Gary Stockton said:
D-4d is common rail high pressure system with finnicky injectors
There are guys on the vegeoildiesel.co.uk/forum using biodiesel in brand new cars and fairly late model BMW's etc. A guy came to seem my new plant recently who was using it on a 3.2CDI E class merc estate.
Bio gets blamed for problems, when from what I can tell, each time it's bad quality bio with poor or nonexistent final polishing / drying.
If you were uncertain, you could run a blend with 10 or 20% dino diesel.
Here's some idea of the sort of set up that you'd need to make good fuel:
from right to left, straining tanks, reactor with condenser, then water wash/dry/ drywash / centrifuge and final polishing / drying
Dry wash
Centrifuge gear pump
I started with a branded processor, but soon found it's limitations and had to modify it. Got the tanks fabricated, but it took ages to figure out all of the plumbing, ball valves, pumps etc.
It's well worth putting a post up on the biodiesel forum. But good bio made from liquid vegetable oil (not solid) will have a viscosity only slightly higher than fossil diesel and if you cetane boost it, the engines ECU etc. will be getting what it expects.