Diesel bad start "cold": the causes. Service and repair diesel vehicles


2018-10-07 23:00:33




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Sooner or later, every car owner faces the problem of difficulty starting the engine. And it happens for both petrol and diesel engine. The latter especially will often refuse to start in winter. And all because of the properties of diesel fuel. Because unlike petrol, there is no spark that would set fire to the mixture. The fuel ignites from compression. Plus, the diesel thickens at low temperatures. But let's not get ahead of ourselves. So let's look at why bad in the morning, start the diesel. The main reasons and solutions see in our today's article.

Starter and battery

Most of the problems with the launch occurs due to wear between these two elements. After all, it depends on them starting the engine "cold" and "hot". If your diesel is a bad start "on cold", the causes may be a discharged battery. The latter, as diesel fuel, is also afraid of low temperatures. During the night it can lose up to 20 percent of its capacity. This is a critical indicator. As a result, even the new Renault Duster launch will be impossible. What is the solution? Way there is only one – charging "planted" of the battery. This can be done in several ways. The fastest option – “jump-start”. diesel bad starting on cold reasonUsing the “crocodile” you are connected to the terminals good vehicle and begin the engine start. However, the way is quite dangerous, primarily for the battery.

The Second, more secure method – using the so-called boosters. Lately they have become very popular among motorists. Booster is a small battery (comparable to size of Power Bank for mobile phones), which within 30 seconds can give a high inrush current mode "Boost" (hence the name). This battery-12-volt and suitable for most passenger cars and vans with an engine capacity of 4 liters. However, practice shows that high-quality “booster” able to run even the engine of the truck. The only disadvantage of this battery – is the price. It is comparable with the cost of three good lead acid batteries.


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The Third way – charge on fixed memory. This is the safe but slow method. After all, to restore the lost 20% charge, the device will need at least 30 minutes of time.

As for the starters, they too fail. Maybe ill adjacent terminal to the device or worn drive gear that engages with the flywheel ring. In any case, to determine the fault, you can “hearing”. The starter will emit different sounds at work.

Low compression diesel engine

This is a problem for vehicles older than 20 years. Compression on a diesel engine differs significantly from the petrol, at least 2 times. Since the fuel is ignited by force of compression, the rate must be at least 20 atmospheres. The petrol engines start successfully and at 8 atmospheres. This should be considered. What could cause the low compression? In the first place is the wear of piston, rings. The latter may lie that forms an ellipse in the cylinder walls. This problem is accompanied by a large Gorom oil. in the morning put bad gasolineBy the Way, compression may disappear in a few, and in one cylinder. In the latter case, the problem with the launch is accompanied by a vibration at idle. To diagnose motor requires measurement of compression. From the obtained results conclusions – to repair the engine or change to a new one. Their hands here is nothing to do – is the work of motormen. Those who are going to buy an old diesel, Council – check the compression in each cylinder. This small operation will save you from unforeseen problems and expenses.

Frozen fuel

This is another common reason why diesel bad start "on cold". The reasons for the crystallization of the liquid. With every decrease of temperature in the fuel paraffin precipitate formed. Fuel becomes cloudy and thick, similar to jelly. how to set ignitionBut how do you operate machines in the Northern regions? In order not to experience problems starting in cold weather need winter diesel fuel. How is it different from usual? Unlike summer, winter diesel contains additives that prevent the formation of paraffin and crystallization of the liquid. For thick fuel is not able to penetrate through the pores of the filter and the line, not to mention the injectors.

Where can you buy winter diesel fuel? This fuel is sold at all gas stations in the cold season. Gas stations in advance preparing for the winter season, diluting the fuel additive “antigel”. Damage the engine it brings – is tested by many motorists. However, some gas stations can sell the remaining summer fuel in winter. To avoid becoming a victim of circumstances, of experienced motorists recommend to carry a bottle of antigel and to add it to the tank. low compression diesel engineEspecially if you expect a strongcold. The proportions indicated in the instructions. What is the freezing temperature of summer diesel fuel? Fuel prefinished already at -5 degrees Celsius. So always ask at the gas stations, the Arctic is the fuel or not.

