Hello Kamuto,
We support both bipolar stepper motors though stepper chip and unipolar motors through p259, these is some documentation about this on: http://vems.hu/vt/help/v3/v3_idle_stepper_hardware.html
Regarding your trigger it might be some noise issue, but when i take into account the other effects (dashlights dimming/tuning on) i would highly recommend you debug any wiring issues first.
Best regards, Dave
dashlight was p259 who controls main engine relay
your new diodes somehow cause it
moved it on injector channel ant it's fine. p259 channel is working, if I shut off car, dash not dimming, if I turn ignition on and off dash is off but you can see few ligths are getting supply from somewhere
so that's not noise. got that issue with p259 before on 3.8 boards, if one relay end has +12 when ignition is switched off p259 will trigger it with no ignition, that sucks really, had to rework all wiring to relay supply from ignition switch.