kawi, the reason you're seeing gunk on places that you don't see on a CTD is because on a TDI the blowby is returned to air intake preturbo, not vented to the atmosphere like a CTD.

 

With nobody doing any real scientific research [ in labs , tear downs ect ] { thats because the chemists recognize the chemical make up , that tells them not to bother } every one els is ignoring/or just not chemists , is doing a lot of good attempts at this , but I take my lead form those that have the knowledge & abilities to do real science .
I admit that there are a lot of ??? with many results , but I do not want to experiment with my truck [ like mentioned above , the chemical makeup says no ] .
Theres an other long thread at Northwest Bombers , that Don M. [ the injector guy ] , many ??? there also .
This is just offered as info for those to make decisions with , believers are on your own .

http://www.nwbombers.com/forum/index...2&hl=BIODIESEL