Abstract: Various embodiments may include a fuel injector cup assembly comprising: a fuel injector cup; a fastening bracket for securing a fuel injector to the cup; and a clamping arm for fastening the cup to an engine. The cup has a main body part with an internal volume. The cup comprises a one-piece body defining the main body part and an inlet stub containing a fuel inlet port hydraulically connectable to the fuel source. The stub has a first external dimension. The main body part has a second external dimension larger than the first external dimension to provide a shoulder supporting the clamping arm. An end of the cup remote from the stub has an outwardly extending flange supporting the fastening bracket.