[v8volvo]

Does it start easily on diesel? If it does, then you don't have a problem with your motor; your issue is with your fuel mix, and the poor starting is a major warning sign that you need to re-think your fuel blend before things get much worse very quickly.

The D24T relay does have an after-glow provision; it is only about 2-5 seconds after the key is released rather than 10, but in a healthy engine running on good fuel, it is plenty. If you find yourself needing more than that, then you have an engine compression, timing, or injector problem (and I it sounds like you have pretty well made sure your unit does not have any of those issues), or again, you need to reduce your veg oil usage.

Let me be clear -- running veg in your mix without a heated fuel system, at a high enough percentage to affect starting, is asking for trouble. Running small enough quantities that it does not affect engine operation -- small enough quantities that you really think of the veg as an additive, not a significant component of your fuel) you can get away with OK, though you will go through fuel filters at 3 or 4 times the rate you normally would, especially in colder weather when there is some precipitate drop-out from the unheated veg, which cuts into your savings a bit. However, running 50-60% without a heated fuel system is a sure recipe for engine and fuel system destruction, landing you with a dead motor and a big bill, at which point the idea of savings from running cheap fuel starts to sound a little silly......