Well it would seem after they flatbed my mini 650 miles back to Baton Rouge, I drive 45 min to pick her up and she's NOT fixed. After my dealer researched it, They determined it to be the timing chain tensioner which is what I thought it was the whole time. They are changing out the whole assembly. The tech said that this could cause the hesitation and black smoke like I was also experiencing by being slightly off timing and misfiring. So we will see once I get her back. It's been almost 2 months in the shop straight for a 1 week fix.

 

check your state lemon law. 2 months probably qualifies you in most states.

 

I have had the same problem and my dealer has been working on my car off and on for last few months. They had the Mini service rep look at my car last time it was in and finaly fixed it by replacing the air mass meter. It runs so much better now!

 

Have you tried pushing the engine hard to remove some of the carbon buildup. It worked on my 320i. I pushed it really hard and a lot of black smoke came out and then it stopped completely. Mind you though the car is in storage for like 8 months.

 

I just had the hesitation and black smoke event... I was doing about 60, heard a click, felt a little hesitation, and noticed a black cloud of smoke behind me. It all happened really fast, about 3 seconds. No CEL and everything was normal the rest of the way home. I have 8k on it, use 93 octane gas, and it's the first time this has happened. The Honda Civic Si behind me wasn't too happy about the gassing he received . Guess I'll keep an eye on it...

 

ok.... so here is how this will break down. you will go to the dealer and what ever tech is hated the most by his SA will be given the car and shot gun spark plugs in it because thats easy, next week you will get the SES lite on and will end up with the intake off and they will clean the intake valves because they are covered in carbon.......three weeks later you will be towed in and they will replace the the high pressure fuel pump and break the feed line connector almost starting the car on fire once or twice but dont you worry they will replace it at no charge! well you will than have happy motoring all over again.... trust me it happens

 

Yeah, that sounds about right... Good thing is nothing happened today. My daily commute is 40 miles round trip with stop-n-go lights, hills, 50-65 mph highway and down hills. I stopped at a Tesoro gas station and filled up with their gas on the way home because I always notice my car runs better with their stuff. I usually gas up on base and base gas stations are notorious for having crappy gas but it's usually 20 to 30 cents less. I'll pay the extra $2 and change for piece of mind. We'll see what happens...

 

since switching the cheveron, i havent had this problem...

 

No repeat of the smoke so far. Either it's the better gas or it was just an isolated incident...

 

My car just got bought back because of acceleration hesitation and random click noise from under the hood with black smoke from the exhaust. All happened with Shell fuel, new spark plugs, new air mass meter, new timing chains and tensioner. They can't figure it out and I asked them to buy the car back. So Mini did. It was frustrating but Mini was very nice to me in the end. I can't buy another new Gen Mini right now after this. I might buy a used 2006 CooperS. I had better luck with my old Mini.

 

Wow, certainly eye opening what can happen . Let us know what you end up buying.

 

I had the same thing start to happen consistently at WOT shifts(auto) where it would hiccup and throw a puff out the tailpipe. I eventually traced it to a vacumn leak at the crankcase PCV connection. The cheap plastic hose was sucking air causing the stuttering. Verified it on a dyno. Replaced plastic hose with a 1" rubber hose along with clamps and fixed the problem. Definitely worth checking out if you have similar symptoms on your MCS since the PCV/Intake manifold are very similar on the N12/N14 engines.

Oh and the MINI tech and service mgr were convinced my torque converter was shot and wanted over 2k for replacement.

 

It happened again on the same portion of highway and under the same circumstances as the first time. I was doing about 65 on a slight incline, changed lanes to pass a slower car, still in 6th gear I slowly stepped on the gas to accelerate and heard some clicking, felt some hesitation and saw a cloud of black smoke out the back and then everything was normal. I'm gonna see if I can consistently duplicate it and then guess I'll take'er in...

 

Mine is in for this symptom right now. I just got the call - "We can't seem to duplicate the problem. Would you like to come down and go for a ride with the shop foreman?"

The car has been consistently knocking/retarding/backfiring for the past 2500 miles. I too believed I got a tank of bad fuel, but it hasn't gotten any better or worse. My concern is that it momentarily kills the ignition (super-knock condition) and it's done it in some bad and dangerous places like entering fast-moving traffic.

