Super old thread but thought I would put in what I found as I recently ran into this issue. Fir not stringing.
It all started after using VoxelPLA in black. It was just one spot of a model I print hundreds of. It got worse and worse. I finally got tired of it and switched back to hatchbox pla but the stringing continued. So I figured I change out my nozzle to a fresh one but all on my luck the fir continued just as bad. WTH why?
I finally found the one setting for me that improved it in Cura. It was the "Outer Wall Wipe Distance". I had it set to 1.2mm as I use a .6 nozzle. I set it to .6mm wipe distance and the fir was at least cut in half to almost gone in the trouble area.
I have another theory as to why it continued after a nozzle change and into Hatchbox filament which never had that issue before. It might have to do with particles left in the extruder gears from the voxel filament? Just a thought, but I am not going to pull apart my orbiter extruder as it seems to be improved with the new settings.
Hopefully this helps anyone who was spending hours searching google and came up to this thread from 2014. Let us know if it improved your "firry" issue.