Engine cranking
 

Lately, upon cold startup, my 4.4 engine will sometimes crank a few extra seconds before it fires. I've changed my fuel filter and have 25K on plugs. When warm, the engine fires instantly every time. Does the pressure regulator ( http://www.realoem.com/bmw/showparts...63&hg=13&fg=10 ) keep the fuel rail pressurized when the engine is off? I'm feeling like its a fuel supply problem.