Long-time lurker, first time poster. I’m experiencing a misfire problem. I’ve done a lot of research on this, but find that every situation is different. The nature of the symptoms has changed slightly as I have tried different fixes, but is the same for the most part. All repairs relevant to these symptoms are listed in my signature.

Rough cold start (now takes multiple attempts to get it started as it stalls). Once warmed up, runs fine for the most part. If I drive it longer than say 30 minutes, power surges in and out, a lot of hesitance. The half-engine yellow/orange light comes on shortly after starting, goes off after it is running better most of the time. The CEL light in the center round speedo display comes on from time to time, stays on until I clear the codes.

Was getting these codes: 2D52 DME: Super knocking; 2D5C DME: Fuel shutoff due to super knocking cyl. 4; 2781 DME: Combustion misfires, several cylinders; 2771 DME: Combustion misfires, cylinder 1; 2775 DME: Combustion misfires, cylinder 3; 2779 DME: Combustion misfires, cylinder 4; 277D DME: Combustion misfires, cylinder 2; 2DCA DME: Fuel shutoff due to super knocking, cylinder 4;

I replaced the fuel filter (probably the first time it had been done. Very black). Also replaced the oil filler cap, which appeared to have no gasket. Oil/filter change, etc. Ran good with no more CEL lights, no codes stored, for a brief while. Over the past couple of weeks, I’ve been getting more codes that indicate misfires (no more super knocking codes): 2783 DME: Combustion misfires, several cylinders; 2773 DME: Combustion misfires, cylinder 1; 2777 DME: Combustion misfires, cylinder 3; 2880 DME: High-pressure system; and others for misfires on cylinders 2 and 4.

I Seafoamed the intake and the gas tank, drove it for multiple 60-minute drives (about 2/3 of the tank). Same symptoms. Rough cold start, periodic hesitation in power, seldom runs on what seems like half-power, CEL lights after clearing codes (but each is inconsistent). I replaced the spark plugs (second or third time in the life of the car, very black, but dry) and the coil packs (appeared to be original). Problems persist.

I figure there are three main contenders for these symptoms: 1) carbon buildup in the intake manifold and valves (which I hoped the seafoam would help with, 2) bad injectors (although it seems unlikely that all four would have problems at the same time), 3) HPFP (even though the original was replaced by dealer under the class-action extended warranty at 49K, 38k ago). My gut tells me it’s probably the HPFP as the misfires are across all cylinders and I’m getting the 2880 code for the high-pressure fuel system.

For what it would cost to take it in to a specialist for diagnosis and fix of any one of these problems, I can replace all this stuff myself and probably be money ahead. The HPFP is the easiest to replace, but most expensive part. Carbon buildup surely requires walnut blasting, which I don’t have the equipment for and would probably have to take it somewhere. Is there some other way to clean the carbon deposits out of the intake manifold and valves? It will be open if I replace the injectors.

Any thoughts on which item to do next or things I may have overlooked would be appreciated.

Andy

2010 Mini Cooper S (2nd owner for past 4 years 25k miles). 87k miles, mostly stock. Chain tensioners replaced (13k miles), HPFP replaced (49k miles), PCV/valve cover replaced (67k miles), Turbo replaced (70k miles), air intake to turbo tube replaced (86k miles), crankcase to intake manifold hose replaced (86k miles).

 

I am going to say it's the HPFP, but I am not as familiar with the N14 as I am with my N18. I know that when my HPFP went out (twice so far, now at 127k) I got the high pressure code and the superknock codes. As for the valves, yeah, they are probably needing attention as well. I have seen where folks have removed the intake and used carb cleaner and gun cleaning brushes and picks to get most of the deposits off, but the walnut blasting is the real way to go.

 

Sorry I did not come back to this to report. Took it in to Mike's Motorwerks in Tempe AZ. Dude is a stud. He narrowed it down to the low pressure fuel pump under the back seat. Replaced it. Didn't do the trick. Turns out, I had replaced the fuel filter under the rear passenger seat just a little while before I this problem started. And when I installed it, it didn't seat properly. So Mike fixed that, then took out the low pressure fuel pump and put mine back in. Didn't charge me for the fuel pump job. Car has run fine ever since.

 

Just had the cold start issue this morning and was surprised at how violent it was. I purchased a 2011 mini cooper s R56 3 years ago now and have put ~40,000 miles on it. I purchased it at ~ 35,000 miles and it is now at ~74,000 miles. Below is a list of all the replacements I've already done, can't exactly remember all:
-replaced all applicable coolant hoses with mishimoto silicone hoses
-replaced turbo hoses with forge silicone hoses
-put in a K&N air filter
-HPFP replaced under warranty
-replaced battery two winters ago, ~12/20
-replaced spark plugs but must have done something wrong because the dealer replaced them again when i took it in
-replaced the coils but again something went awry as they were replaced last year again during inspection ~10/21

I've experienced the cold start issue before and replaced the battery. In the cold, the car idles somewhat rough and then calms down to a steady idle. This morning was a tad below freezing and the start was significantly worse. The idle jumped around between 500-2000 rpm and would not calm down. At one point, it completely stalled out. I restarted the car and the problem persisted this time sending the car into limp mode with an engine light on the main dash. Again, the car stalled. I popped the hood and the engine must have been rattling so violently a cover popped off. I put it back on and checked fluids. the oil appeared to be at a good level, but the coolant reservoir was lower than normal. I recently refilled these fluids and it seems the coolant went from max fill to min fill within a month or 2. After waiting a half hour, I started the car again and the problem persisted but was much calmer. Limp mode was triggered but turned off after taking a spin around the block. I drove to work, ~7 miles, and the car ran fine albeit the engine light was still on.

Any diagnosis from this description? How many times will a HPFP need replaced. If that is the issue, this will be my second one. Can I expect to replace this every ~40000 miles or something?

Thanks for the help!