In a workshop manual, i saw that you had to cut the fuel line and place a fuel presure gauge in series to see if your getting any presure, i think my car has shit fuel presure because it is a bitch to start at times too,
maybe try little things like, replacing the fuel filter, i know thats where im going to start on my 323i, there are many resons why a car wont start aswell, what about the spark plugs? air filter maybe loaded with shit, check every easy thing before pulling the pump off,
let me know how you go.