Oil pressure not registering on Dakota digital gauge.

Just started my 6.4 crate mopar crate engine. On the Dakota digital gauge oil pressure is not registering. The gauge cluster is hooked up to obd2 reader, and bus was selected for input. The engine has been primed before I started it, had valve cover off ,and oil was up in the head. The tach on the gauge is working. Will the engine keep running if there is no oil pressure? Have heard that if there is no oil pressure the computer will shut the car off after 5 seconds. Not sure if this is true. The engine is not ticking or has other strange noises. Is there any other way I can check the oil pressure? Thinking maybe plugging the computer into a obd2 reader ,to see if there is oil pressure. Any input would be appreciated.