Waste Vegetable Oil

Ran the truck on a 90/10 mix of heated WVO and Diesel #2 for a majority of a 600 mile round-trip family visit this weekend.  Things seem to be working very well.  I only have three concerns:

Fuel Efficiency – I’m suspecting a slightly lower MPG on WVO than on Diesel #2.  I won’t be able to confirm until I buy a flow-meter for use when filling the truck with WVO or until I establish enough long-term ballpark figures to look at averages.

Fuel Leak – I’m suspecting a WVO fuel leak.  I’ve noticed large light-colored puddles when I pull out of several driveways now, but haven’t been able to determine the source.  On a side note, the dealership replaced my ICP sensor and CAC hoses to resolve my motor oil leak when I had the truck in for a 5K oil change on 03/18.  I’ve considered that this could be an even worse motor oil leak than before, and that the motor oil is very light in color because it was recently changed, but doubt the motor oil would be that light unless they used different oil this time.

Performance Concerns – Could just be me, but it seems like the truck is running rough when accelerating through specific speeds somewhere between 35 and 55 MPH.  I haven’t nailed down more specifics yet, just feel like something doesn’t seem right.

UPDATE:  03/25/2009

I’m still worried about performance concerns, but am starting to think this is either in my head or only occurs while running on WVO.  I’ve run on Diesel #2 several times and don’t seem to experience the problem.  I’m wondering if this has to do with a cylinder compression issue or maybe injector timing (ie: cetane related).  I’d like to begin running compression tests on each cylinder every 5K so that I can monitor degredation (if any) over time.  Harbor Freight has a compression testing kit for $25, but not sure if it would be able to test a 7.3L PSD.  I’d also like to invest in some PC-based diag and tuning software so that I can spot problems and possibly even fine tune injection timing for WVO.  I’m also considering mixing WVO (low cetane value) with B100 (high cetane value) so that it burns similar to ULSD.

Approximate Cetane levels for Diesel, WVO, and B100 (from Journey to Forever):

• Diesel 45
• Canola Oil 40-50
• BioDiesel 45-65

I suspect that the stuttering that I feel at different points during acceleration is related to a low Cetane level in my WVO.  It sounds like performance can suffer with extremely low Cetane levels (below 40), and performance plateaus once you hit about 50.