Since diesel by nature is a dirty product, there is always at least one filter between the low-pressure pump and the engine to remove any dirt and contaminants, and likely there will be a water separator to remove any H2O which condenses in the tank. Depending on the model, you might have between 25 and 40 gallons of capacity, and on most trucks there is a low-pressure fuel pump which sits inside the tank and pushes the fuel toward the engine at a relatively low pressure. It all starts in the tank, which is where the fuel is stored whenever you fill up. There are many parts which make up the fuel system on a common rail diesel truck, and the path the fuel takes is like a choose your own adventure book there are many different options. It was a great powerplant and was the first of the big 3 to come equipped with common rail fuel injection, but there was one item missing which every other diesel pickup had before and since: a lift pump. One such automotive mystery was started in 2001, when GM introduced the Silverado HD’s powered by the 6.6-liter Duramax diesel V8. While there have been several theories, to this day nobody knows the answer to either. There are many great mysteries which have remained unsolved over the years, ranging from what’s at the bottom of the Bermuda Triangle to what happened to D.B.