Hi Everyone,

First time poster here, glad to become a member of NAM!

I have a 2004 MCS with 92,000 miles, and I've owned it for a couple years (bought it at 70,000 miles)

In first gear, when accelerating and decelerating my mini jerks forward and backward (respectively). I initially chalked it up to one of the kinks of owning a supercharged car, but I wanted to check in with you guys to make sure I'm not making a big assumption. I've read about r56 owners experiencing the same thing, but with no answer as to why (I am aware that the r56 models are turbocharged).

When trying to maintain a steady speed in 1st it feels like the motor is 'oscillating'? I don't know if that makes any sense. Imagine very small acceleration/deceleration instead of maintaining a steady speed.

Major work I did on the car this year was a clutch replacement and flywheel resurfacing. Also the exhaust hangers snapped and cracked my exhaust line but I had that welded up.

Any ideas anyone? Thanks for your help guys!

 

Try turning off the DSC post-startup (before driving) and see if that eliminates the problem. Same thing happened with my 2004 MC40 and that cured it. No idea why that works. In case you're interested, "socalva" on this forum sells a switch board that provides auto-DSC-off on startup, and auto up/down windows. I installed the board on my MINI recently and it works great.

 

I would check the condition of your front end components. Drive shafts, suspension bushings and ball joints, engine mounts, etc. Might find something loose.

Make sure your intake ducting is tight and not leaking. The inlet gaskets on the superchargers are a common spot for intake leaks. With the car running you may be able to hear and/or feel a leak at this location.

 

Whaddayaknow, it worked!!

Amazing, an issue that has plagued me for as long as I can remember, and BAM, cured with something so simple. I wonder why/how DSC affects the r53 in such a way. I'll definitely take a look at that board. Thanks!

 

 

I've driven plenty of manual cars that never jerked with relatively normal accelerations, at least not to the degree that my r53 used to. (check previous post)

 

 

My specific issue had nothing to do with taking off (I know how to take off )
Slowly depressing the gas pedal will result in the jerk, same with slowly pushing on the gas pedal.

 

@Tgriffithjr, as I mentioned above, my 2004 MC40 did exactly the same thing. The DSC, for whatever reason, is enabled upon startup on my MINI (same as "univore" evidently). The jerking is more a function of the car losing power -- starts moving then bogs down badly, then starts moving again, no matter what you're doing to the throttle. This happens only when it's cold but can be disconcerting when the car behind you almost rear ends you. I threw this problem out to the forum months ago and no one could tell me why it occurred. I believe it may have something to do with the signals received by the ECU that is then modifying/suppressing fuel delivery. The problem disappears a couple blocks later. I discovered the DSC-off solution by chance and got in the habit of turning it off right after startup -- a real PITA but first-world problems, right? I'm going to surmise that "socalva" had the same issue since his switch board has a DSC-off programming function built in.

 

 

I thought the same thing when I bought my R53. Adjustment of the throttle, even smooth and/or small movements, caused noticeable movement in what felt like the drive train. It felt to me, as a new owner, that the engine was rocking forward and backward (with respect to the driver's seat) as I drove. Turning the DSC off did not alleviate the issue for me. What did alleviate the issue for me was replacing BMW's **** factory components and replacing components with known failures/issues.

Turning your DSC off is easy, but that seems like a bypass to actually fixing a problem.

 

Good ideas here. I can't imagine what may be the issue with other than the dsc off trick. My bushings are new and I had my mechanic check the engine mounts when he did the clutch job, and I trust this guy fully as I've known him for a couple years and he's works exclusively on minis and Alfa Romeos.

I do agree that the issue feels like a drivetrain one. Was there a specific component that you replaced that fixed the problem? Or werr you a little behind on maintenance and saw improvement in drivability when tackling many issues at once.

Thanks for your input, I'm going to try and find leaks in the inlet gaskets as that is something I haven't checked, although I'm fairly sure they're probably fine.

 

Probably a little bit of both as the car was low mileage and taken care of, but I did not get a complete service history with it. I replaced all the engine mounts with non-OEM units. Vibra-Technics upper mount, BSH Lower, and a Powerflex poly insert on the driver's side mount. I also replaced both axles (factory), the front control arm bushings with Powerflex Poly units, all the ball joints and the tie rod ends (factory). Now it does not feel like the engine wants to remove itself from the car nor does the front suspension feel as loose as my F250. I felt like the engine mounts made the most difference to the throttle rocking issue.

If an intake leak gets bad enough it will turn on the EML light and/or the Check Engine Light. If you aren't throwing codes, I might take a gander but hesitate to take stuff apart without knowing a leak exists. I noticed a hesitation around 2,000-3,000 rpm when transitioning throttle positions when I knew the green supercharger inlet gasket was leaking but I hadn't fixed it yet. It got so bad after a couple weeks that the car would stall when coming to a stop, after driving on the highway and holding ~4,000 rpm for 15 minutes. You could hear the air rushing through the leak if you stood with the hood open.

The main culprit for intake leaks is the green supercharger inlet gasket. I replaced the inlet gasket and the black intake tube that attaches to the supercharger after I serviced my supercharger because the intake tube bolt hole had elongated and allowed significant air leakage. The intercooler boots are also a semi-common leak point. Mine started to crack and I replaced them with Alta units. I run a Detroit Tuned Bypass Valve as well, but I put that in right after I got the car and I have no point of reference regarding the running issues. The hard plastic vacuum lines can crack and allow air to leak as well, I broke the MAP sensor line at one point and caused a vacuum leak.


I don't know if this helps, but you never know on forums what someone might find useful. One man's rocking engine is another man's throttle hesitation. I've had both.