I have a 94 LT1 that I have swapped into a 89 S10 Blazer.  The engine has a persistent problem of no cold start unless you spray ether into the air intake.  This engine had the injectors,regulator, distributor, ECM cap & rotor all replaced along with new spark plugs and wires as needed but the problem persists. The ECM has been reprogrammed for no VATS or emissions. All the parts were replaced as they were faulty not in random order to try and solve the problem.  Anybody got any ideas?  

Possibly when the ECM was reprogrammed, they terminated or modifed the cold start routine in some way. Or the error could be a faulty input to the computer from the temperature sensor. This could be ambient air temp or engine coolant temp. But something is not telling the computer to use the cold start routine.

I've also seen this happen sometimes when the battery is dying and it can no longer keep system voltage above 10.5 while the starter is cranking. 

Bogie