I am having the same problem and have not narrowed it down. I do know that it is a wicking issue. Here is my story:
I'm using BCC's, Kanger coils on a TS3, ProTank, Evods, and something labeled "SMOK RBC" (tried both SmokTek and Kanger coils). (My iClear 30 top coil works ok, but I'm tired of having to tip it upside down between vapes. It either leaks or burns. I can't get a decent vape without a mouthful of liquid.) All of my DIY supplies are from Wizard Labs, with the exception of the VG, which is Humco. I also have the VG from Wizard Labs. It's actually thicker than the Humco stuff. It won't even suck up into my pipettes.
I started going about (70-30) 70% VG with 20% nicotine in PG and 10% flavoring, almost always in PG. Would work great for a few hours (maybe), and then start to burn.
I then started to add distilled water, but adding to the point of gurgling didn't help. It also affected the "feel" of the vape, making it flat.
Now I use (30-80) about 10% flavoring, 20% nic, 40% PG, and 30% VG. Same problem with the burning. I've even added water, but it refuses to wick.
I know it's a wicking problem because if i cover the air holes and blow into mouth piece, it forces air in, causing liquid to flood the coil. When I do this, I get a good vape, but with a bit of gurlgle.
I also know it's my liquid. I just broke down and purchased a bottle of Juicy Peach from my local vape shop ($7 for 10 ml's... UGH!) and it is wicking great. I can chain vape three to four 5-second pulls with no problems. I asked the girl as she was mixing it what the ratio was, she told me 70%VG, 30%PG. What magic ingredient are they using to make this stuff wick?
Is anyone here having success on a Kanger BCC using just PG, VG, Nicotine and Flavoring?