The car won't seize or start. What to check if the car does not start, but the starter turns? Starter problems

1. Check the serviceability of the elements of the engine power system.
2. Check and fix possible faults engine control system after the ignition is switched on.
3. Actions depending on the thermal state of the motor:
   • If the air temperature (parameter TAIR) is below minus 25°C, it is not recommended to start the engine without preliminary preheating of the oil in the crankcase and the coolant. The use of a 220 V starter charger is not allowed at temperatures below -30°C.
   • If the air temperature is -5...-20°C, it is recommended to warm up the engine receiver with warm water before starting. The starter cranking time of the engine should be no more than 10 seconds, re-cranking is allowed no earlier than after 1 minute.
   • Perform an air purge of the cylinders before starting if the air and coolant temperatures are below 0°C or if 2-3 attempts to start it have failed. To do this, press the accelerator pedal all the way down and perform a starter crank of the engine for (3 ± 1) seconds. When scrolling is complete, check the status battery if the voltage of the on-board network (UACC parameter) is below 11.8 V, then carry out battery maintenance.
   • It is not recommended to start the engine from an overheated state when the coolant temperature (TWAT parameter) exceeds 100°C and the air temperature in the receiver is over 65°C.

Starting procedure for a petrol injection engine

1. Do not press the accelerator pedal before switching on the ignition.
2. Turn on the ignition. Perform the necessary actions in accordance with the "Basic recommendations before starting the engine."
3. Do not proceed to launch if:
   • the electric fuel pump has not yet turned off;
   • if the check engine light is on.
4. Turn on the starter scrolling of the engine for the time required for a stable start, but not more than 10 seconds.
5. If the engine does not start, proceed to the analysis of situations of unsuccessful engine start.

No engine crank

1. When the ignition key is set to the "Starter" position, the engine crankshaft does not rotate. There is no dip (up to 10 V and below) in the on-board network voltage, observed on the UACC parameter waveform. Self-diagnosis does not fix trouble codes.
2. • starter control or power supply circuits are faulty;
   • faulty starter relay;
   • the starter or its retractor relay is faulty.

Low engine cranking speed

1. The engine coolant temperature is above 5°C. When the ignition key is set to the "Starter" position, the engine crankshaft rotates slightly. The failure of the on-board network voltage observed by the indicator is below 7 V. The information connection with the control unit is interrupted.
2. Check and eliminate possible faults:
   • Insufficient charge or defective battery. Perform maintenance on the battery or replace it with a good one.
   • No reliable connection power circuits starter to the battery or to the engine ground.
   • The starter motor drive is faulty. Replace starter.

The engine "does not seize" when starting scrolling

1. The engine coolant temperature is above 5°C. When the ignition key is in the "Starter" position, the engine crankshaft rotates steadily. The FREQ parameter (crankshaft rotation speed) is more than 200 rpm. Self-diagnosis of the unit does not fix system malfunctions or fixes individual trouble codes for the primary control circuits of ignition coils 91 ... 98, 231 ... 238, 241 ... 248.
   • Check the condition of the power supply circuits (27b, 27c) and control circuits (1, 20) of the ignition coils.
2. The engine coolant temperature is above 5°C. When the ignition key is in the "Starter" position, the engine crankshaft rotates steadily. Parameter FREQ = 0 rpm. Self-diagnosis of the unit does not fix system malfunctions.
   • Check the condition of the wiring harness circuits (48, 49) of the crankshaft position sensor and the condition of the sensor itself.

Reverse flashes during starter cranking of the engine

1. The engine coolant temperature is above 5°C. When the ignition key is placed in the "Starter" position, the engine "grabs" and stops. Backfires are observed in the intake manifold of the engine. The FREQ parameter (crankshaft rotation speed) is more than 400 rpm. Self-diagnosis of the unit fixes fault code 53.
   • Check for misconnection of the harness wires (circuits 1 and 20) to the ignition coils of cylinders 1.4 and 2.3.

