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BMW 330i Air Mass Meter

How to Check the BMW 330i Air Mass Meter for Problems

The air mass meter, also known as the mass airflow meter, is an integral component of the computer-controlled engine found in most modern cars like the BMW 330i. It measures the volume and density of air entering the engine then sends the information to the engine computer. This computer then uses the measurement to adjust spark timing, fuel delivery, and spark advance. When the air mass meter is faulty, you may experience a rough idle, poor gas mileage, and even stalling. In order to keep this from happening, you have to know how to identify problems with this component.

Activated "Check Engine" light (CEL) on the dashboard

When the CEL is on, it could be due to numerous problems with your engine including the air mass meter--you will have to read the codes from an engine code scanner to learn what the problem is. It's considered safe to drive around even when the light is on. However, once it flashes you must get it checked out immediately. Do remember, though, that when you drive around with the CEL on, your car's engine will not be working at its peak. Because of this, you may experience a loss in power and a decrease in gas mileage. It is therefore recommended that you take care of the problem as soon as you can.

Using the engine code scanner

Spotting problems using the scanner is easy, because it already has pre-programmed problem codes that it can identify. The engine code scanner works by comparing the values output by the air mass meter to the expected values that it should be getting. This simple check-up helps diagnose problems with pretty much every component in the engine.

To examine any possible problems, plug the device into a jack found in or near the driver's side fuse box. It will then automatically scan the entire engine and give out codes. In order to know what these codes mean, refer to the engine code scanner or the car owner's manual. The usual error codes relating to the air mass meter are P0171, P0172, P0174, and P0175.

Other symptoms and troubleshooting tips

Along with the CEL being lit, other signs that the BMW 330i air mass meter include sudden loss of power, slow increase in acceleration, knocking and pinging sounds in engine, and poor gas mileage. Regardless of whether the CEL is lit up or not, if you notice any of these symptoms, take out the air mass meter to replace it.

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  • How to Keep your BMW 330i Air Mass Meter Clean and Efficient

    Your BMW 330i air mass meter is responsible for identifying the amount of air entering your car's engine, and then passes on the information to the engine control unit (ECU). The ECU, in turn, uses the given measurement to balance and deliver the correct fuel load to the engine. However, if the air mass meter is dirty, it won't be able to measure the airflow properly. This would then result to loss of your car's power, decrease of its gas mileage, and appearance of an error code. In order to prevent this from happening, you have to clean your air mass meter.When to clean the air mass meterUnlike other car parts, the air mass meter has no cleaning schedule. This is because it has its own cleaning cycle that activates automatically. Right after the engine shuts down, a short piece of wire found inside the air mass meter is heated to a very high temperature to burn off deposits. When the cleaning cycle fails, dirt starts to build up in the component, which would then lead to your car losing power. Once you notice any signs of a failing air mass meter, then it's high time for you to clean it.Tips to cleaning the air mass meter

    • Remove the air mass meter from the vehicle before cleaning it.
    • Make sure that the air filter, its housing, and all of its ducts are intact, clean, and not leaking dirt.
    • To clean the air mass meter, put the component in a ziplock bag containing a full bottle of 70-30 isopropyl rubbing alcohol and swish it around. To make sure that all the dirt is removed, leave the component in the bag for 20 minutes.
    • If you'd rather use a product that's really meant for the air mass meter, you can find one in an auto parts store. While an aerosol carb cleanser usually does the trick, there are also products less prone to dissolving small components in the air mass meter.
    • Make sure that the component is completely dry before installing it back into the engine, as the cleaning product or alcohol could cause major damage on other components.