my car crank crank it takes 1 minute to start..

I rebuilt my motor so I picked it up from the shop the car would crank and crank then start I told why is doing that he said one of my fuel injector is out so I took off went to another shop to check what was the problem he said a code came up thorny crank sheft was out so I changed it to a new one and the same problem was still thir code said crank sheft I did erase the code when I changed it it crank 1 minute it started....AT FIRST I TURN ON THE CAR WITH STARTING FLUID BUT NOT MINOR.HELP!