The engine "grabs" but does not start

1. The engine coolant temperature is above 5°C. When the ignition key is placed in the "Starter" position, the engine "grabs" and stops. The FREQ parameter (crankshaft rotation speed) is more than 300 rpm. Self-diagnosis of the unit fixes fault codes 53 or 29.
   • Check for incorrect polarity reversal in the harness to the crankshaft position sensor (circuits 48, 49).
   • Check the mounting gap between the end face of the sensor and the timing gear.
   • Check for malfunction and, if necessary, replace the synchronization sensor with a known-good one.

Cold engine won't start

1. The coolant temperature is below 5°C. When the ignition key is turned to the "Starter" position, the engine "grabs" and stalls. The FREQ parameter (crankshaft rotation speed) is more than 400 rpm. The self-diagnosis of the unit fixes fault codes 53, 21 or 22.
   • Check the connection of the coolant temperature sensor or the possibility of an erroneous polarity reversal of the wires (circuits 45, 30d).
   • Check the connections 45 and 30d of the wiring harness to the coolant temperature sensor.
   • Check for proper operation and, if necessary, replace the temperature sensor with a known good one.

Hot engine starts and dies

1. The engine coolant temperature is above 70°C. When the ignition key is turned to the "Starter" position, the engine starts and stalls. The FREQ parameter (crankshaft rotation speed) is more than 1000 rpm. Self-diagnosis of the unit fixes fault code 53.
2. 5 seconds after switching on the ignition, check the absolute pressure of gasoline in the fuel rail with a pressure gauge:
   • If it is higher than 3.5 kg / cm² (high pressure), then check the fuel drain circuit (drain insufficient):
     • clogging of pipelines, hoses and elements of the drain circuit;
     • malfunction (leakage) of fuel injectors;
   • If it is below 2.5 kg/cm² (high pressure), then check the correctness of the fuel filling circuit (the filling is insufficient):
     • leakage and clogging of pipelines and filters of the bay circuit;
     • malfunction (coking or clogging) of fuel injectors;
     • insufficient performance of the electric fuel pump (the fuel pump is faulty);
     • serviceability of the fuel pressure regulator (the regulator is faulty).

The engine starts only when the accelerator pedal is depressed

1. When the ignition key is turned to the "Starter" position, the engine starts and stalls. The FREQ parameter (crankshaft rotation speed) is more than 400 rpm. Self-diagnosis of the unit fixes fault code 53.
   • If the engine starts only with a partially depressed (8 ... 20% throttle opening) accelerator pedal, and the self-diagnosis of the unit does not fix system fault codes (except for codes 53, 54), then perform preventive maintenance of the bypass channel or replace the auxiliary air regulator.

This handbook covers typical faults most types cars that can be diagnosed without the use of instruments. It will help you quickly find the cause of the breakdown and proceed with the repair.

To the list of characteristic features and possible causes It is advisable for a novice diagnostician to add records from personal experience and the experience of others - then you will get a solid database of the causes of malfunctions of cars of specific brands and diagnostics will not present problems.

Diagnostics is the basis of repair. It is not for nothing that the most experienced craftsmen are appointed as receivers in car services, because errors in diagnostics and determining the volume of repairs lead to financial losses for customers, misunderstanding of orders by mechanics and repeated work. Correct Definition troubleshooting is not only available to professional mechanics, it is the result of knowledge combined with a systematic approach. Diagnostics needs to be constantly learned. Do not rely on technology, as diagnostic equipment cannot find the cause of a malfunction, it only shows its effect. Start diagnosing by analyzing the possible causes of the malfunction. Check the condition of the car, find out the customer's driving style and how to take care of the car. Look for the reason based on the facts.

When diagnosing problems, follow these guidelines:

Use the method of elimination, go from simple to complex, do not miss the obvious;

Having found out the cause of the malfunction, take measures so that it does not happen again;

If the electrical network fails due to a bad connection, check all other connections on the network to make sure they don't fail too;

If a fuse blows frequently, find out the cause rather than replace it automatically;

Remember that the failure of one part may precede the failure of a more important component or the poor functioning of the system.

Engine

Engine won't start

Non-technical reasons

Condensation on candles after a long period of inactivity of the car without operation.

Moisture on the distributor cap, high-voltage wires and their lugs (summer morning after a night with temperature changes, dew or fog).

