The codes would indicate that you have a bad HPFP. If you're still under the campaign at MINI have them do it for free. I would also suggest that you find a good MINI shop that'll do a walnut shell cleaning and throw a set of plugs at it. Your car will runn like a top when you're done.

 

The guys over at Knauz Mini have been really good to me in the past with getting BMW to cover out of warranty repairs. I did get the extended coverage for 6 years / 100K miles, but I don't know if that applies here...

I'll check the easy stuff myself and rule them out before taking it to the dealer. Thanks guys!

 

UPDATE: I took the time to pull the coils and plugs. None of the plugs had any real issues other than the spacing on one of them... The interesting part is that I swapped the coils from 1 & 2, as well as 3 & 4. This was two days ago. Since then I have only noticed maybe 10 misfires total. No codes have come up since clearing them before the swap. I have however noticed that even though I'm not misfiring, I am down on power.

I went ahead and ordered NGK Iridium plugs and a fresh set of ignition coils. A buddy of mine runs an auto shop and was able to get me the coils and plugs for $150...

I will report back when the parts are in and she's been tested. I'm also looking into contacting A-Spec Tuning out of Schaumburg for a quote on walnut blasting. I'd like to get a good look at the valves before making that call though.

 

I had a similar issue:

1. Had a coil go out. Replaced the coil and it ran fine.
2. Had stuttering issue at high RPMs. Took it to Motorwerks Mini in Minneapolis and they couldn't figure out what it was. Did a walnut blasting, and valve cover replacement (had a leak) and though response was better at low RPMs and whatnot, I still had the high RPM stuttering issue.
3. Figured combustion needs air, fuel, and ignition, so I just logically went through the easiest route. Gas made no difference so I went to spark plugs (coils were already replaced). I noticed the plugs used were Boschs, and though my car only had 85K (records show only about 20K since the last plug swap), I swapped them out w/ NGK iridiums.

Problem solved. I was quite irritated that Motorwerks Mini missed this to be honest. Haha

 

I'm new to the R56S family. Mine is a 2012 MCS. I have read in numerous threads that spark plugs should be changed around 40,000 miles. Should coils be changed then as well?

Let us all know if the new plugs and coils have cured your misfires! I hope so, as I know how frustrating it can be when you have a problem impacting your enjoyment of your MINI.

 

The new coils are in, and the plugs will go in tonight. The coil swap has fixed the stuttering, as well as a rumble under acceleration at high speeds. It has not however fixed the issue at idle. That issue has been discussed ad nauseum in many threads... It's the problem with RPM drops during idle at traffic signals and during startup. I may look into that issue later if it throws a code.

 

I had the same problem, but with check engine light. At 3000 rpm, turbo should kick in. My problem was that the tube which goes to turbo was cracked in below place which could not be see by free eye. But the cables near it was full of oil. Please see this tube for any crack.

 

I'm interested to see if the plugs will do it. I wouldn't be shocked if one (or multiple) of the plugs got fouled up by the bad coil(s).

 

Mine was the EXACT same last week, turned out to be the HPFP after changing plugs/etc

 

Okay... So I finally got around to changing out the plugs last weekend. The gaps on the stock plugs were all over the place. One was too small, and the others were all too wide. The new plugs have made acceleration and idle much smoother. Unfortunately the new plugs and coils have not corrected the idle RPM drop. I'll look more into that issue when I have the time.

 

When you turn off the engine is there a hiss coming from the the valve cover? I had a leak and it caused some idle issues. Just replaced the valve cover/gasket.

 

Was just going to ask that also about the valve cover crack or any oil residue on the valve cover. Believe Centium has an n18 engine Cooper S , the crack through were more prevalent on the n14 engine cover.

 

I do have the N18. Pepper was built Oct 6, 2010...

I haven't seen any oil leaks around the valve cover or around the vacuum pump.

