650i Hesitation on acceleration from a standstill

[ekm330]

My 2010 650i coupe has 55k miles and has developed a brief hesitation again. After idling at a stop light, the car will hesitate upon acceleration (like a carbureted car with a faulty accelerator pump). It has done this maybe two years ago, no fault codes. Dealer deleted adaptation codes. Problem persisted. Updated software. Per notes on my service ticket, "Found SIB for induction flush with hesitation issue also performed injection flush." Whatever the issue was, it was resolved.

Last week took the car to independent shop that services many of my cars, including my 650. It has the same hesitation issue again from a standstill, no fault codes. They deleted the adaptation codes, updated software and nothing has changed. They told me that the dealer wasted my money by doing an injection flush. The guys now say it could be the torque converter, it could be a solenoid in the transmission valve body, it could be valve body itself. Could be, could be, could be.... we have to throw parts at it until we find the issue kinda deal. Or so they say.

But the one thing the dealer did which they haven't done is the injection flush. And when it came back from the dealer, the issue was resolved. I'm stumped, but I think just throwing darts (expensive ones) at an unknown target and hope something gets resolved seems like a bad plan. Besides, couldn't it still be engine related and not transmission?

One thing to note, the car doesn't get driven a whole lot and while most of the mileage has been highway between Tampa and Gainesville over the years, the bulk of in-town driving is only a few miles from point A to point B. I've discovered this is not a friendly recipe for battery life, but that's a different topic!

Thoughts?

[Timm]

I used to get hesitation when I first bought the car - it only affected the initial pick-up from idle - here's what I did (ignore the title, it is the crankcase Ventilation that caused the problem:

[jclausen]

could the hesitation be the transmission engaging abrubtly. On slow rolling stops then accelerating away does the trans engage abrubtly, like sort of slam into gear? Your battery will not be happy with short trips I recommend a battery tender and just leave it plugged in until your ready to use the car

[ricks5series]

I'm experiencing the same hesitation except only when at operating temperature. So flushing out your injectors resolved your issue?