Hello guys,
I'm sure there are other post on this subject but after spending a lot of time looking around I cant find any solutions. I'll post my issue with some background and freeze frame data from my OBD tool and hopefully get pointed in the right direction.
I have an automatic 2010 Mini Cooper S (R56). I bought it with 50K miles, it currently has 60K miles. I've replaced the valve cover to fix a p115c code; problem solved. After reading some posts from this website, I decided to put on an oil catch can(BSH) and did the rear PCV delete by capping off the ends on the backside. Also I ran some Seafoam on the backside before doing the rear PCV delete to try and clean out some of the gunk that might have built up there. The car ran fine for a while. After a while I started to notice a funny idle problem. At rest sometimes the car would behave like a rough idle; the RPM needle would jump up and down between 800 rpms and 1000 rpms. If I were to let go of the brake at a stop you could feel the car jerking forward a little bit. It wasn't a massive surging of the rpms, but you could definitely notice it. For the last year I've been noticing this problem and an intermittent CEL. Sometimes the CEL is off for a few days or hours and then sometimes it's on for week. It just seems to go on an off whenever it feels like. Lately I was getting a 2B5C (mass air sensor plausibility) and a super knock code as well as a fuel shut off to cylinder 3 code. I swapped out the old dirty air filter for a fresh clean one and swapped out the old plugs for some new ones. I cleared the codes, but I'm still getting that 2B5C code. I swapped out the MAF sensor for a new OEM, and still I get that 2B5C code. I've been spraying carb cleaner around various connections to see if I can find a downstream air leak, but I've had no luck finding any leaks. From what I've read my issue can be related to a throttle body, HPFP, an elusive vacuum leak, or maybe a sensor of some sort. I love Mini Coopers, and I love my car. I don't mind trying to fix it's problems but I need a little help getting pointed in the right direction. At the bottom I've provided some of the live data from my OBD tool, hopefully someone can help me interpret what this data means in terms of how my Mini is performing and what I can do to fix the 2B5C issue. Just FYI, I recorded all these value while idling with the exception being mass air flow and manifold pressure readings.

P.S. Thank you for any help anyone can provide. Also please I know problems get re-posted a lot. If that is the case here please do not delete my post, just tell me and I'll politely move my post to where it needs to go.

Misfire Detection
-misfire rate, cylinder 1 = 511
-misfire rate, cylinder 2 = 2800
-misfire rate, cylinder 3 = 0
-misfire rate, cylinder 4 = 0
---------------------------------------------
Charge-air Pressure Control
-multiplicative boost pressure adaptation = 1.93
-charge-air pressure, actual value = 6 hPa
-charge-air pressure, set point value = -44 hPa
--------------------------------------------------------------
High Pressure Fuel Pump
(this section gets weird so I recorded three different measurements; I recorded a three measurement within a span of an hour)
A)
-Volume control value = 3%
-Rail Pressure, actual value = 1.15 MPa
-Rail Pressure, set point value = 1.28 MPa
B)
-Volume control valve = 7%
-Rail Pressure, actual value = 2.18 MPa
-Rail Pressure, set point value = 2.18 MPa
-Adaptation value, fuel delivery control = 7
-Fuel Injection Timing for cylinders 1-4 was about 285290
C)
-Volume control valve 0%
-Rail Pressure, actual value = 0.04 MPa
-Rail Pressure, set point value = 0.04 MPa
-Adaptation value, fuel delivery control = 0
-Fuel Injection Timing for cylinders 1-4 was about 5500
--------------------------------------------------------------------------
Air Supply
-Throttle value angle, actual = 6%
-Throttle value angle, set point = 6%
-Throttle value, adaptation = adaptated
-Intake manifold pressure = 356 hPa [this value would increase to about 950 when i accelerated and decreased when I slow down to as much as 250. 356 is the measurement when the car is idling.]
-Ambient pressure = 993 hPa
-Air - mass flow = 8.2 kg/h [this value would also increase and decrease as I accelerated and decelerated; I believe this is normal]
---------------------------------------------------------------------------
Oxygen Sensor Control
-Lambda, actual value = 0.02 (a second measure 30 min later said 1.06)
-Lambda, set point value = 0.00 (likewise a second measurement 30 min later said 1.06)
-Additional mixture adaptation = 1000% (the second measurement 30 min later said 14%)
-Multiplicative mixture adaptation = 0.65 (the second measurement 30 min later said 0.01)
-Oxygen sensor voltage before cat =106.00 V (the second measurement 30 min later said 1.5 V)
-Oxygen sensor voltage after cat = 104 V (the second measurement 30 min later said 0.51 V)
-Oxygen sensor controller = 0.00 (the second measurement 30 min later said 0.13)
----------------------------------------------------------------------
Smooth Running Values
-Smooth-running values for cylinders 1-4 keep switching between on two numbers it either says 0.11 1/s or 27.14 1/s there's no range my OBD tool say either one number or the other.
-----------------------------------------------------------------------
Temp Values
-Inside temperature, DME control unit = 56 C
-Intake air temp = 49 C
-Engine temp = 100 C
-Ambient temp = 24 C
-Engine Oil temp = 99 C
---------------------------------------------------------------------------
Valve Gear
-VANOS position, inlet, actual value = 32 cr
-VANOS position, inlet, set point value = 34 cr

