whatever you have done so far installing the alarm, UNdo it.
Return it to as close to original as you can, then try to start it again. If it still will not run the fuel pump turn off the key and short the Brown/Black wire at the ECU connector to ground and turn the key on while holding the relay. If the pump runs start the engine. If you feel the relay click but the pump still will not run then the problem is either the contacts in the relay are burned (or some other internal defect), there is a break in the wire between the pump and the relay, the pump is not grounded, or the pump is malfunctioning and needs replacement.
If the relay does not click short the Brown/Black wire to ground at the relay and try again. Something should have happened by now!
Of course there is the possibility that the coil in the relay is shorted and the overload burned out the control transistor in the ECU, in which case the second you plugged in the new ECU and turned on the key it was burned out as well. I fervently hope this is not the case.
Since you have already checked the relay control wire for voltage when the key is turned on (and it will only be near ground potential for about 2 seconds after powering up the ECU, so make sure the test lead is on the wire before turning the key on) then the only other possibility is the pin in the ECU block connector is bent, pushed back, or otherwise not making sufficient connection.
By the way, the Pink wire is a complete mystery. It is connected to the switched (Red/Black) terminal through a diode the symbol for which I've never seen before, and shorted when the ignition is switched off. Page 19-19 in the service manual is the best view of the internal connections of the ignition switch. It's intent may be to inhibit activating the ECU if the Red/Black (IGN) wire is connected directly to the battery when the ignition switch is not turned on, such as when someone tries to hot wire it, but I'm just not sure.
Good luck with this.