I was out today, and about halfway into my errands, the car started to rough idle whenever I came to a complete stop. The rough idle made my wife say, "It feels like the car is going to stall," but it never actually did. The engine rpm's look about 100 rpm's lower than usual on the tach and remain constant with no dipping or revving. I can also feel a noticeable, constant rate shaking in the car, and acceleration feels under powered.

Edited to add...

And, the CEL just came on as I was pulling into my garage. My code scanner returned P0301, Misfire in Cylinder 1.

I've since searched the code here, whilst I see a few suggestions regarding what to check, I don't see any suggestions that come with instructions. Is there anything I can check on my own? If anyone could offer any suggestions along with "how-to's", then I'd very much appreciate it!!

Edited again to add...

I went outside to shoot a video of the behaviour.


I also noticed for the first time a distinct "chugging" sound.

P.S. Would it be bad to continue driving the car with this problem??

 

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I've currently got the same issue on cylinder 4 of my MCS.
Mini swapped coils 1 and 4 over and the fault stayed with cylinder 4, so they're suggesting burnt exhaust valves as the cause but I won't know for sure until they've stripped it tomorrow. Suggestions of the root cause range from coils, plugs, exhaust valves/carbon build up to high pressure fuel pump failure.

Probably not that helpful, but you're not alone in having this problem right now! It'd be interesting to see if there's a common cause for our faults.

 

Being new to Mini's, I don't really know, but mine gets rough at times and seems a little sluggish. I'm hoping its just carbon build up as mine as 63k and I don't know if the carbon has ever been cleaned off. Looking to do it myself or have it done soon.

 

Most likely carbon build up. Mine was just diagnosed with the same symptoms.

 

To test for fuel injector problems, not sure if this is possible with DI, but you can unplug the injector on the bad cylinder and if there is no difference in the engine then it is most likely the cause of problems. Since you said it is only at idle, it would make me suspicious of a vacuum leak also. Might want to check for that. Carbon buildup is a possibility too

 

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No compression in cylinder 1. :(

I'm really at a loss for what to do. I've already poured $4000 into this car in the past month. At that point, I'd be able to get another car for what I've spent in repairs!! I'm so frustrated and disappointed!! :(

 

Have you done a leak down test?

 

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You do it when the piston is at the top of its stroke where there should be no places for air to go. Then put compressed air through the spark plug hole and you can determine what part of the engine is leaking by listening for the air. Example if you heard air coming from exhaust then the exhaust valves are the problem. There are some good youtube videos on it

 

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Id be helpful to know. An intake valve leak could actually be due to carbon preventing the sealing of the valve. Other than that im not sure.

 

I watched a couple videos of the compression and leak down tests, and they were very informative.

But, let me see if I have this right, at least...

If the leak is at the intake, then a carbon cleaning may solve the problem, as you mentioned. Or, I might have a bad intake valve, which would require a new cylinder head.

If the leak is at the exhaust, then I have an exhaust valve problem, requiring a new cylinder head.

If the leak is going into the crank case and out the oil cap, then the problem is somewhere in the bottom of the engine (i.e., pistons, rings), so the whole engine needs to be replaced.

If the leak is causing bubbles in the coolant, then I have a head gasket problem, and again, I'd need to replace the cylinder head.

Am I understanding this correctly?

 

You would just need to replace the head gasket, but that shouldnt be the problem if only one cylinder is bad. If the cylinder next to it also had a problem then I would think head gasket right away. But what you're saying seems about right, but im no expert. If you can just replace a valve, then you might not have to do the whole head, but im not sure if thats possible. The labor would be similar though. If the head is broken, maybe consider getting it ported if that can solve the problem

 

If it is the intake, then it could be carbon buildup, or a valve that needs replacing. Possibly a valve guide though I haven't heard of those being a problem on Minis. If it is the exhaust, likely a valve that is burnt and needs replacing. Either way, you wouldn't need a whole new head, just pull the head, clean/polish and replace valves as required.

Piston or ring work doesn't necessarily mean a new engine - could be you just need new rings.

no, you'd need to replace the head gasket, which means pulling the head and inspecting/cleaning but you most likely wouldn't need a new head.

Make sure your mechanic checks the intake valves for carbon buildup before tearing the top of the motor apart. This is the most likely issue and it is easy to check and relatively cheap to fix.

 

My MINI is now at the dealership for a diagnostic. Wish me luck!!

 

Hope it goes good!

 

It didn't.

Diagnosis = Cracked Piston.

Solution = New Engine.



I'm just over 5K out of warranty, so the service department is going to bat for me.

My fingers are tightly crossed!!

 

I'm on mobile so I can't see you sign, but if you're unmodded its a defect and you might be able to get it fixed. If they say no, complain to miniusa about it. And does the 8000 include install?

 

Update here:

https://www.northamericanmotoring.co...xxx-miles.html

MINI came through with 80% of the cost of a new engine.