Why the car won't start if the battery is charged

Experienced motorists are well aware that many machine malfunctions manifest themselves at the moment when an attempt is made to start the engine. Regardless of what kind of engine you have, gasoline or diesel, carburetor or injection, atmospheric or turbocharged, it so happens that it simply refuses to start. In many cases, this is accompanied by the fact that the starter simply does not turn. If this happens, then the reason is found quite simply, since in 99% of cases it consists in the fact that either the battery is dead, or the starter itself, as they say, "ordered to live a long time."

However, it also happens that the battery is charged, the starter briskly turns the crankshaft, and the power unit remains completely indifferent to all this and flatly refuses to perform the tasks assigned to it. The possible reasons why the car does not start, if the battery is fully charged and the starting process, it would seem, should go on in normal mode, and will be discussed in this article.

Why won't the car start

Those who are at least in general familiar with the basic principles of operation and the main structural elements of internal motors combustion installed on modern cars, it is quite clear that if the car does not start with a charged battery, then the problem should be looked for in:

  • Ignition system;
  • Fuel system;
  • Electronic control system of the power unit.

The logic here is simple: with a charged battery and a fully functional starter, the engine may not start either because the combustible mixture does not ignite, or because it simply does not get into the cylinders, or due to the fact that the electronic motor control system gives a serious malfunction.

What to check if the battery is charged

In such a situation, many motorists, even realizing what exactly may be faulty, it is not so easy to decide what is better just start looking for the defect. Experienced specialists in the field of repair and maintenance of internal combustion engines recommend checking in the following sequence:

  • Fuses;
  • Electronic engine control unit;
  • Throttle valve;
  • Fuel filter;
  • Fuel pump.

It makes sense to talk separately about each of these structural elements of the machine and what their “fault” may be.


The reason that the engine will not start when the starter is working properly may be the following: there is no electricity to the spark plugs. By the way, they themselves cannot in any way cause problems, if only because the probability of failure of all of them, and even at the same time, is vanishingly small. Therefore, it is very possible that the voltage is simply not supplied to the high-voltage wires connected to them. If the design of the ignition system of a particular engine is such that it is supplied through fuses, then first of all it is necessary to check them.

Electronic engine control unit

All modern engines installed in passenger cars are equipped with electronic control units, which may also be the reason that, when charged battery and a running starter, as well as a working ignition system, the engine may not start at all, or, after starting, it immediately stalls.

This can happen, for example, when the ECM or DPKV sensors fail. The bottom line is that after starting the engine, they send its electronic control unit incorrect data on the composition of the fuel mixture and the position of the crankshaft. The ECU interprets them and issues completely different commands that are needed to the corresponding executive devices. As a result, the engine, as soon as it starts, immediately stalls.

Another "electronic" reason that the engine is impossible to start with full battery energy and forces - the starter, is a malfunction in the car alarm. Almost all passenger cars are now equipped with it, and not all models of these devices are highly reliable. Quite often it happens that it is they who block the start of the engine, believing that they are trying to start it in an "unauthorized" way.

Throttle valve

practice shows that problems with throttle valves are leading by a large margin. These structural elements of modern internal combustion engines are nothing more than mechanical regulators of the flow area of ​​the channel through which, ultimately, the fuel mixture enters the cylinders.

If the throttle valve does not work properly for one reason or another, then it simply, in effect, shuts off the fuel supply. Since the cylinders are empty and there is nothing to ignite, the engine will not start.

See also : Symptoms of the throttle position sensor.

Fuel filter

The filter is one of the most important parts of the fuel system of any internal combustion engine. Its function, as you know, consists in cleaning fuel from various mechanical impurities. It requires periodic replacement, but a considerable number of car owners simply ignore this circumstance. As a result, a moment comes when it becomes so clogged that it turns out to be impervious not only to garbage, but also to gasoline or diesel fuel itself. As a result, the fuel simply does not fall into the zone of formation of the combustible mixture, it does not form, and the engine, accordingly, does not start.

Fuel pump

Another important element of the fuel system, due to which the car may not start with a charged battery and a working starter, is the fuel pump.

If for any reason it fails and does not supply fuel, then the combustible mixture cannot form, as they say, by definition, and therefore be surprised that the starter rotates with all its might, and the engine does not react to this in any way, in this case it is not necessary.

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