Knocking issue
 

I've been running my 300D on WVO for over a month now. Recently while running only on diesel, the car developed a knock in the 2000 RPM range. When switching to WVO the knock instantly goes away. When I switch back to diesel, the knock comes back only after it seems to be running on pure diesel. It seems as if the trouble is in the IP because of the instant change in the knock when switching to WVO and then the slow gradual increase of the knock when switching to diesel.
I'm worried.

I think your problem is in the timing of the IP... I think you are seeing and feeling this due to the difference in flash rates between the two fuels... you may have to play around to find a setting which will accomodate both fuels... or just use one fuel... except for starting...in case you need the diesel in the winter...

The strange thing is that the "knock" goes away instantly as I switch to WVO from diesel. The "knock" comes back gradually when switching back to diesel. It only started knocking a week ago. Never did it before. It sounds as if its only coming from one of the cylinders. If it were a timing issue I would guess it would be more rapid in nature. I don't know what nailing sounds like but it is louder than any knock I've had before.

It's probably a clogged injector. WVO has higher cetane and in your case it burns sufficiently well even with a bad spray pattern that you don't hear the knock. Try running some diesel purge. I've read the VO can coke injectors after some time.

A clogged injector makes sense. I tried an Italian tune up yesterday and it seemed to do the trick. It might have knocked something off in the prechamber.
The coking issue worries me. I've read about it also. I doubt I could have any coking with so few miles but if I do, I'll be in trouble fast. I use diesel to start and shut down own so there's never any cold oil used.