I have fine, low-porosity hair, and I'm a greasy gal by nature. It's just my body chemistry. I have to low-poo or co-wash every day... on or off CG, it's a daily thing.

I have found that with co-washing, if I'm lazy about my scalp and just kind of goop conditioner on, I still look greasy at the roots. I have to flip upside-down and use my finger pads to really, really massage my scalp; I have dense hair, so working it all down to the roots is key. It feels great, honestly, and I know good scalp circulation makes for healthy, happy hair. But some mornings I'm so sleepy...

So maybe try a co-wash with a light conditioner and really, really get in there. As many other posters have said "massage 'til your arms are sore!" See in my signature below, too, that I co-wash with a different conditioner. This one isn't rich enough to be my only conditioner, but it is hands-down the best at cleaning my hair gently.
I sort of blog
I'm mostly away doing field work through mid-May.

Hair: curlybob, fine, dense, low-po, big waves/ringlets (2C/3A)
Co-Wash: Nature's Gate Herbal Conditioner
RO: YTC Carrot, Aubrey Organics GPB
LI: BS Shea Soft Styling Cream (HG)
Styling: KCCC, Garnier P&C Gel
1xWeek: low-poo, gelatin PT or Joico K-Pak
Hair Likes: aloe, coconut oil, humidity, protein, long walks on the beach