I have been curious if diesel fuel is formulated for use in a high pressure application like the Dmax. Most of the fuel the pump picks up is by-passed back to the tank so fuel is constantly recirculating and besides picking up heat from the engine it also adds heat from being under pressure. I wonder if a fan located to blow on the fuel heat exchanger would help. Also the fuel constantly be re-circulated and the ultra low sulphur content of the fuel might be reducing lubricating properties of the fuel to the point that it harms the injectors.