So im having the same problem with my freshly swapped rb25det s1! no spark no fuel! Have 12 volts have grounds on both. Tested the cas at the ecu pins both the 120° and 1° input for cas! getting readings while cranking. tried a buddy's ecu from his s2 rb25det and still nothing changed did an oscilloscope test on spark at ecu no signal being put out on any tested fuel pulse at ecu get one pulse then nothing same thing with a diode at the ejectors plug one flash of the light while cranking then nothing super stumped on this one any ideas??