does the fuel pump prime in 540i before crank?

[toyotahachiroku]

does the fuel pump prime in 540i before crank? i've searched and i've come across people that say they do and they don't. what happens is that for my 540i, occasionally, if left to sit for a long time, it would take a few more cranks to start. very rarely, it would start, stall out and on the second try be totally fine. i've tried cycling the key and waiting with key on engine off but it doesn't seem to affect anything. i've also read that crank position sensor, fuel pump relay, bad ecu could cause this issue. so far, no cel, doesn't blow smoke, never stalls after its started, runs totally fine. i would like to rule out pump priming as a possible cause.

[rotaryboots]

Its not a fuel pump priming issue. Start checking other things. Doubt its the dme. Could be crank sensor, check the fuel pressure regulator. When was the last time you changed the fuel filter? Could a vacuum leak...there's really more questions than answers to your post so far. But no, priming is not the issue.

[toyotahachiroku]

fuel filters, plugs were done earlier this week. no pending or codes for crank position sensor. last time i smoke tested it, no vacuum leaks. rear manifold cover is fairly new as well. haven't checked regulator yet. parts i replaced did make the car run better but never improved on the occasional hard start.