Going to twin tank my 300TDI, these engines use a mechanical lift pump before the injector pump and I'm going to replace this with an electric pump (mechanical ones are prone to failure).
I plan to have two Facet posiflow pumps, one for veg the other for diesel. Just wondering if it is best to switch the pumps on and off when changing over fro veg to oil and vice versa. I should be able to wire them to power with the change over valves or is there no harm in leaving them running but not been able to flow when the valve is shut.

Thanks
Bruce