Drizzle, frost or moisture on the distributor cap, high-voltage wires and their lugs (on a winter morning after a night with a temperature difference).

Water on the distributor cap, high voltage wires and their tips after overcoming deep puddles or fords.

There is a plug in the exhaust pipe (clogged with earth after the maneuver in reverse in a pit, ditch, or otherwise) or moisture (if the machine is in deep water).

Gear engaged instead of neutral position.

The driver forgot to turn off his own fuel or current blocking.

Cause in the electrical system

The fuse has blown.

Poor contact of the ground wire from the engine to the body.

Wires in the start circuit are broken or loose.

Battery terminals are loose or corroded.

The battery is dead or damaged (headlights and windshield wipers will not work).

The anti-theft system (or other system) included in the ignition system circuit is faulty.

Starter gear stuck in flywheel ring.

Starter relay damaged.

Cause in the ignition system

Incorrect ignition timing.

Faulty ignition switch.

Faulty ignition coil.

System connections are broken.

Spark plugs are oily or full of fuel.

Incorrect gap between the electrodes of the candles.

Candles are coked with soot.

There are cracks in the spark plug insulators.

High voltage is not supplied to the spark plugs - the tips of the high voltage wires are loose or oxidized, the wires are very dirty or their insulation is damaged.

The procedure for connecting high voltage wires to the contacts of the ignition distributor cover is violated.

The contacts are stuck and do not open - the gap between the contacts of the breaker is broken, the textolite pad or bushing of the breaker lever is worn out.

The current does not pass through the breaker contacts - the contacts are oxidized or burnt, the gap between the contacts is excessively large, or the clamping spring is weakened.

Faulty parts of the ignition distributor.

The distributor is not tightly fixed - the ignition moment has gone astray.

Broken capacitor (short circuit).

Wear, damage to the contact carbon or its hanging in the sensor cover of the ignition distributor.

Current leakage through cracks or burnouts in the ignition distributor cover, through carbon deposits or moisture on the inner surface of the cover, through cracks or burnouts in the ignition distributor rotor.

Break in the primary winding of the ignition coil.

Open or short to ground in the secondary winding of the ignition coil.

Breakage of wires between the sensor-distributor of ignition and the switch.

Broken wires connecting the switch to the switch or ignition coil.

The switch is faulty.

Proximity sensor defective.

Burnout of the resistor in the rotor of the ignition distributor.

Break in the wire connecting the power relay to the ignition module. Power relay defective.

Faulty ignition module.

The controller is faulty - it does not give impulses to the ignition module.

The crankshaft position sensor is faulty, its installation is broken, or the wire connecting the sensor to the controller is broken.

Solenoid valve defective.

Cause in the fuel system

The solenoid valve in the carburetor gas line does not work when the ignition is turned on.

Lean mixture with a cold engine - the air damper is not covered.

Poor mixture - air leaks, in addition to the carburetor diffuser.

Rich mixture with a hot engine - choke closed.

Excess gasoline in intake manifold– pumping sharp pressing on the gas pedal.

Empty fuel tank.

Fuel does not reach the carburetor or injection nozzles - clogged fuel filter, tubing or tank vent.

Fuel pump defective.

Water in fuel.

Vapor locks in the fuel line in hot weather.

heavy pollution air filter.

Too high fuel level in the carburetor - over-enrichment of the mixture.

Air damper stuck.

Adjusted carburetor.

The carburetor nozzles or injection nozzles are dirty. Faulty gasoline vapor recovery system.

The reason is in the gas distribution system

The timing belt (or chain) is worn out - the phases are knocked down.

The key for fastening the gear on the camshaft is cut off - the phases are knocked down.

Valve clearances incorrectly adjusted.

The engine "does not seize" when starting scrolling

Unsatisfactory condition of the power supply and control circuits of the ignition coils.

The unsatisfactory condition of the circuits of the wiring harness of the crankshaft position sensor and the health of the sensor itself.

The engine "grabs" but does not start

The probability of erroneous polarity reversal of the wire harness to the crankshaft position sensor.

Incorrect mounting gap between the end face of the sensor and the timing gear.

