For what reasons is it difficult to start the engine on the VAZ 2107: description and elimination

Cars of the Russian automobile industry, which also includes the VAZ 2107, do not differ in their quality. If problems arise with starting the engine, it is not always possible to determine the cause at a glance, since problems are possible in different systems. However, there are main reasons why you can identify the breakdown that has occurred, which will allow you to fix the problem yourself.

The VAZ 2107 engine does not start - reasons

There are not so many problems with starting the engine on the VAZ 2107 and they occur infrequently. By and large, they are divided into two categories when there is no spark or no fuel supply. If the engine does not start, the cause should be looked for in the following:

• fuel system;
• power system;
• ignition system.

A difficult start, as a rule, is characterized by characteristic signs by which it is possible to diagnose a malfunction, and then repair the corresponding system or unit. For a better understanding of the issue, it is worth considering possible malfunctions that lead to a problematic launch of the power unit on the "seven".

No spark or weak spark

The first element that you should pay attention to in the absence of a spark or if it is weak on the VAZ 2107 is the spark plugs. It is necessary to check their condition, and then evaluate their performance. Perhaps the part is covered with soot, which prevents the normal formation of a spark. The check can be performed without much difficulty, even if the breakdown occurs in the middle of the road. In any case, a set of spare candles should always be at hand. We perform diagnostics in this way:

• we unscrew the candles one by one from the candle wells and, rotating the starter, evaluate the spark;
• having found a problematic candle, we replace it with a known good one;
• check the spark, install the candle in place and continue to move.

Carbon deposits on the spark plug lead to weak sparking

But, far from always installing a new spark plug helps in starting the engine. Therefore, you have to check other elements of the power system to identify the absence of a spark.

After candles, attention should be paid to high-voltage (HV) wires. They are diagnosed in the following order:

• in the absence of a spark on one of the cylinders, we change the wires in places;
• check for spark
• if a spark appeared on a previously non-working cylinder, but disappeared on another, the problem is clearly in the wire;
• the failed element is replaced with a new one.

Problems with high voltage wires lead to the fact that one of the cylinders may not work due to lack of spark

In most cases, when problems arise with spark plug wires, they are replaced as a set. If checking the spark plugs and explosive wires did not give a result, they begin to diagnose the contacts of the ignition distributor: you will need to open the cover of the distributor and inspect the contacts for soot. If traces of burnt contacts are noticeable, then with a knife we ​​carefully clean off the resulting layer.

After the distributor, check the ignition coil. For diagnostics, you need a multimeter. With its help, we check the resistance of the coil windings: the primary indicator should be within 3–3,5 ohms for a B-117 A coil and 0,45–0,5 ohms for 27.3705. On the secondary winding for the B-117 A coil, the resistance should be 7,4–9,2 kOhm, for a product of another type - 5 kOhm. If deviations from the norm were detected, the part will need to be replaced.

One of the elements that affects the quality of the spark and its presence is the ignition coil. It is also worth making sure that it works.

If the spark disappears on a car with contactless ignition, in addition to the above procedures, you will need to check the switch and the Hall sensor. The voltage switch is located on the left mudguard in the engine compartment. The easiest way to check is to replace the part with a working one. Another diagnostic method is also possible, for which you will need:

• turn off the ignition and unscrew the nut on the ignition coil to remove the brown wire;
• connect a test light into the open circuit (between the wire and the coil contact);
• turn on the ignition and turn the key to start the starter.

The blinking light will indicate that the switch is working. Otherwise, the part needs to be replaced. Quite often, in a contactless ignition system, the Hall sensor fails, which is due to increased loads. When equipping the "seven" or any other classic model of the "Lada" with a similar system, the presence of a sensor in stock will be quite useful. You can check the part with a multimeter: the voltage at the output of a working element should be in the range of 0,4–11 V.

