Merc63

I think these cars are really picky with airfilters.

my blower doesnt like the KNs at all. It bucks and hesitates.

I run stock filters with charcoals and it runs perfect. Must be reversion or the maf doesnt get a good reading with the other filters.

_timothy

Its weird because it ran perfect for 6 months.....

Diabolis

You do realize you're all running K&N air filters, right?

I had a similar issue with a K&N on my 928. Apparently small droplets of the oil on the K&N hit the hot sensor wire on the MAF, which screws up the metering (you can actually kill the MAF if it comes in contact with too much oil). Once you remove the K&N, there's a good chance you'll burn off the oil on the sensor wire and it starts to properly meter the air again.

edwardsflight33

So if I were looking to purchase an aftermarket air filter, does that mean I should go with the Weistec High Flow, because it is dry?

_timothy

except me. I am using the Weistec filters, which have been running flawlessly at WOT until about a week ago. this implies that something has built up or occurred where previous there was no problem. other people are using the AFE dry filters without a prob as well.

for the record, I emailed weistec asking for suggestions. i hope they can take the time to share their input even though it is a pretty low dollar mod.

Diabolis

Yes, I would stay away from the oiled filters.

Not familiar with the Weistec filters - if it's dry then it may very well be something else (hell, even if you were all using K&N it could still be something else). Just threw it out there because I am one of the people that has killed a MAF specifically because of the K&N oil hitting the hot wire, and the symptoms were quite similar (MAF unable to properly meter the air -> ECU plays havoc with the AFR so you get stuttering and hesitation). Timothy, are you saying that people running the AFE dry filters are also having the same issue? If yes, that would indicate a problem with something else.

EDIT: Or like 1st AMG said it could be the air filters / housings again if they're clogged and/or you somehow create a low pressure in the airbox (insufficient air), or have unmetered air going into the engine although I can't see how this would be caused by the filter itself(even if you take out the filters completely, all the air going in still has to pass by the MAF so the leak (unmetered air coming in) would have to be somewhere past that point).

Weistec

Timothy, what does the car do in WOT now? How has it changed from before? Finally, how long did it run well before having issues? These will help us and the community understand what is going on here.

For those running K&N filters... Many customers ran this filter and eventually oiled down the MAF's. This can be cleaned but the reading can be off making the car run bad.

The other part about K&N filters that the community needs to know about... These filters are designed to be ran with oil. You cannot simply wash these filters and run them with no oil. They will not provide sufficient filtration of debris.

A dry filter on the other hand is designed to be ran with no oils. They typically have more weaving and the actual weave design is different. We know this is a small dollar item but there needs to be a lot of thought put into an air filter since it is purchased in such high quantities.

The actual problem many of you are seeing is the MAF not getting a good reading and the car starts to buck or hesitate. This typically only occurs at high load, low-mid RPM range but a few of you are having it in WOT which is surprising.

For those having this issue, which are boxes are you running? We might be able to have a correlation on this if we can understand the air box as well. Thanks guys.

Weistec Engineering

Jasonoff

I have hesitation when the engine is cold (first start). Usually only the first time I get on the throttle then after that it's fine.

Possibly a related issue.

Charcoals removed, AFe filters, OE air box.

johnnyblaze

I ran my K&N filters for 8,000 miles with no heisitation issues at all. Until I got all my mods, LTH, catless x-pipe, ROW airboxes and tune, I then noticed exactly the problems the OP had. Hesitation on inclines. Then I started to notice on the Dyno several times, my car would actually flatten out in the high RPM band like it was holding back. Runs were showing low horsepower for my mods 460, 461, 460 over and over again. But the guy with similar mods (with ROW airboxes and stock filters) was pulling 475-480. We put in AFE filters and dried off the MAFs, my car instantly pulled over 485whp on DynoDynamics. Hesitation was gone also.

Serge laughed and said "f***ing K&N's"

Merc63

Im running stock airbox with charcoals removed and KNs. Blower doesnt like it at all.

ran fine without the blower except a few times in lower rpm high gear rolls it would hesitate a bit.

these are two different cars as well.

im running stock box with stock fikter and charcosl and it runs strong no problems.

ZephyrAMG

I have been running K&N stock no issues for 2 years. You guys say oiled like its dripping with grease like fried chicken....the margins are lightly oiled...

So remove K&N on stock set up even with no trouble???

Diabolis

I can personally attest to the fact that a K&N air filter (out of the box, not something that I cleaned and/or over-oiled) killed the MAF on my 928. The oil particles are either microscopic, or perhaps it's fine dust that has come in contact with the filter element (and is now greasy) and has passed through because it was too small to be captured by the filter, but it certainly did.

