How much?! The air mass information is necessary for the ECU to correctly balance and deliver the correct amount of fuel to the engine. When a vehicle's mass airflow sensor is faulty or defective it can cause a variety of problems, and usually results in very poor performance from your engine.
Symptoms of a Faulty Mass Air Flow Sensor A faulty mass airflow sensor will cause problems similar to low compression or low vacuum, and will also show symptoms similar to when your vehicle has low fuel pressure from a faulty fuel pump.
Here are some of the most common symptoms of a faulty mass airflow sensor:. If you believe your car has a faulty mass air flow sensor, take it to a qualified mechanic so that a complete computer diagnostic can be run. In most cases, a faulty mass flow sensor has a specific code that will generate during computer diagnostics, and is usually easy to determine with computer testing equipment.
Generally, you'll want to clean your mass airflow sensor either every six months, or every time you change your oil. Cleaning it when you change or clean your air filter will be a good way to save both time and money. Remove the Sensor To clean your mass airflow sensor, first, you must take it out. This is done by opening your vehicle's air box and using a flathead screwdriver to pluck it out. When removing the sensor, be sure to never touch the wires.
A disconnected mass airflow sensor can't electrocute you, but the wires are delicate and small. Clean the Sensor Next, you have two choices. The cheapest option would be to take your mass airflow sensor and place it in a plastic bag filled with rubbing alcohol. Take the bag and move it around, making sure the alcohol washes all of the dirt and grime from the sensor. Another option would be to go to your local auto parts store and buy a special mass airflow sensor cleaner, and spray it onto your sensor, but as stated before, this is more expensive.
Dry and Reinstall the Sensor After cleaning your mass airflow sensor with either the cleaner, or rubbing alcohol, let it sit, generally for 20 minutes or more. The sensor has to be completely dry before it can be reinstalled in your car, otherwise you may damage it.
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Here are some of the most common symptoms of a faulty mass airflow sensor: The engine is very hard to start or turn over The engine stalls shortly after starting The engine hesitates or drags while under load or idle Hesitation and jerking during acceleration The engine hiccups Excessively rich or lean idling If you believe your car has a faulty mass air flow sensor, take it to a qualified mechanic so that a complete computer diagnostic can be run.
How to Clean a Dirty Mass Airflow Sensor Generally, you'll want to clean your mass airflow sensor either every six months, or every time you change your oil. Interested in Leasing?If the MAF is bad either because it's not producing a signal or producing an erratic onethe car's idle will return to normal and the car will seem to run fine.
Well, then, this is the article for you.
Before I go on, let me tell you that VW uses several types of mass air flow sensors also known as Air Flow Metersfor the most part they can be divided into two categories. One type has a connector with 4 slots for only 4 male spade terminals and the other has 5 slots for 5 or 4 male spade terminals.
This tutorial is for the MAF sensor with the connector that has 5 slots for 5 or 4 male spade terminals. You'll need to unplug the MAF on your VW to make sure, since some MAF sensors with 5 male spade terminals only have four wires coming out of the connector. The test in this article is for the Bosch MAF sensor that produces an analog voltage signal that can be measured by setting the Voltmeter in Volts DC mode.
It seems to me that the most common fix, in my experience, to solve a MAF issue on a VW has been to just clean it. Well, this MAF sensor easily becomes contaminated with dirt and stuff from the air filter not performing its job or the box that holds the air filter is broken or not sealing correctly. Although I don't have step by step instruction on how to clean it, Googling the subject will bring you a lot of good articles on the subject.
As a last note on the subject, don't use carburetor or brake clean spray or gasoline to clean your MAF sensor with. These solvents can damage the sensor. Also, don't attempt to physically clean the sensor with anything. Your local auto parts store will have a MAF sensor cleaning spray.
The second most common problem I have encountered on most VW's over the years is air leaks between the MAF sensor and the Throttle Body especially true if it's a turbo-charged engine where the plumbing between the MAF sensor and Throttle Body seems to run for miles. It is crucial, yes very critical that you first check that there are no air leaks between these two. Otherwise this air leak will skew the results of your test and you might end up replacing a good MAF and in the process throwing money away.
How do you check for air leaks? With your eyes and hands. That's right, no special tools required.I'm an online writer and proud owner of an Audi 1. The more oil and dirt that accumulates on your MAF, the worse it serves its purpose.
The dirtier it gets, the less accurate the reading it sends to your ECU computer. These readings can cause lower gas mileage and a small loss of power. Cleaning your MAF will not only extend the life of the sensor, but it will also help keep the power level and gas mileage where they should be. So if you feel a lack of power when you hit the gas, or have noticed a change in your miles per gallon, the MAF sensor is the best place to start on your Volkswagen or Audi.
