Turning the key, rattling the starter and ... the engine does not start. Sooner or later, every car owner is faced with such a problem. What to do in this situation?
In general, there are many reasons why the engine may not start, and it is impossible to consider all of them within the framework of one article. However, there are “basic” conditions that are necessary for a successful launch. We will discuss them now.
A successful start-up requires a supply of fuel with operating pressure, air and a timely spark. It is also extremely important to prepare the right fuel-air mixture. These conditions must be checked first of all when the engine refused to start.
Checking the candles and spark
If the engine does not start within five seconds, it is useless to twist the starter. You can try to start more, but this is unlikely to give any sense. Moreover, an excessively long operation of the starter can lead to overheating and even fire.
If you try to start the carburetor engine for a long time, gasoline will flood the candles and make further attempts to start impossible in principle. Injectors have a purge mode, so the candles can be dried without removing them from the car - you just need to press the gas pedal to the floor and turn the starter.
But these are half measures. First of all, you should unscrew at least one candle, put the wire on it again and place the candle on the engine so that there is a distance of about three millimeters between the metal part of the candle and the metal of the engine. Turn on the starter and make sure that a uniform spark jumps between the spark plug contacts. Do this test for each candle. If there is no spark on any candle, then there are global problems in the ignition system.
It can be:
General faults:
- Defective candles (carbon deposits, destruction of the insulator)
- High-voltage wires are faulty (insulation is broken, the current flows “to the left”, not reaching the candle)
For injectors:
- Faulty ignition module
- No power to the ignition module. Power is supplied from the engine control unit, but the signal to the unit comes from the ignition switch. Therefore possible malfunction of the ignition lock contact group .
- Engine control unit defective
Errors in the ignition control system are usually visible during diagnosis and cause the Check Engine lamp to turn on.
For carburetors:
- Hanging charcoal in the ignition distributor (distributor) cover
- Burnout of the resistor in the distributor rotor (in the distributor runner)
- Burning or play of the contact group (for contact ignition)
- Switch malfunction (for contactless ignition)
- Malfunction of the ignition coil
- Lack of power on the coil. The power to the coil is fed through the ignition switch, so you should check it contact group
When there is no spark on only one candle, you need to replace this candle with a new one or change its high-voltage wire. Too wet candles also need to be replaced with new ones, or at least dried in a flame. This is necessary because current cannot pass through wet contacts and there will be no spark.
If there is a spark on all the candles, we check the fuel supply.
Checking the gas supply
Indirectly determine the supply of gasoline to the cylinders by the appearance of the candle. If the candle twisted from the cylinder is wet and smells of gasoline, then everything is in order with the fuel supply. However, it is better to verify this more reliably.
On injection engines, this requires depressurizing the fuel system using a special valve at the end of the fuel rail. Unscrew the cap and press the valve with a screwdriver. Gasoline should spray from under the valve. Then release the valve and turn on the ignition. At this time, it is obliged to start the gas pump, restoring the relieved pressure in the system. If the pump is silent, turn on the starter. When and when the starter is on, the pump does not work, most likely there is a malfunction in its power system.
If the pump has started, then once again we check the pressure in the fuel system by dumping it through the same valve in the ramp. Once again spraying gasoline indicates that everything is in order with the fuel supply system. When gasoline does not spray and does not appear out of the valve at all, we can talk about a faulty fuel pressure regulator in the ramp (constantly bleeds gasoline through the return line to the tank) or a certain plug in the main fuel line (for example, due to freezing of water in poor-quality fuel )
On carbureted engines, it is much easier to check the fuel intake. It is enough to remove the air filter cover, slide the throttle lever of the first carburetor chamber, simulating pressing the gas pedal and see if gasoline sprays from the nozzle of the sprayer. You can pump gas into the carburetor with the manual pumping lever, which is found on all mechanical gas pumps.
Checking the air supply
In the air supply system, malfunctions are extremely rare and come down to either a clogged air filter or blocking of the air channel by a foreign object. Such malfunctions are unlikely to occur in a well-maintained personal car. But if the car, for example, is service or recently bought, it will not be out of place to make sure that the filter is intact, and that a rag is not stuck in the channel after a recent repair.
These are the basic actions that can be quickly performed when the engine does not start. If there is a spark on all the candles, gas enters the engine and everything is in order with the air supply system, you need to “go deep”.
As already mentioned at the beginning of the material, it is difficult to describe all the reasons why the engine may not start, within the framework of one article. Therefore, we give only a general list.
- Starter does not develop starting speed
- Insufficient on-board voltage (weak battery)
- Lack of compression in engine cylinders (piston rings are worn out, valves are stuck)
- Timing disruption (timing belt is torn or jumped on one / several teeth)
- There is no signal from the crankshaft position sensor or other “vital” sensors of the injection system.
- Engine control unit malfunction
Other. The search for such malfunctions is already more difficult to carry out in outdoor conditions, especially if it happens in winter. You need to take the car in tow and pull it into the garage or car service.
What to do in this situation?
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