replacement engine won't start

2006 Malibu had a blown engine (4 cyl.) I so
had a wrecked 2007 Pontiac G6 with the
same family engine. I looked at the engine
swap list from GM and it said they would
interchange so I did the swap. Now I have
power throughout​ the car and the engine
rolls over but won't start. The G6 engine
does have a total of 4 sensors that the
Malibu engine did not. If I'm not badly
mistaken they deal with a Variable Valve
Timing feature the G6 has. I've been told to
just not hook them up and the computer
won't ever know they are there and it should
run fine but it won't start. Could this be the
problem? Any advice would be
tremendously appreciated.