Does your car shake or vibrate when you start it and then drive smoothly? If so, you are not alone. This a fairly common phenomenon.
It does not matter what car you drive. Below are most common reasons with details car shakes when starting then runs fine. I hope you question in the mind will cleared read these reasons.
The most common cause of your car shaking when starting is a worn engine mount. This means that the engine may shake and move a lot when starting.
Read Below reasons.
Reasons Why Your Car Shakes When Starting Then Runs Fine
Here are some common reasons with detail. Read this and finish of your question about why your car shakes when starting then runs fine.
1) Clogged Fuel Injectors
When the fuel injectors are clogged. They will not deliver the correct amount of fuel or spray pattern to the cylinder.
Any of these problems will result in incomplete combustion in one or more cylinder, which can lead to misfires.
When a car has a clogged fuel injector, the misfires typically become noticeable while driving and worsen when the vehicle goes faster. Misfires rarely resolve themselves. However, sometimes the misfires go away soon after starting the engine.
When starting a cold engine, the ECU uses the programmed fuel map and sensor inputs the determine fuel flow. If the fuel injector is clogged, it will cause imbalance in the fuel-air mixture, resulting in a misfire when starting. This can cause engine vibration, rough idling or even stalling when starting.
Related article: Why does Your Car Squeals When Starting? & Reasons
2) Engine Misfire
An engine misfire refers to a situation in which one or more engine cylinders fail to ignite fuel, resulting in an incomplete combustion cycle. This is obvious to the driver because it usually means the check engine light is on and the engine is running rough.
In some situation, a misfire may only occur briefly when starting the engine but once start the engine runs fine. In this case, the check engine light probably won’t come on because by the time the car detects that there may be a problem, the problem will be resolved and the vehicle will run properly. Common causes of misfire problems include,
- problems with spark plugs
- damaged ignition coil
- Electronic sensor error
- Fuel delivery problems
- Damage ignition cables
3) Low Fuel Pressure
With sufficient fuel supply, the engine will not function properly. Fuel is maintained at a specific pressure to ensure the correct amount is injected into the engine. If the wrong amount of fuel is injected in to the engine, it will run rough.
This can cause the car to shake when starting as the engine needs enough fuel to start the first combustion cycle. Too low fuel pressure can result in insufficient fuel flow and a lean air-fuel mixture. A lean fuel mixture will cause brief misfires when the engine for the first time, which is why the engine will begin to vibrate.
Once the engine starts, the fuel pressure stabilizes as the engine control unit uses real-time data and sensor to detect that more fuel needs to be pumped to compensate for the pressure loss. The engine then runs smoothly. A drop in fuel pressure can occur for a variety of reasons, including:
- Defective fuel pump
- Clogged Fuel filter
- Fuel Leak
- Fuel Pressure regulator defective
4) Problems of Spark Plug
The spark plugs are responsible for igniting the air-fuel mixture drawn into the cylinder. If spark plugs are worn (eroded tips) or dirty (contaminated), this can cause malfunctions.
A dirty spark plug can cause the engine to vibrate when starting but the run smoothly. This because a dirty spark plug is often caused by oil holding the spark plug in place and producing a strong spark. When the engine is running the heat generated inside the engine burns oil contaminated from the spark plug. This means your car is now running smoothly.
More Information: Why does My Car Squeaking When Turning? + Reasons
However, since oil is likely to get back into the cylinder when the engine is cold the oil will contaminate the spark plug again and the same thing will happen the next time you start the vehicle.
5) Engine mounts worn
The engine mounts serve two purposes, firstly they serve to support the engine and the transmission in the engine compartment. The second is to absorb the movements and vibration that the engine and transmission cause while driving. Worn engine mounts are the most common cause of your car shaking when starting. They can also cause the vehicle to vibrate when it is tun off.
When the engine mounts are worn, the engine vibrates excessively and can be felt throughout the vehicle. The initial shock and the movement of the crankshaft as it begins to rotate cause the engine to vibrate more when starting. When the engine revs during gear changes or hard acceleration, there is no load on the engine bearings, so the engine may not shake as much, especially when idling.
6) Loose Components
A loose component in an engine-related component may indicate excessive movement of the problem part when starting the engine. It could simply be a vibration coming from a loose component. A loose component can be caused by one of the following problems:
- The heat shield appears
- Freewheel reel
- Mask not protected
- Exhaust system loose
7) Low oil Level
Although a low oil level can cause problems, it is not the actual cause of engine vibration when starting the vehicle. Oil lubricates the engine rotating components and helps seal the piston in the cylinder.
A low or missing engine oil level means that without adequate lubrication vibration can occur when staring due to friction or contact between metal parts. Additionally, without a sealed combustion chamber, the engine would fall apart. This may only be noticed for a short time if the oil level is low during starting, as a small amount begins to circulate after starting. Motor protection may be sufficient to prevent vibrations.
8) Starter Error
The starter does exactly what is it supposed to do. Its job is to draw power from the battery and turn the steering wheel to start the engine. Since starter motors are not involved in the combustion process, they rarely cause strong vibration in the event of a problem, you may event feel some vibrations.
A starter motor that is not fully engaged with the flywheel can cause the car to have difficulty starting, meaning the vehicle will shake until it starts.
However, once started everything will go completely smoothly. Additionally,
If the starter motor teeth are worn, the starter motor may jump on the flywheel, which will also cause the engine to vibrate when you try to start
9) Timing out
Engine control is the synchronization of the cams with the crankshaft so that everything works precisely and on time. The order in which the combustion cycle occur is as follows:
first, air and fuel are supplied, the piston compress the mixture, the spark plugs ignite the mixture, then the exhaust gases are expelled from the exhaust system. If any of these events occur too early or too late, misfire or improper cylinder operation may occur.
The timing belt and timing chain are responsible for maintaining timing. The belt/chain rotates the crankshaft and camshaft at the same time. If one of these is worn or the pully fails, the timing can easily be mis-adjusted, which can result in vibration or a rough running engine when starting.
10) Damaged Engine
As mentioned above, operating the engine without oil or when the oil level is low can result in engine damage. If damaged, rotating components may become out of sync or out of balance. This causes the motor to vibrate or wobble.
It may happen that the irregular operation is only noticed at startup, However, with this type of problem, the faster the engine runs, the more vibrations and vibrations become. It should be noted that the transition of a damaged engine element from stationary to moving state is much more noticeable than during operation.
11) Power Steering Problems
The power steering system makes steering easier with hydraulic or electrical assistance. If there is a problem with the power steering, you may experience
Shaking or vibration when starting the engine. There are several possible causes related to power steering that can cause your car to vibrate such as:
- Low or dirty power steering fluid
- Level Defective power steering pump
- Power steering belt worn
Why Does My Car Shake Until it Warms Up?
It may not be receiving enough air, fuel or spark to run efficiently. Dirty filters and defective spark plugs can often slow down your engine.
The crankshaft damper can also cause engine vibration. The main function of this part is to prevent vibration. A faulty part can trigger an alarm. The longer you have the problem unresolved, the more intense the vibration will become.
Conclusion
Hopefully You know the answer to your question. This is why is my car shakes When I turn it on. So why not follow this tip in advance to eliminate all because of your car shaking before it happens?