Stock Airbox vs. Cold Air Intake

[roadbiker_2]

All, I have a 05 ZHP that was purchased with a K&N Cold Air intake setup and have had issues with throwing P0171 and P0174 codes at highway speeds with both cruise on and general driving. Speed has been around 75-80 MPH.

Anyway, the first time it did this I had the car taken to a BMW independent shop as the car was 4.5 hours away and had them look at it. He smoke tested it and said it had some vacuum leaks and the CCV needed to be replaced.

I did the CCV replacement and put the Cold Weather CCV on the car as it didn't have it on there and I live in Illinois and replaced all of the boots and other rubber items including the o-rings on the fuel spreader. Cleaned things like the ICV and throttle body and rebuilt the DISA with the Titanium rod kit available on the internet.

The car runs beautifully, but I still get a nuisance set of codes every now and then on the highway. Sometimes it will go a week, other times it will throw the code in say 50 miles or so.

Anyhow, today I went to a Certified Mechanic and we used his Snap-on scanner to look at the Fuel and O2 sensors and everything appears to be in line, we even did a scan before cleaning the MAF in case it was causing the issue with being dirty. Signals look very similar both before and after cleaning the MAF. It was suggested that I go back to the stock Airbox as it is more stable and can prevent a harmonic issue as he was calling it, at speed. In other words, the cone shaped air filter was causing some resonation issues and was causing false readings at the MAF.

Has anyone else experienced issues with their Cold Air Intake, and would they care to share their experience? Also, is anyone selling a standard stock Airbox on a car that is being parted out?


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[cornercarver]

Haven't had this issue on mine, but as I understand it the MAF doesn't like turbulent air. Ideally it should be getting sucked straight through, so look at your CAI and see if the way the air enters the box is causing it to blow at the filter from an angle.

[Reasoned1]

I installed a K&N CAI on my 2004 330xi last year, and I like it--no issues other than the common jingling at light throttle. I'm about to install the same on my 2004 330i ZHP. I'll let you know how it goes... although I won't be running it until springtime.

[roadbiker_2]

All, not sure what the jingling you describe would be, this car runs so smooth at idle that you almost can't tell it is running. Anyway, perhaps the air is getting disturbed, does someone know what the stock filter looks like for the K&N? I will post what is on mine and let me know if this is right. Perhaps the prior owner put on a different filter.


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[roadbiker_2]

https://uploads.tapatalk-cdn.com/20170203/cdac6741960ed5296f4419dd66513730.jpg

This is what is on the car.


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[hcbeck2689]

I have a stock box you can have if you want it.


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[Rovert]

Do you have that screen on that evens airflow out? You put it in between the filter and MAF. Or is that only S54? I had a stalling issue then i realized I need to use the screen inside my OEM air box. Once installed I've never had an issue since.

[roadbiker_2]

http://www.knfilters.com/mobile/mProduct.aspx?prod=RC-4630


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[roadbiker_2]

This is the filter that should be on that intake. Interesting that it has the cover at the front


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[3ZHPGUY]

I've had a Dinan CAI for years and didn't have any issues with it until a few years ago. Had it checked by the Steelership and thy said I need to start with replacing the MAFS. The car doesn't give me any performance issues except an occasional rough idle. With the MAFS being +$300.00, I jut live with it.

I've heard the oil on the CAI may have something to do with it.


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[Cadeez]

I've had my K&N CAI for almost 3 years, never had any issues...other than abstaining from pressing the loud pedal. I've never washed, cleaned or oiled it, which may not be great, but it's still "relatively" pink. Plus, the oil can damage the MAF and throw codes if it's on there a bit too thick, so I decided to just not oil it. It does come pre-oiled out of the box. I do however take the MAF off and clean it about once a year, literally spray the shit out of it with some CRC MAF cleaner. Do it 5-6 times, letting it dry for a min or so in between sprays, all good after that. I can't imagine that the non K&N filter you have is causing any issues, but I suppose it's possible? Either way, you posted that link to the correct K&N filter for this CAI, which you can probably pick up at your local Autozone. It's a bit bigger, and frankly, it just looks better :)

http://i374.photobucket.com/albums/oo184/jcadell/IMG_5357_zpsjjk00occ.jpg (http://s374.photobucket.com/user/jcadell/media/IMG_5357_zpsjjk00occ.jpg.html)

http://i374.photobucket.com/albums/oo184/jcadell/IMG_5358_zpsmdknb10k.jpg (http://s374.photobucket.com/user/jcadell/media/IMG_5358_zpsmdknb10k.jpg.html)

[roadbiker_2]

Thanks for the post, I have an offer to send an Airbox, I just need to pay freight. I may also pick up the K&N filter as well. I just did a 4.5 Hour trip and avoided 75 MPH, which is where the car has thrown the code. I went 65-70 and then cruised at 80 MPH. I think there may be some validity with the resonant issue with the filter.