 

I got a set of Beru spark plugs for my 2010 Cooper. All of the existing plugs were too loose - installed by the dealer a year ago. Oil had escaped past two of the plugs. I cleaned this out, replaced them, and torqued them to spec.

While at it, I replaced the spark coils with OEM Bosch parts. So, I should be good for another 50 K miles.
Such a simple thing. Something you might want to check first if you have stumbling issues.

Now the car runs like new, and is a joy to drive. It's smooth as silk, and the gas milage went up 5 miles to the gallon. Gee, I wonder why?

I think I'll add checking the torque of the plugs twice a year to prevent future problems.

 

Mine did the exact same thing. Spark plugs.

 

I just replaced the plugs for the second time on my JCW at about 56k. 1 step colder NGKs, since I recently went to a stage 3 tune. I was getting some stutter at idle and WOT. I checked the plugs after only a couple hundred miles of driving and they looked like this . The plug for cylinder #2 is pretty much black. They were are still gapped to .22

Could this be a sign of a bad coil?

 

That #2 plug tells a story of perhaps running rich or burning oil, the other three look fine. You want the porcelain area to be medium-brown tan color, could have a dying coil. When I change my plugs 10k miles ago I had three clean plugs and one that was darker than the other three, looked exactly like your #2 plug. One cylinder I'm told gets more carbon build-up than the other three.

 

Thanks Systemlord.

I did some logging and AFRs seems ok. Just a little rich on heavy load.

I do have to keep an eye on oil levels. And just noticed last night more oil residue on the valve cover in a few small spots, And I've had to replace once already, ugh...

I'm going to order some coils, I've been wanting the red IP coils anyway.

 

Ok, replaced the coil for cylinder 2 with a Delphi, because I could get it quick and relatively cheap from Amazon.

Didn't seem to fix the issue. Still stuttering, checked the plugs after about 50 miles, 1,3,&4 look good. #2 is black again.



I tried to get a look and the gunk in the cylinders of #2 & #3 with a scope. They don't look that bad. #2 is definitely worse. I did just have a walnut blast done.





The oil residue on the valve cover seems to be pretty constant. I cleaned it up a bit the other day and it seems to be back.



I had the VC replace under warranty maybe 5000 miles ago.

Another mini friend suggested adding a OCC or maybe that I had a vacuum leak, but I don't understand how either of those could fix / cause a problem that seems to be isolated to cylinder 2.

 

It's not the valve cover that's leaking oil, it's the O-ring and PCV hose not sealing properly. As for your dirty #2 cylinder you must have an oil problem, either valve seals or the rings aren't sealing good anymore. A leak down test is in order! You need a couple of cans of BG 44K to add to your tank, it's the best at removing carbon from the combustion chamber and piston tops. What video probe do you use? I need one of those.

 

FWIW, I was thinking a compression test. Is that an N18 engine?

 

I had a compression test done yesterday. only 90 in cylinder 2 not looking good. 1 was 180 and 3 & 4 were 165.

I think piston failure is coming :( mulling over options...

As far as the O ring and PCV hose, do you just recommend ordering a new O ring and reseating the hoses?

I use this its not the best but it was relatively cheap. You can't do screen shots or video, but it has a good LED light and I just take pics with my phone.

 

It's an N14

 

Your going to either need to rebuild or buy a new engine, I would take this time to do your own build with forged parts.

Number #3 and #4 are the only healthy cylinders you have, the #1 probably have the most carbon build-up around the rings and piston tops exaggerating the reading of 180 psi. My #1, #2, and #3 all read 165 psi and #4 180 psi, the latter has the most carbon on piston tops exaggerating my psi rating. It's well known that some N14's cylinders go bad prematurely do to flaw in machining of the cylinder walls, you can thank Mini USA for that. How long you had your tune?

I just heard a police chase on I5 pass by including several helicopters, it's Saturday night getting started!

 

Yeah, I think I'm leaning towards the forged route.

If I do that how much more reseliant can I expect it to be? How much more will I be able to push the car?

I've been tuned for a while in one way or another.