fuel injectors stop fireing

O.K. here I go, I took a engine out of a 1976 280z and put the engine into a 1977 280z, The motor was running fine in the 76, but now the injectors will not put the gas into the motor.I can pour gas directly into the intake and the motor will run till that gas is all burned up.There is gas in the fuel rail under pressure so I know the fuel pump is pumping, it just won't get it passed the injectors. The only difference I nocticed in the two cars was that the distributor on the 76 had three wires coming from it and the the 77 only two. I changed the distributors around, didn't help. And last but not leasest the plug on the wiring harness that goes into the main computer is a little different, both of the computers will plug in with no problem but one computer box has more prongs were the harness plugs in, does this matter?
Any help or advise will be gladly accepted. God knows I need it!

Thanks Paul.