When the driver discovers that the VAZ 2107 car is twitching, first of all there is a feeling of alertness and, of course, this is terribly annoying.
Usually, a visual inspection of the engine is ineffective. To identify the cause, it is necessary to determine under what conditions the machine jerks.
The most common options are:
- the car starts to twitch and stalls during acceleration;
- the car jerks when the clutch pedal is pressed;
- during braking;
- at speed with the accelerometer pedal depressed.
If the VAZ 2107 car periodically twitches in the 2nd and 3rd cases, then you need to pay attention to the operation of the clutch and its condition. The rest of the cases can be harbingers of a wide variety of malfunctions.
Main reasons
Most often, the VAZ 2107 twitches due to low-quality gasoline. If the fuel was poured into an almost empty tank, the first jerks will begin almost immediately. If there was already a certain amount of gasoline, then the car will be able to drive relatively quietly for a certain distance.
Also a sign of poor fuel quality is the black color of the exhaust when driving. The engine loses power, but the car continues to run. There is a small chance that when driving, all low-quality gasoline will be used up. Alternatively, you can dilute it with a better one, for example, at the nearest gas station.
Another reason explaining the jerking on the move of the VAZ 2107 is condensate that forms in fuel tank... Since water and gasoline have different densities, they stratify. The moment water enters the carburetor, a jerk occurs. More specifically, the injector supplies water to one cylinder and gasoline to the other three.
Another reason why the VAZ 2107 car twitches may be in the fuel filter. If the replacement is not performed in a timely manner, then even at low revs the car can move in jerks. The gas pump generates pressure, which, with low-quality fuel, creates voids and when accelerating, or on the move at speed, the car jerks.
If water is present in the fuel, the filter cleaning sheets swell, which prevents the normal flow of gas to the carburetor. A phenomenon such as a "vapor lock" may also form, which blocks the operation of the gas pump. Appearance conditions:
- the engine is too hot;
- in hot weather;
- at low speeds.
Because of this plug, the required amount of fuel does not enter the injector, and the engine stalls. This can happen when driving at low speed, as well as when starting off. The fastest, simplest and most effective way to get rid of this problem is to put a rag with cold water on the gas pump.
If the car jerks when accelerating, then most likely it is the carburetor, or more precisely, the problem is in the valve idle move and jets that are clogged. The reason for the jerks of the VAZ 2107 during movement may even be a small bubble in the hose, due to which excess air from the slots enters the carburetor. All hoses should be checked for cracks or cuts.
If the injector and fuel are in order, and when driving and starting off, the jerks did not disappear, then you can check the distributor. To do this, you need to remove it and carefully examine the contacts. They are responsible for distributing momentum to each candlestick. If the ignition in one or more cylinders does not occur, the VAZ 2107 engine begins to triple and double when driving.
If everything is in order with the distributor, then you need to check the wires going to the candles. It happens that the insulation is broken, which leads to "penetration". The next step is to inspect the ignition coil. Malfunctions in this element or outgoing wiring can also lead to jerks when starting off or on the move VAZ 2107.
Usually, candles fail very quickly, but in some cases before that they can produce a spark in an arbitrary order, which, in turn, causes jerks, and the VAZ 2107 simply stalls. If the VAZ 2107 car twitches, then first of all you need to check the quality of the fuel supplied to the injector. Then you can check the rest of the elements.
Required clarification:
- jerk- short-term spontaneous change in engine speed regardless of the position of the gas pedal. In daily use, there are usually a series of jerks;
- failure- a noticeable delay in the response of the engine to pressing the gas pedal. Approximately it can be considered as the limiting case of a jerk.
Conventionally, three types of jerks can be distinguished:
At the moment of the beginning of the movement;
- during overclocking;
- with steady motion, i.e. with a constant position of the gas pedal.
A warning
When operating the DAAZ “Solex” carburetor, a very unpleasant defect occurs: when the gas pedal is pressed, a strong failure occurs, the engine stalls, and often there is no idle. Movement is possible only when you press the gas pedal to the floor, or you have to continuously “swing” the pedal. The reason is the clogging of the fuel jet of the main metering system of the first chamber.
For an experienced car enthusiast it is necessary to remove the upper carburetor cover as described above, unscrew the two air jets, unscrew the two fuel jets with a thin screwdriver and remove them from the wells with a long wooden toothpick or a pointed stick. Do not mix up the jets when reinstalling! Then use a syringe or a clean, lint-free cloth to remove gasoline from the float chamber and blow out the carburetor with compressed air, especially carefully - the wells of the fuel nozzles.
