Agreed, the FIP just wasn't designed for it. The only time I've seen it done successfully with the DPA was where a dual tank system had been fitted, one with veg oil or biodiesel, one with regular diesel. Engine was started on regular diesel, switched over to veg oil in transit and then switched back to regular diesel at least 15 mins before reaching destination and engine shut off shut to flush out the veg oil. All rather complex and a bit of a faff to be honest. Too easy to get wrong in a hurry. It was being done as an experiment to see if it WAS possible, which it was as long as you were scrupulous about flushing the pump. But the owner went through a few pumps whilst experimenting (not cheap) and eventually gave up on it due to complexity and risk of screwing things up. Went back to dual tank regular diesel in the end if I remember correctly. I was always hungry when around/driving that vehicle though as it did smell good!

I had the same experince with used veg oil and bio-diesel made from used veg oil, the cost in blocked filters and recovery exceeded the savings by a good margin. OK with twin tank / heater set up and Bosch pump but even then it was a lot of faff, OK for high mileage but that meant buying 80L veg oil a week. Worst was stopping on the elevated section of the M4 at on a friday night (for those who don't know its busiest section of road in the UK and has no hard shoulder). Police towed me off and left me in sight of the services "not our job mate...".) 2 hours wait.. After about a 1 1/2 hors waiting behind the barrier as instructed I got cold so I got back over the barrier to get my jacket out the car. Phone rang so I picked it up thiking it was the recovery wagon. Guy said "we told you not to get in your car, stay over the barrier!" They were happy to watch me for 2 hours on the CCTV but help? no. And I'd been for p*ss.

Must be something about the M4 - had a similar experience in the middle of the night mid-winter back in the early 90's somewhere between Swindon and Membury services when the radiator let go on the 110. Spent 30 mins sitting over the barrier then decided that it was probably safer sitting in the vehicle with the hazards on than freezing to death at the side of the road. Got a rollicking when the AA turned up 3hrs later for being in the vehicle - told them that as it was now 3am and below freezing and that even the M4 was relatively quiet at that time of day, I'd take the risk and that it was my hide on the firing line, so bloody well shut up!

But this discussion is a long way from making a hand-crank!