Maybe I could get suggestions here on how to solve the ground potential issue? There must be a lot of electronics experience here based on the complexity of the CDI

I'm using a Fairchild ISL9V3040P3 ignition driver IGBT (n-channel). (datasheet: http://www.fairchildsemi.com/ds/IS/ISL9V3040P3.pdf )
For some reason there is no spark if i connect the grounded side of the primary coil to the emitter, and non grounded (marked +) to the collector. However, if I switch them, it works.
When I do this, the voltage spikes from the primary coil will be directly connected to the ground of the control board(since the IGBT needs the control board ground as a voltage reference for the gate) and I suspect this will cause problems. Everything (radio) I connect to this pulsating ground is likely to be disturbed.

-I tried to look for a P-channel ignition driver instead, but no luck..

-If I use a optical isolator, the control board will be separated, but the secondary side of the optocoupler still needs a supply voltage and IGBT emitter/ground, and again, that ground will be pulsating.
I really want to use the radio battery pack for the control board too, to keep everything as simple as possible (not needing to charge multiple battery packs before driving, adding weight etc).


Suggestions are welcome!