Alternative to antigel

If there are no special means to prevent crystallization of fuel will allow the brake fluid. Some craftsmen use alcohol, adding it to the tank. However, the brake fluid more gently works with the components of the fuel system. But I advise to use additives specifically designed for this. One liter of tools worth about 500 rubles. The total volume is enough for 1000 liters of fuel. Additive capable of lowering the crystallization temperature to -40 degrees.


Where does it come from? It could be condensation 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 condensation in cold weather. Also water gets into the tank from the gun. The laws of physics nobody cancelled – condensation can form in the tanks of gas stations themselves, even though they are hidden under the ground. As a result, the water gets into the tank and settles in the arteries. And as you know, this liquid is not mixed with diesel fuel. Infiltrated water may also damage the high pressure pump.

How to deal with this problem? Trucks often install additional filters-separators. Fuel passing through them, cleaned from impurities. Including separator collects condensate. From time to time it is drained, remove the special valve at the bottom. If it's a passenger car, which is used in the Northern region, it does not hurt to install the separator. how to start a diesel in the coldThe Advantages of this filter is appreciated by many drivers. This is a really effective device that can protect the engine from water hammer, and the tank from internal corrosion. Some devices are equipped with heating. This ensures a successful start at temperatures as low as -50 degrees Celsius. However, the cost of these units – 30 thousand rubles. Separators without heating you can buy for 7-9 thousand.

The Air in the fuel

Oddly enough, but because of this diesel bad start "on cold". Causes – the presence of air traffic. As is known, the cylinders of the diesel engine air and fuel are fed separately. And if the system was formed “tube”, the proportions of mixing are violated. The motor will seize and immediately stall.

The Oxygen in the injection pump falls due to damage in the fuel rail. Inspect the attachment and condition of tubes. Unacceptable cracks and streaks of fuel on them. This can cause excess air suction. This diesel motor is unable to operate normally. How to fix the problem? The air tube is removed by the opening of a special slop valve on the filter.

Too thick oil

As is known, diesel engines use a different lubricant than gasoline. However, this does not insure the vehicle from difficult runs, especially in winter. With decreasing temperature the engine oil starts to thicken. The starter even with a charged battery it will be difficult to turn the flywheel, and with it the crankshaft. Usually diesels use engine oil with viscosity of 15W-40. heating fuel for diesel engineWhen operating in extreme conditions, specialists recommend lowering the bar to 5W-30. Thinner oil allows for easy rotation of the crankshaft, which is especially important for the engine lower temperatures.

Ignition timing Angle

In the diesel engines also have this option. If it does not comply with the norm, the motor will work intermittently. Noticeable excessive vibration, diesel bad start "on cold". The reasons in the incorrect corner of an advancing of ignition. Also, this parameter can be "shot down". How to put the ignition? This procedure requires certain skills. Setting timing involves the adjustment of fuel injection that is supplied in exactly the specified time at the end of the compression stroke. If you deviate from the normal parameters occurs incomplete combustion of fuel in the cylinders. Because of this, possible detonation and shaking at idle. why start bad gasolineHow to put the ignition? The parameter is set by turning the fuel pump on its axis. The angle can be changed by turning the pulley of the camshaft. To go to set up, need to get to the engine flywheel after removing his hood. You should find the stopper to the flywheel that drops into a slot, and scroll the element with a key.

So we will put in motion the crankshaft. Turn handwheel in a clockwise direction is required before work the stopper pin. Then we find the drive shaft of the injection pump. Diesel it should not leak. Combine the marks on the flange of the pump and the drive coupler. Further scrolling the crankshaft another one turn and see if the labels matched. Then control the position of the scale. After tightening the drive clutch raise the stopper to the flywheel. The shaft moves 90 degrees. The stopper should be placed in the groove.

