My '08 R56 is giving me fits. It starts in the morning, runs for 5 - 10 minutes then quits. It will not restart. A few hours later or the next morning the same. The only DTC showing is P0303, but that DTC has been intermittent for many miles prior to this issue. I have replaced the DME, HPFP, fuel filter, fuel pressure regulator, fuel pump, crankshaft and camshaft position sensor, and thermostat to get rid of other codes. When it quits it does not sputter or stutter, it just stops running.

Can anyone give me some guidance?

 

Coils and plugs should be next or you need to walnut blast your intake valves, apparently your 3rd cylinder isn’t happy. Use only oem coils and plugs, you can use the ngk’s that are same part number just make sure you pick up from a reputable source not Amazon where you can get knock offs.

 

I’d be curious of the HPFP, too. Depending on where it was purchased, and if “refurbished” or new, some aftermarket pumps are known to be sketchy.

 

Thank you for your reply and suggestions. My question is would coil packs and spark plugs cause the issue I am having with it running fine for 5-10 minutes then quitting and not starting again until it cools down? To my way of thinking they may cause the DTC of P0303, but not the quitting issue....unless I am missing something.

 

Do you know of a way to check the HPFP? Before I changed it, I was getting a code that said it was bad. After replacing I am no longer getting that code.

 

In case anyone is curious, I found and fixed my problem. The wire harness to the crankshaft position sensor had been crushed when I installed the new knock sensor. I know I was not careful enough, but in my defense I was laying on my back with the bottom of the vehicle only inches away from my nose. Not much room, but still I shouldn't have made such a mistake. Anyway, after repairing the wires the stop running issue was fixed.

Thank all of you that offered suggestions.