96 sentra timing chains,gears all have been replaced but it wont start any ideas on 1996 Nissan Sentra

everything has been checked firing, fuel,compression but it will not start it just backfires but never starts

Asked by for the 1996 Nissan Sentra
Re-check chain alignment , if it's backfiring(through throttle body) then your valve timing is possibly off.
thank you atleast now i have somewhere to start
Other thought...........Had an old mitsubishi brought to me years ago , (in pieces) , put it together and was spitting back through intake .....ended up this thing had 3 converters on it and ALL 3 were stopped up causing excessive backpressure (engine can't exhale) loosened exhaust to create a leak and it fired right up. IF you haven't started taking the chain stuff back apart , that might be something to investigate?