2001 Saturn SL2 starts then dies

Does your security light stay on or flash when the key is on?Get a noid light and test each injector connector for a injector pulse. My guess is you don't have a injector pulse. Also see if your injector fuse is blown in the under hood fuse box.

Ok keep me posted also check that injector fuse and let me know what you find.

If you had a bad crank sensor you would have no spark and the car wouldn't start. But you said you have spark and the car starts on starting fluid. It really sound's like your security system is keeping it from starting you said you have 45psi of fuel pressure which is great. But the fuel isn't getting into the engine when the security system activates it shuts off the injector pulse. Which it doesn't sound like your getting much pulse.

If the scanner you rented won't read body control module code's then you wouldn't see the code if you had one the bcm shuts down the injector pulse as part of security. You never said you had remote start before on that car to have remote start you need to install a bypass module because you have a passlock sensor to allow your car to start. Check it out.
I'm not sure if they wire the module in to replace the passlock sensor or how they do it but if it failed and they wired it in in place of the passlock sensor then that could be your problem.I would look in to that.