Turn the key to run, but not all the way to engage the starter and listen carefully near the bed to hear the pump turn on, the pump should run for 5-10 seconds at a whine sound.
Hm, it may be losing prime. I don’t think mine runs that long. You can try the same procedure 3 times then attempt to start. Have you serviced the fuel filter? Are any codes present?
It runs 10-20 seconds (Feed in tank Pump) , Plus you need to allow the internal Clock to re-set before it will run ... again ... W/O engine running.
Also it needs to make more then 45/50PSI to overcome the COV in the CP4 to open the FCA feed circuit, plus you need to make more then 1800PSI Cranking rail Pressure for the Pressure sensor to send signal to ECM/PCM to Fire the hot hole. This is 1 of many reasons why it won't start.