I would say it could definitely cause a no start. I installed an adjustable fuel pressure regulator and found it ran like a bag of sh1t with it adjusted way too high, so bad it fouled my plugs and wouldn't start again.
If i were you id replace the line and get a fuel pressure gauge either to electronic to go inside the cabin or just a cheaper one to check it inside the engine bay. i believe it should be 3 bar with no vacuum connected and 2.4 bar with a vacuum source connected