Hi Zorokun, welcome!
You mean, the combustion enthalpy? Generally speaking, you have to decide whether water is produced liquid (recent central heating) or gaseous (applies better to Diesel, but be consistent in this choice when comparing fuels).
Other remark: biodiesel tend to produce a bit less heat than petrol distillates at identical mass but they're denser, which compensates when comparing per litre.
Then, the faster and safer way is to find the heat of combustion already computed, or better, measured. Certainly available on the Internet. For not too light petrol distillates it's 44MJ/kg.
Or you can compute it from the heat of formation of the fuel, of CO2 and of H2O (liquid or vapourr?). You need a table of enthalpies of formation, available on the Internet; this will give CO2 and of H2O, and either your biodiesel or similar molecules, from which you deduce your biodiesel which uses to resemble methyl palmitate. If you have an other methyl thingyate tabulated, with the same number of unsaturated bonds (probably none), adjust the length of the fatty acid by the added heat of formation of the proper number of -CH2- groups.
Don't expect more than hints to do the job by yourself: that's how this forum works. About Asap, if you've never computed a heat of combustion, you first success will take a couple of hours, with finding the doc, understanding the signs, and all real life annoyances.