I have a 07 MCS, with 80k and an Alta stage 2 kit including the 3" exhaust. I went for a drive a few days ago and with in a block of my house the motor went dead, no hiccups, no backfires, just silence. My first instinct was the fuel pump. The motor would turn over, run for a brief moment and stall out. So i did some research and spoke with a couple technicians who work on Minis. They suggested it was the LPFP, and so i went ahead and replaced it, and the fuel filter. After the new pump was in i fired it up, which required quite a bit of coaxing, but after a minute of cranking, pumping the gas and colorful language, it started, and idled smoothly...Then the check engine light came on. So i ran my reader, and got two conflicting codes. P115c and P115d which are too low and too high MAF. Got out and checked all the intake hoses i could see and reach. Nothing cracked, loose or hissing. Took it for a test drive around the block, and there was no boost. No coughing, no backfires, no rough idle. Just boost-less. So now im stumped, I would be grateful for any suggestions

 

Hi 2_wheel_tuesday,
It sounds like it fell into limp mode. You will have to reset the system. You can do it with the BMW scan tool, or possibly disconnect the battery for a few minutes. Once reset, it should boost again.
BMW likes to over complicate everything!

 

Well i went ahead and tried a cold start after disconnecting and reconnecting the battery. Still same issue. Car fired up without any drama. After a warm up period gave it some gas and revved it a little. Couldnt hear the recirc valve "pssht". Still took it for a spin, and same issue. No boost. So i went back to the garage, hooked up my OBD2 reader, same codes MAF codes. I cleared the codes and then fired up the car again. Hard starting, died three times before if stayed running. Had a very heavy lope to the idle, and the gas pedal was completely unresponsive. I am beginning i had the unfortunate luck of losing both fuel pumps. But before i go and drop a thousand dollars i want to be sure. No i am not taking the car into a dealership to be gouged. If you can think of any other possible causes i would be grateful, thanks

 

If you go to sites like Mini Mania and others, they can point out how to get your car out of limp mode, as a standard OBD 2 can not do this. Although the BMW/Mini OBD2 CAN tool can take it out of limp mode in many cases. (ones like Icarsoft)

reprogramming may need to be done, but look into sites that describe how to use the buttons on your dash to do this.
As most things BMW designs, makes it hard for non BMW shops to work on them. This site is a good one for answers you seek.

It is also possible that the fly by wire throttle controller may have bit the dust, or needs to be re-calibrated. (behind the gas pedal)