If you're having trouble pulling the cable tight enough for the adjuster's range because of the extra length and poor routing or whatever, you could screw in the lower limit screw a few turns before attaching the cable. Prolly take a bit of trial and error.
Originally Posted by
ursle
I suspect your outer cable may be breaking down allowing flex, not allowing you to tension the cable properly.
That could be it, try shifting into the big ring without turning the crank to compress the housing, and see if it deforms and and takes up cable pull without moving the derailleur further.