Little cups will work and you don’t have to stretch harness and fuel lines as much. I’ve used 4 coffee mugs before. Can test for injector signal at connector with noid-light. Not as good as oscilloscope, but will at least verify you do or do not have injector pulses from DME.
https://www.amazon.com/dp/B004FELH04/
With increased supply of counterfeit parts in market, it’s not uncommon to get bad parts right out of box. So any new parts should also be tested and measured to confirm they are working. I returned brand-new distributor cap & rotor last week because they were defective. Spark goes in, but didn’t come out. Guess how I tested that? Every single part on car has test to confirm functionality based upon clear black&white all-or-nothing criteria based upon measured
numbers. Until you measure, you have no idea what’s wrong.
https://www.pelicanparts.com/techarticles/Porsche_944_Turbo/04-FUEL-Fuel_System_Pressure_Tests/04-FUEL-Fuel_System_Pressure_Tests.htm
