The causes of jerking and twitching of small cars during the ride

To the carburetor malfunctions often include sudden jerks and twitches small car while driving. In most cases, the carburetor is not to blame. Most often, jerks and twitches while driving with-held in one position for the gas pedal causing the problem in the ignition system. Carburetor may cause falls only in the case where the bottom of the float chamber were found a few drops of water or small debris, which sometimes comes close to the main fuel jet dispensing systems and, barring the passage of gasoline, can cause irregular, but very sharp jerks up to stopping the engine. If jerks occur only when you pedal, this is evidence of contamination of the pump the accelerator. To distinguish the fault of the ignition system of the fuel system malfunctions, it is necessary during a trip to retain control of the diagnostic gas pedal in one position and choose a test section of road with a prolonged rise of the hill. When pulling the car there while driving up with a constantly pressed the gas pedal then it may be because: broken spark plug gaps or misconceptions on the electrodes inside the burnt out core of high-voltage wire and burned-out resistor at the tip of the high-voltage wires, high voltage insulation breach of spark plug wires or spark plug tip especially with metal shielding, burnt resistor runner distributor, contact failure between the thumb and the central coal terminal in the cap of the distributor, the water dew on the inside cover of the distributor, bearing wear in the distributor ignition - ("Lada", "Moskvich"), incorrect gap between contact breaker, faulty condenser, faulty ignition coil. The electronic ignition systems for reasons of sharp twitching car while driving can be added to a faulty switch or intermittent contact failure of electrical wires connected to the Hall sensor. For reliable operation of any ignition system is of great importance of high-purity elements - the ignition coil, distributor cap and high-voltage wires. To determine whether to blame the spark plugs in pulling the car, it is best to replace the entire set of candles on a known-good and after leg for an offer in 10 minutes. Check the candles on the various stands makes sense only when purchasing a new kit called the store. But even well-functioning on the stand, under normal pressure, the spark can in a short time on a motor malfunction. The best stand to check the spark plugs - this is your engine. No booth will not be able to create a whole range of loads at a candle as this will make any normal engine. The maximum term of a standard spark plug is measured in thousands of kilometers and the vehicle is according to different manufacturers from 15 to 30 thousand kilometers. Operation of the candles could go on and more time, but this increases the probability of failure. In the automotive aftermarket today there is a huge range of spark plugs. But the quality of this product is low. When buying you should remember that high price does not necessarily mean good quality. For maintenance the engine should check the gap on the plugs, clean the ceramic insulator and reliable contact with high voltage wire. The candle has a built-in resistor usually has a name starting with R. In this case, it makes sense to measure the resistance of the candle, which should not exceed 6-7 Com. One candle is unemployed increases fuel consumption by 25%. To test the replacement of candles in the shop should always be checked three sets of motors for the most common: - the size of a key on a 21 mm - the size of a key on a 16 mm - for cars, "Ford" with thread diameter of 18 mm. Three different sets of serviceable candles - is the key to quickly find the problem. The presence of candles in the studio is also necessary, as the presence of a wrench 13. Spark Plug fears hit, so that fell on the floor is working candle may then be destroyed. Check high voltage cable tester is to measure their electrical resistance. The resistance wires may be different, depending on the type of ignition system. Contact ignition systems for the general resistance of the wire can be from 0 - 6 Com. For electronic ignition systems - from 2 to 15-17 Com. Experience in repairs shows that the greater resistance than the above when the car jerks occur, and in some cases even impossible to start the engine. Each spurt - it misfires in the cylinder. In addition to measuring the total resistance of the wires should pay attention to the field wiring from the distributor cap with ignition coil and spark. In the joints should not be moisture, oxidation, or mud. Contact must be reliable. When the routine at the motor you will see or hear the crack of a spark between the central and lateral contact ignition coil - you can be sure that this was the cause of increased resistance to one or more high-voltage wires or increase the gap between the electrodes of a candle. Check the slider is in its overall inspection and measurement of the resistor or current-carrying plate. Resistor for electronic ignition systems is usually a Comment. To contact ignition systems - 5 - 6 Com. Burnt resistor is the cause of the car jerking while driving. Removal and installation of thumb should be done carefully so as not to damage the rails. When removing the cap ignition distributor must always pay attention to the condition of the central carbon contact. Fritz is stuck coals in the housing cover. Between the thumb and charcoal air gap is formed, in which there is an intense burning coal contact. The air gap in this area also contributes to the emergence of jerks while driving. On some car models in the case of the central carbon contact may be a resistor whose resistance must not exceed 10k. Therefore, the diagnosis should always check the resistance of coals. Burnout of this resistor is also a cause of jerking the car. Coal with a resistor usually has a shiny side surface. Water dew on the inner surface of the distributor cap is the reason for jerking the car. Crack or open the lid body burnout is the reason for replacing the lid on a new one. On many cars ignition distributor cap has a protective metal screen connected to a mass of the engine. The screen absorbs radio interference, which arise as a result of arcing of the distributor. Over time, between the screen and the cover of the distributor is going to dust, dirt and moisture that contribute to the passage of high voltage on the outer surface of the cover of the distributor. To exclude this possibility, you should regularly maintain cleanliness in this place. For reliable operation of the contact of the ignition system is of great importance to the magnitude of the gap junctions breaker. On any 4-cylinder engines gap must not exceed the limits 0.35-0.45 mm. During the operation there is a natural wear of the breaker and the gap is reduced. This leads to a disruption in the pricing, there are jerks while driving and ignition timing is later. The increase in the gap above the norm may occur as a result of an illiterate adjustment. Advance angle in this case becomes the past. Quickly and easily check the