The alternator should not effect the start of the car. I have a countryman with a bad alternator. It starts right up with a jumping box. I would say let's start from the beginning and check fuses and connectors to the injuctors and coil packs.

 

Hey I am having this same problem. 2010 cooper S automatic with a p15E8 code. Mine with a shot of ether will pick up a bit and run but stop shortly after I stop spraying. I replaced the coolant temp probe and cleared the engine codes. Will this code turn off the fuel pump??? Or is that the next part to swap out? Thanks in advance

 

Check to see if power to the coils . the green wire is hot. if the test light don't light up. and then check the fuse. if its good nine time out of ten it's the bad fuse block in side the car right side kick panel. take to dealer cause dealer because it will have to be re programmed. i had the same problem.

 

Grounds were good on all plugs. When some one said reset the ECU are they just meaning clear the codes? Also I checked for codes again after I did the ground check and I got a U0101 and P0503 eek starting to get out of my comfort zone

 

Hey all I ended up installing a new cabin fuse box and it cleared up my power to fuel pump issue. Also no codes coming up anymore.

I had no evidence or water damage or burnt solder points. Not sure if they just fail at some point?

anyways just want to say thank you