The basics are: It has to have fuel from the injectors, spark at the spark plugs, air in and out of the cylinders (cam is turning) and compression. Timing of valves and spark timing are also critical but the engine should attempt to start if they are close. Stop replacing parts until you're sure of the basics; get professional help if you can. You may make it more difficult to diagnose ultimately if you continue to replace parts not proven to be faulty.
Jim O'Neill - Chino Autotech Inc., Auto Club SoCal AAR
SAE Int'l SoCal Section Board of Governors,
Vice Chair, Service Technology Programs
NASTF Service Information/Communications Committees
Auto Value/Bumper-To-Bumper CSC Nat'l Council
ASE CMAT-L1, CA. Smog Check Technician
AMI AAM Accredited Automotive Manager