A method to calibrate the fuel injection in at least one combustion chamber of a Diesel engine includes: a) recording the combustion noise power or amplitude in the combustion chamber over a piston position range [γ1i;γ2i], b) at the same time, recording the piston position during the same piston position range [γ1i;γ2i], c) determining from the preceding recordings for which piston position Kmin-i the measured combustion noise power passes through a minimum Pmin-i when the piston moves from position γ1i to position γ2i, d) adjusting the fuel injection according to the determined piston position Kmin-i.