Right, as thom has suggested there are engine specific cleaners. For ease of use go for these imo.
Now, in regards to biodiesel it is a combustible heavy oil, more efficient than normal diesel, and less of a pollutant overall. It is also a detergent, i.e. will run through your system cleaning everything it goes past, however at the same time it will chow down on anything biological in the system, these include rubbers, nylons etc. So fuel piping, injector seals, piston rings are all susceptible to perishing. This is of course if you run it for ages.
So you can use it to flush the system in a neat form.
