88 4.0 with Renix. New fuel pump. New fuel filter.

Pump runs while cranking and hits 40psi. Engine starts then fuel pump shuts off and vehicle idles fine until about 20 psi at the rail then dies. I have repeated this several times and even crawled under jeep while my daughter started it so I could verify the pump is turning on and then off once it starts.

I thought it could be the regulator but that is completely non electronic and wouldn't cause the fuel pump to not turn on.

Anyone have any ideas?

Disregard, I’m an idiot, I knocked one of the wires off the fuel pump resistor, plugged it back in and it’s fine now.

Nice find!!