97 z28 no spark no fuel no com. with pcm. installed reman pcm, checked power feeds to pcm all good, also grounds. got the car a part put it all back together 2 weeks no start car was apart for 1 year any help? could it be vats system?

It could be, but the security light should come on. If you have a scan tool seee if it can talk to the computer

Another thought. Does the car crank? When the VAT is cative it prevents cranking and prevents power to fuel pump. I should not affect ignition