I have always wanted a way to test injectors. I often recycle things by repairing or restoring to make things work again. Injectors are rugged, but they often fail to work properly if contaminated with fuel residue. The contamination happen when injectors are on a fuel rail that has been left to sit for years. The fuel turns to varnish leaving the injectors stuck. If solvent is used to free injectors, they can be cleaned and evaluated by flowing and measuring the fuel delivery.
In about 16 hours total time, working a couple hours at a time, a working flow bench was developed. The unit uses a micro controller to control the injector duty cycle and counts. I developed the software, hardware. New fuel filters and used fuel system components were used to make the test panel. The unit cost about $100 for new parts, mostly in the controller and graduated cylinders.
Here is a 1 minute video of a test run.