Wildcat05

Ignoring all warnings, I recently replaced my stock air filter with a K&N oiled filter. Within a few days the check engine light came on so I replaced the MAF and put in a new stock filter. The CEL went off on its own in about a week. I thought I was in the clear, but now the CEL is back on. Ran by Schuck's for the codes and got the following:

P1128 Oxygen Sensing Adaptation Area 2 (Cylinders 1 - 3) - Rich Threshold
P1130 Oxygen Sensing Adaptation Area 2 (Cylinders 4 - 6) - Rich Threshold
P0420 Catalytic Converter Conversion Too Low Bank 1

Got the definitions from an earlier thread. I did not clear the codes. Does this mean that I fried the oxygen sensors as well? And if so, how many oxygen sensor do I need?

For the cat code, I believe I now qualify for the federal replacement mandate as I had codes P0420 and P0430 late last year. Has anyone else had their cats replaced under this warranty? Any advice appreciated.

arenared

What year/model is your car?

amondc

How many miles on your car? If less then 80k you are ok. if you are over I have some cats off a 99 that I will make you a good deal on.

Wildcat05

2001 S with about 40k miles.

Turboflyer

I would like to help those that want to use the K&N filter. I am not involved with the company in any way though I have used them on just about everything since the company started. I cannot answer your question directly because there are just to many variable and sometimes things happen near or at the same time you do something else and it drives you nuts. I really doubt you could put enough oil on the filter to kill the cats. When an AOS goes you will pass way more oil than that and they survive. But, if the filter oiled the MAF sensor wire then there was too much oil on the filter. Some folks think more is better, but not on a car with MAF sensor. So here has been my solution. I have at least two for each vehicle. After I clean and dry it. I spray each pleat sparingly. I then allow that filter to capillary until I need it the next time. If it is pink all over you are good to go. 70K on an 01 S with K&N original MAF. Hope this helps.

mikefocke

I doubt you needed the new MAF and
I doubt you fried any O2 sensors.

First rule of debugging is to suspect the most recent thing you changed. In this case it sounds like it was the air filter and it is a common thing to have these troubles if the filter is over oiled.

I'd remove the filter and wipe it down with a clean lint free rag to remove any excess oil.

Then proceed along the air intake tube towards the engine cleaning as you go.

Remove the MAF and clean it.

Clean the throttle body.

Once you have cleaned out all of the intake, dump a can of Techron into the fuel tank.

Now start the car and ignore the CEL for 100 miles. At about 100 miles, reset the CEL/codes if they haven't done it by themselves.

See if the codes go away over the next 100 miles.

In 2 tanks of gas, change your oil.

And ask yourself why you are using an air filter that filters air less effectively (meaning more and bigger dirt particles get through to the engine) than a stock air filter? And one that can cause you this trouble. (If you change back, you'll still have to do all this cleaning.)

There are on-line instructions on how to do each of these things.

AlpharettaRK

I have a K&N on my 3.4 and am always (every 3-4 months and the car isn't driven daily) getting a wide variety of codes about aging 02's (they are all less than a year old) and rich and lean thresholds. They are almost always fixed by spaying down the MAF with electrical cleaner. Try that before you do anything else. I've never had the conversion rate on the cat code, so I don't know about that one. My experience leads me to questions using a K&N on cars with this style MAF, I'm considering switch back to a stock air filter to see if that makes a difference.
Cheers
Randy

AlpharettaRK

I guess while I'm thinking about it does anybody have a stock air filter setup they want to clear out of their basement and make me a smokin' deal? I believe any 986 or 986s pre '04 are the same.
Cheers
Randy

Wildcat05

Thank you all for the advice. The puzzling thing to me is that I went back to a stock air filter a few weeks ago and the car has been running fine.

schwank

FWIW wildcat, my 01 S has thrown those codes on occasion. Most recently I threw one 02 sensor code after I blew the AOS.

I have Matrix clear them and they stay gone for probably 8-9 months at a time. I've chatted with their factory-trained Porsche tech and have no reason to believe that they are bad or need to be taken care of immediately, unless they come back right away.

Edit: How ironic that I posted this before I left for work. Then threw a CEL right on Country Club in front of the golf course on the way to work.... same exact place the AOS blew 2 months ago. I bet it's the o2 again for me. Odd that it only lights up when it's raining.

Macster

aftermarket filter is the aftermarket filter or its installation in some major way (negatively) affected air flow past the MAF and this resulted in the MAF being unable to accurately and consistently measure air flow.

If the MAF's input to the engine controller swings too wildly, widely, and if I suspect some reality filter in the engine controller gets invoked too many times the DTCs you started this thread with could be the result.

By going back to the stock air filter air flow past the MAF restored to its previous acceptable state and all is well.

Sincerely,

Macster.