Fuel pump problem yet again

[karl webster]

Anyone here have an idea what is going on???? I have recently had a prob with my pump. It was holding itself flat out and wouldnt stop. I Have taken a pump off a good running truck that i have that i have driven for a good few miles with no problems. Put it onto my truck, I have driven approx 500miles with no power at all when car was under load. My engine man had a play with the pump at the weekend ad hit the pin in on the top of the pump that is something to do with the transfere pressure i am told. What i carnt understand is that it was fine on the other truck,put it on mine and no good. After he did the transfere bit it was defo alot better but it had a really bad diesel knock. Ran it for around 100miles after turning the pump down on the two 12mm nuts to change the tranfere pressure and now the pump has started to rev itsself flat out and cutting out etc etc. Its like i have very little controll over the throttle. I do run on cooking oil and i am aware that the first pump was probly due to that. THe second pump couldnt possibly be to do with the oil tho. No chance at all as it had probs as soon as i put the pump on.
Any advice would be great. I am aware of the probs with running on oil tho and ive been doing it for several years with no problems so just help on the pump itself if anyone can give any light on it. Thanks karl