Why is your car losing power?

Every car owner wants their vehicle to operate perfectly for as long as possible. Of course, without proper maintenance, a vehicle will eventually give up on you. In this article, I want to share some important aspects of why your car might experience a loss of power.

I will start by pointing out the worst causes, moving towards issues that can be fixed on the driveway.

Low compression

This is the worst scenario you could expect, but in some cases, compression was not the cause of power loss. When one piston experiences low compression, the vehicle will idle rough, and misfire might occur. If all pistons have low compression, then the car will not start.

Compression issues and power loss is more common in older cars. This is caused by engine components wear such as piston rings or the issue might be more hassle-free, only needing a carbon clean to clean blocked parts.

Bad Fuel Injectors

Most vehicles on the road are fitted with fuel injectors unless the car is old and has a carburettor. Fuel injectors are responsible for giving the right amount of fuel needed for the combustion process. The vehicle’s ECU is responsible for the fuel injectors and the amount of fuel they spray.

If the fuel injectors were to become damaged, then the correct amount of fuel would not be sprayed, and the vehicle would not be able to generate a sufficient amount of power.

Pay attention to dirty fuel injectors, in some cases the car’s injectors are dirty and do not require replacement. Consider buying some injector cleaner from time to time. It could save you thousands in the long run.( Click here for diesel injector cleaner) (Click here for petrol injector cleaner)

Bad Fuel Pump

The fuel pump is responsible for pumping fuel from the vehicle’s fuel tank to the injectors at a specific pressure set by the car’s manufacturer. When the ignition is turned on the fuel pump gets pressurised ready to pump fuel once the vehicle is started.

A sign that the fuel pump is damaged is of course loss of power, but misfire can also occur once the vehicle is started. In some cases, the vehicle will not even start. Also, listen for a whining noise once the ignition is turned on., it can indicate fuel pump issue.

Diesel Particulate Filter (DPF) (Diesel Engines)

The DPF is responsible for collecting the soot from the combustion process in a diesel engine. DPF is located under the car on the exhaust system. If a diesel engine is not driven correctly the DPF could get blocked with soot. Regeneration is required for the DPF to clear itself from the soot collected. Therefore, if the vehicle is driven in a city or on short trips, the DPF will not be able to regenerate.

A blocked DPF will cause a loss of power due to blockage on the evacuation system.

Read more: Diesel Particulate Filter (DPF)

Bad spark plugs/ignition coils (Petrol engine)

A petrol engine requires a spark inside the engine cylinder to cause an explosion for the piston to move up/down and create compression.

The ignition coils are responsible for the electricity provided by the car’s battery to the spark plugs for a spark to be created. This spreads a signal to the combustion chamber so the air and fuel mixture can be ignited.

The spark plugs on a petrol engine should be changed on every other service.

If the spark plugs or ignitions coils fail, the performance of the engine will fail too. Depending on the vehicle, there is an ignition coil and spark plug on every cylinder, if one fails, it will affect the performance of the car.

Mass Airflow Sensor (MAS)

Mass Airflow sensor is responsible for the measurement of air flowing into the engine and fuel mixture of your vehicle. A wire sends signals to the vehicles ECU which then knows how much air and fuel is needed for the combustion process. The MAS sensor is located between the airbox and the intake manifold.

Over time the sensor could get dirty with fine dust particles and the readings could be incorrect. I advise when servicing the car to clean the sensor with an electric cleaner or MAS cleaner.

A bad reading from the sensor will cause a loss in engine power.

Owning a Renault Traffic van, I experienced this issue. Before diagnosing a dirty MAS sensor, I cleaned the EGR valve with no results. After cleaning the MAS sensor, I was impressed with the difference it made.

Dirty Fuel Filter

The fuel filter is easily forgotten when doing a service or even overlook. On some cars, the fuel filter is located under the bonnet but on others is under the vehicle on the fuel lines.

The filter can be neglected, especially on cars where the fuel filter is under the car.

A clogged filter can cause an engine to surge, splutter or hesitate. This happens when you accelerate the vehicle. Under normal driving, the symptoms of a clogged filter might not be so obvious but when accelerating the filter will restrict the flow of fuel needed for the engine.

Dirty Air Filter

The air filter has a major role in the combustion process of a vehicle. The role of the air filter is to hold any debris, bugs and other impurities from the air and keep it from entering your engine which can cause serious damage.

An air filter can get clogged by the impurities collected and restrict the flow of air needed for the combustion process. This will impact the functionality of the car because the engine will not be able to regenerate the power it should.

Everything in life is somewhere else, and you get there in a car.

 E. B. White

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