Starter spins - no flashes

If the VAZ 2107 has a problem in which the starter turns, but there are no flashes, then, first of all, you should pay attention to the timing belt - it may have broken. When a timing belt is installed on a car from the factory, there must be special grooves in the pistons, so the meeting of the pistons and valves when the mechanism drive breaks is excluded. If the belt is in good condition, you will have to look for a spark and fuel.

A broken timing belt can cause the starter to turn and the engine not to seize because the timing mechanism is not working

First, we unscrew the candles and evaluate their condition: if the part is dry after a long rotation by the starter, then this indicates that fuel is not entering the cylinder. In this case, the fuel pump must be checked. The part on the injection and carburetor engines is different, so the diagnostic methods will be different. In the first case, you need to listen to the operation of the pump in the gas tank, and in the second, you will need to check the performance of the mechanism.

If we unscrewed a wet candle, then we apply it to the cylinder block and ask the assistant to turn the starter: the absence of a spark indicates problems in the sparking circuit (candles, wires, coil, distributor). If there is a problem with the temperature sensor on the injector, then the engine will also fail to start normally. This is due to the fact that the temperature sensor sends a signal to the control unit and, based on the temperature, a rich or lean fuel mixture is supplied.

Video: checking the spark on the "classic"

LOST SPARK VAZ

Starter spins, grabs and won't start

On the "seven" there are also situations when, when you try to start the engine, there are flashes, but the engine does not start. There may be several reasons for this phenomenon. If we are talking about an injection engine, then the problem is possible due to a failed Hall sensor or a crankshaft position sensor. If the latter fails, incorrect signals are sent to the control unit, which leads to the formation and supply of an incorrect fuel-air mixture. It is also worth checking the spark plugs and BB wires.

Due to problems with the Hall sensor or the crank position sensor, it is possible that the starter turns, the engine seizes, but does not start

On a carburetor engine, a problem may occur if attempts were made to start the engine with the suction cable extended. Usually it happens like this: they pulled the cable, in addition they pressed the gas pedal and try to start it. As a result, the engine seizes, but does not start due to flooded candles. There is too much fuel in the combustion chamber and the spark plugs are wet. In this case, they are unscrewed, dried or replaced with spare ones, the suction is removed and they try to start the engine.

Starts and immediately stalls

To understand such a problem, when the engine starts and immediately stalls, you first need to pay attention to the following possible causes:

• ran out of fuel;
• poor quality of gasoline;
• BB wires or spark plugs have become unusable;
• low engine compression.

After checking and making sure that all of the listed factors of a stalling engine do not apply to our situation, the problem should be looked for in the fine fuel filter, which can become clogged. In this case, the engine will stall due to the fact that the filter element is unable to pass the required amount of fuel. In addition, if errors occur in the computer, there may be problems starting the power unit. Checks of this device are recommended to be carried out under service conditions.

A clogged fuel fine filter can cause the engine to start and then immediately stall.

Another reason why the engine may stall is a clogged strainer on the carburetor engine. For preventive purposes, it is recommended to periodically clean this filter element. To do this, you can use a toothbrush and gasoline. Along with the filter, its seat is also cleaned.

Doesn't start cold

After a long parking of the car on the carburetor "classic" to start the engine, you need to pull out the choke - a damper that blocks the access of air to the carburetor and increases the fuel supply. If this cold start technique does not help, then you should understand the causes of this ailment. The problem, as a rule, is associated with a malfunction of the power supply system, ignition, or with the starter. A clogged carburetor, a worn distributor, or a dead battery are all among the main causes of difficult starting of the engine.

One of the possible problems that the engine does not start on a cold lies in unstable sparking. Checking the ignition system involves standard actions: diagnostics of all elements, evaluation of the quality of the spark. A properly functioning spark generation system should ensure trouble-free operation of the VAZ 2107 engine in any mode. Then pay attention to the fuel pump and carburetor. The latter, for example, can become clogged. The reason is possible in violation of the float chamber adjustments. In addition, the trigger membrane may be damaged. The membrane in the fuel pump may also be damaged. In both cases, it will be necessary to disassemble and troubleshoot parts, install new ones, and adjust (in particular, the carburetor).