The final stage is the installation of a cover of flywheel and tightening of mounting bolts. Start the engine and check its operation.At idle the engine should not emit unnecessary vibration and movement must be without holes and jerks.

Candles, relays

Yes, in a diesel engine also has candles. However, unlike gasoline, they are not responsible for the arson to the mix, and for its glow. In other words, is heating of the engine. Diesel becomes less cold due to the glow plugs. They are particularly relevant in winter time. Therefore, if the start motor is bad, you should see it spark. They may not produce the normal heating fuel for diesel. winter diesel fuelThese elements are powered from the relay and equipped with its control unit. The latter controls the heating of the candles in accordance with the specified amount of time. After a certain operating time supply voltage on the spark stops. Relay no longer works because the heating fuel for diesel is already produced. But not always. It happens that the candle stops at the initial stage. Here, the problem is in the electronics. Worth checking the operation of the relay and the electronic unit. The mechanism should produce a "click". If the system has a fuse, check it. Perhaps the element burned out when the shock voltage, and an automatic open circuit. With the replacement of fuse elements is resumed.

It is worth measuring resistance themselves glow plugs. This is done by using multimeter. This tester is diagnosed, the operation of the relay. But the surest way-to attempt to start the motor to advance working unit and relays. This method will allow you to quickly identify the reason for the bad start diesel.

Pump, injector

Last in the process of operation can be very dirty. In the formation of lacquer and sulfur deposits. Also do not forget about such notion as natural wear of the injector.

The Main difference between fuel system of a diesel engine in that the fuel supply is under great pressure. On modern units with injection "common rail", the figure is 200 MPa. For comparison, the injector operates in the range of 4-5 MPa. Contamination of the injector leads to difficult operation of the pump. As a result, the fuel supply pressure drops. A way out – cleaning or replacement of injectors (depending on their degree of wear). Remove and diagnose the data elements alone is not recommended. All checks should be made on specialized stands. freezing temperature of summer diesel fuelIt is Worth noting that a dirty injector, in addition to low pressure, not capable of spraying the mixture under a normal torch. This appears in the work of the engine-the engine which at idle, lost thrust, increasing the flow rate.


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

  • Keep a good battery. In 80 percent of cases, the problem lies in the planted battery. Do not use too old battery, whose age is 5 years or more. For greater certainty worth to buy “booster”, which will provide inrush current regardless of the degree of discharge of your battery.
  • How to start a diesel in the cold? If the run is made in the frost, should be “Wake” the battery. To do this for a few seconds, the included headlights of a car.
  • If there are severe frosts, bring the battery home for the night. Periodically clean the terminals on the battery, if they are oxidized. To do this, use the special sprays or aggressive sandpaper.
  • Choose the Right oil. Remember that with decreasing temperature it thickens. And change the oil “in place” will not work. For cars with mileage less than 100 thousand miles it is recommended to use synthetic or semi-synthetic oil with a viscosity index 0W or 5W.
  • Before a long Parking lot can be poured into the oil 100-150 milliliters of gasoline. Fuel will thin the grease, and the motor run without any problems "cool". The procedure does not harm the motor, however it should not be misused.
  • Before you run the starter hold the key 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, displays a corresponding icon on the instrument panel.
  • If the motor does not start within 10 seconds, turn off the starter. Otherwise prolonged his work will entail a strong discharge. Usually the motor enough 1-2 seconds to start.
  • Use antigel. And pour it into the tank before fueling.diesel engine pre-heating
  • In severe cold the first 1-2 kilometers, you should drive at low speeds and rpm to all nodes in the car is normally warmed.


So, we found the reasons why diesel bad start "on cold" and how to solve this problem. As you can see, in most cases, the problem is trivial. However, when it comes to worn injectors or stuck piston wheels, repair should be left to professionals.

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