Hmmm, well given what you have said my only recommendation is to try a protein treatment, followed by a deep conditioning. Sometimes protein can really perk up fine and high-porosity curls! And if you have been using silicone-heavy conditioners, you should probably use a good strong clarifying shampoo before both treatments, then protein, then deep condish. I hope others chime in here as well.
Medium/coarse, low porosity, dense, mix of 3s
CG (again) since Nov. 2012

Cleanse: SM Moisture Retention, Elucence MBC, KC Come Clean
Condish: Giovanni DL, Cure Care, Ion Treatment, GVP Balm, AOHR
Stylers: KCCC, SM Souffle, AOMM, SS CEJ, JCRR, JCCC

Trying out steaming!