Hi all, newbie here. I bought a 2012 Countryman S last year. I've come across a random misfire that I'm looking for help pinpointing. Here are the symptoms...

I am getting a random misfire when punching it. If I gradually build up my speed, no issues - even at 80+ mph. However if I really try to accelerate quickly by stomping on the gas pedal, I get some shakiness and rough running followed by a check engine light and the yellow flashing light indicating half engine power on the dashboard. It obvious that at that point, I am losing power as I can no longer accelerate at a fast pace. I've cleared the code several times and repeated the steps above with the same result each time.

My first thought was carbon build up. I did a Seafoam treatment but that didn't seem to help at all, although it did spit some gunk out of my tailpipes. I already changed the spark plugs and coils and that did not correct the issue. My next bet judging off what I've read on the forum is a walnut blast. I really hate taking my vehicles in to the stealership, so if I can avoid that, I would really be happy.

Other than carbon buildup, is it possible that there may be an issue with the turbo? My train of thought here is that the issue only seems to happen at high speed acceleration. I'm wondering if there's a boost leak somewhere that might be throwing things off.

I wouldn't call myself mechanically inclined, however, I know enough to get myself in trouble. I have done some pretty major repairs before but only after a ton of research and sometimes calling on the help of a friend. New to MINI and any help would be appreciated! Thanks!

 

Carbon, not likely as it seems to be a rarely shown issue with the N18.

What are the codes you erased? That would be the first clue to solving the problem.

In my 2011 the issue you described was the HPFP - fuel pump.

 

The code is P0301 Cylinder 1 Misfire. Sometimes it will say Cylinder 3 or 4. That's why I say it's random. Plus I've already swapped out all the plugs and coils. Thanks for the reply!

 

The fact the misfires are skipping around is a sign the problem is common to all cylinders. Minnie.the.Moocher I think is on track: HPFP. I would add if the HPFP has a low pressure pump supplying it fuel the low pressure fuel pump has to be suspect.

 

Symptom I had also with HPFP.

 

From what I've read, the main symptom of a bad HPFP is a no start. I'm guessing with 3 replies suggesting the HPFP possibly being the culprit, maybe a misfire at high acceleration is another symptom? I saw that it seems some dealerships will replace this under good will. I planned on calling my dealership tomorrow and asking about it but I'd like to be as educated and prepared as possible for when I do talk to them.

FYI, I took this in to MINI of Austin when I first experienced the issue a few weeks back. They said it was spark plugs and coils and wanted $750 to replace. I told them thanks but no thanks and replaced them myself for about $200 worth of parts and 15 minutes worth of time.

 

Just for clarification, MINI of Austin suggested plugs and coils were the issue. I changed these out and it didn't help at all. Still trying to track down the culprit, hence this post. Anyone know if the 10 year/120,000 warranty extension for the HPFP applies to 2012 models?

 

It will depend on the build date. The extension is VIN specific. You can find out by calling and asking. Our 12 was covered.

 

Ok, so I just called MINI of Austin and they said that the HPFP would be covered under extended warranty but only if I used OEM plugs and coils when I switched those out. Which I didn't, although I did buy the highest grade plugs and coils AutoZone had to offer (almost certain it wouldn't make a difference as long as I used a quality product and not junk - open to thoughts around that though). Service advisor says not using OEM plugs and coils could cause misfire to continue happening - not sure this holds much truth, but maybe you guys would know better. So now I'm in the pickle of choosing whether to go buy another set of plugs and coils at $100/coil and $25/plug so that they would cover the HPFP under warranty or to go buy a new HPFP, install myself, and cross my fingers that it is in fact the cause of the misfire. Would love to hear everyone's input and thanks again for all the replies!

 

Well, you could have used the highest grade of plugs and coils but that doesn't mean they were the right ones.

Not long ago I came upon a Porsche Cayman owner who was having misfire issues with his car's engine. He had replaced the plugs with new ones, high quality/name brand plugs (I forget the brand name).

I looked up the plug and while the plug compatibility chart indicated the plug was the "right" plug I looked at a picture of the plug. It was clear the plug was *not* the same type of plug as the factory plug. The replacement plug had a recessed electrode. Porsche plugs are extended tip which run hot during low speed running to keep the plug clean but at high speed running are cooled by the incoming charge.

