2001 Trooper Engine Trouble

Rebuilt engine, installed, started right up but had loud tic and started leaking oil. Pulled engine, fixed leak, inspected heads, re-installed,turns over but doesn’t run. Weird thing is, first time I try to start it each evening it runs for about a second and then dies and then won’t try to run again till the next day. This has happened 5 days in a row. I sprayed starter fluid in intake, no luck. I borrowed scan tool, no codes set just won’t start.
Any ideas?

Loud tick=Low oil, improper building of engine…anything.
Perhaps the computer needs reset or is shot…or the O2 sensors are shot.
Is there a chance you crossed some wires upon install? That’ll cook any onboard electronics

When the engine does not run is there spark at each of the spark plugs? Is the spark timing somewhere close to correct? What is the compression?

I know this is a rebuilt engine but you have to go back to basics when an engine will not start i.e. fuel, compression, ignition, and event timing(s).

My first guess would be some kind of timing problem. The valves and/or the spark may not be properly in sync with the compression cycle. Double check all the timing marks again.