 

1) have you had the intake valves cleaned? Search for carbon buildup and walnut blasting, this is a common problem with the N14s. If it hasn't been done previously then at 60K you're due.

2) mis-fires on cylinders 1 and 2, try swapping those coils with 3 and 4. If the misfires move to 3 and 4 then replace the coils. If they stay on 1 and 2 then see above for the valve cleaning.

the MAF code I'm not sure about, could be an air leak but since the misfires are on 1 and 2 I'd go after that first.

 

Remove the catch can and return the PCV system back to stock and see what happens. Or if you have access to a smoke machine, smoke test the system and see what you get.

Sounds like a vacuum leak issue and that is the only new factor in the mix.

Your fuel pressure and measured air volumes will fluctuate considerably with the issue you've got because the car is constantly trying to adapt to overcome the issue.

 

 

Well I swapped the coils around. My obd tool showed that the misfires from cylinders 1 and 2 went to 3 and 4, and I still had misfires on the original cylinders (1 and 2). I thought maybe new coils would remedy this, so I got some from amazon ( ) this is the link to the ones I bought in case anyone is wondering what I used. After installing the new coils my symptoms got worse. I still had the same misifres as before (cylinder 1 and 2 as well as a new misfire on cylinder 3). In addition, the car was running terrible; the idle became more erratic and it felt like the car was struggling to move. So i put the old coils back in and things went back to the way it was. I'm gonna return the coils and keep trying things. There is a mini/bimmer mechanic not too far from me, so I might take it to them to get a second opinion on whats going on.

Also I tried removing the oil catch can and putting the PCV system back to stock, but it didn't seem to help my symptoms, and the CEL keeps coming back with the down stream air leak code.

I still appreciate the advice from squawskibum and nkfry. And I'm gonna keep playing around with the car till I figure things out. I'll report back when I have some more info on what's going on.

 

If you still have an air leak code ie; vacuum leak, you need to start with a smoke test to see if they system has a leak anywhere. If the smoke test doesn't provide definitive answers I would pull the VANOS solenoid and check it for debris stuck in the screen, it doesn't take much at all to clog or upset them.

Pull the solenoid and spray it out with brake clean, reinstall, clear the codes and see what that gets you.

 

I talked to the local mini specialist about a smoke test and what's been going on with my Mini. After a brief conversation, he felt very confident that it was a bad throttle body. He quoted me 830$ to replace it, but suggested that I do the work myself since it's not difficult to swap out. So i bought the VDO throttle body from pelican parts and swapped it out. My CEL went away and no more funny idle issues. The mini idles very smooth now and runs nice. I couldn't believe it. In hindsight it was still worth trying the other thing first. We always hope it will be an easy fix and we can't know if its something simple or not until we try the little things first. I swapped the TB out 2 weeks ago, and the mini is still running nice. In fact, after swapping out the TB, the CEL cleared itself in matter of minutes. I still hooked up my code reader to wipe the code from the memory. Now my mini is still having some misfires issues. After moving the coils around and seeing that my misfires stay in the original place and move to new spots, plus my misfires happen at idle, I'm suspicious that I might need to adjust the timing chain in addition to replacing the coils, but I'll look around at other postings before I go on about that. Again thanks for your help guys; it was much appreciated, and I look forward to talking about minis some more.