In Jim Pasha's Tech Forum in the June edtition of Excellence (page 196), he says that he does not recommend K&N air filters for Porsches (968 included) with mass-airflow sensors because the oil gets sucked out of the filter and residue is deposited on the sensor which can be ruined. Or it can throw the sensor out of calibration causing a lean condition that the computer has a hard time trying to compensate for. I have been using a K&N for some time now with no known problems so far. I was wondering if anybody had heard about this or experienced this condition. And what is the best way to check my mass-airflow sensor for oily deposits?
mike
this is yet another perpetuation of bad, or at least incomplete information
this problem arose years ago when a few 928 guys improperly oiled the filter
you are only supposed to apply oil to the forward side of the filter, and very sparingly
too much oil will cause the problems
jim is being overly cautious, taking into account the average user who fails to correctly oil the filter
[quote name='flash' post='35009' date='May 3 2007, 09:24 PM']jim is being overly cautious, taking into account the average user who fails to correctly oil the filter[/quote]
That's what I was thinking. My filter is very ligtly oiled and I would think that iit would take some mega-suction to get any oil off of it.
mike
I had a rich/lean condition. Lean on part thottle @ 3k and rich as oil peddling arab after 4k. I had a CEL for the O2 sensor. Replaced the O2 sensor still had the problem.
I borrowed a MAF from Pete, and it fixed the problems I was having.
I cleaned my MAF and reinstalled it, I have no problems.
I feel my problem was I oiled both sides of the filter. I then had K&N oil on my MAF sensor wire, which threw it out of calibration or affected its sensitivity.
Needless to say make sure you only oil the far side of the filter.
What do you mean by the far side? top or bottom? I recently cleaned and reoiled my K&N and oiled both sides. I guess i will have to clean and reoil it again.
the far side, or front side or forward side is the side that faces the incoming air, as opposed to the side that faces the MAF
the filter comes oiled correctly from K&N - this is how much should be on there - it is a VERY light coat - this is a case where less is truly more
hope that helps
Thanks, Flash. That is what I thought but wanted to make sure. I will reclean and oil my K&N.
What must I remove to visually check my MAF?
Tom
The MAF (Mass Air Flow) sensor is between the two large hose clamps right after the air cleaner cover, loosen those clamps- remove the MAF elec plug (about 1/2" by 2.5" on the bottom side)- remove the air cleaner cover and the MAF will pull right off.
PS.. you can wait till the MAF is free to remove the plug, it's long enough
Can you clean the MAF with carb cleaner while its in the car, engine running type of thing? Lots of smoke, I know, but is that safe <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />
[quote name='Renalicious' post='35048' date='May 4 2007, 05:25 PM']Can you clean the MAF with carb cleaner while its in the car, engine running type of thing? Lots of smoke, I know, but is that safe <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />[/quote]
No, it is best to remove the MAF to clean it. [color="#ff0000"]DO NOT TOUCH THE SMALL WIRES INSIDE! [/color]
[color="#ff0000"]
[/color][color="#000000"]There is a speacial cleaner for the MAF. If you are not having any problems, it is probably best to not mess with it.[/color]
Do not spray the MAfs while the car is running. There is a wire that you can see if you remove the air cleaner housing, this is what you need to be clean. You can run a Q-tip with carb cleaner up and down this wire in order to clean it.
The wire heats up and a reading is made by the car from the air passing over it. If the wire is coated with oil it will take more current to make the reading and show a lean/rich mixture. A clean wire is a happy wire(did he just say that) and that is what we all want, isn't it?
The Oaks just ran and the Derby is tomorrow(read tooo much beer)
Signing out from KENTUCKY "THE BEST 2 MINUTES IN SPORTS"
You need to be very careful when cleaning the MAF sensor. The wires inside can be a little delicate. Most auto stores carry the cleaner. Remove the MAF from the car. Just spray the cleaner in the housing and let it sit so that residue can drain out.
I am up in the air about K&N. My Passat had a K&N drop in for at least 3 years. I have cleaned and reoiled about twice in those 3 years. I've stopped using it cause it seems that my MAF is starting to not work as well. I have been getting very bad gas mileage. Though it has not thrown any codes yet, my mechanic and I have narrowed it down to the MAF. Have already replaced the O2 sensors and that did not help. Now I'm sure a lot of you will guess that I did something wrong like over oiling it. I did not. I would spray it once very lightly and let it sit so that the oil will spread on its own. I may go back to using K&N filters someday but I don't think anytime soon till I can find out for sure what is causing the poor MPG. Just be careful.
Hmmm, I'm considering cleaning my MAF on the basis that my idle is a bit rough, and I may have over oiled my K&N back when I cleaned it last year. I noticed there was quite a bit of "sticky-ish" dust at the bottom of the airbox, so I think it was excess oil from the filter. Although my MPG isn't that bad (I don't think) it hasn't changed since last year averaging about 20 MPG highway / city. Then again, the idle might be rough because the car is driven only one a week <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />
EDIT: Ok, I have bought some intake cleaner at NAPA, Pro-flo, or something (I can't quite remember off hand lol. The logo is an angry drop spraying himself with something, hehe). They're a brand that has a lot of other products however. Also got a K&N recharge kit, I figure it's about time to clean it anyways as its looking rather dirty everywhere.
I use the CRC MAF sensor cleaner each time I change oil and filter and clean and reoil my K&N filter element (5,000 mile interval). After cleaning the filter element and drying thoroughly, I reoil only the outside of the element and allow it to dry overnight before reinstalling the element and operating the engine. Many happy years of trouble free K&N filter element use. Good luck, Bob Blackwell.
Bob, where do you get the CRC MAF cleaner?
[quote name='cosimo' post='35131' date='May 7 2007, 09:41 AM']Bob, where do you get the CRC MAF cleaner?[/quote]
Should be able to pick it up at any auto parts store.
Something else to be aware of ... the MAF cleans itself every time you turn off the engine. After a 30 second pause it heats briefly to something like 1,000 degrees to burn off anything that's on the wire.
Also, the wire itself is only about 7/100s of a millimeter, so extremely delicate. Absolutely cannot touch it with anything.
Finally, there's a gentleman up in Boulder, CO who rebuilds/recalibrates these for 928s. I've spoken to him and he's looking for the specs so he can also do our 968 version. He asked me to mention to everyone here to see if any others are interested.
Since the MAF goes out of calibration gradually, the effect is subtle. We had to replace the one on my wife's Lexus last summer and the change was dramatic. So hoping the guy in CO will be able to go ours.
Keep us pposted Tom, there are probably several 968 owners who will be interested in this service. Good luck, Bob Blackwell.
I am absolutely interested, and furious at Porsche for dropping support for cars like ours and the 928. I still buy Volvo parts for my daughter's 1978 244.