I have no idea what a C63 MAF sells for or whether it can be cleaned or have the platinum hot wire replaced and recalibrated, but if it's anywhere in the range as the 928 MAF ($1K+), *I* wouldn't take the chance. MB almost certainly wouldn't swallow the cost either - they'll probably tell you that you have voided the warranty.

ZephyrAMG

Removing K&N this Friday. Replacing with stock filters.

_timothy

Thank you for the email response as well as your response on here.

I misphrased the post you quoted. This really occurs just shy of WOT, not at WOT. I will be in 3rd or 4th at around 4-5k RPMs and 3/4 throttle applied. The car will suddenly lurch and hesitate as if fuel has been cut off but I don't get any dash lights/messages and no CEL. I lay off and everything seems to be normal.

Today, I drove through my wormhole into mexico and did 2-3-4 WOT in S+ all the way to 5th and there was no issue to try to "test" other conditions. I'll try tomorrow at 3/4 throttle from 3-4 and see if it happens again. It started happening for the first time about a week or so ago. I didn't think anything of it at that point.. but now its recurring and I am a little concerned.

My mods are MB ROW airboxes, no charcoal, your filters, secondary cat delete, and a tune and they worked in total harmony for a bit over 6 months without any issue from the get-go. This weekend I will definitely reseat the airboxes although I am rather puzzled if that turns out to be the issue since I haven't touched anything under the hood in 6-7k miles beyond checking oil. It has been extraordinarily humid here lately as well.

ezatnova

Sub'd. I am having the EXACT same symptoms. Has been a year or so now, but i'm getting fed up with it. I was attributing it to my tune but maybe it's not. I have stock air filters, with charcoals removed. I have checked a million times to ensure the air-boxes are properly sealed.

Anyway, exact same thing for me. WOT is perfect. Anything 50-90%, in any gear (usually 2 or 3 given normal travel speeds) causes lurching and bucking around 5k rpm. I found an easy way to duplicate it at reasonable speed is put the car in M2 or S2 and give it the right throttle. It should replicate it fairly easily when the tach hits 5k or so. Here's a vid of mine. You can hear the sound clearly, and see my phone lurch from the hesitation.

http://www.youtube.com/watch?v=TTPKX...ature=youtu.be

Ezec63

I also just got long tube headers installed on my car and am having similar issues. Also if im in manual mode in 3rd gear at a decent rpm(4 -6K) and keep the revs stablized like im doing a roll race waiting for 3 honks. Then i punch the pedal it seems like the revs rise a bit and the clutch is dropped and i get a crazy jerk from the car it feels like the rear end of the car is about to explode. Keep in mind i have a 12 coupe that has the MCT trans so i dont know if its just bad clutch management and the computer is doing a "rolling clutch drop" and im also getting similar hesitation as others here. Just got a CEL the other day "P2626 - O2 Sensor Pumping Current Trim Circuit/Open (Bank 1 Sensor 1) " I have MBH headers and Eurocharge Tune

ezatnova

Interesting. Seems like a different issue because what we are discussing only happens at part throttle. Could be more of an MCT thing but that doesn't make much sense either.

GRam

Have about 7,000 miles on my '11 P31 car with the eurocharged tune and afe dry filters and charcoal deletes. Runs like a champ, no matter the throttle settings/load/gear etc.
The problems you guys having only coming in the facelift cars with the mct trans? Wonder if it's a "trans tuning" issue instead of fuel/spark/air??
I ask because I'm having same issue with my modded Cummins.
But I'm positive that it's troubles are trans tune related, nothing related to the engine enhancements..

mr747

Ever since I've put these carbonio airboxes I've been having nothing but issues

Check engine light come on tonight codes p2626 and p2414 came up

I reset them took it for a thrash and nothing

When I let the car sit for 2 days and then jump in again it throws a code

Do u think my oxy sensors are gone

Ezec63

Might just be a coincidence with the carbonio boxes as they shouldnt affect 02 sensors at all. Yes i would say your first 02 sensor on bank 1 is shot try replacing it and see how she likes it.

If you see 2 post above i was having the same issues and it was right after i did long tubes which i thought caused the issue but it wasnt as soon as i replaced it the car ran awesome and has been rock solid since. I also got multiple misfires a day after posting that and the car would go into limp mode. When we diagnosed the car it ended being a combo of the 02 sensor and my variable intake actuator has been stuck closed causing alot less air up top than the computer was expecting.

mr747

ok well the light has came back
what is the cheapest place to buy these oxy sensors

is it bad to thrash with the check engine light on

Whats to stop this happening again???

Merc63

You need a new sensor bank 1 primary upstream.

Grab online. I got mine locally at a parts store, 250$ each.

mr747

There is no way to stop these sensors fouling is there???

Merc63

They can go bad after a while.