Water + ECU usually means foosty (technical term!) connections, try disconnecting / reconnecting ECU plugs to see if it makes difference, ECU may have to be opened up to be dryed out properly if you flooded the seatbox with water.
Ps, it would be nice if the oil coming into the ECU from the injector wiring loom could serve the purpose of keeping the water out !!!!!!!!
More Ps, fuses in seatbox, particularly 20A no 4 for pump relay, remove and check for foostyness.