# K&N air filters causing mass air flow sensor to go bad?>?



## JB's Turbo (Jan 25, 2002)

I had a Mass air flow sensor to go out in my new beetle in oct 01. VW replaced it for free thank goodness. In Jan 02 I had the same mass air flow sensor to go out that is 3 months. My dealer states it was going out because of my K&N air filter allowing too much air to pass by the sensor plus it is allowing extra heat to be generated braking down the MAF. Has any one had trouble with the MAF and has a K&N installed? K&N gave me a FULL refund. I can tell a HUGE difference in proformance between my K&N and paper air filter. The K&N is a whole lot better. I want it back. K&N states they will test the MAF on the VW.


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## Brown E (Mar 19, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (JB's Turbo)*

I have to check my MAF...the car is throwing an engine code incorrect air flow. Perhaps the MAF is going bad but i have had the k&n p flo on for a while and have changed it to an HKS custom intake filter. Though i am hesitant to unplug my MAF to check it.


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## DerGolfGTI (Feb 21, 1999)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (JB's Turbo)*

I doubt that's the cause of the failure. We also had a K&N filter in the car and the Mass Air Flow sensor failed about 14,000 miles later. 
The dealer did replace the MAF under warranty and did not suggest the failure was caused by the K&N. My feeling is that there were probably a bad batch of MAFs manufactured by Bosch or whoever makes them - that or its just a poor design. The new MAF has been in there with the K&N for another 12,000 miles so far.
One thing I did wonder about was if the oil on the K&N filter could cause some problem for the MAF. I remember reading someone's suggestion on the forum that over-oiling a K&N might cause problems with the MAF. If there is any relation between failing MAFs and K&N filters, I would be more inclined to believe its related more to that than just flowing more air.
Regards,
Tom
98 GTI (VR6)
00 Bug (1.8T)


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## Brown E (Mar 19, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (DerGolfGTI)*

does anyone know if there are aftermarket high flow MAFs for our cars?


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## Cooper (Sep 11, 2000)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (JB's Turbo)*

You might want to post the same question on the Mk. IV forum. I think it's been discussed there. If I recall correctly, the concern is an over-oiled filter throwing oil.
I've had K&Ns in all my cars with no problems.
I realize that posting is preceding sentence means that the filter is throwing on to the sensor as I type.


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## TDIBUGMAN (May 15, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (Cooper)*

Either the sensor is freaking out because of the increased airflow (not likely) or the oil from the gauze is contaminating the wire in the MAF. When many first install the filter, the MAF is fine; it usually after cleaning it (and subsequent over-oiling it) the sensor fails. Make sure you blot off any excess oil, and keel your MAF clean!!!


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## JB's Turbo (Jan 25, 2002)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (JB's Turbo)*

thanks for the responce. I have thought of the overoiling the filter to be the problem but i clean it every 10k miles and i have not cleaned it since the 2 maf sensors went bad??! I dont know what the problem is.


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## Nitrobug (Oct 13, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (JB's Turbo)*

I thought I was alone here on this one. I had a mass air flow go bad on my 98 NB just about a month after putting the K&N drop in filter in the car. Well I didnt think anything of it and the Dealer replaced it for free ok great. Well that was on 12-11-01 on 12-26-01 I bought a ABD quick flow intake. Everything was fine untill 1-14-02 thats when the check engine light came back on so out came the quick flow and in went the air box with drop in k&n ok so we get to the dealer and they changed the sensor once agian he said he thought oil from the filter got in the MAF and ruined the sensor. So we come back home and after 5 days I put the Quick flow back on, Sure enough the next day my girlfriend is driving the car and calls me at work and says the light is back on. Well once agian out comes the quick flow and in goes the box with K & N. Well once back at the dealer he tells me the car was running too rich and they are putting in a stoc filter and they want me to run the car for 3 or 4 weeks and see if the light stays off. So far so good and it has been 3 days but I miss the power. I have yet to clean the either K&N so they were still in the pre olied state, But i wish I could find a soultion to this problem cause this sucks big time if any one can help please let me know what I can do to get the MAF to stop buring out while using the Quick Flow.
Thanks, 
Brandon


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## rudyr (Nov 29, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (Nitrobug)*

Anyone have any problems with the ITG foam filter?


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## Kevbelz (Dec 27, 1999)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (Nitrobug)*

I have a 01 GTI 1.8t with a garret chip, blow off valve, and K&N airfilter.
A few days ago my car wouldn't start, it would turnover but not start.
SO, I switched back to my old stock chip, and had the car towed to VW for what I thought would be a quick ignition fix.
Well, they called me soon after to tell me that ignition box was bad and needed replacement and my dashboard was blown so they were fixing that. Then 2 hours later they tell me that my Mass air flow blew which blew my O2 sensor because of the K&N, and if i don't bring a stock airfilter to the dealer to put in my car, they are going to void my warranty. So the next day, I buy the friggin $12 filter from the parts department at VW, and bring it to srevice department (12 feet away) they take it happily. Then 2 hours later they call me to tell me the ECU is throwing off all kinds of codes, like the Antislip is not working, the ecu is bad, the mass airflow is broken again, the O2 sensor is blown again. Now, they notice that my ecu is tampered with and tell me that if I want the car serviced under warranty, I need to get a stock ECU back that shows no signs of tampering. 
Anyone have any experiences they would like to share? What do I do next?