I suspect this one will be solved by the owner collective since most dealer service departments seem to be turning a blind eye to the problem.

I think I'm going to clean out the Mass Airflow Sensor and put plugs in it just to see what happens. 3 tankfuls of Techron treatments got me nowhere.

 

Cleaning the MAF is a good idea but before swapping the plugs I'd give it one or two seafoam treatments and see if it's the burnt carbon buildup on the valves that's causing the problem.

 

I've been reading that in some of the threads - I think that's going to be step 1. Step 2 will be a catch can. Step 3 is plugs/MAF.

Good bet this will be carbon deposits considering the car is a daily driver and gets 110 mile of highway daily - now at 48K. I need to flog it more than I have been.

 

Been thinking about trying to run SeaFoam through mine as I've been having the same issues. I really want my dealer to do a carbon cleaning, but they said they wont unless its throwing CEL's. I've never gotten a CEL.

It just seems silly to me, cuz by the time the misfire codes usually pop up on the cars that have had carbon problems, the motor is usually toast. I'd like to be proactive in the situation.

I've never used SeaFoam, and to be honest I'm a little un-easy about doing it. I know its been discussed briefly before, but has anyone actually done it on this motor yet? What is involved, step-by-step? Does it have any affect on the turbo? Sorry for the newb questions :(

Also, to save me time, what size socket does the R56 Spark Plugs take?

 

Just got done with SeaFoaming my car. Did it through the PCV tube. Did the process 3 times actually, seemed to help my motor a TON. It idles smoother, runs smoother, and no hesitation or pinging anymore...and the motor just sounds "cleaner". Smoke was initially black, which is usually indicative of carbon....I highly recommend anyone with an R56 over 30k miles to do a SeaFoam treatment.

I'm also about to change my plugs tonight, took them out earlier and they didn't look too bad, but figured I'd change them anyway, seeing how the interval on a JCW is at 30k. Even though I don't have a JCW, I have ran high boost for nearly 15k miles now so I'll follow the JCW spark plug change interval for good measure!

 

I can't duplicate mine... From a stop my car takes off with no problems even if I really stomp it. Traveling at highway speeds if I stomp it, it'll downshift (auto) and take off with no problem. It doesn't knock either so I don't know what's up, it's only done it twice about a month apart...

 

I have been seeing this also. Sometimes as posted, sixth gear-pull out to pass and the "hiccup" hits then it runs fine. It also does it when cold and mid throttle acceleration. Its a much milder event then. I have pulled the codes and there is nothing there, even in the pending stack. I have also been seeing the timing chain rattle so maybe they are related. God only knows, just hope it has a resolution before the warranty period expires.

Specific: 07 MCS, 28K miles and driven hard and put up wet. 24 miles down back roads to work each day-covers the entire rev range/throttle position. Just finished a 1000 mile drive at 70+ averages, a/c on and 39mpg. Hopefully that would have decarboned it some.

 

Guarantee there are codes stored in the DME....most likely a "Superknock" code.

Trying SeaFoaming....fixed my problems.

 

An engine is always adjusting the timing depending on conditions, this seems like as the engine tries to adjust the timing it freaks out or something and you get that "superknock". It might be a computer issue...

 

Seafoam, Seafoam, Seafoam. The knock/super-knock/cut-out is the ECU rolling the timing back to accommodate the pinging produced by carbon deposits. There's an long/active thread on this and the results have been overwhelmingly good after treatments.

My 2cents.

 

Mine did it again today, guess it's not the gas, been paying .30 cents more per gallon for "better premium gas". Strange thing is it only does it on the same highway, on the same spot, going 60 mph. It's a slight incline and when I go to change lanes and speed up I get a clicking/knocking sound, a puff of smoke, slight hesitation and then all back to normal. It only does it on that very spot under those conditions...

 

Follow up. The car spent the better part of the day at the dealers and ended up getting a new timing chain tensioner. It also got a new intake manifold as the last spell of cold weather was causing all kinds of cold start stalling or half engine power CEL conditions. It's been about two weeks but guess what? The motor still stumbles/backfires on passing someone and it still attempts to stall on really cold mornings(about 14) after start up. It goes back next weekend for three days - getting a new right rear shock assembly and another look at the cold start problem.