Starts ok, but if turn of, will not restart

cars runs fine, it will never stall while driving, but if ignition is turn off, car won't restat, it will crank, but won't run, computer is been replaced twice, and crank sensor been replaced, injectors relays test good, but when the car cranks it has not injector pulse, even if car is cold or warm, after starting the car even for 20 seconds and turn off teh ignition and will not restart,