value of the gap junctions on the chopper (UZSK) can avtotesterom. Before checking the gap with a feeler gauge 0.4 mm thick to make sure the bearings, which fixed the breaker mechanism. To do this, remove the cover of the distributor, to try to move my arm rack of contacts in the vertical direction. Perceptible backlash mechanism shows a strong bearing wear, which in turn makes it impossible to accurately adjust the gap. This problem is common on cars "Lada" and "Moskvich". Installing a new bearing eliminates this problem. In an extreme case, if you can not find a new bearing, you can eliminate backlash reliable jamming of the old bearing. This will provide a good spark formation, but the mechanism of vacuum ignition timing will stop working. Contact surfaces must be parallel to each other. In operation, the chopper with the time on one side of the contact bump may appear, on the other side - hole. Mound must be carefully wipe the small diamond nail files. Hole cleaning is not necessary. Adjusting the gap, be sure to check the value of the resistance tester closed contacts, which should be less than one ohm. In the open position contact the tester should show infinity. Any discrepancy between these values ??will lead to disruption of sparking. The most common fault interrupter contact - is erasing the dielectric cam violation of the connections between the electrical conductivity of metal parts. Often occurs with a mass disconnection. The wire is made of a copper braid, without isolation, and can fray through moving parts. Contact on the distributor ignition system installed capacitor, which serves to reduce arcing between the contacts breaker. The capacitance of 0.25 microfarads. This parameter can be measured by the tester, but according to capacity does not mean the proper operation of the capacitor. With a total failure of the capacitor due to the strong arcing contacts for a few seconds, are covered by soot, which conducts electricity poorly. The spark is lost and the engine will not start. Violation of the capacitor may not be complete. A partial breakdown of the insulation at first leads to the disappearance of a spark in the ignition system, which causes an abrupt jerking the car. At the same time to contact surfaces, the blackening is beginning to appear. To see the status of the contact surfaces, you need to switch off the ignition push contacts and carefully consider them. Covered with black soot contact point to a faulty capacitor. Light gray, matte surface contact point to the defective capacitor. To eliminate the possibility of a partial breakdown of the capacitor to replace it with another, known-good, be sure to clean up the contacts and make a trip to the control within 10 minutes. Car Capacitors domestic production in the parameters are suitable for any contact systems of foreign origin. Ignition coil (CC) is a transformer that converts the voltage pulse on-board network in the high-voltage pulse. Standard coil consists of two - primary and secondary windings. The primary winding is pulsed voltage of 12 volts. Synchronously with it, appears in the secondary high-voltage pulse, whose magnitude depends on the design of the ignition system. In contact ignition systems of high-voltage pulse up to 10-20 thousand volts. In electronic systems, pulse is 30 - 60 thousand volts. The resistance of primary coil in the ignition contact is 3-4 ohms. The resistance of the primary winding in the electronic system is less than one ohm. The resistance of the secondary windings of the two systems is from 4 to 15 ohms. Before replacing the BB should make sure that the resistance of the primary winding and the ignition system. Compliance with the resistance is not a guarantee of efficiency coil. The high voltage secondary winding, under favorable circumstances, can penetrate the layer of dirt on the surface, near the output terminals of the windings. Therefore, it is important to keep this place on the reel in a clean and dry. Periodic breakdown of isolation, poor contact at the terminals short-circuit may cause sudden twitching car while driving. The most rapid diagnosis - is a suitable replacement of the coil to the parameters to the ignition control and ride for 10 minutes. For the diagnosis of a stock must have two coils - for the resistance of the ignition system and electronic. Failures in the circuit do not occur very often. Therefore, to test the coil is better to check spark, high voltage wires, contacts, slider and coal. Fault switch also can cause the car jerks while driving. The symptom is as follows. A cold engine start up normally, the car rides well for a short time (15-30) minutes. Then start jerking and failures, the engine stalls due to lack of spark in the ignition system. After a 10-minute pause engine start up and normal driving for a short time. After 5-10 minutes, start again jerks, the engine loses power and stalls. If the engine immediately after stopping to check on the central wire spark, then it is not there. After a pause, the engine start up again and a ride with breaks can last very long. In this case, can help replace the switch. With a total failure of a switch engine does not start. Installing another switch, you need to pay attention to his contacts in the plug. Not allowed oxidation or loss of individual wires plug. Tightening the bolts holding the switch to the metal surface contributes to a better cooling of the switch. In the packaging of the new switch is embedded conductive paste which is applied before installing the metal side of the switch for better cooling. The waveform, which can verify the oscilloscope, is a major test if the switch. Another reason jerks while driving occurs on motors with installed vacuum regulator ignition timing of the mechanical type. For example, consider this a fault in a car VAZ 2108. At idling speed in the tube leading from the carburetor to the regulator ignition should not be the slightest depression. The vacuum in the tube appears after a small throttle opening. If there is a vacuum tube regulator begins to move in the direction of Hall sensor ignition, and after the closing of the throttle the vacuum disappears, and Hall sensor returns to its place. Together with the Hall sensor are moved his three wires. During the operation, as a result of these movements can occur grinding isolation of one or more wires. If there is a complete break at least one wire, the ignition system will stop working and the engine will not start. But a partial breach of contact or isolation can lead to disruption of the ignition system is in the Hall sensor movement. When such a failure the motor can operate smoothly at idle speed, but after pressing on the gas speed can not rise steadily, the engine jerks in the throes begin misfiring due to violation of the contact on the damaged wire. After removal of the vacuum tube, the inlet of the carburetor vacuum to regulator timing, engine speed is able to smoothly increase, because when you press the gas wire Hall sensors remain stationary. The same problem can occur on contact ignition system. Only the contact breaker summed up one wire.