Let off Throttle - Acceleration Continues

[tftimbn]

Hi everyone

I’m having an erratic issue. Over the last week or 2, if I let off the throttle, I would get a second or 2 of continued acceleration, there would be no coast down when injectors stop firing. After the brief moment, the RPMs would coast down normal, burbles will go if in sport, and all is well.

However, now, if I’m in 3rd gear and/or 3000rpm+, when I let off the throttle, this continued acceleration does not stop. Its very minor so I do in fact lose speed, but its comparable to *gently* pressing the accelerator. However, according to MHD, accelerator % is 0.

I will have no burbles, double revs on downshifts, and when I try to re-apply throttle, the rpms bounce and dip like a slipping clutch. Also, the efficient dynamics will not be in the blue zone during coast down, it will read somewhere between 30-40mpg as if I was using the gas. As well, instead of my AEM AFR reading - - - for being out of range, it reads an AFR of around 15.

18 F80 DCT
Single turbo on MHD tuned by Wedge
Video of issue:

[slaughter.mode]

Who's working on your tune? Is it Steven or Ken? What transmission tune are you using?

[E92inSG]

check the log, accelerator pedal may show 0% but check the throttle %

Originally Posted by tftimbn

Hi everyone

I’m having an erratic issue. Over the last week or 2, if I let off the throttle, I would get a second or 2 of continued acceleration, there would be no coast down when injectors stop firing. After the brief moment, the RPMs would coast down normal, burbles will go if in sport, and all is well.

However, now, if I’m in 3rd gear and/or 3000rpm+, when I let off the throttle, this continued acceleration does not stop. Its very minor so I do in fact lose speed, but its comparable to *gently* pressing the accelerator. However, according to MHD, accelerator % is 0.

I will have no burbles, double revs on downshifts, and when I try to re-apply throttle, the rpms bounce and dip like a slipping clutch. Also, the efficient dynamics will not be in the blue zone during coast down, it will read somewhere between 30-40mpg as if I was using the gas. As well, instead of my AEM AFR reading - - - for being out of range, it reads an AFR of around 15.

18 F80 DCT
Single turbo on MHD tuned by Wedge
Video of issue:

[McBobby Jr]

Honestly I’m not sure what’s up with your car, but I’ve had a similar thing happen on my 240i. After going wide open throttle in it, the throttle body would get stuck open and still go for another second at full boost with my foot off the gas even on the brake pedal which was concerning. I have a datalog that even shows on MHD where I’m off the accelerator completely and the car still accelerates. But man, what turbo kit are you running because it sounds nuts. I’m guessing you are running the 4N kit?

[Schultz28]

Originally Posted by McBobby Jr

Honestly I’m not sure what’s up with your car, but I’ve had a similar thing happen on my 240i. After going wide open throttle in it, the throttle body would get stuck open and still go for another second at full boost with my foot off the gas even on the brake pedal which was concerning. I have a datalog that even shows on MHD where I’m off the accelerator completely and the car still accelerates. But man, what turbo kit are you running because it sounds nuts. I’m guessing you are running the 4N kit?

I had this happen on my F80 about a year or so ago. Freaked me out a bit. I remember asking about it and people thought I was crazy, that there is no way that could have happened. Luckily, it's only happened once.

[McBobby Jr]

Originally Posted by Schultz28

I had this happen on my F80 about a year or so ago. Freaked me out a bit. I remember asking about it and people thought I was crazy, that there is no way that could have happened. Luckily, it's only happened once.

Yea, not sure why my car does it but it’s done it multiple times although it’s been awhile. It’s like my car gets a boost surge and the turbo gets stuck and the car keeps going. Luckily, nothing bad happened on my end. I can imagine this issue could make for a serious accident in a situation where there is traffic ahead and the car won’t stop.

[Swavyy.F80]

I’m having this same issue with my single turbo F80 but only happens in higher rpm 4k and above then revs up to about 5-6k and won’t stop till it feels like which is a real safety concern. But if I drive the car normal in comfort it’s like factory.