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Roger, BMW Master Tech
Category: BMW
Satisfied Customers: 3044
Experience:  10 yrs. experience as BMW Master Technician, shop foreman and dealer.
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550i: My '08 550i M sport threw a 2B70 code and is running

Customer Question

My '08 550i M sport threw a 2B70 code and is running a little weirdly. Some hesitation at low RPM, especially when HOT (runs great when it's 40 degrees outside) and strong throttle response.
Submitted: 2 years ago.
Category: BMW
Customer: replied 2 years ago.
Not STRONG throttle response. STRANGE throttle response. Strong when COLD. Soft when hot. Especially if I've been driving around on a hot day, if I come around a corner and give it a third throttle, it hesitates and stutters a little, and then starts to pull. Occasionally on full throttle, it feels like it's only giving about 75% all the way to redline. When it's cold it pulls like a beast. Air filter is clean, intake looks clean. I guess it must be something related to Valvetronic?
Expert:  Lou P replied 2 years ago.
Hello my name is ***** ***** i will do my best to help you , i strive for EXCELLENT service and nothing more.sorry no one has assisted yet. Are you still needing help ?
Customer: replied 2 years ago.
Expert:  Lou P replied 2 years ago.
Ok. Can you post to me your vin number ? Do you have any other codes ? What have you tried so far ? Also research ?
Thanks ,Lou
Customer: replied 2 years ago.
WBANW53508CT51832I'd swear it started happening right after I got an oil change at Jiffy Lube. They over filled it, but only by about 8oz...those things are SUPER touchy (oil level meter was only in the yellow). I had my indy drain a little.Anyway, not to throw you off the trail... but I do remember that.That said, around last November I changed the plugs. (At around 95k miles) OEM Bosch plugs...same as I took out. Car has no mods at all.
It had been severely bogging down with heavy throttle in high gear under a car would with bad spark knock, but I guess the sensors make the computer dial back the timing to avoid the knock. There was a MARKED improvement in the low end torque. Before the plugs, in 4th gear at 40 miles an hour, i put my foot 3/4 throttle and it would just lay there...the engine would even dive a little. Changed the plugs and it was a beast. It was also getting into winter.
Now the symptom is different. It hesitates...occasionally lurches a couple times, and then takes off. Even from a dead stop, if I hammer it (regardless of DTC setting) the engine dives a few hundred rpm, and then takes off. Used to be that it would just start pulling solidly, and then really light up around 3500rpm...the BMW way.Main thing is, when it's 50 degrees outside, it's not a problem. When it's 90 degrees outside, it happens really badly.Seems like an intake thing to me. Like hot air moving too slow. I checked the air filter, the MAF, all the intake hoses. All good. No other codes besides the 2B70 on the work order....but he said there were a couple other "major" codes that weren't related. Indy looked it over really carefully, too. I've used him for years. He has an AutoLogic and is generally pretty good with diagnosis. He said he couldn't feel it when he drove it, too. But he only drives it about once a year, and then just gingerly around town at 40mph.Let me know if that helps.I know the car really well, and I'm certain something's up. But I can't be sure what.
Expert:  Lou P replied 2 years ago.
Excellent feedback mike. That helps a lot. Now I am curious about the other codes you speak of. From memory I think the current code had to do with the variable intake runners which affect airflow depending on which way they were positioned when they failed. They change the flap position internal of the intake to keep a good power curve from idle up to higher rpm's. So you either have short intake runner or long intake runner depending on the rpm's. I'll get back more info tomorrow. Lou
Customer: replied 2 years ago.
I'll look into the other codes today. Thanks!
Expert:  Lou P replied 2 years ago.
ok, really hard to find the code 2b70 in my system, bmw is the worst with correct information. i put in a call to a friend havent heard back yet , the other codes nay prove helfpul. may not. well have to wait and see what you come up with.

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