Passat 2005 Running On Used Soy Oil And B100

The winter is here and I've starting to see some interesting stuff with my car. First, I've stalled two times when switching from SVO to BioDiesel when coming off the freeway. The leading theory is that the computer is throwing a code that stalls the engine because the BD is to cold. Going from hot svo to cold BD could be a problem. At first that didn't make sense beacuse it was rarely happening. Then I realized that it was happening when I had about 1-2 gallons left in the BD tank. Less fuel in that tank means its gonna get cold faster. To solve that problem, at least in the winter, I'll be making sure I keep it somewhat full. Second, the other day I started the car cold at night and I started to drive but could not go over 30 mph. I drove about 30 seconds, stopped the car and then started again and it was fine. Ed Beggs of Neoteric said "Sounds like a viscosity-related computer issue. Went into limp mode from too-cold biodiesel. Key on/off reset it. By then it was warm enough." Sounds correct. He also said that there is a special chip that VW makes for people running BD. Seems like you gotta make the computer happy in the cold so I'm going to look into finding that chip. I'm also thinking about having the Vegtherm heating device be on when using BD and svo.