Recently, my new GTI needed a new MAF for emissions, as the old sensor was completely dead from the previous owner running the car with no air filter.
So if you're willing to trust an eBay product, that is also an option. Doing this job as a beginner will take you around 30 minutes if you are replacing the MAF sensor, or around two hours including drying time if you decide to clean the sensor and put it back in.
No special tools are needed for the job. It is very straightforward and easy enough for anyone to accomplish. If you are already showing a "check engine" light on your dash, or you think you are feeling the symptoms of a bad MAF, here is an easy way to check the problem.
Yep, that simple. If you unplug your MAF and your car all of a sudden perks up, then the MAF is more than likely the problem, and cleaning the sensor is a great place to start.
Warning: If your check engine light is not already lit up when you try this test, unplugging the MAF sensor will cause it to illuminate. You can easily reset the light by unplugging the negative terminal on the battery for ten seconds which is what I would suggestor driving for sixty miles so the car can cycle.
If your check engine light is already on, then this is a great test to try, but before you try it, head to your local auto store and get a free scan. The tools needed for this job are very simple. You should have most of them in your garage or tool drawer. I've not listed it for three reasons. If that is the case you can easily find a bit or screwdriver for those screws at any hardware or auto store for cheap.
The chemical that is used to clean the MAF sensor is completely up to you. There is a large variety to choose from at your local auto parts store, or you can use rubbing alcohol from the grocery store for about a dollar.
I always use rubbing alcohol and have never had a problem. It cleans, dries quick, and is cheap. Screws to replace the 5-point Audi Torx screws can be bought at any auto shop.
Another option is to just re-use the 5-star screws and put them back in the same way you took them out. Unclip the harness connected to the middle of the MAF. The clip can be removed using your thumbnail. If it won't pop up, try a small screwdriver. Be gentle so you don't break the clip. Once you hear the clip pop, wiggle the harness off of the MAF.
All of the harnesses use the same type of clip, so once you learn how to release one, you can use that technique for coils or any other harness that needs to be taken off for repair.
7 Symptoms of a Broken MAP Sensor
Here you have a choice: you can either remove the sensor from the housing or remove the housing and sensor as a unit. If you still need to remove the 5-point tamperproof screws, I recommend removing the whole unit.
Once those screws are out, disconnect the other side of the MAF from the turbo inlet pipe. Most VWs and Audis use pinch hose clamps, so use your pliers to squeeze the clamp open and slide off the inlet pipe. When putting the MAF back on, you can use a screw-type hose clamp to save yourself some hassle next time. If you are choosing to remove the sensor only which I recommend if you have regular 6-point Torx screws : Unscrew the two bolts in front of and behind the harness plug.
Gently wiggle the sensor out of the housing.Well, it plays a vital role in helping an automobile to maintain its fuel-air ratio.
Based on that piece of information, the ECU determines the amount of gas that fuel injectors need to send to each of the cylinders.
You should be careful about bad MAF sensor symptoms because a little malfunction in this device leads to poor engine performance. Fortunately, detecting bad MAF sensor symptoms is not rocket science.
Just be alert for these common symptoms:. Hot-wire MAF sensor is the most commonly used sensor. As a result, the engine will run rich at idle and lean when it is running. A change in fuel economy is the only way to detect that there are some problems with the hot wire. If the wire is just dirty, caused by dirt from the oil or spider webs, cleaning it will solve the issue. The engine runs rich or lean because the sensor frequently sends reports that are either higher or lower than the actual airflow.
There is no solution for a damaged sensor but to replace it. The same glitch can be the outcome of an issue with the engine control system.
So, diagnose it if the MAF sensor turns out to be fine. In fact, it is hard to detect this symptom of bad mass airflow sensor when the control system runs smoothly. You have to look into a change in the mileage to spot this issue. These are the bad MAF sensor symptoms that indicate that the sensor is completely out of order.
As a result, the engine either halts or idles roughly. Replacing the MAF sensor is the only solution to this complication. How to tell if your Mass Air Flow Sensor is bad? When the sensor is just dirty, cleaning it up will bring order into a disruptive engine system. Clean it with rubbing alcohol MAF sensor cleaner. Put it back into its place when it is completely dry. Be careful not to damage the wires when removing and reinstalling the sensor.
