Why does the car jerk when starting off
Content
Any malfunction of the car makes its owner nervous. One of these problems is the jerking of the car when starting off. This can be caused by both trivial reasons, the elimination of which does not require large expenses, and serious breakdowns. In any case, it is imperative to establish the cause of such jerks and eliminate it.
Why does the car jerk when starting off
If, while starting off, the car begins to twitch, then usually the reason is associated with a malfunction of the clutch or CV joints. In such cases, it is imperative to carry out diagnostics in order to immediately determine the breakdown and begin to eliminate it.
The main thing is not to panic, you need to make sure that the engine is warmed up to operating temperature before starting the movement, there are no problems with the ignition and the fuel supply system. If everything is normal here, then we must continue to look for the reason.
Driving style
Inexperienced drivers often let go of the clutch pedal abruptly, causing the car to jerk off to start. There are no malfunctions, you just need to change the driving style, learn how to smoothly release the clutch and at the same time add gas.
It is necessary to determine the moment of clutch engagement on the car. To do this, start off without adding gas and smoothly release the clutch. By determining in which position the clutch starts to engage, you will be able to move smoothly. There is no clutch pedal on a car with an automatic transmission. In order for such a car to move off without jerking, the gas pedal must be pressed smoothly.
The problem with the CV joints
In front-wheel drive vehicles, the power from the gearbox is transmitted to the wheels using the inner and outer CV joints. In case of partial failure of these parts, the car will jerk when starting off.
Signs of a CV joint malfunction:
- backlash;
- knocking while driving;
- crunch during turns.
The replacement of the CV joints can be done at the service station or on your own. These are relatively inexpensive parts and require little time to replace. Having an inspection hole and a set of keys, you can replace the CV joints with your own hands.
The procedure for replacing the CV joint:
- Removing the wheel from the side where the CV joints will be replaced.
- Loosening the hub nut.
- Unscrewing the bolts with which the outer CV joint is fixed to the final drive shaft.
- Dismantling the axle. It is removed along with the inner and outer CV joints.
The axle shaft is removed together with the inner and outer CV joint - Removing clamps and anthers from the axle shaft. After that, the shaft is fixed in a vice and the outer and inner CV joints are knocked down with a hammer.
Clutch malfunctions
Very often, problems associated with jerking a car at the start occur when the clutch breaks down.
The main clutch malfunctions:
- wear or damage to the driven disk, repair consists in replacing it;
- seizure of the disc hub on the gearbox input shaft. They clean the splines from dirt, remove burrs. If the damage is large, then you will have to change the disc or shaft;
- the wear of the pads or the weakening of their fixation is eliminated by installing a new driven disc;
- weakening or breakage of springs, wear of windows is eliminated by replacing the disc;
- seizure marks on the flywheel or pressure plate. You will have to change the flywheel or clutch basket;
- loss of elasticity by spring plates located on the driven disc. Eliminated by replacing the driven disk.
Replacing the clutch disc is performed in the inspection pit. The front of the vehicle can be raised using jacks or a winch.
Work order:
- Preparatory work. Depending on the design of the car, you will need to remove the starter, propeller shaft, resonator, exhaust manifold and other parts.
- Dismantling the gearbox gives access to the clutch.
- Removing the clutch cover. After that, all parts are removed from the flywheel. A new driven disk is installed and the mechanism is assembled.To replace the clutch disc, the gearbox must be removed.
Video: car twitches when starting off due to clutch problems
Broken gearbox
When the gearbox is faulty, then, in addition to jerking at the beginning of the movement, there may be difficulties with gear shifting, there are extraneous noises. It will be possible to diagnose and repair the gearbox only at the service station. It will be easier with a mechanical box, since it has a simpler device and is usually inexpensive to repair. To restore the automatic transmission, you will have to spend more money.
Steering malfunctions
The steering rack is responsible for transmitting power from the steering wheel to the front wheels. With certain malfunctions, jerks may appear during the start, in addition, vibrations are felt in the steering wheel. If the tips are worn out, they begin to dangle. This leads to vibration of the front wheels, so jerks occur at the start, as well as when accelerating and braking. Worn steering elements are not restored, but replaced with new ones. It is difficult to do this on your own, so it is better to contact a service station.
Problems with engine operation or mounting
Jerks of the car at the start of movement may be associated with malfunctions or engine mountings. There are many options here. One of them is floating speed, which can be determined from the readings of the tachometer, they will either increase or fall. If there is no tachometer, then by the sound of the engine you will hear how the revolutions change. As a result of unstable revolutions during the start, the car may twitch. It is possible that some injectors are clogged, as a result of which fuel is supplied unevenly to them, and the engine does not work correctly.
Improper mixing of air and fuel leads not only to jerks at the start, but also during movement. Often the cause is associated with damage to the rubber flange of the duct, which is popularly called the "turtle". Another reason may be the failure of the engine mounts. If this happens, the fixation of the engine is broken. During the start of the movement, it will vibrate, as a result of which shocks are transmitted to the body and the car twitches.
Video: why the car twitches at the start
If jerks at the start of the car appear in a beginner, then it is usually enough to change the driving style and learn how to smoothly release the clutch. In other cases, if such a problem occurs, you must immediately determine the cause. This will eliminate the malfunction and prevent more serious damage. Steering faults can lead to accidents, so only a professional should fix them.
