Have you tried priming the nib and feed? Turn the barrel as if you're opening it, but not all the way. Turn upside down (over your inkwell!) and close it tight again. Clean off possible ink on the threads. Try again. If that does not help, maybe try opening the tines a little bit. You should be able to pull them apart a little from the shoulders, using your thumbs.
Thanks for the hint. I had to repeat this procedure several times for to finally get some really meager ink flow. Looks like the pen wants to have hard starts all the time. When tapping the nib carefully on to the paper it burps. Haven't experienced this with my other ED pen.