Yes, can hear fuel pump running. Thats good, the ECU processor must be running
Dead battery about 4 weeks ago.
I don't remember if this one has the tipover switch or not. If yours does and it got dislodged while the battery was out it might be the problem.
Yes good one David, according to the diagram it has the Bank Angle Sensor (42) connected to the ECU, I think the contacts of the sensor need to be closed.https://www.thisoldtractor.com/guzzi007/schematics/2004_750_Breva.gif
The next thing I want to know is. Does the pump run while the bike is cranking over? The way to tell this is connect a small 12 Volt lamp to the Red wire that powers up the coils, injectors and fuel pump. The easiest way to do this might be wrap a small wire around the 87 pin of the Secondary Injection relay (12), run it to one side of the lamp. The other side of the lamp goes to chassis.
This lamp will light when the key is turned on while the pump primes (based on a timer in the ECU) and it should light again while the bike is cranking over triggered by pulses from the Crank Position Sensor (2) (you won't be able to hear the pump over the racket the starter makes)
If the red wire is not alive you don't have power to the coils or injectors and the bike will never start.
You haven't had the sensor off have you? some owners pull them off and stick an "O" ring or extra gasket on to fix the oil leak and wonder why the bike won't start. The sensor is a coil of fine wire wound over a magnet.
As the gear spins under the magnet it causes ripples in the magnetic field which are picked up by the coil and sent to the ECU as a low Voltage sine wave. The ECU recognizes the motor is turning over and grounds the coil of the Secondary Injection relay turning it On to power up the fuel and spark.
You can check the sensor with an Ohmmeter, it should measure about 680 Ohms the sensor has a plug about 18" away, should be easy to find, just trace the cable.