740 b230f non turbo

hi
i had the following problems:
the car died suddenly (engine shuts down and lights come on) and wouldnt restart right away. it normaly restarted after a while.
i was told changing the distributer cap would probably help.
so i took it of and removed the debosits on the contacts.
i restarted the car, let it idle and finally hit the road.
after 30 seconds it died again.
but this time it didnt start after a few hours or the next day.
later i found out that the fuel pumps wouldnt run so i checked the relay
but that one works fine and the pumps work to. i couldnt get an switching current so i did the abe crombie hall sensor test.
turn ignition on
connect a sparkplug to the coil and grounded wire
pull of hall sensor connector and connect blue(grey) wire with black wire
upon connection the plug sparked but no switching current(pumps didnt run).
i heard a clicking (injectors ?)
the red wire had 12v and the grey one 5v
but why dont the pumps run
i read that the ecu pulls the relay as soon as the hall sensor sends a signal
right ?
so whats between the ecu and the relay and whats behind the relay (does the ecu start sth else as pulling the relay?)
i had the pump pins(passive circuits)connected (pumps running)and the system relay works but still it wouldnt start

anybody got any ideas ?

stef