Starting an automobile might cause vibrations, and this is a regular problem. Engine and fuel issues are the most common culprits for a shaky start, but there are other possibilities.
When starting a cold engine, vibration is a normal occurrence. It’s possible that vibrations won’t be felt for a while once the motor has warmed up during repeated starts. These symptoms are often a sign of underlying issues that need to be addressed.
No matter how hot or how loaded the machine is, vibrations will occur. However, they may only appear in particular working modes (idle or high speed, cold or hot). On a cold engine, the vibration can be felt, but as it heats up, it fades altogether.
That bothersome problem that comes slowly and steadily but is subtle enough to go unnoticed is here. This is a major issue, so don’t take it for granted and get to the bottom of it as soon as possible.
Why do cars shake when starting? Possible reasons
There are several possible explanations for experiencing vibrations when starting a car:
1. Low fuel in the tank
There is a simple reason why you should always check the fuel level in your tank, no matter how banal it may sound.
2. Using low-quality fuel
There are a lot of gas stations selling low-quality fuel that may contain a significant amount of water on top of the fuel itself. Pour 1 to 2 liters of petrol into a bottle and let it sit for a few hours to remove any water. In the event that there is any water present, it will settle to the bottom where it will be readily apparent.
It is possible that the frozen gasoline is to blame if your diesel engine stalls soon after starting at a low temperature. Severe frost, as you may be aware, can cause diesel to freeze.
3. A discharged car battery
Charging is required for a wide range of devices and equipment in each vehicle. Although the motor and all energy consumers are off, some devices may still use a small amount of power even when they are not in use.
When an ignition relay or fuel pump fails to operate, it’s usually because the battery isn’t fully depleted.
If starting the internal combustion engine becomes more difficult, you should also examine the starter.
4. A bad fuel pump
When engines start up but instantly stall, the fuel pump is usually to blame. Incorrect engine operation can be caused by the fuel filter being clogged or the fuel pump malfunctioning.
A blocked gasoline filter will either not pass the fuel through itself at all or pass it, but at a very slow rate.
If this is the case, fuel will enter the cylinders, but there will be insufficient fuel to ensure optimal engine performance after the engine is started.
As a result, the automobile shakes and may stall a few seconds after starting. Ask yourself how long it has been since you had the gasoline filter changed. Periodically, it is necessary to replace this component.
5. Bad spark plugs
The ignition system’s spark plugs are critical components. Spark plugs, like all other auto parts, degrade with time and eventually stop working altogether.
In addition, the production of black or white carbon deposits, which can be caused by a variety of reasons, may be to blame rather than wear. It’s common for carbon deposits to form when the air fuel mixture is poorly produced or when the fuel is of poor quality.
7. Faulty spark plug wires
It’s possible that the insulation on the high-voltage wires that link the spark plugs to the ignition distributor or coil will wear out over time.
Humidity can produce a voltage short circuit in the insulation, which can lead to an incorrect engine functioning perceived as vibrations.
8. Worn-out timing belt or timing chain.
The chain or belt will begin to wear down as a result of long-term use since it is no longer properly adjusted. Even if the belt or chain isn’t worn out, this problem can occur if the engine is started in extremely cold weather.
9. Problems with ECU
The electronic control unit and related systems are frequently implicated in faults of this type. Furthermore, it is important to keep in mind that these defects may not always be indicated by dashboard lights. This will necessitate a thorough examination at a reputable auto repair facility.
10. A bad oxygen sensor
Poor cylinder compression is one of the most frustrating issues. A major overhaul may soon be required because the internal combustion engine is nearing the end of its operational life.
11. Engine mounts
The automobile shakes because of faulty engine mounts. When the automobile is idling, the problem can be sensed more clearly than when the motor is beginning.
Engine vibration is particularly pronounced in this situation when the engine compartment temperature has not yet risen. Softening rubber in support structures can reduce the severity of vibrations, which can be beneficial for those who suffer from motion sickness. The engine mounts must be examined in order to get an accurate determination.
12. Bad injectors
There are many reasons why the cold engine may vibrate when it is turned on, including dirty or faulty injectors.
13. Faulty idle speed sensor
RPM might float on a cold engine due to issues with the idle speed or actuators. The crankshaft speed can fall to dangerously low levels during sudden acceleration, causing the engine to practically stall. Vibrations will be felt strongly when this occurs.
Other reasons why a car vibrates when starting
Have you lately had your car’s engine serviced?
If the engine was recently disassembled for maintenance, or even an overhaul, the crankshaft may not have been correctly balanced when it was reassembled and installed. As a result, the vibration is raised.
The differing weights of the cylinder piston group sections can also lead to imbalance and vibrations after the engine has been repaired, as we can see. In order for the vibration to be as intense as possible, the weight differential must be large enough.
Compression decreases when the valves wear out. There are a number of consequences of this condition, including a lack of fuel compression and a lack of ignition or intermittent ignition of the fuel charge.
No matter how it starts, the engine is operating at a reduced capacity, resulting in significant body vibrations. Cold starts may result in vibrations that are reduced or eliminated entirely as the vehicle warms up.
Aside from that, poor LPG installation and tuning is a common cause of excessive vibrations for many motorists (for example, when the system immediately supplies gas to a cold engine without starting the engine on gasoline).
Finally, transmission issues may be to blame for higher vibrations in some circumstances.
Conclusion
In order to find out why your automobile shakes when it starts, a thorough examination of all of the listed components should be performed, not just the engine itself. Engine mounts are a good place to start because they are frequently the source of vibrations in vehicles.
