'95 F250 7.3L PSD - does this truck have a lift pump for the fuel? I noticed some of the WVO conversion companies sell an electric pump - is this to help out the OEM engine mounted pump & is it necessary as long as the VO is heated?
The 95 has a single pump munted in the engine valley. It is a "tandem" style pump. It has a diaphragm side to draw fuel from the tank and a piston side to pressurize it for delivery to the injectors. It's all driven by a pushrod to the camshaft.
I think a small electric pusher pump is a good addition to any truck. The fuel type is irrelevant. But it will take some pressure off the stock pump if a more viscous fuel is to be used.