Munich77

My car has about 21,200 miles on it and is already on its second fuel pump. Even before the fuel pump replacement, my g/f and I noticed an occasional sporadic sputter/hesitation while trying to accelerate. In total we noticed the sputter/hesitation maybe twice or three times. The dealership could not find anything (no codes were thrown) and the hesitation has not showed up for a long time.

Yesterday I filled up the car and on the way back home driving on the highway I noticed a hesitation/sputtering while accelerating. It is as if the car refuses to accelerate. I have also noticed the same thing driving the car today. What is interesting about the problem is that it only occurs as follows: driving at around about 60 miles an hour and slowly accelerating. The hesitation appears around 1700-1800 rpm and last until about 2,200 rpm. If I am not driving at that speed and accelerating in the same rpm range the hesitation does not appear. If I am driving at that speed and I punch it then there is no hesitation either. The hesitation while occasional is persistent.

Does anyone have any idea what causes this? Since it only appears at 60 mph (highway speed), I don't think that I have a bad tank of gas. I will of course be watching it as I burn through this tank. Since it also happens only at that speed, could it be something that is due to transmission programming? Are there any technical service bulletins out about this?

Jake545i

I'm having the same issues. Very frustrating. It could be what I'm fearing, and the VANOS is acting up. Not sure, but I may be trading the car in this week.....

It does it to me in any gear at the RPM's that you listed above. Very slight sputter/hesitation. Once above that RPM range, the sputter goes away, but I can still hear a sort of vibration sounding sputter.

My wife noticed it today, and confirmed that I wasn't hearing things.

If anyone can help confirm this for us, I'd appreciate it!

Thanks

ericdiver

I will say something since no one else has, I had a small hessitation around 1500 for a whe and sometimes it felt like I would step on the gas and there would be a delay or feel sluggish then last Saturday I had the active steering malfunction abs malfunction then the I drive screen go blank and the car loss some power, the car has the oem battery and reading that 4 or 5 years is pushing it as BMW are very hard on batteries, the car started fine but when I changed the $200 batt at autozone witch FYI is german made and has more cca than oem, but when I changed that the hessitation and harder starts ( by which I mean cranks more than usual) are gone and the car feels smoother and stronger than ever, I know your car is newer but a new battery might help, just some info to share

bigbadbull

What was the production Date? This will help narrow down some problem and potential solutions

Sounds like a MDS 81 configured N54 motor. If it is you have what is know in the industry as Turbo Lag. You can get the farm if you google turbo lag and N54 or search it out at e90post.com

If the car was made before March of 08 then you have the Laggy software that got installed with one of your HPFP replacements. If the car is a Pre MDS 81 ecu you can have the programing updated to a newer non laggy/less laggy version. Not bought but actually built at the factory ( look on inside of drivers side door jam, it should be there).

Basically what is happening is the Waste gates are staying open and not developing boost rapidly, where on the older version of the software and hardware they were closed at low RPM's and you had instant power and torque. This was done as a possible "fix" to help the HPFP last longer ( it does not) , and for the people that complained about the waste gate rattle at low RPM's , but sacrificing low end power and introducing lag to the system while the boost builds back up.

PS when did you have the HPFP's replaced , we might be able to get a rough Idea of what engine control soft ware they loaded up on it, as per the TSB for the HPFP replacement.

JCM 8c