Often, car owners are faced with the fact that when ignited, the starter only clicks, but does not turn, and, as a result, the car does not start. But it happens that the starter turns properly, which is heard by the characteristic sound, but the car still does not start. What to do in similar situation?

Reasons why the car won't start

Any modern car at its core, it represents a kind of symbiosis of numerous components, systems and mechanisms, as a result of which not only its characteristics are improved, but there is also a greater chance of encountering a situation where the car simply does not start. The localization of such problems can be different and, as a result, the causes vary. Among these are:

• Lack of gasoline, oil and other automotive fluids;
• Discharging the battery and / or the formation of rust (oxide) marks on its marks that prevent the transfer of charge;
• Problems with candles, injector (carburetor);
• Malfunctions in the electronics system;
• Problems in the operation of the fuel pump;
• Clogged fuel and / or air filters;
• blockage throttle valve.

In some cases, problems manifest themselves differently - car won't start, starter spins. The reasons for this are usually in the fuel system or ignition system, which is why it is important to immediately diagnose them.

INTERESTING! Some car companies undertake full Maintenance over a specified period of time. So, in case of any breakdown, the owner just needs to call the warranty service center and specialists will immediately arrive to carry out repairs.

The starter turns, but the engine does not start. How to find the reason?

The reason for situations in which engine cranks but won't start there can be several factors, however, in case of such problems, first of all, it is necessary to pay attention to the correct operation of the ignition system and the power supply system, that is, the fuel supply.

IMPORTANT! It is advisable to carry out diagnostics of these systems only in cases where the operation of the starter proceeds without jerks and unnecessary sounds. In this case, the problem, as a rule, lies in the starter itself.

Diagnostics of the ignition system

First of all, you need to unscrew the candle and check for spark. To do this, a high-voltage wire is put on the switched off candle, and its skirt is touched to the metal part of the engine. If a spark appears during the rotation of the engine, then the candle is serviceable and does not require replacement - that is, the problem lies elsewhere.

INTERESTING! Depending on the type of engine, the absence of a spark indicates problems of various localization. So, problems in an injection car indicate a malfunction of the ignition module, in a carburetor - a malfunction of the ignition coil.

The ignition module, due to the design and execution features, is almost impossible to check on your own, which cannot be said about the coil.

To diagnose the ignition coil, you need to remove the central wire of the distributor cover and bring it to a distance of about 5 mm to the metal part of the engine, excluding any contact. If there is no spark after the engine is cranked by the starter, the coil is out of order.

If the coil is good, you need to perform the last check of the ignition system - remove the cover of the distributor and check it for defects and damage. If the diagnostics of the ignition system did not give the expected result, and the starter still works, but the car does not start, you need to proceed to the next step - diagnostics fuel system.

NOTE! In most cases, problems of this nature lie precisely in the ignition system, so all diagnostic steps should be carried out as carefully as possible.

Fuel system diagnostics

This assembly must be checked sequentially, starting from the fuel pump and ending with the injector (carburetor).

In vehicles with an injector when the ignition is turned on, the sound of the electric fuel pump running should be heard in the cabin. If this sound is not present - the reason is in the pump motor - either it burned out or does not receive voltage. Therefore, first of all, you need to check the pump itself and its safety system.

Machines with a carburetor are more difficult to diagnose, since the pump is driven by a camshaft. In view of this, to check, you will need to disconnect the end of the hose from the inlet fitting. So, if after that you swing the pump priming lever several times, then fuel should pour out of the fitting or hose.

When the starter turns, but the car does not start, the problem may also lie in the injector rail, or rather, the presence of gasoline in it. To check, it is enough to press on the valve of the fitting that connects the pump - gasoline should come out of it.

An essential part of the diagnosis is check the fuel filter for blockages. This is not surprising, because situations often arise when, due to a lack of fuel, the car does not start, the starter turns, the relay clicks.

Also follows check throttle valve, which, if contaminated, can cause idle move starter.

What to do when the engine does not start, but the starter clicks

Often, car owners are faced with a problem such as “turned off the car and does not start, although the starter turns”. The implementation of the measures and recommendations indicated above, in the vast majority of cases, can solve the existing problems. However, sometimes the relay may be faulty. To eliminate and eliminate problems of this kind, you should also diagnose the relay, after which you may have to repair or replace it.

Starter Relay Diagnosis

"The car does not start, the starter is spinning"- the cause of such problems can often be identified and eliminated on their own at an early stage, but for this it is necessary to responsibly and carefully diagnose the starter relay.

To check the condition of the retraction relay, it must first be carefully removed from under the hood. After that, the starter must be cleaned of dust, dirt, mechanical debris. Oxidized contacts are processed with fine sandpaper.

The next step is to place the starter in close proximity to the battery and prepare two wires of the required length. It is advisable to use wires with "crocodiles". Then, with one electric drive, you need to connect the positive terminal of the battery with a similar output on the solenoid relay. After that, they do the same with the second wire, connecting the "minus" contacts. If a characteristic click of charge sounds when the wire is connected to the relay, then it is working and can be installed back. Otherwise, it should be repaired or replaced.

Relay repair or replacement

Repair and replacement is a fairly simple process:

Summing up, we can conclude that situations when it did not start car and starter twists, although they cause some inconvenience, but often they are not critical, since they can almost always be resolved on their own.

But do not forget that it is better to prevent the situation than to courageously solve problems, so the first rule of the car owner is to regularly check the correct operation of all systems and mechanisms of personal transport.

Often there is a situation when you turn the key, the starter turns the crankshaft confidently, but the car cannot be started. Some drive the engine until the battery runs out, in the vain hope that it will suddenly grab. In fact, after two or three unsuccessful attempts, you should be taken to troubleshooting.

1 The engine does not start when the starter is running - possible damage

When the starter turns, but the engine does not start, it is difficult to find the cause right away. It is required to look for faults in quite a few places. Let's start with the starter. We turn the key again and listen to the sounds it makes. The characteristic smooth buzz of an electric motor should come from it without failures and nothing more. If you hear clicks, hum and extraneous sounds, we are looking for a problem in the starter. In good condition, the engine most often does not start, because fuel does not flow or it does not ignite.

If the fuel is supplied, the ignition is in order, the starter turns, but the engine does not start, we are looking for the cause in the electrical equipment: we check individual sections of the electrical circuit and its elements. The reasons can be very simple: the fuse is blown, there is no contact due to a break or oxidation. Rarely, but there are breakdowns of the electronic control unit. Sensors that send erroneous signals to the computer may break down, and it incorrectly regulates the ratio of fuel and air, its supply to the engine.

A phenomenon is possible when the engine shakes violently when starting, it seems to start, but does not catch. The reason may be electromagnetic pickups that prevent the sensors from correctly processing data and sending a signal to the computer. Pickups can create an electromagnetic field of the starter. If there are crankshaft position sensor (DPKV) failures, the engine will not be able to start. At the same time, fuel is supplied normally, the crankshaft is well scrolled by the starter.

Malfunctions at startup, when the starter confidently cranks the crankshaft, are quite common and do not depend on the type of engine.

2 Diesel - troubleshooting specifics

The ignition of fuel in a gasoline and diesel engine is fundamentally different. The compression stroke in a diesel engine occurs without fuel, it is injected at the very end of it, when the temperature in the cylinder reaches 700 °. Ignition of the fuel occurs when it comes into contact with hot air. Excess heat from the head is removed by the cooling system. In order to maintain the temperature necessary for igniting the fuel inside the combustion chamber, a cold engine is heated by glow plugs before starting.

If a cold diesel does not start, we start looking for a problem with candles. The starter can turn for a very long time, but with faulty candles, even at + 5 °, it is difficult to start the engine, not to mention the frost. First, we check the health of the control unit. We connect the light bulb to the candle bus and ground, turn the key. If the unit is good, the light will come on. Then we turn the key to its original position, turn off the power bus and check the glow plugs. We connect one contact of the 21 W light bulb to the candle, the other to the plus of the battery. If the spark plug is good, the light will be bright.

