2000 monte carlo alarm problem

I just dropped a rebuilt engine into my 2000 MONTE CARLO ss. All lighting is on, but when I turn the key.... engine does nothing. It does have remote start so I think the problem is within the alarm system. I have tried to turn off the alarm system thru the radio and that did not solve the problem. Battery, alternater and starter are all new. Again, all lights, radio, message board etc works. When I hotwire the motor, it runs perfect.
This one has me stumped, is there a wire somewhere that I missed, a fuse maybe???

Chuck