Nospig

Hi, i have installed a set of aem ign1a coils on a s5 fc rx7 running a power fc. made the wire harness and changed dwell with datalogit. i have spark at all plugs however one coil t2 gets hot fast. Using an infraed thermometer to verify, lead coils and t1 see no temp change, t2 plus 20deg C in about a minute. Have tried different coil, plug, HT lead no change. Thought it may be "c" pin from coils sharing common engine ground on front housing so tried running a dedicated engine ground to rear rotor housing for t2 coil, still made no difference. Apart from the triggers "a" pin, and now "c" pin the other pins are common for all coils. "b" pins are all grounded with ecu ground. "d" run to battery and 85 on relay. " e" to 87 on relay.
Have i done something wrong? Should pin "b" run to battery? Any help would be appreciated. Thanks.