Thanks for the confirmation Brian. Your suggestion on the fuel pump is probably spot on, but if not, given his scenario, a simple nitrous fuel solenoid plumbed to the test port and activated before startup while the fuel pump is running would be a bandaid until the real problem is found. I'd run the outlet back to the return line or fuel fill hose. Simple, cheap and easy to use.I will bet the low pressure (supply) pump is the culprit.
Keith, it does have a Schrader valve on the fuel rail.