My limited experience is that Passiflora edulis is slow to ripen over the winter. I've heard that 'Frederick' even has problems ripening in the cool summers in San Francisco. There is probaby nothing wrong with your vine; I think this is normal.

Ohh really? Huh I guess that might be the case, it's still growing healthily, thanks.

The only two thing that I could recommend is first, let your fruits fall of the vine instead of picking them. And second, leave them on the ground or on the kitchen counter for two weeks until they look extreamly wrinkled... That's when they taste the best!

Hope this was helpful,

Daniel