DCT bucking, how to avoid?

[Koldun]

I've had the same problem, and I think I've identified the issue as not giving it enough gas, rather than too much. Try it with the power button off, or in a lower S mode, and it shouldn't buck if you're trying to drive off gently.

Otherwise, whip that bitch like she owes you money.

[BPMSport]

I have zero problems with this if I'm easy on the gas. Power mode will make this worse. If you modulate the throttle carefully the car won't do it at all.

A tune helps, especially with the cold start cat warmup phase turned off.

A client of mine talks a little bit about it here:
http://www.m3post.com/forums/showthread.php?t=744663

[PurM3]

This happen to me when I didn't give enough gas.

[JoM3z]

You're not giving it enough gas...

[BPMSport]

Originally Posted by m3an

funny you mention this as every dealer loaner I get (which are 2013 bmw 328) experience the same thing, under full throttle they buck like crazy until you left off or the car shifts.

I've had a bunch of 328 and 335 loaners and they were all fine full throttle (other than the 87 octane they probably had in the tank). Maybe this is an F series issue?

[808MGuy]

I had this too and eventually learned how to ease on to the throttle while still being able to get going quickly. Also, as Mike said, a tune helps get rid of this as well. After I got my Evolve tune, this has gone away. I can pretty much floor it now from a stand still with no problems.

[BPMSport]

Originally Posted by 808MGuy

I had this too and eventually learned how to ease on to the throttle while still being able to get going quickly. Also, as Mike said, a tune helps get rid of this as well. After I got my Evolve tune, this has gone away. I can pretty much floor it now from a stand still with no problems.

Exactly.. Most of my customers mention how much smoother the car is post tune as compared to the stock programming.

In terms of DCT, I could see how some people are saying that giving it more gas makes it better.. With my tune the DCT will engage slightly faster, so it possible the bucking is happening before it's fully engaged.

In my case, being 6MT, I've only experienced this when giving too much throttle while the linkages are fully engaged.

[TVMA Doc]

Originally Posted by sycd

"gradually increased" ... Yeah until 1210 miles, lol.

Wow, you had the patience to spread it out over 10 whole miles?

[mamadub]

Originally Posted by eisenb11

Sounds like we have it figured out. I was able to counter the lurching by applying more power... So forcing my foot down probably fights its tendency to move backwards from the force of acceleration. I'll play around with the bracing late too.

After my breakin service of 1240 miles, I did gradually increase the use of the throttle.... Until about 1246 miles.

Right now, however, I'm not running high RPMs for sustained periods.

I remember when this happened to me and it freaked me out. The above is the exact advice I got and it never happened again.

[eisenb11]

Haha, this is an old thread of mine. I found 2 ways to deal with this once the bucking starts.

1. Shift (albeit prematurely)
2. More poooowaaaaah!

[swamp2]

Originally Posted by saeedg48

get a 6spd

Wow, open mouth, insert foot, drool all over it and look really silly...

One tip, probably mentioned in the threads the other poster linked to: Place the right edge of your foot so it rubs against the transmission tunnel just to the right of the gas pedal. This help stop your foot from moving in response to inertial effects. Other than that, just don't use that throttle mode. It really has very little purpose...

[ksflatlander]

Originally Posted by elh0102

Throttle mapping is too sensitive in Power mode for smooth modulation. I found it very problematic on track; basically nothing but a sales gimmick. You can open the throttle as fast as ever necessary in the normal mode, and it's much easier to balance the car in a turn when near the traction limit.

This.

[MasterofGoing Faster]

I have the same problem and it is NOT operator induced. Dealer could not diagnose it as it happens intermittently. Will continue to pursue diagnosis though. I believe it may be fuel system related. More likely to occur in warmer weather, shortly after start-up, under hard acceleration, like this ... revs to 2500 RPM, stalls down to 2000, up again to 3000, stalls down to 2500, up to 3500 stalls down to 3000, up again to 4000 .... Lurching, porpoising ... embarrasing for anyone observing such a premium sports car trying to get off the line. Only happens about once a week and will not repeat again after the episode (except possibly if it sits for a few more hours in the heat after some hard driving). Definitely stalling out, then resumming full throttle application. DSC is not intervening. And don't tell me to "just ease into the throttle"; why did you buy your M3 anyway? First thought it could be M-DCT clutch engagement issues but it has happened in both 1st and 2nd so I'm less convinced that it would affect both clutches (unless it happens to be a system failure in the clutch control circuit).

[Pontrelli]

Originally Posted by tjsabec

I have a 6mt and have experienced the lurching. For me it is only when the car is not warmed all the way up and I am using the power throttle responsiveness. Solution? Don't engage power throttle responsiveness until the car is fully warmed up. I personally feel that the foot modulation comments are off base.

Ofcourse..whenever the car is still in cold start mode its going to buck and hesistate when accelerating..isnt this common knowledge by now?

[eisenb11]

Originally Posted by Pontrelli

Ofcourse..whenever the car is still in cold start mode its going to buck and hesistate when accelerating..isnt this common knowledge by now?

This still happens, even when out of cold start mode.

[TheYoungConnoisseur]

Had this problem with an e39 m5 but was actually loose engine mounts and would buck like a mofo in first when gently accelerating like a normal go get the groceries style accel in 1st only. Hopefully this is just a mapping/foot issue.

Have yet to drive the new m3 yet.

[CptSlow]

Originally Posted by MasterofGoing Faster

......shortly after start-up, under hard acceleration......

Sounds really good for the car.....

[jeff4598]

Dinan tune helped a lot and then I put power setting on highest for a week to train my brain and when I backed off to sport setting it was a breeze.

[Phantom_9192]

First thing to do when this happens if you have Power on:
- Turn Power off.

If the issue goes away, you know what the problem was . (Hint: it was not the Power button)