My 1982 VW Westfalia is converted to a 2-tank system for diesel or veggie oil. The diesel is flowing into the veggie tank and the fuel isn't being recognized so van thinks it has no fuel. The VW mechanic I go to doesn't have conversion experience. SO I need a referral to mechanic who can trouble shoot this problem. Ideally will be in the East Bay but SF possible if I tow the van there.