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[edwin.colo]

Wow, super interesting you wrote this yesterday. Today I went to get the airbag recall on my 04 ZHP (dealer is 40 min away 90% highway). I was going 75-80 mph most of the time and on the way back got the same two codes. I have the Injen SRI. I've replaced most of the common vacuum leaks since I've owned it.

Ive had no issue for the month that I've had it installed but my daily commute only gets me up to 65 mph, maybe.

¯\_(ツ)_/¯


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[roadbiker_2]

Well, I will say that I am going to call K&N on Monday. As mentioned in my first post, everything looks fine at idle and at 3000 RPM on the Snap-On scanner. Apparently turbulence causes issues with the MAF properly metering the flow.


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[cornercarver]

This is what is on the car.
I know a lot of people who would tell you this is the problem; At 70+mph, you're getting a ram-air effect, where the engine is no longer drawing air in by itself because the high pressure area in front of the radiator is cramming 70mph air into the funnel and blowing it into the side of the air filter. The air becomes turbulent to the point that it screws with the MAF's signal to the ECU and throws a code (or two.) Considering that you said you only get the codes when driving at 75-80mph, I'd say this is a strong candidate for the cause.
28966


You might be able to remedy this by fabricating a baffle something like this (you could test the theory with a piece of cardboard or something taped there temporarily) so the air is no longer blowing directly at the inlet.
28967


I'm not a fan of these CAI's because they defeat the purpose of the sealed air box which BMW designed to take advantage of the ram air effect, unlike the K&N setup where air can escape around the sides of the incomplete box.

The other thing you could do is swap in your old box (if you still have it) or borrow one for a day and see if that fixes the problem. Or borrow someone's MAF... Process of elimination. That's what mechanics will do until they find the problem, which can get expensive. :(

Good luck... Keep us posted with your results for future reference.:thumbsup

[roadbiker_2]

Well, I did have an offer for a free box from someone earlier, still working out details on that. I happen to have the luxury of having not one, but two ZHP's (Tongue in Cheek), which means I have all of the above. I also have all of the above for maintenance issues as well, Cold weather CCV, DISA, VANOS, etc. Maybe two of things can mean a whole lot of maintenance . . . I'm getting caught up, but my sons car really threw some cold water on getting the other ZHP done.


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[Damian]

I had a few problems with my K&N as well. About 6 months ago I kept getting a code that would magically disappear by the time I got to my local indie. Turns out that I had a vacuum leak at the F-connector that plugs into the Intake. It wasn't much and took high RPM's for it to reappear. A quick change of the rubber grommet and all was good again.
Other problems included oil getting on MAF sensor and more recently my filter kept falling off. I tried new clamps but it still kept happening so I am back to stock for now... I do miss the sound tho...

[johnrando]

That's a bummer. Love the extra sound.

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[edwin.colo]

Well, I did have an offer for a free box from someone earlier, still working out details on that. I happen to have the luxury of having not one, but two ZHP's (Tongue in Cheek), which means I have all of the above. I also have all of the above for maintenance issues as well, Cold weather CCV, DISA, VANOS, etc. Maybe two of things can mean a whole lot of maintenance . . . I'm getting caught up, but my sons car really threw some cold water on getting the other ZHP done.


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Roadbiker, Did you ever solve the issue?

I was having both p0171/p0174 codes at highway speeds and I believe a new fuel pump has solved my issue. Mine was original (150k miles).
I've had the new pump for 9 days and the code has not shown up yet (knock on wood).
I'll update this if something changes.


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[roadbiker_2]

I have the Airbox, but the car is with my son in college. He will be home for Spring Break in about two weeks. I have determined that the intermittent SES light, with codes P0174 and P0171 in this order, were the result of turbulent flow into the MAF at highway speeds. Specifically at 75 MPH. The SES light has not throw for almost a month now with him driving regularly around Milwaukee, as well as the 4.0 hour drive to take the car up to him. I stayed away from from 75 on the highway, and it never showed up.

As the car currently has a K&N Cold Air Intake on it now, I will need to reuse the upper Intake rubber I just replaced on the wife's car to do a quick road test once it is home. It was throwing the P0174 and P0171 codes roughly every 30 miles if you put the cruise on at 75 MPH.


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[roadbiker_2]

We picked up a code reader as well, so resetting the Codes is not as big of a deal, but it sure is irritating to see! I would do a thorough check of the upper and lower intake boots, like everyone else suggests, along with checking the three vacuum plugs at the back of the intake. The part number for vacuum caps are 11611437560 and you will need two, and 11611727176 for the larger one and there is only one of these.

If you have not been under the hood at all, I strongly recommend getting four new Torx T-40 bolts as these are sometimes stripped, or will become stripped. The part number on these are 11611440384.

As I was also doing a Cold Weather CCV, all of these lines were replaced, but I did not see any failures here. I will say that he went from using 1 quart of oil per 800-1000 miles to practically using nothing at this point once the oil separator was done. I was amazed, but not surprised at this. I am just glad that this got done before the infamous freeze up and hydrolock. Both of my ZHP's are now done.


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[roadbiker_2]

The Torx T-40 are what hold on the DISA and the bracket that holds the ICV in place


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