I pointed this out to the Cayman owner. The owner removed the new plugs and installed *factory* plugs and all was well with the engine.

A HPFP is a pretty expensive item to replace if one has to pay for it out of pocket. Assuming it would cost more than replacing the aftermarket plugs/coils with factory coils my advice would be to replace the plugs and coils with *factory* plugs and coils and then if the symptoms continue get the car in and take advantage of the extended warrranty on the HPFP.

I will add that in the past with all my cars and I intend to do the same with my JCW when the time comes I have used factory plugs, coils, MAF, oil, oil filters, transmission fluid, transmission filters, air filters, O2 sensors. I have no desire to use my cars as test platforms to try to find suitable replacements for factory hardware. (The factory stuff ain't bad. 317K miles on my Porsche Boxster, 161K miles on my Porsche Turbo. When I sold these cars -- just recently -- neither one was manifesting any issues from using factory parts/fluids.)

 

Thanks RockC and everyone else for the input! I'm curious what others think about this as well. I'll certainly consider it as a possibility for the continued misfire, but I've never experienced it before. These were the "right plugs and coils" according to AutoZone - I also verified through the manufacturer's documentation but I do realize there's a possibility that they could be wrong. Anyone else think this could be the culprit, or at least a good "re-starting point". It would suck to have bought and changed these out (spending around $200) only to realize I needed factory plugs and coils instead but hey, live and learn! Thanks again everyone!

 

They aren't going to just replace the HPFP without diagnostics, which usually means they are going to scan for the codes that will tell them what to replace. If it is the HPFP and no codes are showing it could be that the problem is just beginning. In my case I waited until the right code showed up and then took it in.

If part of the diagnostic routine calls for having OEM plugs/coils then you are going to be out of luck unless you let them change them out. Non OEM electronics are often troublesome in these cars, although it would be odd for you to get the same issues before and after the changes.

Good luck, been through this and it can be a pain. Since this isn't stopping you from driving the car at normal speeds, I'd just monitor it and wait until it gets worse.

 

Thanks Minnie.the.Moocher. I'm curious if you happen to remember what code you were waiting on to show up. Also, and I don't know if it's related or not, but awhile back I was getting a thermostat housing code that came and went. When I took it into the dealer last time, they said they didn't get that code. It's popped up a couple of times since but I haven't seen it in several weeks now. Not sure if it's just a fluke as I never cleared this code - it just went off on its own. Any chance this could somehow be related?

 

https://www.northamericanmotoring.co...vestigate.html

Other codes relating to thermostat could certainly be involved.

 

Thanks Minnie.theMoocher, I'll check out this thread now.

Anyone know where I can buy OEM spark plugs and coils for cheaper than what the dealer wants to charge? $500+ tax seems really excessive. I called the parts department and got the part numbers...Plugs: 12122293697, Coils: 12137575010

When I look these up, it shows the plugs are Beru and the coils are Delphi. Is that correct? I guess I was just expecting to find MINI name brand since they made such a big deal about using "Factory" plugs and coils. Thanks!

 

Way Motor Works
ECS Tuning
Pelican Parts

All good vendors that I've gotten OEM parts at a fair price from.

 

https://www.ecstuning.com/Mini-2012-...gine/Ignition/

The newest part number on the coils are ~153. We can still get the older parts ~010. Yep factory is beru and Delphi.

 

I had aftermarket coils on the car when our hpfp went and it was replaced.

 

Jwanck11 - did they mention anything about the coils and plugs? Do you recall them saying anything about the HPFP only being replaced if factory cols and plugs were used?

 

ECS TUNING, can you private message me? Why are the "GenuineMINI" parts so much more than the Beru and Delphi parts if they are in fact the same parts?

 

We are direct with a lot of the MINI manufacturers.

 

Nope - not once.

Also I got the plugs from ECS that are the same as genuine MINI but are much cheaper because they dont have MINI printed on them.

The dealer should not care that you have aftermarket plugs and coils. They are unrelated to the HPFP.

 

That's what I thought too Jwanck11. Sounds like I should start preparing for a heated debate with the service adviser. We'll see how it goes! Thanks for the reply!

 

I hear you. I would stay calm and be respectful, but be firm. If the hpfp is bad, they need to replace it.

 

Will do Jwanck11 - Thanks! I'll post an update once everything gets figured out. Thanks everyone - great community here with a ton of helpful information!