What is MAF?Where is it ? How do you clean it?
Did a search could not find.
2005 F150 Lariat

 

MAF is a mass airflow sensor. It is located near the firewall on the air intake. To be honest I'm not sure how you clean it I would assume just blow it out and make sure it's clean.

 

It can be removed from the intake and you can use some aerosol throttle body cleaner on it to remove any debris from the wire. The MAF is very delicate, so don't get real aggressive with it and don't try using any sort of brush on it.

 

Use electronic parts cleaner only, not throttle body cleaner. You can get CRC electronic parts cleaner at Walmart for about $4 or check auto parts and electronic stores. Just spray it on, holding the MAF so the excess drains off. It dries with no residue left. Other types of cleaners may leave a residue that will collect dirt and defeat your cleaning efforts.

It is a simle procedure, takes about 10 minutes and can make a world of difference if yours is dirty.

 

Can somone post a picture exactly where is the MAF?

 

What engine do you have?

 

2005 Lariat 5.4...

 

Here it is. Just pull back the red tab and gently work it loose pulling straight back. Then unscrew the MAF with a hex screwdriver and remove. Clean and replace. That's it!

 

sweet thanks for the info...

 

The Mass Air Flow sensor on the 5.4 Liter is a hot wire type thats uses a temperature sensing resistor (thermistor) to measure the temperature of the air entering the sensor. The electronic circuitry within the sensor keeps the temperature of the wire at 70 degrees C, (160 degrees F) above the temperature of the incoming air.

To test the MAF, perform a thorough visual inspection. Look at the hoses that direct and send air, especiallty between the MAF sensor and the throttle body. Also check the electrical connector for the following:

* Corrosion
* Terminals that are bent or pushed out of the plastic connector
* frayed wiring

I recommend using a good electrical contact cleaner to clean the terminals with such as LPS CFC FREE Electro Contact Cleaner, which is what we use on our aircraft. WD40 and similar silicone based spray aerosols will leave a residue behind that can trap dirt and defeat the purpose of cleaning the terminals.

You can do a simple test to see if the MAF sensor is functioning properly. With the engine running at idle speed, gently tap the MAF sensor with the fingers of an open hand. If the engine stumbles or stalls, the MAF sensor is defective. This test is commonly called the tap test.

If you have a digital multimeter you can test the frequency output of the sensor and compare the reading to specifications. Normal idle frequency for the 5.4 Liter should be 2.37 to 2.52 kHz.

If you suspect the sensor is faulty yet still produces a signal to the computer, the computer will often accept the reading and make required changes in fuel delivery and spark advance. However, if the sensor is not reading correctly, the computer will process this wrong information and perform an action assuming that info is being supplied is acurate. For example, if a MAF sensor is telling the computer that 12 grams of air per second is going into the engine, the computer will then pulse the injector for 6.4 ms or whatever figure its programmed to provide. However, if the air going into the engine is actually 14 grams per second, the amount of fuel supplied by the injectors will not be enough to provide proper engine operation. If the MAF is unplugged, the computer knows that the sensor is not capable of supplying airflow information, so it defaults to a mixed amount of fuel based on the values of other sensors such at the TP and MAP sensors.

If the engine operates better with the sensor unplugged, then suspect that the MAF sensor is defective. A sensor that is not supplying the correct information is said to be skewed. The computer will not set a DTC for this condition because the computer is often unable to detect that the sensor is supplying the wrong information.

Hope this helps you better understand what the MAF does and how to troubleshoot it.

 

Now that is great information thank you...

 

Nice write up.. But could expand on how to use a digital multimeter to read the kHz of the sensor...

 

Would a faulty MAF cause the engine to skip or miss. My engine was missing at certain RPMs then I change air filters and the problem went away for a week or so. Then problem returned so I deduced it was an airflow problem.

Reid

 

You need a true RMS Multimeter to perform the frequency test on the MAF sensor such as a Fluke 87 multimeter. To measure the frequency output of the sensor at the electrical connector simply use a T-pin and gently slide the tip alongside the signal wire toward the metal terminal inside the plastic connector. DO NOT PUNCTURE THE INSULATION of the signal wire itself with the T-pin as this can indeed cause a short! Then use either an alligator clip attachment for your digital multi-meter or a jumper wire with alligator clips at both ends to attach to the T-pin and the positive (+) meter's lead. Turn your meter on to DC volts and select the Hz button for frequency and duty cycle. On the Fluke 87 Digital multimeter the Hertz button is located under the "Hold" button and is marked as "Hz". Once the display comes up and is reading in kilohertz (consult the instructions that come with your multimeter to get it to display this), with the engine running at idle, measure the frequency across the signal wire on the MAF sensor by touching the negative lead of the meter to ground. With the engine at idle you should get a reading of around 2.37 to 2.52 kHz, which is the normal range. Hope this helps!

 

Yes, the MAF can cause this if the sensor is skewed, (not reading correctly).