In any weather, the diesel engine will not start if the fuel pump is airy or the damping valve is faulty. We check with a light bulb - whether power is supplied to the valve. If it is, remove and put on the lead wire. A good muffler valve makes a clicking sound. If the valve is in order, air remains in the fuel system. We unscrew the return line of the nozzles or the plug through which we will bleed air. If there is a manual pumping of the fuel pump, we apply voltage to the valve so that it opens, and we pump diesel fuel until it flows instead of air. If the low pressure pump is electrically driven, turn it on.

If it fails, when it is not possible to pump diesel fuel, we check the fuel filter: it may have been blocked by dirt or paraffin.

3 Gasoline engine - checking the fuel supply

The engine does not start if there are defects in the fuel system: gasoline does not flow, the starting device is faulty. To check the fuel system of a carburetor engine, we carry out the following operations:

1. We sharply open the throttle valves of the carburetor, observing the injection of gasoline (the air filter cover was removed in advance). If the fuel is atomized, it is fed into the carburetor.
2. If fuel is supplied, but start cold engine impossible, check the starting device. We close the air damper - it should completely block the primary chamber, and the throttle damper should open slightly by 0.8 mm. To check the operation of the throttle, you will have to remove the carburetor.
3. When the accelerator pump does not supply gasoline, it is not in the carburetor. We download manually, we start the engine.
4. We check the operation of the fuel pump: remove the hose from the outlet fitting and pump it. After a few strokes, gasoline should splatter.
5. If it was not possible to pump up gasoline, we check the fuel filter, the mesh in the carburetor sump. We change the dirty filter, wash the mesh.
6. Fuel still not being supplied? We disassemble the fuel pump and check the diaphragms. If they are torn, gasoline does not enter the carburetor, but into the sump, diluting the oil.

The oil should be changed, flushing is not necessary. We change the diaphragms, pump up gasoline and start the engine.

On vehicles with an injector, the engine will not start if the electric fuel pump is not working. Its serviceability is determined by the buzzing after the ignition is turned on. Sometimes the cause is oxidized terminals or a fuse, but it happens that the pump burns out. There may also be no or insufficient pressure in the rail if gasoline has got there. On the opposite side of the gas line connected to it, under the cap, there is a valve. We press it - gasoline should splash from there. If this does not happen, we check the fuel filter, the intake mesh, the fuel pump pressure reducing valve (located in the gas tank).

4 Ignition - how to find and fix a breakdown

If the malfunctions with the fuel supply have been eliminated, and the car does not start, we begin to check the ignition. We unscrew the candles and check the formation of a spark. We put a wire from the distributor cover on the candle, touch the metal on the car with a skirt, and at this time the starter assistant turns the engine. On a working candle, a strong blue spark is noticeable. For injection engine the absence of a spark indicates a malfunction of the module, for a carburetor - a coil.

It is impossible to check the injector module at home, but the coil can be checked. On older models, one cylindrical coil is installed, on modern ones - a dual or monolithic module. The most advanced short circuits that are installed on each cylinder directly on the candles without wires. Coils with wires are checked simply: we pull out the central wire from the distributor, bring it to the metal of the car at a distance of 5 mm and turn on the starter. The presence of a spark indicates serviceability.

Often the distributor fails in the car - the burning of the contacts of the breaker-distributor does not allow the engine to be started. If the distributor is contactless, the Hall sensor may have broken. This is not a typical malfunction - sensors rarely fail. Among the most common distributor malfunctions:

• resistance burned out on the slider;
• the cover of the distributor burned out;
• the wires of the Hall sensor are broken;
• beating of the distributor shaft through worn bearings.

We check the cover of the distributor by replacing it: the car of experienced drivers is always equipped with a spare. Contactless ignition with a distributor has a switch that is responsible for stable sparking. A faulty switch can cause the engine to not start. We detect a malfunction by hand - a broken switch is very hot.

In cars with an electronic system, various sensors most often fail. The fault is fixed, and an error message appears on the panel, each of which is assigned a code. Often ignition failures are due to wiring when there is no power. With some ECU malfunctions, the engine cannot be started. We repair the block in a car service or change it to a serviceable one.