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## rudyr (Nov 29, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (Kevbelz)*

At least they're letting you put stock stuff back on and honoring the warranty. Worst case scenerio you're out about $650 for a new ECU and you'll still get to keep it as a spare. Cheaper than paying the list of problems they just told you about!


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## Kevbelz (Dec 27, 1999)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (rudyr)*

The car was running beautifully before this, I can help but think either I f**cked up the ECU while swapping the chips back, or they messed up the car while fixing whatever went wrong with the ignition.


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## rudyr (Nov 29, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (Kevbelz)*

Am I the only person who is going with ITG as an air filter? Placed the order this weekend, but all I ever see is people with K&Ns. I wanted to avoid the oil issue, so I went with lightly oiled foam instead.


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## MADBUG (Dec 14, 2000)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (rudyr)*

Yeah I had a K&N for awhile and ran into the same trouble.The MAF went out,and then some time after that the vaccum was making a strange noise.You,know.When you first start the car and it sounds like a vacuum or a jet getting ready to take off,then a few minutes later it shuts off.I think it's the secondary air pump.Anyway,I ditched the open element and put the factory air box back.The bad sound immeadiately went away.
Technically,the airbox is a better bet anyway.


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## DerGolfGTI (Feb 21, 1999)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (MADBUG)*

There are probably 2 issues in all of this - the MAF may have problems dealing with the extra air from the mods which replace the airbox. I don't think that causes it to go bad, but it may cause a miscalculation in the air or fuel flow and throw an engine code.
*If* anything makes the MAF actually go bad, its probably oil from the K&N. My MAF went bad after having the K&N in for a long time, and I also had not re-oiled it. Perhaps there was too much oil to begin with? I don't know.. then why didn't it go bad sooner? There could just be a bad batch of MAF sensors out there.
Anyone with a stock filter have a MAF go bad?
Tom



[Modified by DerGolfGTI, 3:32 PM 1-28-2002]


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## borch (Mar 1, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (DerGolfGTI)*

My mass air flow sensor went out at about 25,000 miles… stock air box, stock filter. Go figure.


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## Brown E (Mar 19, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (borch)*

What is this incorrect air flow code that i keep pulling? Is this indicating that my MAF is blown or going to to out soon? This code has been on for some time...i cleared it then right as soon as i drove it in the street the CEL came back on. But recently my Forge DV which i have had for about 12000miles is unusually really really loud. My power seems to have been cut down by 13 hp it seems. I dont pull like i used to. And this just started happening yesterday. Or could i have a leak?


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## Kevbelz (Dec 27, 1999)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (rudyr)*

If your filter doesn't cause the MAF problem, I might go with it. keep us informed.


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## Datic (Feb 19, 1999)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (JB's Turbo)*

I've had a K&N drop in in my 99 1.8t since new, and I now have 70,000 miles on it. I've not had any problems with the MAF or anything else like that. Have cleaned it every 25,000 miles, and was very careful not to over oil it...


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## silverspeedbuggy (Aug 8, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (JB's Turbo)*

I have had the ABD system in my car for almost two years with no problems. I have heard of a lot of people with bum MAFs.
Sorry for your problems, I feel for you.


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## Kevbelz (Dec 27, 1999)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (rudyr)*

I got my car back from VW, and no CE light is on. Even though they say that my K&N blew out the MAF and O2 sensor, and even after replacing the K&N with a stock filter, and these were blown again. but no CE light.
Anyway, I am driving my car with stock chip and filter for the day. I feel like an old lady. my car just doesn't GO anymore.
Anyone know if there has been many MAF problems with stock airfilters, and are we expecting a recall? PES (who installed my Garret Chip) says that the problem effects all 1.8t's, not just modified engines.


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## rudyr (Nov 29, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (Kevbelz)*

I thought the MAF problem affected like 1 generation or so of units. I was under the impression that there is a new/improved part #. I'm hoping it made it's way to the 2002s along with the revised window regulator...


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## Nitrobug (Oct 13, 2001)

*Re: K&N air filters causing mass air flow sensor to go bad?>? (rudyr)*

OK Sorry to drag up suck a old topic but I wanted to let everyone know what I found out. Ok first off I talked with a K&N rep at the winternationals drag race here in So Cal last weekend. First off the oli in a K&N filter WILL NOT make the MAFS go bad, Second to cure the problem they told me you have to clear all settings out of the computer. First you make sure you have the 4 digit radio code for your vw. Then you disconnect the negitive batter wire from the battery, Then install your cold air intake ot K&N filter and leave the battery disconected for at least 1 hour then re connect and drive with in 5 miles the computer will read the new settings for air intake and will not throw on the check engine light . I will be trying this soon just want to know if anyone has already done this. Let me know
Thanks,
Brandon


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