Sounds like restricted fuel flow to me! I'd check your filters. Veggie oil will tend to clog filters sooner than diesel, simply because waste oil still has some particulate matter (5 micron filters only remove 'most' of the 5 micron particles), and because it can dislodge other gunk collected elsewhere.

I'm gonna bet your filters are clogged, since the symptoms are very similar to what we experience on my friend's long-range veggie bus. When the filters begin to clog, power is lost. You can feel it happen, and know you need to change the filters soon.

Many WVO enthusiasts install fuel pressure gauges above and below the fuel filters, and compare the values. As the pressure rises above the filter and drops below the filter, your filter is becoming saturated. You can just watch the gauges and change your filters just before you get enough differential to cause a problem. Its the same technique used for industrial filtration systems. Monitor your pressure, and extrapolate your filter load.

Your prefiltering sounds good. The smaller you can filter the better, but letting it settle for a few days will prevent loading your filters, making them last longer and work faster.

I'd say check those filters and strainers, and get back to us.

Peace,
sam

__________________
"That f***in' biodiesel is makin' me hungry."

1982 300TD Astral Silver w/ 250k (BIO BNZ)
2001 Aprilia SR50 Corsa Red w/ 5.5k (>100 MPG)