09-29-2015, 07:46 PM | #1 |
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Hesitation and jerky shifting on a cold-start
My N26 engine has 19.5K miles. My car recently started hesitating when accelerating slowly after sitting for an extended period of time along with jerky shifting from 1st gear to 2nd gear. The symptoms seem to disappear or is lessened when the car is fully warmed up but noticed yesterday that at 60 MPH, when I take the foot off the accelerator and accelerate again, I can feel the hesitation.
It's been at the dealer for diagnosis and they seem stumped. They said they have contacted BMW regarding a diagnosis and remedy. I assume when the mechanic took a test drive, he must have felt what I was describing otherwise they would not have kept the car and contacted BMW. There are no CEL or any warning messages on iDrive. Anyone experience something similar? Wonder if there is a leak in the system? |
09-29-2015, 09:28 PM | #3 |
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But it happens at 0 mph slowly accelerating to 15 mph. Turbo lag at that speed range? I've had the car since new 23 months ago and never felt it like this before. Plus I assume something is not right if the dealer is spending the resources and manpower if it was simple turbo lag, but who knows. Maybe they want to milk it for all it's worth while I drive their brand new 2016 x3.
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10-01-2015, 08:04 PM | #5 |
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Finally got the car back after 4 days at the dealer. They reprogrammed the DME after finding fault in the software and issues with VANOS when cold.
Also they found fault with the transmission gear selector switch. Funny thing here is that I have 2TB programmed and when the mechanic replaced the GWS, he ordered the sport trans gear selector switch instead of my original replacement which was part number 61319296896. So now I have 61-31-9-296-898 with a leather base. |
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10-01-2015, 08:32 PM | #6 | |
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07-03-2017, 07:28 PM | #7 | |
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Hesitation and jerky shifting on a cold-start
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Hi, I am encountering the same issue as well on my N20 engine. Jerks during upshift from 1st to 2nd when cold but the issue disappears after the engine warms up. However the dealer claimed they were unable to reproduce it. Is there a particular description or defect code for this fault or issue ? Perhaps this can help me point the dealer to the correct direction. Many thanks in advance. |
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07-03-2017, 07:45 PM | #8 |
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My n20 is horrible about this, almost stalls. Not interested in letting the dealer keeping it for 3 days only to report that they couldn't "reproduce ".Placing it in sport and pushing the gas pedal through the floor board fixes this altogether.
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07-04-2017, 08:20 AM | #9 | |
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07-04-2017, 08:43 AM | #10 |
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I also get this in my car. I really think it is the ECU protecting the drive-train during cold starts by limiting torque. Try to go full throttle from a cold start and you will see.
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07-04-2017, 02:24 PM | #11 | |
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Hi, Thanks for the feedback. Am not sure what is a piggy back tune. But I do not have any modifications on my car. Yes, I experience the effect when in the parking garage after a cold start and moving in the garage at a slow speed. Engine appears to be attempting a slow upshift from gear 1 to 2, but does not do it well and it results in a jerk. ( feels a little like a new driver learning manual transmission and releasing the clutch too fast at the last instance ) This effect disappears after the engine warms up. Interestingly I never had this effect when the car was new, appeared recently after about 15k miles. Did the fix by dealer solve the problem for your car ? Was wondering if they have a technical term for the problem or solution ? |
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07-04-2017, 03:41 PM | #12 | |
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07-06-2017, 03:54 AM | #13 |
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Thanks to all for the feedback.
A little disturbing that this happens after 15k miles and not when new. In my humble opinion, I suspect the computer must have detected some change in the engine / transmission and instructed a different behavior. Hope I can find a way to make the dealer see this issue. |
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06-28-2021, 01:55 PM | #14 |
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Isn't that slippage from 1st to 2nd when starting from a Pause caused by the intentional anti-wear protection implemented by BMW that doesn't lock the TC when is not hot enough ?
I don't recall were i read this, but doesn't make sense 100% because it also occurs even though you are running hot -> Stop Engine -> Start again. And it does this only on the 1st upshift when you actually press the gas more than 10% and not rolling on ~ 1000 rpm. I have it on my F30 LCI 2016 320d with ZF8HP50Z and had it on my previous F30 2013 with ZF8HP45. |
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11-13-2021, 05:22 AM | #15 | |
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Anyone managed to solve the issue or at least diagnosed it correctly? Link to the video: |
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