BMW Repair: 1999 BMW 318I E46 Wont start, fuel pressure gauge, bmw 318i e46

Question
Twice my car would not start but somehow got going eventually. On the third occassion it just gave up on me and has been standing for the past 2 or three weeks. There is cranking and the engine does turn but will not fire/run the engine. I checked all the fuses and only the one called the Overload JP was burnt. I replaced with another one with no luck. The fuel pre-pump works fine but I can not test the main fuel pump. There is a round cylinder under the car next to the rear right wheel with blue hoses coming out of it. One of these blue hoses seems to have developed a hole which I closed with insulation tape and tested and still no luck. What is this unit and what is its purpose? Lastly, how do the fuel hoses run from the tank to the engine?

Answer
Knowing that the engine turns over and that you can hear the fuel pump are good clues.You must not have spark(the spark plug not firing).Check for spark by removing a spark plug lay it against metal,turn the motor over and look as your turn the motor over.
You should find out this first.The crank sensor mat be bad.Put a scan tool on it and you will be able to see the codes that are listed.It would be good to put a fuel pressure gauge on it so you'll know what it is because you hear it but how much pressure is really there.