MAF Sensor cleaning to improve gas mileage!

msanta · Aug 15, 2006

I recently read an article from this month's Consumer Reports which talks about how a dirty MAF sensor can decrease fuel economy. As I was upgrading my OEM air intake to a Volant CAI I noticed how easy it is to remove and check the MAF sensor. For members that are conscious about maintenance and keeping their vehicles in good shape, an excellent idea will be to clean the sensor every time you clean or replace your air filter. I don't know for sure how dirty the MAF sensor can get in our 4Runners but is also good to check it out when we do the air cleaner check. The magazine had an advertisement for CRC MAF sensor cleaner, I think it wouldn't hurt to keep that sensor clean!!!So, all said and done, I will go to the auto parts store today and get a can of sensor cleaner to keep my 4Runner's nostril clean clean

CRC

greasefingers · Aug 16, 2006

:iagree:

The MAF sensor is one of the most critical sensors for keeping the air to fuel ratio correct. I would recommend cleaning this every 30 k miles. Otherwise the resin will thermally insulate the heated wire and thermister. The will cause the engine to think that more air is actually entering the intake. Remove it and spray contact cleaner in it. CRC makes an aerosol Electrical Cleaner that does a good job for this, or use what Msanta listed above. Do not touch the wires but spray the cleaner several times into the MAF. Let it dry in the sun for several minutes. It should not throw a code unless it

jharris2 · Aug 17, 2006

greasefingers said:
:iagree:

The MAF sensor is one of the most critical sensors for keeping the air to fuel ratio correct. I would recommend cleaning this every 30 k miles. Otherwise the resin will thermally insulate the heated wire and thermister. The will cause the engine to think that more air is actually entering the intake. Remove it and spray contact cleaner in it. CRC makes an aerosol Electrical Cleaner that does a good job for this, or use what Msanta listed above. Do not touch the wires but spray the cleaner several times into the MAF. Let it dry in the sun for several minutes. It should not throw a code unless it

msanta · Aug 17, 2006

This is probably the best maintenace job I have ever done so far on my truck. Easy to do and it definitely made the truck more responsive. I will tell you about the gas mileage after I fill up, it also feels very smooth at idle. After 60K my sensor was really dirty, I couldn't take pictures of before and after, but I could see the difference. Afterwards it was nice and shinny.

Light_Mania · Aug 17, 2006

I'm a little surprised that a "hot wire" MAF sensor needs periodic cleaning. These are normally pulsed periodically with high current to incandescense to vaporize anything that might deposit on them.

I'm also a bit puzzled that it wouldn't be factory recommended maintenance if it makes such a difference in mileage/driveablility.

It could be that those who are seeing remarkable benefits are using over-oiled K&N filters.....:cannon:

RL Lemke · Aug 17, 2006

How about some photos describing where & how?

I might add that I have regained the smooth idle I had when the 4Runner was new by using Amsoil fuel stuff with each fill on my recent 4,500 mile trip.

Cleaning the MAF concerns me. I screwed-up a car once by using a spray designed to clean the intake side while running the engine. Never ran quite right after.

greasefingers · Aug 17, 2006

Do not use brake cleaner on the MAF. CRC makes two types of less harsh solvents for this. The 4 wires in the MAF are thin and strong (like a light bulb), but heat over time can make them brittle. [RL Lemke] It is my guess that your MAF was ready to go at any moment and while cleaning it, it simply broke.

Next time I clean mine I will take a picture, but on the 4th gen, cleaning the MAF is the easiest maintenance item on the vehicle (easier than changing the HVAC filter). Remove the electrical connector on the air-box tube and the two Phillips head screws. Blast the MAF 3 or 4 squirts and let dry for 5 minutes. Re-install.

msanta · Aug 18, 2006

Those with oil filters that require oil would probably need more cleaning than the ones without it. Also, depending on the environment and driving conditions, you may need to clean it more or less. It's a good idea to check it when you replce or clean your filter and if it is dirty, pump a few sprays from the crc can. It definitely won't hurt!

schwalmy · May 7, 2007

hey team im looking into doing this for the weekend
any tips or suggestions would be really really great
does the batt need to be disconnected?
any help would be great as im new at this
thanks
schwalmy

jeober · May 7, 2007

Cleaning the MAP sensor is a good idea and I've done mine out of curiosity.

However, if the MAP sensor goes bad or bad enough so the air/fuel ratio is sensed too far out of range for the O2 sensor feedback to trim then you'll get a MIL indication. Only then is the engine running out of calibration.

schwalmy · May 7, 2007

whats the "MAP"?

jeober · May 7, 2007

whats the "MAP"?

Oops, I meant MAF sensor which is mass air flow sensor. I mixed up MAP which is manifold absolute pressure sensor.

MAPs are used instead with other methods of engine calibration known as speed/density. If memory serves Ford and Chrysler used this at one time.

greasefingers · May 7, 2007

jharris2 said:
When you cleaned yours, what difference did you see afterwards?

Sorry I did not answer your question before. I have never noticed any difference (from before & after) but I clean mine on a regular basis. I supposed if you never clean it over 100,000 miles then you would probably see a slight decrease in fuel economy?

It falls under the same category as the pvc valve. There is no maintenance schedule for it but if you forget about it then it will gum-up some year and the can cause backpressure which if left too long can cause leaking oil seals.

greasefingers · May 7, 2007

Light_Mania said:
I'm a little surprised that a "hot wire" MAF sensor needs periodic cleaning. These are normally pulsed periodically with high current to incandescense to vaporize anything that might deposit on them.

I have read about this type of MAF (using the pulsed hot wire to burn off any gunk) however, I do not know if the runner has this built into it? I know the 3rd gen runner does not have the pulsed feature.

JB. · May 8, 2007

Here are a couple of pics from my '05 V8. From other pics I've seen, the '03 and probably the '04, too, have MAFs that are in a housing that is slimmer and more cylinderical and, to my eye, look easier to clean. My purpose in cleaning it was to solve <a href="http://www.toyota-4runner.org/showthread.php?threadid=17181" target="_blank">this</a>, which it didn't do. I just sprayed cleaner in every hole in the housing. Didn't notice any improvements from the cleaning at around 20k miles, but I'm glad it's such an easy service to perform.

schwalmy · May 9, 2007

so all wires must be disconnected?
do we spray on the sensors only or also on the connections?
schwalmy

JB. · May 9, 2007

schwalmy said:
so all wires must be disconnected?
do we spray on the sensors only or also on the connections?
schwalmy

I don't remember the details of the procedure because there was nothing important to remember other than be gentle and don't touch any of the sensors. You just pull a couple of screws and you're there. I only disconnected the plug so I could get a better look at the unit. It was electrical contact cleaner so you can spray it all over if you want, but the sensors are in the bottom portion of the housing.

schwalmy · May 9, 2007

thanks very much!

Even Steven · May 9, 2007

msanta said:
I recently read an article from this month\'s Consumer Reports which talks about how a dirty MAF sensor can decrease fuel economy. .

The magazine had an advertisement for CRC MAF sensor cleaner,

Consumer Reports had an advertisement in it? I thought they did not allow advertisements?

greasefingers · May 9, 2007

Re: Re: MAF Sensor cleaning to improve gas mileage!

Even Steven said:
Consumer Reports had an advertisement in it? I thought they did not allow advertisements?

The have advertisements for the most common reason

MAF Sensor cleaning to improve gas mileage!

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