Q: I want to replace that little short fuel line hose, going to the fuel pump, from the pre-filter, with a much longer one. Will a longer hose cause any problems? Why is that hose so short there?
A: All diesels are fuel injected and not carbureted. Diesel powered cars and trucks need a much higher fuel pressure to provide proper combustion of diesel fuel under a very high compression ratio. Some cars and trucks utilize steel fuel lines to minimize the risk of leaks from rubberized fuel lines in long lengths to reduce vaporization and expansion. Try using a longer hose between the pre-filter and fuel pump. Remove any points of air leakage.