gcheddar

My check engine light came on, so I checked it out with VAG-COM and got code 17521/P1113 about air flow resistance getting too high (intermittently). I figured, maybe, the air filter is in need of cleaning (it's one of those reusable K&N filters).

So I took the filter out, cleaned it with the K&N cleaning spray, rinsed it, dried it (though, maybe not long enough), oiled it with the K&N filter oil, applied some K&N sealing grease to the edges (maybe I was too messy here with the grease), then plopped it back into the car (2000 Audi A6 4.2 ART).

I cleared the codes and started the ignition. It sounded funny upon startup - like maybe some cylinders weren't firing - not the usual purring roar. But after several seconds the engine sound went back to normal. I took it out of the garage and drove around for about 15 minutes.

Upon heading back home, I came down an exit ramp off the highway and braked for a red light. When the light turned green I tried to go, but couldn't - the engine had stalled and the battery indicator lit up in the instrument cluster.

I quickly scrambled to get it going. I put the car in park, turned off the engine and turned it back on and everything was fine.

Well, I suspect not fine. But does anyone have any ideas on what to check? I'm kind of thinking I mis-cleaned the filter. But either way, I'm wondering how to fix.

TheSilverBullet

I believe this is why most folks on here would say that you shouldn't use those K&N air filters in our cars.

Apparently, the MAF is very sensitive and any excess oil (or other foreign materials) will cause erroneous readings. I've even heard that too much oil can actually permanently damage the MAF (hopefully this isn't the case for you).

Of course, there are others on here who have been running a K&N filter for years and never had a problem. I suppose that if you are very careful when cleaning/re-oiling the filter, it may not be an issue. However, personally I would rather err on the side of caution, and I always use the Audi OEM paper air filters, which I change after every other oil change (I do my oil changes every 3k -- again on the safe side -- so this results in the air filter being changed about twice a year).

I would recommend cleaning the MAF (there are several products for this, I use one made by "CRC") and replacing the K&N with a paper filter, if for no reason other than to troubleshoot. Also, when cleaning the MAF and replacing the filter, make sure to clean out any excess grease or oil that is left behind by the K&N filter and/or in the hose between the filter and the MAF.

Hopefully this solves your problem. If not, you may want to test the MAF.

gcheddar

Thanks for the suggestion. I'll try it out. As for the cleaner you recommend, are you referring to their degreaser products (like these: http://j.mp/crccleaner).

Just Me

i'll answer that - no. Specific MAF cleaners are made by a couple companies, primarily CRC and 3M. They are expensive but wont damage your hot wire system.

G

Audifanatic007

Definitely clean the MAF sensor with the specified cleaner as previously listed but there is a rather easy way to check the MAF sensor... while at idle disconnect the MAF sensor and see if the idle changes at all....If it does MAF sensor is good, if not then that's you issue.

Redneck Truck

Leaking brake booster or associated vacuum hose?

massboykie

Hey Cheddar

I've had an oiled TrueFlow filter in my car since I bought it and I have never had any issues with oil in the MAF etc. I know that there are people out there that say the oil will contaminate the MAF, but I think a lot of that is based on people over-oiling their filters and then blaming the filter for the problem. My 2c

FYI, I always clean my MAF when I clean the filter (not sure if this is what is saving me, but I suppose it might be). It cannot harm anything and the CRC cleaner mentioned above works great. Here's a link to the info http://www.vaglinks.com/Docs/Misc/CR...aner_05110.PDF

NEVER USE BRAKE CLEANER on the sensor, as it will kill it. Other chemicals might also leave behind a residual layer on the sensor which will cause damage.

Here's another method that I've used with good results, but the CRC is just a lot easier. You can get the alcohol in any pharmacy. http://www.vaglinks.com/Docs/VW/MKIV...eaning_DIY.pdf

Hope that helps.

Cheers
Massboykie

TheSilverBullet

Thanks for answering the question. Here is a link the CRC MAF Cleaner that I was referring to:

LINK

gcheddar

Perfect! Thanks guys! I've got my weekend project all set (also replacing the brake pads).