Video: solving problems with starting the engine using the example of the "six"

VAZ-2106. We start a completely sick Zhigul (AUTO will not start)

Since one of the main elements involved in starting the power unit on the "classic" is the starter, it should not be deprived of attention. The most common starter related problems include:

• problems with the retractor relay;
• failure of the overrunning clutch (bendix).

Of course, do not forget about the battery itself, which may need to be recharged.

Doesn't start hot

Owners of the VAZ 2107 sometimes face the problem of poor starting of the engine on a hot one, and the situation is inherent not only in carburetor, but also injector engines. First, let's deal with the "sevens", which are equipped with a carburetor power unit. The main reason is the volatility of gasoline. When the engine warms up to operating temperature, and then turns off, the fuel evaporates within 10-15 minutes, which leads to starting problems.

After warming up the engine to operating temperature and stopping it for 10-15 minutes, the fuel evaporates, resulting in difficulty starting

In order to start the engine normally, you must fully press the gas pedal and purge the fuel system. Otherwise, gasoline will simply flood the candles. Since we are talking about a "classic", the cause may be the fuel pump, which overheats in hot weather (during the summer). The node, when overheated, ceases to perform its function.

The design of an injection engine is somewhat more complicated than a carburetor engine, therefore there are many more reasons that can lead to certain problems, including poor starting of the engine. Malfunctions may occur in the following units and mechanisms:

• in the coolant temperature sensor;
• in the crankshaft position sensor;
• in the air flow sensor;
• in fuel injectors;
• in the fuel pump;
• in the idle speed controller;
• in the fuel pressure regulator;
• in the ignition module.

The list, as you can see, is considerable, and car diagnostics will be required to find out the problematic element.

Doesn't start, shoots at the carburetor

What to do when the "seven" does not start and shoots at the carburetor? In most cases, the cause lies in an incorrectly adjusted ignition timing or in a lean fuel mixture. Another option is possible when the gas distribution phases have shifted. In fact, there are many reasons that lead to shots in the carburetor, so we will consider them in more detail.

1. Spark plug wires are connected incorrectly. As a result, the spark does not appear at the moment of compression, but on other cycles, which leads to incorrect operation of the cylinders.
2. Late ignition. In this case, the spark appears after the moment of compression, i.e. too late. The working mixture burns throughout the entire stroke of the piston, and not during compression. When the intake valves open, a new fuel mixture is ignited, while the previous portion has not yet burned out.
3. Problems with the distributor. Malfunctions with the ignition distributor can lead to improper operation of the engine in all modes. One of the simple reasons is the poor fastening of the knot.
   

   If there are problems with the distributor, the engine may not work correctly in all modes.
4. Problems with the ignition switch. In this case, the part is replaced with a new one, since repair is a pointless and costly undertaking.
   

   Switch failures can also cause carburetor pops. In case of breakage, the part is simply replaced with a new one.
5. Timing belt (chain) offset. The problem may be related to their incorrect installation during the repair work, which led to a violation of the phases of the timing mechanism. In addition, failure of parts responsible for the normal operation of the drive (shoe, tensioner, damper, roller) is possible. The situation may arise when the chain is strongly stretched. In this case, it will have to be replaced.
   

   Due to the displacement of the timing belt or timing chain, the valve timing is disturbed, which leads to shots in the carburetor and difficult starting of the engine
6. Lean fuel mixture. In this situation, you will need to check the fuel level in the float chamber. Fuel and air jets also need to be diagnosed - clogging of the elements is possible. If the carburetor has not been cleaned for a long time, then with the help of special tools it is necessary to perform this procedure. The urgency of the problem indicates the need to check the accelerator pump.
   

   If the engine does not start and shoots into the carburetor, then the possible cause is the wrong fuel level in the float chamber. In this case, float adjustment will be required.
7. Burnt inlet valve. Valves can bend or burn out over time. To identify a malfunction, it is enough to check the compression in the cylinders. If suspicions are justified, you will need to remove the head and repair it.
   

