Make sure that the ecu capacitors have been changed.
They have a nasty tendency to leak while a car is down for an extended period.
The electrolyte that leaks from the capacitor casing contains boric acid and amonia salts and will damage the ecu board, leading to all kinds of problems, including the one you are describing.
After you have investigated the ecu, it's time to start checking the basics relating to the fuel pump system.
The fuel pump runs anytime the key is in the start position.
After the engine starts, the ecu controls the fuel pump operation by grounding one leg of the fuel pump relay coil, located inside the mpi relay.
If the ecu doesn't "see" the engine running, the ecu won't ground that leg and you wont have power at the pump when you release the key to the run position from the start position.
To check for this, remove the fuel pump cover plate (in the trunk under the carpet, drivers side) and check for power on the black/white wire.
If there is power there while cranking, but it goes away a few seconds after the engine starts, you will be checking the mpi relay/crank angle sender and a few other things related to the fuel pump control circuit.
Good luck, and check out that ecu PRONTO!!!
It's a common problem that left unrepaired will cost serious money to remedy.