Turning the ignition key, the driver observes the same picture every time. The indicators light up first. dashboard, indicating the presence of fuel and battery charge. V extreme position the starter turns on and starts turning the crankshaft. To start a serviceable engine, a few revolutions of the crankshaft are enough, but what to do when, when the starter is working, but the car stubbornly does not want to start? The culprit of such a situation may be the most various faults, because the normal operation of the motor is ensured by several automotive systems.

ICE start. How does this happen?

car engine works only if several conditions are met:

1. Enough air-fuel mixture enters the cylinders.
2. At a certain moment (at the end of the compression stroke), the candle generates a spark of the required power.
3. The crankshaft and camshaft rotate with strict interaction, ensuring the timely filling of the cylinders with a combustible mixture, the correct functioning of the gas distribution system and the operation of the gasoline pump in carburetor internal combustion engines.

By turning the ignition key, the driver energizes the starter solenoid relay, which turns on his electric motor and ensures engagement with the crankshaft flywheel ring gear. As it rotates, the crankshaft converts angular momentum into reciprocating motion of the pistons and drives the camshaft (or shafts). The latter ensures the timely opening of the valves, due to which the combustion chambers are filled with the fuel mixture at the right time.

The engine power system is responsible for its preparation and delivery. As soon as the piston reaches the top point at the end of the compression stroke, the finely dispersed fuel mixture is ignited by a spark formed on the candle (in diesel units, ignition occurs due to strong air compression). After that, the microexplosion acts on the piston, which moves down and makes the crankshaft rotate - this is how the engine start circuit looks like.

Why does the starter turn normally, but the engine does not catch, does not start?

In half of the cases when the car refuses to start, the starter is to blame. At the same time, the other half falls on situations where the starter regularly rotates the crankshaft, and the engine starts only after repeated attempts or is completely silent. This could be due to a variety of reasons.

Driver inattention or negligence

The notorious human factor can manifest itself in the most unexpected way. For example, a banal lack of fuel or an alarm that blocks the fuel pump. And it also happens that some "well-wisher" scored exhaust pipe, or a negligent driver, turning back, stuck in a pile of soil or a snowdrift. Such reasons are not included in the category technical faults, however, nerves can spoil a lot.

Technical problems - starter malfunctions

Every more or less experienced driver will distinguish the sound of a starter, which regularly rotates the engine, from the useless buzz of its electric motor in the absence of engagement with the flywheel. When starting troubleshooting, you should definitely make sure that the starter is functioning normally, and during its operation there are no extraneous knocks, clicks and failures.

The starter is considered defective in such cases:

1. The bendix gear cannot engage with the flywheel ring gear. This manifests itself in a loud metal rattle that appears when the starter is turned on. The reason for this phenomenon is the wear of mating surfaces, chipped teeth, etc. The solution to the problem is to install a new flywheel or crown. The latter can be rotated 180° and thus dispense with the purchase new part.
2. Overrunning clutch or retractor relay stuck. At the same time, the starter motor hums, but it does not make any attempt to start the engine. In some cases, repeated attempts to turn on the starter help, but this only postpones the need for repair or replacement for a while.
3. Loose crown. A similar malfunction happened on cars at the end of the past - the beginning of this century, including the popular "nines". In this case, the starter engages with the crown and starts to turn it, but it turns on the flywheel with a rattle. Only replacing the latter will help.

Video: Watch everyone who has problems turning on the starter. Helpful advice from an auto electrician.

Problems in the fuel system

Even the most “peppy” battery and a new serviceable starter will not be able to start the car if there are problems with the fuel supply to the cylinders. For this reason, the next thing to check is the engine power system.

1. Fuel pump

For carburetors and diesel engines this unit is located directly next to the head or cylinder block. Injection power plants equipped with an electric pump, which is installed in fuel tank. Their work is judged by a short buzz that appears after the ignition is turned on. As for the gasoline pumps of carburetor engines, they are mechanically driven by a cam mounted on a camshaft.

Checking the performance of the fuel pump is easy - to do this, remove the hose from the carburetor inlet fitting and lower it into a suitable container. After that, fuel should be pumped up with the manual pumping lever or by turning on the starter. If the result is negative, we check the passage of gasoline through the fuel line and clean the mesh located in the top cover of the pump. If this does not help, then inspect the membrane and valves of the fuel pump. After replacing damaged and worn parts, the device's performance will be restored.