   To check the valves for burnout, it is necessary to measure the compression in the cylinders

Doesn't start, shoots in the muffler

In most cases, shots in the muffler are inherent in the VAZ 2107 with a carburetor engine, but sometimes the situation can also occur on the injector. The main reason is that the fuel-air mixture does not have time to burn out in the cylinder and explodes already in the exhaust system. The result is a strong bang. Some motorists advise you to first check the carburetor itself and the air filter, but, as a rule, the problem lies elsewhere.

First you need to make sure that the thermal clearance of the valves is adjusted correctly. If the parameter does not correspond to the norm, for example, the gap is less than necessary, then the valves will not close tightly. In this case, the fuel mixture at the time of compression will enter the exhaust manifold, where it will ignite. Therefore, timely and correct adjustment of the valves can eliminate the occurrence of such a situation.

One of the reasons for the presence of shots in the silencer is improperly adjusted valves. The thermal gap must be checked and adjusted if necessary.

In addition to valves, the problem may be in the ignition system, or rather, in the correct installation. If the spark appears too late (late ignition), then popping in the exhaust system will not work. Since some of the fuel will be thrown into the manifold, the element may burn out as well as the valve itself. This situation can occur if the problem is ignored for a long time.

If the advance angle is set correctly, but the shots are still present, you need to diagnose the quality of the spark. A weak spark is possible due to violations in the contacts of the explosive wires, the ignition distributor or the contact group. Candles themselves can also fail: special attention should be paid to checking them. The occurrence of shots in the muffler on the VAZ 2107 may indicate a violation of the gas distribution phases: a similar situation occurs in the cylinder, as with late ignition.

On the injector "seven", the problem, although infrequent, but manifests itself. The reason lies in the failure of the phases, valve clearance and malfunctions of the ignition system. Problems, in principle, are similar to a carburetor engine. In addition, a breakdown may be due to poor contact of a sensor, which leads to incorrect data being sent to the control unit. As a result, the electronic unit will form the wrong combustible mixture. In this case, vehicle diagnostics cannot be avoided.

No fuel

When there are problems with the fuel supply on the VAZ 2107, then regardless of the type of engine, it simply will not work to start the power unit. You will need to understand the causes and fix the problem.

On the injector

On the injection motor, the fuel pump, which is located in the tank, may break. We check its performance and, based on the results obtained, perform certain actions: we repair or carry out further diagnostics. Checking the fuel pump on the injector "seven" is quite simple to perform: just turn on the ignition and listen to the operation of the mechanism. If there are no signs of the functioning of the node, in the absence of operability it is worth understanding in more detail.

On an injection VAZ 2107, fuel may not enter the engine due to problems with the fuel pump located in the tank

On carb

With a gasoline pump on a carburetor engine, things are somewhat more complicated: the mechanism will have to be dismantled, disassembled and diagnosed with the condition of its structural elements. A malfunction of the pump leads to the fact that fuel does not enter the float chamber of the carburetor or does not flow, but in insufficient quantities. You can try to pump up gasoline manually, and also check the fuel pump:

1. A hose is removed from the outlet fitting and lowered into a prepared container with fuel, which is necessary to supply gasoline to the carburetor.
2. A prepared hose is put on the outlet fitting, and its other end is lowered into another empty container.
3. The assistant starts the engine and keeps the speed within 2 thousand rpm. In addition, start the stopwatch.
4. After a minute, check the performance of the fuel pump by measuring the amount of pumped gasoline.

If the fuel volume is less than 1 liter, the fuel pump is considered faulty.

Video: why fuel is not coming from the tank on the "classic"

Gasoline not getting to carburetor

To determine the reason why the engine on the "seven" does not start or starts, but with difficulty, it is not necessary to be a specialist or contact a service. It is enough to understand at least a little which system in the car is responsible for what. This will allow you to correctly identify the faulty mechanism or element and take appropriate action.