I bought my truck a month ago and it already had a WVO setup with a 2nd tank, etc installed. I have not tried to run WVO yet - but I do plan to get setup and run it in the near future. This weekend we took our first road trip in the new ctd and 30 miles down the road I realized something was wrong when I was 1/4 tank lower than when I started! I quickly realized that the "purge" switch was on for the auxillary system and the 2nd tank had 1/4 tank more than when I started. Obviously the system was pumping fuel from the main tank into the 2nd one.

I quickly turned off the purge switch and turned on the 2nd tank to drive on it for a while. What happened next was that the fuel from the 2nd tank was obviously pumping into the main tank because it went back up after several minutes. I am very confused by this becuause I don't think this is how the system is supposed to work? The system is a copy of the "Greasecar" setup and uses some of their components.

Anyone have any input on this?

 

The most likely cause is the electric solenoid valve that does the switching is sticking, or it was plumbed wrong. You should study the plumbing, find the valve(s), and take the return valve or hose off and make sure its switching.

 

This happened to me recently. I lost about 10 gallons of diesel since the biodiesel in my secondary tanks was returned to the diesel tank, which Id only just filled =(
Looks like the electrical connection to the return valve was bad.
Im running bio in my WVO system until Im sure everything is trouble free. I turn the coolant heat off though.