Marlin PID tuning just doesnt work, What am I doing wrong?

I have tried a few variations on the values in this command but basically I am sending M303 E0 S200 C8 which works fine until I turn the part cooling fan on. Then its just all over the place and PID tunes either fail to heat or trip thermal runaway.

One strange thing that has happened a couple times is the PID tune appears to be successful, but comes back with Kp 0 Ki 0 Kd 0 seems like mighty odd numbers to me.

Setup:

• Legit E3Dv6 with sock and .4mm nozzle
• Prusa I3 MK2 style x carriage with a bl touch instead of PINDA
• Ramps 1.4
• 320W power supply
• Enclosure (22-30C when doing the tuning)
• Heated Bed (off when tuning)

Thought: I am controlling the printer with OctoPrint I think this means that the cooling fan is either 0% or 100% is there a way to limit this in marlin?