I need some help. This just started happening tonight. After my car was completely warmed up running at 105 degree Celsius, when I completely mash my foot down and go into over boost... at around 3500-4000 and over I start getting many exhaust pops and during these pops my power is dropping severely. I'm concerned but hoping it's something as simple as spark plugs maybe? Car has almost 50k on it and I don't believe they've been changed yet... but I fear it's something massive like the turbo or intake manifold causing the issue, or maybe even carbon build up... which my car would then turn into a lawn ornament as I have zero dollars for that.!

 

Is it going into limp mode (engine half filled on tach) or throwing any codes?

Could be spark plugs or possibly an ignition coil, those are the easiest/cheapest to look into first anyhow. I had a coil go around 45-46k miles.

 

There is no limp mode or CEL of any kind... just exhaust pops and burbles as if I let off the gas, except I'm full on the gas... and each pop and burble make the acceleration stop.

 

Couldn't hurt to pull the plugs and check them. I replaced mine and the idle was smoother immediately.

Does it idle rough or stutter anywhere else in the rev range? Any mods installed?

 

I noticed a slight stutter during idle the other morning, but it was -12 degrees ferenheit so I chalked it up to cold weather. Today however was much warmer, and the idle is fine today, only the high rpm stutter/pops... for mods I have an Invidia Q300 catback & the previous own had a stage 1 manic tune done on it.

 

I'd definitely check them being that it's also tuned. Kinda hard to diagnose without having any CELs but I'd start with the plugs and see what you find.

 

Initial thoughts are check plugs and coils, then depending on mileage carbon buildup. Worst case, high pressure fuel pump. Mine is doing almost exactly the same thing with the same previous symptoms and depending on your build date you might have the same fuel pump that is prone to failure.

 

My HPFP was replaced under warranty about 10k miles ago at mini dealership so I ruled that out from the start. Also I was under the assumption the carbon buildup was a bit of a stretch with the n18 motor. I know it can still be an issue with high mileage though, but I am going to purchase 4 coil packs and spark plugs and change them, hopefully this solves my problem.

 

Your plugs could probably use to be replaced anyhow, given the mileage and tune, so you'll only benefit from that in the long run anyhow. If they turn out to be the solution then you'll have some spare coils for down the road or can return them.


Let us know how it works out

 

I currently have the same exact problem. I have a 2008 s with 120k miles. Im about to change my spark plugs out. Hopefully thats the problem. If not doing carbon cleaning after.

 

If those are the original plugs and you've not carbon cleaned before... holy cow, it'll feel like a totally different car afterwards.

 

Not getting the sputter but getting a half CEl every time I hit half throttle. I'm guessing carbon build up. Is sputter common with carbon build up???

 

The N14s were good for carbon buildup but also the '07-'10 have a warranty replacement out for the HPFP.

I'm guessing the CEL doesn't stay on for you? If it does, you should pull the code.

 

The more I drive my car with this issue I'm almost certain it's an issue with plugs or coils... Because idle is 100% fine before & after warmup. Even while driving normally on the highway it's fine. It's only occurring when I absolutely mat it and over boost comes on.

 

I'd bet more on coils then.

 

So things like coils & plugs DON'T trigger a CEL? If it were something bigger like carbon buildup, would that trigger a CEL?

 

They can, but only if you let the problem continue to get worse.

I had a bad misfire when I went Stage 1 initially because of a bad coil pack. I let it go for like 3 or 4 days and eventually it just got worse and worse because the coil was shorting and melting itself on the inside. I hobbled myself over to a BMW dealership and bought a set of new coil packs and it fixed it right away.

Though mine just misfired, no exhaust pops or bangs. More of a stuttering if I mashed my foot down.

 

Yes, you are correct. It goes off as soon as I re-start. Are you suggesting it could be my HPFP causing the temporary CEL?

 

So I wasted my money and started with changing my coils 2 weeks ago which didn't change anything. The reason why was because spark plugs were change 30K miles ago. Today I swapped out my plugs and problem SOLVED!!!!! Smooth all the way to the limiter. Hopefully this is also your solution.

 

I'd think so if the plugs and coils turn out to be okay. It could just be that whatever the issue is isn't manifesting itself all the time so it isn't causing the CEL to stay on permanently. I'd venture to guess that once the bad component (whatever it may be) will eventually get worse and trigger an always-on CEL.

Since it's only during full throttle I'd assume the spark isn't sparking as needed for the amount of fuel being injected, hence the exhaust pops from unburnt fuel hitting the exhaust (sort of like sport mode does). Now whether that's the plug not sparking correctly because it's bad or because a coil isn't functioning properly, I couldn't say. What leads me to believe it isn't the HPFP right off the bat is the fact that you're getting unburnt fuel, which I'd think would mean the fuel flow is adequate.

 

At least you've got fresh coils in there? You could consider it preventative maintenance

 

Just purchased this ignition kit from ECS tuning this morning, expedited the shipping so I should have it either tomorrow or Monday morning! Will let you guys know how it turns out once replaced!

https://www.ecstuning.com/Mini-2012-...ion/ES2893833/

 

Update:

So I had already ordered parts for ECS Turning on Friday. Saturday I go to work as usual, try to leave work and BOOM limp mode right away... apparently the misfire had become violent enough for my ECU to do something about it as the engine light was flashing on the speedo as well...

So seeing as I need my car 24/7 for my job, I tried to find some plugs and coils at some local vendors with no luck. I finally had to bite the bullet and purchase 4 coils and 4 plugs from MINI dealership for almost $500...

Good news though! All 4 plugs/coils replaced and car is running better than ever! Problem solved.

 

I am experiencing this exact issue. It's been happening intermittently when I get on it full on at highway speeds. Until today, it never threw a CEL but this evening on the highway it threw a CEL and the engine must've gone into limp mode because power was way down. Pulled off to nearest exit and read the codes. 2 cylinders experienced a misfire. Thanks for all of your helpful info on here. I will try new spark plugs first and go from there! I'm hopeful that will solve my problem! I will post an update as to what my results are soon.

update:
I changed my plugs with Genuine Beru OEM plugs and this solved my problem.
I would recommend starting there for your issue because from what you described my problem was exactly the same as what you seem to be experiencing. The Gap on my old plugs was shot. Which would stand to reason why when getting on it and the boost increases the plugs weren't able to do the job.