2008 535xi AWD acceleration question
 

I just bought an 08 535xi (6-speed manual) from a BMW dealership 3 days ago. I LOVE this car so far and it is mint and loaded. I specifically wanted a 6-speed because I used to have a 2011 328i which was also a stick. The 3 series was NOT AWD and was very smooth through every gear. The 08 I just picked up is quick but not smooth like the RWD 3 series. It seems to have a "miss" feeling or "pulsates" very slightly on hard acceleration. The car still moves perfectly and is fun as hell to drive. Is this due to the car being AWD? I've never had and AWD car before. The car has 76k but was dealership maintained with service records. It shows the spark plugs being changed back at around 50,000 miles. I'm just looking to see if anyone has any insight on this. I have the dealerships powertrain warranty for the next 3,000 miles or 3 months. Thanks!!

At 50,000 miles I had a similar problem on my 08 535XIT turned out to be carbon build-up.

Try to get the dealer to do this for free - have them contact BMW for a goodwill authorization. If not, you'll pay $500+ to clean the carbon bulidup using crushed walnut shells to blast off the deposits (no kidding).

Good luck!:thumbup:

My 08 535xi @ 49,000 had same symptoms and had radical improvement after walnut shell blasting. Cost $575. You should see the squirills sniffing my tailpipe.
Apparently this carbonized oil buildup is minimized with high rpm driving ;-)

I guess that it why I only really feel it on acceleration? She's smooth as anything in the higher rpms.

Traction control kicking in?
Dirty intake valves?
Lack of proper tune?
And 30k miles seems to be the limit on oem plugs in a n54 engine..
I would go get a Cobb give it a proper flogging , uninstall make dealer fix the weak points.. But that's just me..

Not going to start an oil thread but different oils carbonize/polymerize differently as well.

UPDATE- I spoke with Otto's BMW in West Chester PA who sold me the car. I have an appointment on Friday (with loaner car) me to drop off the car and they'll fix whatever the issue it is. They said it's a regular thing and should only take a few hours to fix. I can't wait to see what the car feels like when I get her back afterward!

Zeke - Please PM me or update this thread with what Ottos tells you and how their service is....as you know, I just bought mine from there this week as well and I'd like to see what your "regular thing" is and how good of care they take of your car.

I absolutely will!

I brought the car in today and met with the service manager who said they are going to do a full check up on it. Apparently it already had the valves cleaned 2 years ago so they put in new plugs. They took it out for a test and still doing it. He told me they looked in the the valves and they are carboned up again and they're going to have to keep it the weekend. They gave me a 2012 335xi coupe to beat on over the weekend though. I just drove that 80 miles back home and I like my 5 year old 535xi alot more than the coupe :) I'll keep you all posted. Definitely A++ for the dealership though for taking care of me!

Does that mean they are cleaning the valves for free?

They are doing whatever needs to be done to the car to get it to 100% on them!

Since the labor and parts for the BMW "Whatever" repair can be very expensive - glad to hear the dealer is picking il the tab !!!

Good luck! Let us know what happens next week.

Nice. Definitely sounds like a good dealership. I got my car back yesterday with 6 new injectors and it is running like a champ. Now it's time to reinstall my Cobb and dci's.:D

My car is doing the same thing for the past couple of weeks, again only on acceleration. Did the dealer fix it and what did they say was the problem? Thanks. Chuck

The service manager called me on Saturday afternoon and left a message that the car is done. he said I was right about the carbon build up but they didn't use walnut shells to clean the valves out. He said they used another BMW authorized method? I'll find out when I get it. I need to drive an hour and a half out to the dealership to get it. Hopefully the weather will cooperate at 7am so I can head out there right after work before this "ice storm" hits us. I'll definitely keep everyone posted.

I picked up the car this morning and all is good. To keep it short the dealer did a complete diagnostic and found it to feel like a slight misfire on the initial test drive. They replaced the spark plugs (I saw the the plugs were replaced exactly a year ago (10,000 miles ago) on the car fax, but it says on the repair ticket (CBS data states spark plug replacement was due)) and took it out again and they said the issue was still there. It felt "heavy" on acceleration. They then removed the intake and found large carbon deposits on the back of the intake valves and in the intake port area. they cleaned all 6 cylinders (didn't say by what method) and also replaced a section of vacuum hose for the waste gate control valves. They did a complete vehicle diagnostic and and everything checked out fine. The HPFP was already replaced 15,000 miles ago and that was fine. They stated the fuel injectors were also showing no trouble codes. They also topped the oil of with 1.5 qts since it was a little low. I'm very pleased with the way I was treated by this dealership and I love this car! I would love to see what the bill would have been if I had to pay for everything! Thanks for everyone's help with diagnosing the issue in the beginning.

Wow, go Otto's. Looking forward to getting some service there now...

I've got 15k miles or until May 8 2014 under CPO and full warranty package.

good to hear another dealership stand behind their product.

I never though these DI engines were such a PITA, how much does a carbon buildup costs to clean if you are out of warranty?

All DI engines to one extent or another have carbon build-up issues on the intake side. Driving style and oil choice impacts the build-up, because build-up is a result of two things:

1. Amount of crankcase gases routed back through the intake
2. Tendency of the oil to carbonize as it's being sucked through the intake

In addition, the n54 is a uniquely designed and hard-to-work on twin turbocharged engine. At what point was this ever gonna be anything but a PITA :)

...

I've actually been pleasantly surprised at the reliability of these engines now that they are coming up on 6 years old. They're not great, but they are not bad.

I bought my 2008535xi in Aug 2012. I became fixated on the MPH meter and kept my foot light on the accelerator. Yeah I ran it hard occasionally but that wasted gas.

So now at 49,000 miles I had a walnut blasting session and wow the performance is much better.

So I propose the gas milage I save by driving easy is lost with one $575 walnut blasting session. Leading to the thought process of have fun and drive this magnificent beast hard cuz you ain't saving money driving real easy to improve MPH

Not worrying about MPG I started to use the 6 speed shifter and really enjoy the sound of that high compression engine responding. 7 Grand is the place to be!!!! I hope other new owners don't have to learn the same lesson. Drive it hard.

I never had a car this nice. I haven't come close to its performance limits.

I could go on and on and on and........:cool:

Exactly. If you want to save gas get a Prius. Don't get me wrong I would love to save some gas but I love more smashing the pedal when getting on the freeway. :thumbup: