Been lurking this site for awhile, first time poster. I need help figuring out the issue I'm having with my girlfriends 2008 R55 Mini with N14 Engine.

Its throwing code P2188 (too rich at idle). It does not have any other codes that have been thrown in the last 3K miles. Just P2188. Clear the code it comes right back within 3 key cycles. Below is a freeze frame data shot from the last time it has thrown the code. And I'll include the backstory on the car below that.



So this all started with a coolant leak. I replaced the thermostat housing and coolant tube from water pump to coolant housing since the end where the o ring was broken off. Took the car for a spin around the block and noticed it had a CEL and the transmission was basically missing 4th and 5th gear.

Pulled codes and it had multiple codes for transmission. I asked her how long it had been slipping and I guess its been awhile. Drained the transmission fluid and it was extremely dark and smelled really burnt. This is the start of all my fun.

She bought this car used about a year and a half ago before she knew me. I hardly ride in this thing as I usually drive, but things i noticed when i do ride with her, is that sometimes it starts and dies, idles like your riding a vibe plate, hesitates from idle, and other little issues.

At this point after doing research the best option was to find a low mileage used transmission. I found the transmission and decided I'm going to do major maintenance at the same time. Ordered a timing chain and tensioner, intake gaskets, oil filter housing gaskets (Since it was leaking), vacuum pump, transmission filter and gasket, oil pan sealant, fuel filters, spark plugs, air filter.

Long story short is I yanked the entire engine out of the mini, swapped the transmission, checked carbon build up (it was bad) so i performed de carbon walnut blasting, installed timing chain and guides (using cam locks and flywheel pin), cleaned throttle body assembly, installed gaskets, and vacuum pump.

Put the car all back together, borrowed a snap on Verus from my nephew and put the transmission in learn mode.

At this point all seemed good except for the P2188 code. I've been chasing this for almost 3 months now. Car was still idling a little rough, has an occasional misfire but not enough to throw a code. Ran 3 fuel tanks of injector cleaner through the car. Fuel trims were all over the place so for good measure i installed a new O2 sensor in the exhaust manifold that showed me no improvement.

I never checked the injectors while I had the car apart. So two weeks ago I pulled them out and the tips were pretty coked up with carbon. I cleaned them up and ran some carb cleaner through them. One of them was leaking as I had suspected while watching fuel trims. So I ordered a set of injectors which changed the STFT to a range of +/- 5-7% vs huge swings before that. LTFT also came down from +7% to +3%.

At this point I'm lost with this car. I'm not a full time mechanic, but this isn't my first rodeo. I've cleaned all sensors multiple times, i've sprayed carb cleaner all around the intake, throttle body, boost tube connections, valve cover, vacuum lines. Ive taken apart all boost tube connections and cleaned them and put it back together. I've taken the valve cover off to verify that the timing is still correct (no slippage) Tonight i performed a compression test 175-170-170-172. Can't find my leak down tester at this time. I don't see anything abnormal on the freeze frame data that I'm aware of, even did some data comparisons vs a co workers R55 mini.

From what i've found from hours of research is that code P2188 is usually associated with another code (failing or out of spec sensor, or failing component) This car is driving me nuts. My next course of action would be leak down test and see if I can find a smoke tester to check for leaks. Any input is appreciated as I need some out of the box thinking.

Thanks,

Chad

 

Any ideas? I should add that the car runs amazing at this point. Idles nice and smooth. No hesitations, no more starting and dying. Just lacking boost from the check engine light.

 

I have the same code plus the P1497 code. I was told to replace my Valve cover, mine could be a bad PCV system or cracked valve cover. My Mini has rough idle, stalls at idle and some stumbling and hesitations

 

Your idle rpm and fuel pressure are both really low.

 

I replaced the valve cover yesterday along with the coil packs and spark plugs.
I swapped in a fuel pump I bought from ebay and another member on this site let me try 2 of his pumps. All resulted in the same results with the same codes.

 

My Mini isn't covered under the extended fuel pump warranty. My car was manufactured 9/2006(2007 model)

 

Did you log data with the different fuel pumps? 600psi seems really low and could be the fuel pump or the fuel pressure regulator

 

Oh oops thought I was talking to the op. Mtdew have you logged any data?

 

Did you replace the PCV tubes as well? The passenger side is prone to cracking on the bottom side where it connects to the intake manifold.

do you have smoke in your exhaust?

Edit: I was confused about who I was talking to originally and I thought that was your data above.
There are several threads about the PCV system on NAM
https://www.northamericanmotoring.co...pcv-valve.html

 

I agree with that. Idle is usually right up around 800. I wasn't driving the car when this occurred so not sure what was going on. The fuel pressure at idle is usually right around 700 PSI and I've seen it as high as 1450 PSI driving it around. The fuel pump is covered under the extended warranty. Do you think low fuel pressure could cause a rich condition? My brain tells me it would be lean. I talked to the mini service advisor and he stated I would have to bring it in for them to diagnose the HPFP. I have the TSB for diagnosis and it doesn't meet the failure criteria. The closest mini dealer to me is 110 miles.

 

I would think if injectors were sticking open you'd see a drop in fuel rail pressure and a rich condition. There's always the possibility of a compound issue. Are you able to perform a compression test?

A BMW dealer should be able to scan it for you as well if there happens to be one closer.

I'm sure someone here knows a reputable shop with the right equipment in your area. Are you near a major city?

 

Were your new injectors oem?

 

lets say during this freeze frame event that the ecu noticed some extra air in the system via the maf or map and said "oh crap I'm not getting enough fuel" before the freeze frame stored then proceeded to changed the duty cycle of the injectors and pumped out a bunch of fuel causing a rich condition even potentially bogging down the engine causing the low rpm. Now you have a bank one too lean code because of the reaction of the ecu. Then when you hit the gas and get going the leak seals itself and the ecu says "oh ok everything's good" then pulls the fuel trim back positive. And the cycle continues

 

What does your downstream o2 read?

 

Compression Test came in at 175, 170, 170, 172. I have a local BMW dealer, and a couple local mom n pop shops that specialize in import cars. I'm in Santa Maria, CA.

The injectors were not OEM, but the fuel rail pressure became much more stable once i installed the new injectors. That was due to one of them leaking previous to replacement.

If this is the case, then i should see a big swing in short term fuel trim while graphing them correct?

I'll have to check tomorrow, she currently has the car at work. I was looking in my phone at screen shots I had taken but I don't have one. I want to say it was around .74 volts, but I'm not positive on that.

 

I would definiteley take it to the dealer and get it scanned. You probably have some unmetered air somewhere. It looks like I have a similar issue but I've smoke tested the crap out of it and can't find any leaks.

 

The BMW dealer should be able to at least pull all of the stored codes just make sure you get in a good drive cycle if you've already cleared the codes.
On another note do you notice a difference in performance (boost is back, idle stable etc) when you clear the codes?

 

You'll definiteley see radical changes in fuel trim with an air leak.

 

Long term fuel trim is usually anywhere from 1-3.5% I usually see short term fuel trims from - 5% to 4%. I have seen STFT drop as low as - 10%

 

Update for anyone reading this thread for the same issues. I took the valve cover off to verify timing one last time before I was going to take it to a dealer (since i've read several threads with timing gears slipping). Anyways i took a shot in the dark and decided to try and flush the PCV system in the valve cover. I spray it full of degreaser and flushed it out with water as good as I could. Not much came out of it. I then dried it all out by using the air compressor. Reinstalled the valve cover and now its been 500 miles trouble free. Got the mini smogged today. So in other words it turned out the be the valve cover. I'm assuming I will be purchasing a new one shortly if the code comes back.

 

Hi did the new cover sort the rich at idle problem out. I have same and just stumbled on to your thread.