diesel is badly started.

Pump, injectors

The latter can become highly contaminated during operation. Inside, varnish and sulfur deposits are formed. Also do not forget about such a concept as the natural wear of the injectors.

The main difference between the fuel system of a diesel engine is that the fuel supply is produced under high pressure. On modern aggregates with the injection of Common Rail, this figure is 200 mPa. For comparison, the injector operates within 4-5 MPa. Contamination of the injectors leads to a difficult pump operation. As a result, the fuel supply pressure drops. The solution is to clean or replace the injectors (depending on their degree of wear). It is not recommended to unscrew and diagnose these items by yourself. All checks should be made on specialized stands. It is worth noting that dirty nozzles, in addition to low pressure, are not able to spray the mixture under a normal torch. This is felt in the work of the engine - the motor throws on the idle, the traction disappears, the consumption increases.

Advice

Below we will highlight a few tips on how to start a diesel in the cold :

• Keep the battery serviceable. In 80 percent of the cases, the problem is precisely the battery planted. Do not use an old battery that is 5 years old or older. For more confidence it is worth buying a "booster" that will provide starting current regardless of the degree of discharge of your battery.
• How to start a diesel engine in the cold? If the start is made in the frost, you should "wake up" the battery. To do this for a few seconds, turn on the headlights of the car.
• If there are severe frosts, bring the battery home for the night. Also, periodically clean the terminals on the battery if they are oxidized. To do this, use special aggressive sprays or sandpaper.
• Correctly choose the oil. Remember that with decreasing temperature it thickens. And to change such oil "on the spot" will not work. On machines with mileage less than 100 thousand kilometers, it is recommended to use synthetic or semi-synthetic oil with a viscosity index of 0W or 5W.
• Before long parking, you can pour 100-150 milliliters of gasoline into the oil. The fuel will dilute the lubricant, and the engine will run "into the cold" without problems. The procedure does not harm the motor, however it should not be abused.
• Before starting the starter, hold the key slightly in the third position. During this period, the glow plug will have time to heat the fuel and prepare it for ignition. As a rule, on modern cars the corresponding icon on the instrument panel is displayed.
• If the engine does not start for 10 seconds, turn off the starter. Otherwise, its continued work will entail a strong battery discharge. Typically, the motor is 1-2 seconds long enough to start.
• Use anti-gel. And fill it in the tank before refueling.
• In severe cold, the first 1-2 kilometers should be driven at low speeds and speeds, so that all the nodes of the car normally warm up.

Conclusion

So, we have found out, for what reasons the diesel is badly got "on cold" and as this problem to solve. As you can see, in most cases the problem is banal. However, if it concerns worn nozzles or stuck piston wheels, repairs should be entrusted to professionals.