Can a Bad Alternator Cause Engine to Shake?

Can a Bad Alternator Cause Engine to Shake

An alternator is important for the continuous running of a car and it is designed to last a long time. However, just like other parts of a car, the alternator may go bad and need replacement.

If this happens you will be faced with various problems that need immediate fixing in the car. But the question is, can a bad alternator cause Engine to shake?

A bad alternator can cause the engine to shake if it fails to provide enough power to spark the plugs. Since the alternator provides the power that charges the battery, if the spark plugs are not supplied with enough power to spark due to a bad alternator, it will cause the engine to shake.

What Does it Mean for a Car Engine to Shake?

A shaking car engine means the engine is vibrating and depending on the problem could be a rattling noise.

Engines are usually held in place by engine mounts that prevent them from moving around but due to a worn-out mount or some other issues in the engine, the engine may start shaking.

Normal shaking is not unusual when a car engine is operating at an optimum level, however, you should be concerned when the shaking/vibration increases beyond normal.

You will know it has gone beyond normal when you are hearing rattling noises coming from the engine area.

Can a Bad Alternator Cause Engine to Shake?

A bad alternator will most definitely cause an engine to shake. Amongst others, one sign of a bad alternator is engine shaking which may lead to car shaking.

An alternator is responsible for charging a car’s engine and other electrical components therein, this is done through the conversion of chemical energy to electrical energy. Over time, as a result of use or wrong connection, the alternator can go bad or get worn out.

Other than charging a car’s battery, the alternator also provides power that causes a spark on the spark plug. If in the process of causing a spark, the spark plugs misfires, there will be a shaking in the engine, this will in turn cause the car to shake.

A damaged alternator will not provide electricity enough to power the spark plug, insufficient power to the spark plug will cause engine shaking and may even result in the engine going off.

The process of causing a spark by the alternator is usually while the car is been driven hence the possibility of it going off. If this happens, you will most likely see the check engine light on.

What Other Things Can Cause Engine to Shake?

A shaking engine is not an uncommon thing in a car and a number of issues or problems in the car are known to be the cause. It has been established that a bad alternator can cause an engine to shake, now let’s look at some other causes

1. Bad Timing Belt

One of the many causes of engine shaking is a faulty timing belt. A timing belt works by connecting and synchronizing the rotation of the camshaft and crankshaft in time for unobstructed combustion.

Timing belts are made from rubber; therefore, they get worn out easily.

A faulty timing belt will cause engine components controlled by it to underperform, underperformance by turning at an inconsistent speed which will lead to shaking and noises from the car’s engine.

2. Faulty Fuel Intake System

The fuel intake system ensures that the right amount of fuel is injected into the cylinder for internal combustion to take place. When the fuel intake system goes bad the engine is sure to shake and vibrate.

All that may be required to fix a faulty fuel injection system may be the components of the system so that fuel can go through easily.

3. Worn Out or Broken Engine Mount

Engine mounts are in place to ensure a car’s engine doesn’t shake with the continuous movement of the car. Most cars usually have at least four mounts, if any of these mounts get worn out then the engine may be unbalanced which will eventually result in its shaking or vibration

4. Faulty or Worn Out Spark Plugs

This can be said to be the most common cause of engine shaking. When spark plugs get faulty or worn out, they misfire or do not fire correctly on the cylinder. If this is the case, you will have to replace the worn-out spark plugs with new ones.

5. Loose Hose

Loose hose whether air or vacuum hose is another reason why an engine can shake. If this has been established to be the cause, all you need to do is a screw and reattach the hoses back in place.

6. Engine Failure

An internal engine failure is a worst-case scenario. Some mechanical problems and broken parts in the engine will cause not just vibration but serious shaking of the engine and car. Nobody wants to experience engine failure but it happens.

What to Do When your Engine is Shaking?

Knowing what to do when an engine is shaking is dependent on the cause. Different cause requires a different solution.

In determining what to do, you will need to first troubleshoot to know the root cause of the shaking. Now let’s look into some of the causes of a shaking engine and proffer solutions.

If your engine is shaking as a result of a broken or worn-out motor mount, you will need to replace it. Before replacing, you should also check other mounts to know if they are in good condition or will go bad soon

In a situation where your engine is shaking because of a faulty fuel intake system, all that may be required is a thorough cleaning of the injection system and in more serious cases you should have it repaired or replaced.

For a bad timing belt, you definitely need to get a new one and ensure it is properly installed to avoid slipping or falling out.

Cons of a Shaking Car Engine

Although normal shaking is common, once it increases there are downsides to it. Some of the downsides of a shaking car engine are;

  • It Could Lead to More Serious Problems in the Engine: If you notice your engine shaking, the best thing to do is find the cause and fix it. Failure to fix the problem in time will lead to more serious problems in the engine, even engine failure.
  • Uncomfortable Driving: For someone that likes noiseless driving and others, a shaking engine will make driving uncomfortable and rough. Normal shaking may increase to rattling noises coming from the engine area which makes driving uneasy.
  • Spending Money not Planned for: If you do not have any kind of car insurance, you will be spending money you do not plan for on repairs and replacement. To prevent this, fix all causes of engine shaking as soon as you can.


Routine and timely maintenance is an effective way of easily detecting problems in a car. If you are unable to find why your car is shaking, take it to an auto shop, they will be able to find the problem and proffer a solution.