For an inexperienced car enthusiast it is better to immediately contact a car service. To get to the service, cut a piece of PVC tube 1–1.5 cm long (at least from the washer tubes) and put it on the stop lever of the second chamber drive. The engine crankshaft speed will be approximately 2000 rpm. Use the clutch and brake pedals to maintain a safe speed.
Jerk at the start of movement
At the moment of the beginning of the movement, the limiting case of a jerk — a failure — often takes place. The most unpleasant sensations are associated precisely with the delay in the response of the engine to pressing the gas pedal. Sometimes the engine even stalls.
The reason for the failure can be either a malfunction of the carburetor accelerator pump, or a malfunction of the vacuum corrector of the ignition distributor.
For work, you need: wrenches for “8” and “10”, Phillips and slotted screwdrivers, a clean rag, a piece of thin copper wire without insulation with a diameter of less than 0.3 mm, a compressor, a can of liquid type WD40, possibly a portable lamp.
PERFORMANCE ORDER
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Jerks during acceleration
The jerks can be caused by low level fuel or a clogged fuel filter in the carburetor, a malfunction of the fuel pump, or clogging of an additional fuel filter, malfunction of the ignition system.
For work, you need: wrenches for “8”, “10” and “13”, Phillips and slotted screwdrivers, a clean rag, a piece of thin copper wire without insulation with a diameter of less than 0.3 mm, a compressor, a can of liquid type WD40, possibly - portable lamp.
PERFORMANCE ORDER
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Jerks with steady motion
| GENERAL INFORMATION |
Such jerks are more often caused by a malfunction of the ignition system. Diagnostics required, contact a car service... The only thing you can try to do yourself:
Examine the engine compartment carefully. Switch off the ignition and check the reliability of fastening and seating of all wires and connectors at the switch, ignition coil and distributor. Start the engine and listen to its work - the crackle during high voltage breakdown “to ground” is weak, but distinct. In complete darkness, a spark is clearly visible during breakdown;
- replace spark plugs regardless of their condition and mileage. Pay attention to the condition of the candles - if it is abnormal, you may need to contact a car service.
With regard to a car, a jerk is a short-term, spontaneous change in the speed crankshaft engine regardless of the position of the gas pedal. In daily use, there are usually a series of jerks. The extreme case of a jerk is a failure, a noticeable delay in the response of the engine to pressing the accelerator pedal.
Conventionally, three types of jerks can be distinguished:
- at the moment of the beginning of the movement;
- during overclocking;
- with steady motion, i.e. with a constant position of the accelerator pedal.
To determine the causes of jerks when driving a car with injection engine special diagnostic equipment is required, therefore, in this case, we recommend contacting a car service specializing in the repair of fuel injection systems. However, as practice shows, in most cases jerking is caused by insufficient fuel pressure in the engine fuel line ("rail") or a malfunction of the throttle position sensor.
If you have some skills, you can identify the cause of the jerks yourself.
Jerk at the start of movement
At the moment of the beginning of the movement, the limiting case of a jerk — a failure — often takes place. The most unpleasant sensations are associated precisely with the delay in the response of the engine to pressing the gas pedal. Sometimes the engine even stalls. A jerk occurs at the moment the throttle valve starts to open, when, according to the signal from the throttle position sensor, the ECU determines the moment of transition from idle to load mode and must increase the amount of fuel supplied through the injectors. With insufficient pressure in the fuel line, even with an increase in the duration of the injection, there is not enough fuel for a smooth start-off.
The reasons for the decrease in pressure can be:
Jerks during acceleration
The cause of jerks during acceleration can be, as in the previous case (see "Jerk at the moment of the start of movement"), insufficient pressure fuel in the fuel line. The ECU, having received a signal from the throttle position sensor about the intensive opening of the throttle to a large angle, seeks to maximize the fuel supply, but due to the reduced fuel pressure, it is not able to do this. The reasons for this phenomenon and the method of checking, see "Jerk at the moment of the start of movement".
Jerks with steady motion
Such jerks are most often caused by a malfunction of the ignition system. Diagnostics and repairs are required (see section 9 "Electrical equipment"). On the way, you can try to do it yourself:
- carefully examine the engine compartment. Switch off the ignition and check the reliability of fastening and seating of all wires and connectors at the ignition module and high-voltage wires... Start the engine and listen to its work - the crackle during high voltage breakdown "to ground" is weak, but distinct. In complete darkness, a spark is clearly visible during breakdown;
- replace spark plugs regardless of their condition and mileage. Pay attention to the condition of the spark plugs - if it is abnormal, it may be necessary to repair the engine or its systems.
The sensor is not demountable and therefore not repairable. If a sensor malfunction is detected (see Section 9 "Electrical equipment", "Engine management system"), it is replaced as an assembly.
