My friend bought a new dodge diesel and it starting knocking and gave poor mileage. I am not sure what all was done to the engine but he told me that finally they adjusted the timing to 0. The timing was at -4 . Getting info from Dodge was like pulling teeth. Cummins would not even tell them what the timing was suppose to be at. They tried 7 positive an the enginve sounded good. But they could not leave the timing there. This may be BS but that is what I thing was told. How the timing got to -4 is not known. For what ever it is worth Jim