Emulate injectors - how?

Dodge Durango 99 5.9L, converted to run on LPG (single point). When running
on LPG injectors are disconnected to prevent them from working (or rather
the common positive lead is routed thru resistor so that voltage drop on
injectors is insufficient for them to operate), and naturally PCM complains
about open injector circuits. Alldata is pretty vague about P0201-P0208
codes, and only says "if induction kick is not detected PCM will set the
code". Apparently it checks not just for correct resistance but also for the
'inductive kick'.

Anybody knows how to properly emulate injectors on this engine?

Peter