I was recently trying to find information regarding the suitability of Steyr Monoblock engines to some alternate fuels, and it was mentioned the unit-injection system would either require some fuel density detector or having the injection adjusted individually for each fuel used. At least with a common-rail engine, it's simpler to just do a remap instead... An associate professor from Illinois Tech had even proposed the usage of gasoline on turbodiesel engines with just a remap.
https://www.autoevolution.com/news/d...te-186175.html