Confessions of a WVO Tenderfoot…

I have learned a lot about waste vegetable oil in the last year.  From designing our system, implementing it, troubleshooting it, to actually using it.  There has been one thing that has caused many hours of head scratching and deep thought.  Read further to learn how this $25 part cost us $100’s in diesel fuel…


Shortly after we began using our WVO system, we started to notice an issue.  For a reason unknown to us, after about 10 miles on the highway, when driving on WVO, our bus would begin to slow down.  It seemed as though it was starving for fuel.  City driving was fine.  We went through our system multiple times, perused the internet forums, asked questions to our WVO-using friends, and even talked with Leon of WVO Designs.  Many possibilities went through our heads.  Maybe we had a restrictions from a fuel line that was too small?  Perhaps our valves were bad (we actually replaced the ones we had because of this and a leakage issue)?!?  Maybe our tank wasn’t vented (nope… tried that)?!?  I never thought it was our filters, because we hadn’t run enough WVO yet (less than 100 gallons).

We found a workaround.  When the bus would slow down, we’d have to quickly switch our fuel valve to the diesel tank, run diesel for a few seconds, and switch back.  Over many highway miles (trips to Indiana, Illinois, across Michigan), this cost us $100’s in diesel fuel that we would not have used otherwise had our WVO system been running optimally.

This weekend, while in Chicago, I had an epiphany.  The Prefilter!!! When we built the system, we put a prefilter on it, to catch any gunk that came out of the military aluminum fuel tank we bought.  It cost only $25 and would save us some hassles, right?!?  I took it off and went to clean it.  Even without the filter on it (which was clogged), I could hardly blow through it.  I couldn’t imagine our engine sucking fuel from the back of the 34 ft. bus to the engine in the front.  It was very RESTRICTIVE.  I couldn’t believe it.  I took it off and hoped for the best.

For the 200 miles of highway from Illinois back home to Michigan, I didn’t have to switch once.  We drove home, for free, for the first time.  It was a great feeling.  It resulted in multiple cheers from Nancy and I.  Our diesel tank never moved from the red… it was nearly empty when we left Chicago.


We can now leave Michigan with confidence in our WVO system in a few short days, when we hit the road for the summer in Two Birds.