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Visiting Old Volks Home
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Discussion Starter · #1 ·
mass air flow sensor cleaning guide
procedure summary
This is a guide to cleaning the Mass Air Flow (MAF) sensor, infamously known to VW owners as a problem part. This problem seems to have become
more widespread with the release of the Mk. IV platform, which is apparently due to a bad batch of sensors from the Bosch factory. Although most of
the faulty MAFs have been weeded out after having failed on their owners, the more hardy MAFs often survive until just after the car's warranty
expires. In most cases the owner is left holding a bill for several hundred dollars for a new MAF and labor costs.
The reason this guide was created is to help those owners who are having trouble with their MAFs. Symptoms include poor gas mileage, reduced
power, poor engine performance, and often result in the MIL (Malfunction Indicator Lamp, also known as the "check engine light") being triggered.
This guide was designed specifically for people who either have had no positive results after multiple dealer visits regarding MAF related service, or
are out of their warranty period.
tools needed
 Philips head screwdriver
 A helping hand or a vise grip of some sort
 91% Isopropyl Alcohol
 Large Ziploc bag
 Compressed air cleaning spray
 Paper towels
removal instructions
1. Open car hood.
2. Unplug the MAF sensor, (see pic 1 and 2).
3. Locate the two Philips head screws that secure the top of the airbox and loosen them (see pic 3).
4. There is a ring that holds the hose onto the MAF, get your vise grip and press the two tabs together to loosen the ring's grip.
5. Lift the airbox's top off by pulling upwards and towards the car cabin. There is a smaller corrugated hose connected to the airbox top
dierectly below the MAF sensor, remove that by pressing the two press points together.
6. On either side of the MAF are two philip's head screws that hold it in place, remove them.
7. The hole that the MAF sensor resides in has a rubber ring that creates a seal, also making in difficult to get the sensor out, some wiggling
and pulling will free it.
cleaning instructions
1. Take the large Ziploc bag and place the MAF sensor in it.
2. Pour enough Isopropyl alcohol into the bag to completely cover the MAF sensor (see pic 4).
3. Gently shake the bag to allow the alcohol to pass through the sensor.
4. Take the MAF sensor out and let the excess alcohol drip off (see pic 5). Dipose of the Isopropyl alcohol according to local laws.
5. Set the MAF sensor down on a paper towel to drip/air dry (see pic 6). You may want to use the compressed air spray to blow dry parts such
as the connector port.
6. Allow the MAF sensor to dry completely before reinstalling it in the car. This will take between 1-12 hours.
7. Reinstall using the above instructions in reverse.
 

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We've got one of these that I made up a while ago, except I used the carb cleaner method. I did mention the alcohol method, which I have used before and it worked well, but I will add this to the list as well.

You're gonna get a lot of n00b comments about using nothing but MAF cleaner though lol, take a peak at my DIY discussion.
 

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Visiting Old Volks Home
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150 Posts
Discussion Starter · #3 ·
Ha well I am just trying to go through my list of bookmarks thats like 3 pages long. I'm deleting the old ones and posting a few I found extremely helpful.
 

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Much appreciated. If I was able to work on my car I'd be adding a few to the list, but hopefully after next week I can atleast get a few more up.

Keep 'em coming though, we can always use them.
 

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Visiting Old Volks Home
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Discussion Starter · #5 ·
Much appreciated. If I was able to work on my car I'd be adding a few to the list, but hopefully after next week I can atleast get a few more up.

Keep 'em coming though, we can always use them.

just counted 84 pdf guides that might come in handy for the do it yourselfer
 

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Visiting Old Volks Home
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150 Posts
Discussion Starter · #6 ·
My block just got back from the machine shop :) clean block and new part makes me a happy boy. I just dropped 4 grand on new parts and of course the machine shop. but I just got this mk4 and have plans for this little science project. I thought about looking into wiring in a twin charger. I know it's a huge problem to face but I think with a little wiring I can pull it off
 

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Just drive
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Could a fouled up MAF cause my probs? I have had trouble starting at times. VAGCOM recognized a crap ton of coes and it was recommended I change the 409 relay, which I did. Car still doesn't want to start at times. Could it be a messed up MAF?
 

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Car will run with a bad maf, but really rough. I don't think it would cause it to not start though.
 

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i love bringing up dead threads =D anywho, will cleaning the maf possibly get rid of codes such as running too lean? i was thinking about purchasing a new one but if i can get away with just cleaning id much rather do so. just curious.
 

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G&M Performance
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i love bringing up dead threads =D anywho, will cleaning the maf possibly get rid of codes such as running too lean? i was thinking about purchasing a new one but if i can get away with just cleaning id much rather do so. just curious.
Its a possibility. It will only help if your problem is linked to bad MAF readings. I say just clean it anyways. Its not hard and doesn't take a lot of time. I've clean mine twice since I bought it like 6-7k ago. Noticed a little bit of difference when I did.
 

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well i started getting the codes when i put my sri in...and it hasnt gone away since. its not a huge problem or anything but itd be nice to not see my check engine light come on everytime i turn the car on =P
 
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