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Tsukasa Azuma. Show Comments 7.The most reliable early symptom of a failing or failed MAF is the illumination of the check engine light on the instrument panel. After the scan, the scanner will display one or more alphanumeric codes, which may be looked up in a reference book that accompanies the scanner if the scanner is one that does not display the summary of the code on its screen.
If you do this and the scanner codes refer to a malfunctioning MAF, you will need to have the MAF inspected and likely replaced. Mass air flow sensors are rarely repaired, as it is usually more cost-effective to replace them. Because the MAF is instrumental in maintaining proper balance of air and fuel inside the engine, MAF failure can cause a range of engine performance problems.
These may include low gas mileage, shuddering, stalling, knocking or pinging. These symptoms can appear, however, before the MAF fails to the extent that it will register the check-engine-soon light. Sometimes the MAF will begin malfunctioning because it is dirty. Although the air that passes through the MAF is filtered, microscopic particles will still get through and accumulate on the sensor.
In these cases, you may be able to restore it to full functionality by removing and cleaning it. If you remove the mounting bolts and wiring harness, you can remove the entire mass airflow sensor unit and open it to expose the sensor. The sensor is a small unit with two exposed wires; the wires heat up when the car is running, and the MAF measures the airflow by detecting how quickly the flow of air cools the temperature of the wires.
Mass Airflow Sensor Failure
Spraying these wires clean with MAF cleaner or electrical contact cleaner and leaving the MAF to air dry is the best approach to cleaning this sensitive instrument. Once it is dry, it can be reinstalled and the car can be started again. If engine performance is restored or the check-engine-soon light goes off, it is likely that the MAF was dirty and not broken.
Performance Because the MAF is instrumental in maintaining proper balance of air and fuel inside the engine, MAF failure can cause a range of engine performance problems.User Name Remember Me? Mass Airflow Sensor going bad 'maybe', symptoms? Hey all, I had the old check engine light on my jetta TDI a few days ago and noticed what seems like reduced power and while coasting or slightly applying the gas caused the car to buck a little.
I had a local mechanic who put the car on his computer and got the code E out of my car which according to his book was the mass airflow sensor. While checking my cars computer he reset the check engine light and after the car seemed to run ok and even today its running ok but I can feel a slight hesitation during acceleration. So if it is the MAS going are my symptoms what one would experience? And is the MAS just the small sensor part between the hoses or can a E code be everything involved in engine air flow?
Unfortunately my local VW dealer doesnt want to look at the car unless the check engine light is on even though I had the code and the description of the code. Thanks for any info. Doug D. TDI s : Golf 1.
A CEL sets for a reason.
There seems to be some redundancy in the ECM. If a control point fails, performance degrades but the function is often simulated by the ECM picking a fixed substitute value.
That's probably what you are experiencing. The MAF isn't that pricey. I'd tend to believe the CEL and replace the component. Check the charge pipe too. The nibs that hold the upper hose in place tend to wear and the pipe can pop out, but that would be a different code. Fuel Economy: Who cares? Great fuel economy comes as a bonus! If power and performance improves with the MAF unplugged If power and performance goes away with the MAF unpluggedTurbocharged engines may use both, but naturally-aspirated engines typically use one or the other.
By maintaining and repairing your MAP sensor, you'll keep your engine running smoothly. When idling, intake pressure usually ranges from in. Because this is lower than atmospheric pressure, air rushes into the intake. When the driver uses the engine to brake, pressure can go as low as 10 in. Upon accelerating, however, the open throttle body allows air to rush in faster, increasing pressure in the intake.
At wide-open throttle, intake and atmospheric pressure are nearly equal. So, how will you know that your MAP sensor is going bad? Here are the key problems to look out for:.
A functional MAP sensor is a critical part of the maintenance of your vehicle. If you suspect that you may have a problem with your MAP sensor, check the following elements first. Benjamin Jerew. Benjamin Jerew is an ASE-certified Master Automobile Technician with over a decade of experience in auto repair, maintenance, and diagnosis. Poor Fuel Economy. If the ECM is reading low or no vacuum, it assumes the engine is at high load, so it dumps in more fuel and advances spark timing.
This leads to excessive fuel consumption, poor fuel economy, and possibly detonation. Lack of Power. If the ECM is reading high vacuum, it assumes the engine load is low, so it cuts fuel injection and retards spark timing. On the one hand, fuel consumption will go down, which seems like a good thing.
However, if too little fuel is consumed, the engine may lack power for acceleration and passing. Failed Emissions Inspection. Excessive fuel generates higher hydrocarbon HC and carbon monoxide CO emissions, while insufficient fuel may lead to higher nitrogen oxide NO x emissions. Rough Idle.