11 Causes of Car Losing Power When Accelerating (Diesel & Petrol Engine)

If you are driving your car and notice that you are losing power as you accelerate, there can only be one of two reasons for this. Either you do not have enough fuel in your vehicle or you do not have enough power. And there are many reasons why your vehicle losing the POWER especially when accelerate, some common causes are:

  • Mechanical problems such as: Low compression, Clogged fuel filter, Dirty air filter, Clogged Exhaust Manifold
  • Malfunction of Sensors such as: camshaft position sensor, MAF sensor, Oxygen sensor, Crankshaft sensor and all sensor relative to the EFI system.
  • Malfunction of Actuators such as: Bad injectors, bad fuel pump, bad spark plugs

11 Causes of Car Poor Power When Accelerating in Diesel & Petrol Engine

There are little different causes between diesel and petrol engine. For more information, please see 11 possible causes below:

1. Low Compression (Diesel & Petrol Engine)

In order for a car’s engine to function properly and provide adequate power to the vehicle, there must be great cylinder compression throughout the combustion process. If the compression is low, then the power of the engine will be low. The result will be an engine that does not function properly.

2. Clogged Fuel Filter (Diesel & Petrol Engine)

The fuel filter is located in between the fuel injectors and fuel pump of your vehicle. The job of the fuel filter is to screen the gasoline for any impurities which may exist in it. That way, when the fuel pump sends the gasoline into the engine, those impurities won’t be there. The fuel filter is literally a barrier between the contaminants in the gasoline and the engine of your vehicle. If you were to have a dirty fuel filter or one that couldn’t perform its job properly because it’s damaged or clogged, then those contaminants would find their way into the engine. Once that happens, the engine will eventually lose its power and the overall functionality of the vehicle will be impaired.

3. Bad Air Filter (Diesel & Petrol Engine)

The internal combustion chamber of an engine is responsible for mixing gasoline and air together in order to generate the power that is needed to run your vehicle. Before the air can enter the chamber, it must pass through an air filter that screens out bugs, debris, and other kinds of impurities that may exist in it. If these impurities were to get into the engine, they would damage it immensely. However, air filters tend to get clogged after they’ve been used for a while. Once an air filter gets clogged, it will limit the amount of air that can get into the internal combustion chamber. This will negatively impact the functionality of the vehicle because the engine won’t be able to generate a sufficient amount of power to run the car.

4. Clogged Exhaust Pipe (Diesel & Petrol Engine)

There are two filters in an exhaust pipe; the muffler and the catalyst converter. The job of the catalyst converter is to cut down the amount of pollution generated from the exhaust gasses. As for the muffler, its job is simply to decrease the amount of noise that is made. If the exhaust pipe or any of its filters were to get clogged, it would weaken the functionality of the engine by reducing its power and making the vehicle drive slow when trying to accelerate.

5. Camshaft Position Sensor Malfunction (Diesel & Petrol Engine)

The vehicle’s camshaft position sensor is responsible for gathering information about the camshaft speed of the vehicle and then sending it to the electronic control module. This module is a computer which exists inside most new cars that are made nowadays. Once information about the camshaft speed is sent to the ECM, the computer will then manage the timing of both the fuel injection and ignition based on this information. However, if there is a malfunction with the camshaft position sensor and it’s not able to send this information to the ECM, then the performance of the engine will be greatly impacted and likely won’t be able to function properly.

6. MAF Sensor Malfunction (Petrol Engine)

The main responsibility of the Mass Airflow Sensors is to measure the amount of air that flows into the engine and then report this amount to the Powertrain Control Module. From there, the module will use this information to calculate the load that is being placed on the engine. If there were to be some sort of malfunction with the sensors, then the engine’s performance would be diminished.

7. Oxygen Sensor Malfunction (Diesel & Petrol Engine)

When exhaust gasses leave your vehicle’s engine, the amount of gasses which leave is measured by the oxygen sensor. The electronic control module then uses this information to figure out the real-time air-to-fuel ratio that exists in the vehicle’s engine. The oxygen sensor is positioned inside of the exhaust stream. It enables the engine timing and fuel injection system to do their jobs efficiently. The oxygen sensor even provides support with emission control as well. But if a malfunction were to take place with the oxygen sensor, then it wouldn’t be able to accurately send information about the air-to-fuel ratio to the electronic control module. This would cause the engine to start performing poorly and it would ultimately have a negative impact on the environment.

8. Bad Injectors (Diesel & Petrol Engine)

A fuel injector is an important management component of a vehicle’s engine. They are located within the fuel system of a vehicle and their main job is to spray fuel inside of the engine. The computer of the engine is what controls the fuel injector and the specific time intervals and patterns in which the injector sprays fuel into the engine. That way, the engine can perform the best that it can under different driving conditions. You will find that most vehicles on the road these days have fuel injectors in them. If a fuel injector were to become damaged or malfunction in some way, then the engine would not be able to generate a sufficient amount of power to run the vehicle. You can expect all kinds of engine performance problems to take place since the fuel injector is a crucial part of the fuel system.

9. Bad Or Weak Fuel Pump (Petrol Engine)

The responsibility of the fuel pump is to take fuel from the gas tank and transfer it into the engine of the vehicle. Not only that, the fuel pump ensure that the fuel is delivered at the right pressure so that it can meet the demands of the engine for maximum performance. If something were to malfunction or go wrong with the fuel pump, there would be acceleration problems with the vehicle and the performance of the engine would ultimately be jeopardized.

Read also: Symptoms of a bad throttle position sensor

10. Bad Spark Plugs (Petrol Engine)

Spark plugs are an important component of a vehicle’s internal combustion motor. After the ignition coil sends an electrical signal to the spark plugs, they transmit that signal to the combustion chamber so that its air & fuel mixture can be ignited by an electric spark. If the spark plugs were to ever fail, then the engine’s performance would diminish and eventually fail altogether.

Read also: Causes of Car High Fuel Consumption in Diesel and Petrol Engines

11. Bad Ignition Coil (Petrol Engine)

The ignition coils of the ignition system serve as an electronic engine management element which is responsible for converting the 12 volts of power generated by the vehicle into 20,000 volts. This amount of voltage is needed in order to generate the electrical spark which can ignite the air & fuel mixture of the engine. If the ignition coil were to fail, then the vehicle would be unable to accelerate and its power would be lost.

Another Causes of Vehicle Poor Power

  • Bad Turbo charger
  • Bad EGR valve
  • Bad Injection pump delivery valve ( Conventional Diesel Engine)