engine airflow

Something Your Car Needs to Run…Engine Airflow!

What happens when your engine is sucking in too much oxygen, or too little?

This week on Cars 101 – oxygen. Something your engine needs to run. But what happens when your engine is sucking in too much oxygen, or too little? Well, most cars nowadays can account for that. Cars have a special sensor called the mass airflow, or MAF, sensor, to measure the amount of air flowing into your engine. But what if this sensor malfunctions?

A faulty MAF sensor can cause several problems with your engine’s performance, including but not limited to a rough idle, mild to severe hesitation during acceleration, loss of fuel economy, loss of power, and even stalling out, whether your car is automatic or stick shift. In the ‘80s and ‘90s, MAF sensors were in an evolutionary phase, and cars from these decades are very likely to have unreliable, weak MAF sensors.

What the MAF sensor is responsible for is converting air flowing past it into an electrical signal, which is read by your car’s ECU. When the volume and density of the air flowing past that sensor changes, the ECU makes minute adjustments to the air/fuel mixture and injector timing in order to optimize performance, emissions, and economy. If the MAF sensor becomes dirty or malfunctions, or a wire wears out, then your car will almost certainly run rougher, waste more gas, lose power, and jerk or stall.

Problems with your MAF sensor can also cause the dreaded check engine light to light up, but the code may not directly tell you that your MAF sensor is malfunctioning. It could indicate anything from an O2 sensor to “low air volume” or similar description. Problems with the MAF sensor can be related to wiring, the sensor itself, actual airflow, a vacuum leak, or leak or tear somewhere in your intake system.

In actuality, symptoms or codes which seem to point to a bad MAF sensor may not be related to the sensor at all. For example, one common condition in higher mileage cars is that the duct running from the air filter to the throttle body gets torn, allowing air to enter the intake system past the MAF sensor, causing your engine to get more air than the computer accounts for. This can cause the same symptoms and codes as MAF sensor failure.

Another possibility is simply that your MAF sensor is dirty. Any vehicle with more than 20,000 miles could easily have contamination built up on the MAF sensor. As with most automotive maintenance items, the older your car is, the more likely you are to have problems.

Eventually, around the late ‘90s, car manufacturers designed and implemented a self cleaning mechanism which superheats the sensor and burns off any contamination which accumulates. However, on older vehicles, it will eventually be necessary to manually clean the MAF sensor.

Even if cleaning the sensor does not fix your problem, it can only help. Most mechanics recommend that you clean the sensor every time you get a new air filter as regular preventative maintenance. If you experience any of the symptoms of a malfunctioning MAF sensor, call ExperTec Automotive of Huntington Beach today at (714)-848-9222 to schedule an appointment. ExperTec is Huntington Beach’s favorite AAA approved auto shop!