Try contracting your pecs and squeezing them as hard as you can the next time you do chin ups.I have practiced and have been able to pump out nearly 20 reps.I can also strap on weight and pump them out.I may try doing db flys in order to help out my pulling strength,heavy curls also help.
my new routines-
W#1-
clean & press
Bent rows overhand standard grip
Weighted chin ups
chin ups
cheat chins
db flys
push ups
curls
W#2-
military press
Bent rows underhand
weighted pull ups
pull ups
cheat pulls