Methods and systems for improving fuel injection repeatability

A system, comprising:

• an engine comprising a plurality of cylinders;
• a plurality of port-fuel injectors and a plurality of direct injectors, wherein each cylinder of the plurality of cylinders includes at least one port-fuel injector of the plurality of port-fuel injectors and at least one direct injector of the plurality of direct injectors;
• and
• a controller with computer-readable instructions stored on memory thereof that cause the controller to:
• determine a fuel mass correction value for each of the plurality of direct injectors based on a fueling error thereof at a reference direct injector pulse-width (PW);
• and
• when the reference direct injector PW is signaled to a direct injector, adjust a PW signaled to a port-fuel injector of the plurality of port-fuel injectors based on the fuel mass correction value of the direct injector of the plurality of direct injectors, wherein the port-fuel injector and the direct injector fuel a same cylinder of the plurality of cylinders.

A method, comprising:

• determining a pulse-width (PW) correction to be applied to a port-fuel injector based on a fueling offset of a direct injector learned during a diagnostic and a port-fuel injector transfer function;
• maintaining the fueling offset of the direct injector following the diagnostic;
• and
• applying the PW correction to injection parameters of only the port-fuel injector at a reference injection PW of the direct injector;
• wherein the port-fuel injector is positioned to inject in an intake port of a cylinder and the direct injector is positioned to inject into an interior volume of the cylinder.