[katienotkathy]

Long post incoming, sorry.

tl;dr: Since I bought my Mini CPO in Dec. 2016 it has been infrequently/sporadically doing a severe jerking motion when accelerating at low speeds. The dealership has diagnosed and attempted repair a few times, but the issue persists. My warranty coverage expired, dealership is refusing to cover continued repairs, and I don't want to be on the hook financially for further diagnosis of this issue. Looking for advice about how to actually get this issue resolved or the vehicle replaced.

The long version:

I bought my 2014 Cooper S CPO in Dec of 2016. It has an automatic transmission. The day I drove it off the lot, it did this weird jerking thing when I was accelerating onto the highway. I previously drove a 2006 Mini with a CVT so I was used to the bucking movement that would happen around 8-12mph. This was similar, but more intense and just a single big lurch, almost like what happens when you pop the clutch on a manual transmission. Because of my past experience with my previous Mini, I thought it might be a fluke. It didn't happen for a while after that, but then started happening somewhat frequently (every 5-6 rides), so I took it in to be serviced. Here's the rough timeline:

1) Feb 2017 -- took in for initial service due to jerking, they said it was a computer issue. Updated software. Issue appeared to be resolved.
1a) In case it matters: During this time, I was also having an issue with the car pulling to the left. Took a few visits to resolve, they ended up realigning and swapping tires.
2) Sometime in early 2018 (I think), my check engine light came on. Had to have a recall replacement done. I believe they reset or updated the software again. The jerking problem began happening again.
3) December 2018 - Jerking became severe. After previous service, it was happening infrequently, mostly in sport mode so I stopped using sport mode. I finally took it in in December because it began happening consistently enough to reproduce, even in normal mode. They found that my motor mounts were cracked (at only 30k miles???), said that was causing the issue, and did a courtesy replacement even though my CPO warranty technically did not cover that issue.
4) Since then, the issue has happened very infrequently and the jerk has not been severe. A few days ago however, I was making a left turn and the car jerked so heavily that it actually locked my seatbelt. I thought I had stalled for a second in the middle of the intersection, but then the acceleration engaged and I went flying through the rest of my left turn. It was honestly scary, so I'm taking it in again.

Through my 2.5 years of experiencing this issue, here's when I have generally found that it jerks. Again this is sporadic, so it happens maybe 1-5% of the time (except for when it got very bad in Dec of 2018):

• 
  Tends to happen when engine is cold (most recent jerk that caused seatbelt locking was on a warm engine though)

• Tends to happen when vehicle is accelerating on slight or steep incline
  Between the period of the original software update and the second software update, the issue never occurred

• Seems to happen when I am accelerating, but hesitate for a second on the pedal, and then reengage

Now, the extra rub: My warranty expired in March of this year. This is clearly an issue that has been happening since I owned the vehicle. My goal is to:
1) Get this issue fixed, and
2) Not have to pay to get it fixed

OR get rid of this dang car.

Anyone have words of wisdom? Thoughts about how to get this properly diagnosed? With an issue like this, is it possible to get Mini to buy the car back from me? I'm at my wits end.

 

[mike1967]

how many miles has it got on it,
needs a proper diagnostics run with a flight recorder attached so can see what its doing when it does it, honestly they are so complicated so many thins can cause this, i would be airing towards high pressure fuel pump has a intermittent fault maybe that said could be wiring fault, or ecu fart so many things, the cvt gearboxes are silly complicated as well live data is the start not a cheap thing to diagnose any intermittent faults

 

[katienotkathy]

Thanks for the reply! It's low mileage, has ~32k miles on it. Also quick clarification -- it does not have a CVT transmission (the CVT I mentioned in my post was my previous mini).

Do you know if the dealerships use flight recorders? Is this something I could request?

 

[mike1967]

Thanks for the reply! It's low mileage, has ~32k miles on it. Also quick clarification -- it does not have a CVT transmission (the CVT I mentioned in my post was my previous mini).

Do you know if the dealerships use flight recorders? Is this something I could request?

they should have flight recorder that said if not then most tuning garages will have could exlain what car does to them to be honest main dealers just throw parts at stuff depending on what their diagnostics says trouble you have if no codes stored they wont know what needs doing, where a good tuner will use flight recorder to ensure either maps were correct and for finding running faults like what you may have. 32k is no miles

 

[katienotkathy]

Yeah, so apparently it's throwing an error code and they're replacing a crank shaft censor. Their story is that the past issues were caused by something else, it's a coincidence that the symptoms have been the same, and this will definitely fix my issue. *shrugs* I'm a little skeptical, but they're working with me to cover 85% of the cost of repairs even though I'm out of warranty. Guess I'll keep working with the dealer for now.

Thanks for the info. If the problem continues, I will pursue a shop that will do a flight recording.

 

[mike1967]

Yeah, so apparently it's throwing an error code and they're replacing a crank shaft censor. Their story is that the past issues were caused by something else, it's a coincidence that the symptoms have been the same, and this will definitely fix my issue. *shrugs* I'm a little skeptical, but they're working with me to cover 85% of the cost of repairs even though I'm out of warranty. Guess I'll keep working with the dealer for now.

Thanks for the info. If the problem continues, I will pursue a shop that will do a flight recording.

bmw them selves should be able to lift the fault code log off data this should have every fault code the car as ever had and in what order and when, as its crank position sensor i would ask you when the car played up was oil level low on it, i have seen it on cars with low oil to cause timing issues as the timing is variable via the camshafts vanos sprockets that relies on oil feed to work correctly, those engines must have oil level kept at the top mark or even a few mm above it, as they do use a bit of oil its easy to run them down low,,
i have also found the wiring between the under bonnet mev17.4 ecu can get broken seen this a few times now think it happens when people fit a battery and drag it over the wiring damage

 

[knt]

What quality of fuel are you using?

Might be worth using 1 or 2 tanks of Shell V-Power or 99 RON fuel or equivalent in other parts of the world.