1999 Nissan Altima car cranks over but wont start.

I have a 1998 altima and a 1999 altima. The 98' was wrecked but ran good. The 99' has a good body but has a rod knocking. Both cars ran just fine the day I pulled the motors and trannys out. The next day I put the good motor in the good body. Everything was exactly the same, every sencor, every plug, every hose, every wire, absolutly no differance. With everything done and hooked up I put the battery in it. Then I put the key in the ignition and cranked it over, no start. The fuel pump is working, ive got fire through the plug wires, if you spray starting fluid in the breather it will start until it burns all the fluid. Ive checked all the wires and hoses, ive checked the computer hots and grounds, everything checks out good. I put a scanner on it and checked all the sencors and they all check out. Their is no injector pulse. Do you think its the security system and how do you reset it. I tried to do it by unlocking the doors with the key and still no start. Its been 4 days of hair losing, kicking, cussing and still "NO START"