It looks like any of the K2 fuels and the Processed fuel from AAI Industry can't be used by the Insectitrons.

This is odd, as long as fuel of chemical type(coal, solid fuel etc.) it should be acceptable. I'll check it, thanks for the info

It looks like my mod is compatible with AAI Industry fuel, but K2 changes it's fuel type to own vehicle fuel type if both installed, so to keep with K2 vehicle fuel progression I will have to change fuel type my mod uses if K2 is installed, this will be added in next update

Edit: I am wrong at the part where AAI Industry fuel is compatible, I will think over how I do the integrations

Trains can still use all burning fuel types but the car can only use Processed fuel and K2 Fuel.

Update is out, only K2 fuel if mod is present, so it is balanced around other normal vehicles rather than locomotives.
AAI is now compatible aswell