Besides an oscilloscope we have 2 different ways to measure the return flow of (diesel) injectors. The general method is to catch the returned fuel into a cup and compare individual returned volumes with each other. A high amount of returned fuel is a sign of a faulty injector. This method is easy, in-expensive to apply and gives in most cases the best result.

Besides catch up cups we have a device that can measure the flow of each cylinder (up to 4) and log these during driving. The device came when return flow system were applied under pressure, the general catch up method could not be applied giving a restriction to measure return flow for diagnostic reasons. When a problem occurs this return flow device can observe the return flows of the connected cylinders during driving circumstances. Were the catch up cans can only be applied to idle situations.