2.Fuel filters

Along the way the fuel passes from the tank to the engine, there are several filter assemblies - coarse meshes located on the fuel receiver, in the gasoline pump and carburetor, and in addition, paper filters located in the section of the fuel line. The intensity, and even the possibility of supplying fuel to the internal combustion engine, depends on their purity. If you find a blockage, clean or replace the filter elements.

3. Throttle and nozzles

Gasoline ICEs run on fuel mixture, which is prepared in the carburetor or intake manifold (in injection cars). In the first case, the fuel passes through a whole system of channels, jets and sprayers that are in the carburetor. In the second, it is supplied by injectors according to signals from the electronic engine control unit (ECU).

The air supply is dosed using a throttle valve, which, depending on the design of the engine, can be mechanically or electrically driven. Clean the parts of this assembly and the throttle itself. Also, check if fuel is being supplied to the cylinders. If you are dealing with an injection car, then press the fitting spool located at the bottom of the fuel rail - while gasoline should flow from there under pressure. If the trickle is too weak, then we check the filters, the fuel line and the fuel pump pressure reducing valve.

In carburetor engines, the fuel supply can be judged by sharply opening the throttle - in this case, a portion of fuel will be injected into the diffuser from the sprayer of the accelerator pump. In addition, gasoline power units inspect the spark plugs - they should not be dry. Otherwise check up presence of a control signal on atomizers. If everything is in order with this, then you should unscrew the fastening of the ramp and move it away from the manifold in order to inspect the spray nozzles when starting the engine. The absence of fuel streams or their low intensity indicates the need to clean or replace the nozzles.

As for diesel engines, they supply fuel under high pressure, and a much more complex pump (high-pressure fuel pump) and nozzles of a special design are responsible for this. To repair these units, special equipment, so in this case it is better to contact specialists.

Something else useful for you:

Video: Starter buzzes, but the engine does not turn

4. Malfunctions of electronic systems

To check the ignition system, we turn out and remove the candle from one engine cylinder. Having installed a tip of a high-voltage wire on its contact nut, touch the cylinder head with a candle skirt and scroll the engine with a starter. In this case, a powerful spark of purple or blue hue should appear on the contacts. If the spark is too weak (or not at all), then we check the operation of the computer, ignition coils and distributor (in the ICE of the old design).

Other causes of difficult starting when the starter is running

1. The timing belt is torn, or loose and jumped a few teeth - in this case, the valve timing is knocked down, due to which the engine cannot start. It is enough to replace and set the belt according to the marks, unless such a nuisance ended with a meeting of the pistons with the valves - in this case, an overhaul of the engine will be required.
2. Crankshaft rotates with a noticeable effort, which can be caused by various mechanical damage to the crank mechanism and the cylinder-piston group. Check if the engine cranks when trying to start it in top gear "from a tow" (for manual transmissions) or by rotating the crankshaft pulley of cars with automatic boxes gear changes. A relatively slight rotation indicates that the cause of the malfunction is hidden elsewhere.
3. One of the mounted units is jammed, which creates increased resistance to the rotation of the motor shaft. To find the “weak link”, you need to loosen and remove the belt, and then try to manually turn the pump, generator, air conditioning compressor or power steering pump. If the breakdown occurred far from the service station, then you can get to the nearest car service only on those cars in which the pump is driven timing belt. On other engines, you can try to connect the crankshaft and coolant pump pulley with something suitable - a rope, a rubber strip cut from an automobile chamber, etc.
4. Failure of sensors connected to the computer - crankshaft position (DPKV), Hall, etc. Due to their breakdown or malfunction, the engine control unit does not properly regulate the combustible mixture or injects and ignites the fuel at the wrong time .
5. Sometimes the cause of a failure or incorrect interpretation of the signals of a particular sensor is electromagnetic interference from the starter and other electrical components. In this case, it is difficult to identify the malfunction, so it is possible that you will have to turn to specialists for advice.

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