Poor start on a cold diesel. Cold car hard to start

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Modern cars are equipped with various options that should make it easier to start a cold engine, but often these devices do not cope with their tasks, and the engine starts poorly on a cold one, or even does not start at all. At the same time, a warm engine can work very easily and well.

In the early morning, fuss and fuss begin under the hood of the car in an attempt to warm up the unit and start it. Every car enthusiast dreams of getting into his car in the morning, just starting it and driving, and not thinking whether the engine will start or not.

Let's figure out why the car does not start well when cold and find out how to solve this problem.

Root of the problem

Cold start problem is quite difficult to solve because there is no exact answer to the question of poor cold start. For basic reasons, you can take the absence of a combustible mixture in the combustion chamber or a malfunction of the candles. This is a consequence. Everything else is a reason. Sometimes the fault is in the wrong fuel supply to the chambercombustion. The mixture may not be enough or, on the contrary, it is too much.

Main reasons

Among the main reasons for a poor launch are the following:

• Poor fuel quality.
• Clogged nozzles.
• Ultra low air temperature.
• Clogged fuel fine fuel filter.
• Clogged coarse filter.
• Fuel pump malfunctions.
• Dirty air filter.
• Dirt in the throttle or idle valve.

Do not immediately try to find all or one of these symptoms. If the car does not start well when cold, the first step is to observe the behavior of the car during start-up.

Looking for symptoms

Often the starter will work fine when starting, but the engine will not start. If you unscrew the candle, it can be both dry and filled with gasoline. It's kind of an indicator. The smell of fuel can also tell a lot. If gasoline does not have a pungent odor characteristic of it, then the reason is in it. However, if the candle is wet and the gasoline smells the way it should, then the essence of the breakdown is hidden somewhere else. If everything is in order and the smell of fuel is correct, the injectors are completely clean and the pressure in the fuel system is normal, then you should continue searching.

Ignition problems

When cold, the car does not start well due to several reasons. So, you should definitely check the battery level. If it is heavily discharged or nearing the end of its useful life, it may not be able to supply enough current tolaunch. You can understand that the reason is in the battery by the way the starter behaves. It does not spin the engine, or spins, but is unstable.

There is often a problem with Honda distributor cars.

Here, the reasons should be sought in the ignition distributor cap. If there are problems, then the starter will spin the engine well, but the car does not start well on a cold one. Candles in this case will be filled with gasoline.

Distributor and armored wires

There may be problems with the armored wire. This is also a frequent breakdown in distributor cars.

You don't have to make any effort to find this problem. It will be enough if the starter makes a few turns. The wires, if the reason is in them, will light up. In this case, they should be replaced.

Ignition coils

Often a bad start can be associated with severe wear on the ignition coils. If only one coil is installed in the car, then diagnostics can be carried out using a tester. But if there is more than one coil, then it is almost impossible to make a diagnosis, and all at once they almost never fail. For a normal start, even one working coil is enough. The coil option should be checked last, if everything else has already been ruled out.

Candles

Sometimes the car does not start well when cold due to some kind of spark plug problem.

As practice shows, this is a fairly popular reason for bad starts. When dismantling the candles, traces of dirt, plaque and soot of various colors can be found on them. In addition, they can be filled with gasoline and smell strongly. In this case, the candles are carefully cleaned with a steel brush.

If there are traces of gasoline on it, then this indicates that they were flooded. It is necessary to always have a set of serviceable ones in the trunk, or better - a new one, so as not to clean and dry the old ones, but simply install new ones.

Compression

The car may not start well in cold weather with little or no compression in the combustion chambers.

Ideally, before starting the engine, check the compression level, but in reality, no one does this. But you need to know the reasons for her disappearance and be able to eliminate them.

Other reasons

Problem starting may be due to a faulty starter. Frozen oil, condensate in the exhaust system, crystallized antifreeze. To get out of a situation where it is difficult to start a cold car, it is necessary to use oils with a viscosity of 5W30, 5W40 or 0W30 and 0W40. The starter must spin the crankshaft up to 100 rpm. The most important thing is fuel. It must contain saturated vapors.

VAZ

If a classic VAZ does not start well when cold, it means that the settings have disappeared or a lot of small defects have accumulated in the car. Minor maintenance required.

During this inspection, checkfluid levels in the engine crankcase, gearbox, fluid level in the cooling system and brake system.

Next, they inspect for leaks of oil, fuel or antifreeze. If the machine has been standing for a long time, then the fuel may evaporate from the float chamber, it is necessary to replenish the level with a hand pump. During this check, special attention must be paid to candles and high-voltage wires.

If the VAZ is carbureted, then this element may be clogged. You should also examine the membrane of the starting device, the tightness of the tubes of the vacuum amplifier, the membrane of the gasoline pump. Also make sure the starter is working properly.

The injector does not start in frost: reasons

If it does not start well on a cold injector, then here you should look for a malfunction in the injectors. The injection unit will work like a clock, but only if they are in perfect condition. Their condition is especially relevant precisely in the winter, when clots of non-fuel origin can seriously impede launch.

It is often customary to change nozzles according to the regulations from the car manufacturer. They also need to be washed regularly, especially since the quality of the fuel leaves much to be desired. When washing nozzles at home, be sure to monitor their tightness.

If the injection engine starts and immediately stalls, then this is a sign that the ECU is trying to supply a rich fuel mixture to the combustion chambers. Candles are filled with gasoline and as a result the engine will not work well.

Diesel units

If for gasoline engines the first problem is spark plugs, then for diesel engines it is bad compression. It does not start well on a cold diesel engine with low compression. The motor will work a little better if it is warm.

Bad compression is signaled by uneven operation, vibrations, blue smoke from the exhaust pipe. If you look under the hood and open the engine, the unit will be covered in oil. Another lack of compression can be identified by a decrease in power, increased noise during operation, as well as high fuel and oil consumption.

If it is difficult to start on a cold diesel, then the first thing to do is measure the compression level.

If the unit is fully functional, then its level is from 30 kg/cm2. Measure it through the candle holes.

You can also look for the cause in the injectors. During the operation of engines on low-quality fuel, the injectors wear out a lot. First, the control valve is depressurized, and then the injector tip is decalibrated.

It is also worth inspecting the injection pump. Each element of the pump and the injection system as a whole are subject to severe wear. If the engine does not start well and you need to rotate the starter for a long time to start, then it will be useful to check the pump.

It would be useful to check the candles. They do not differ in large dimensions and are often hidden behind the motor. If one or more spark plugs fail, the engine will not start in the cold. The spark plugs should be replaced. These are typical reasons why a car does not start well when it is cold. But for a better start, it's worth buyingpreheater.

So, we found out the main reasons why the car won't start.