Have spark, pulse, fuel pres, but the motor wont start. when i prime the injectors it runs for 5 sec the stalls out. what else can it be?

May need special priming sequence for pump. Haynes manual should have the proceedure. My van has a safety switch like that. Contacts have to be shorted for exactly 5 seconds with key on for mine to reset and prime in tank pump.

run the fault codes and check for problem ECM
There is an electronic component failure in the injector circuit that when over heats , shuts that injector circuit down
try replacing the ECM with a known good unit

no injector pulse - DodgeForum.com

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filling the filters before installing will make priming go more quickly.
once the pump is primed crack open the fuse line at the injector while cranking until you have fuel pulsing out, close it then move on to the next injector.
keep doing this until the engine runs smoothly.
it may start running before all the injectors have been purged so keep clear of all moving parts and a fire extinguisher handy would be a good idea.

flooding out
incorrect injectors or bad injector seals

I saw what you replaced, didn't see any testing?
The basics, if it cranks good but won't start, have a helper crank it while you check for spark at the spark plugs. If spark everywhere, use a gage and check proper fuel pressure and fuel injector pulse.
How long since a tune-up? Any applicable trouble codes?

Need to check to see if the fuel pump makes noise in the gas tank (humming when the key is cycled (aka priming the pump)) or check for fuel pressure at the rail with a fuel pressure gauge. Check if you have injector pulse when trying to start the car (purchase the correct noid light for your GM and see if it lights up when you try to start the car).
Need to check for compression with a compression gauge - cheap and easy to do. Or check for spark with a spark tester - also cheap and easy to do.

An engine needs 3 things to run fuel, spark, and air, but they must occur at the proper time, that being said, buy, or borrow a noid light. This is a light that you can plug into the injector to see if it is getting the pulse from the computer, do not use a test light, you will fry the computer for sure. If the injector pulse is there you have to check the timing to be sure the timing chain has not jumped. Bring the number one cylinder up on top dead center of the compression stroke, then pull the distributor cap off and make sure the rotor is pointing at the place on the cap where the number one wire is hooked on. If it is the timing is good, if not it is possible that the timing chain has jumped or someone has installed the spark plug wires incorrectly.

Since it sounds like you also carried over the OBD2 connector, do you have access to an OBD2 scan tool with datastream mode? If so, you should be able to monitor various sensors to see if that offers a clue as to why it stalls. When it just spins over have you checked for spark, fuel, and injector pulse width?

Then the fuel injectors are not pulsing,replace the crankshaft sensor,it controls the spark,but also the pulse for the injectors.