electrical problem 240sx doing odd things but wont start

[llama_of_doom]

91 240sx it wont start I connect the battery and tightened it down, inside all the electronics are working and the interior lights are on the head lights pop up and illuminate just fine but when I turn the key I dont hear the fuel pump prime, I know for sure its not turning on I am getting no fuel pressure. But more importantly I hear a loud click and all the electronics turn off and the car is completly dead. It will continue to do this unless I hook the car up with jumper cables to another car and try and jump start it. Only then will my car turn over but still the fuel pump is not turning on so I am not getting any fuel. What could be causing this electrical problem? my battery is fully charged and tightened down whatever is the cause of this electrical problem is also causing the fuel pump to not start, that is my theory. I grounded the car with many wires throughout the engine bay and I regrounded the starter. I dont know what else to try at this point....

my problem sounds similar to this guy

zer...-help

I am not aware of my ecu burning out though what is tha eccs that he reffers to? I also didnt see this guy mention the problem where the car wont turn over by itself

[Vegascorbin]

Sounds to me like your fuel pump took a dump and shorted out. Disconnect the pump at he tank and see what happens. you can also check for voltage to the pump at the same time.

BTW: ECCS is Nissan for ECU

[240FeVeR]

have someone turn the key on while u check the voltage at the pump. if it's getting power then the pump is bad.