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Most Common Symptoms Of A Faulty Mass Air Flow Sensor



Vehicles are becoming increasingly complicated as they have a greater number of electronic components. When these parts fail it is not always as easy to diagnose the problem as with an older, simpler engine.

In many cases, you’ll need to find a reputable expert in car services in North Sydney to help you diagnose the issue. They can plug your vehicle into the diagnostic machine and identify the issue.

However, in some cases, such as the mass airflow sensor, it is still possible to identify the fault through the symptoms displayed.

The Role Of the Mass Airflow Sensor

The mass airflow sensor or MAS monitors the amount of air entering the vehicle’s engine and tells the central computer. This then calculates the amount of air that is needed depending on speed, acceleration rate, and several other criteria. In turn, the ECU will control the flow of air and other combustion components to ensure the engine runs smoothly.

If the MAS becomes faulty you will notice several issues with your vehicle.

  • It becomes difficult to start

This happens because the MAS isn’t sending the correct information to the ECU. It is, therefore, impossible for the ECU to get the right balance regarding air and fuel, you’ll struggle to start the car.

  • Hesitates when accelerating

A lack of air means your engine isn’t burning cleanly and the pressure in each piston on combustion will vary. This will cause the car to hesitate as you try to accelerate.

  • Can stall straight after starting

Because the engine is cold and the MAS is still sending incorrect information it is likely to stall as soon as it starts. You may need to start it several times to get it running.

  • Your engine sounds like it has hiccups

The hesitation when accelerating due to a faulty MAS will result in your engine sounding like it is hiccupping.

  • You can smell fuel from the exhaust

When the mixture is wrong due to the wrong amount of air being introduced there will be either too much or too little food in the chamber. Too little causes the engine to run lean, causing acceleration problems. In contrast, excess fuel will cause it to run rich and you’ll notice the smell of fuel from the exhaust as it hasn’t been burnt properly.

When this happens you’ll also be shortening the life of the DPF.

Clean Or Replace

The decision regarding this will be made by you in conjunction with your mechanic. In many cases, the MAS has simply become clogged due to dust and other debris in the engine. It can be cleaned by blasting it with an air pressure line.

You can also place it inside a plastic bag with some rubbing alcohol and gently swirl it around. This will remove the dirt and grime, potentially allowing it to work properly again.

It’s always worth trying this approach. But, if it doesn’t work you’ll want to replace the MAS. It’s a surprisingly simple job. But, remember that the wires are delicate, so it’s best to avoid touching them.

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