94 w140 s320 won't start

[Cydal]

Hi I obtained a 95 Mercedes s320. Car cranks but doesn't start. So far I replaced the fuel pump since old pump was bad and drained/replaced 5+ year old gas. Checked fuel pressure at fuel rail and it's around 55 psi. Spark plugs, ignition coils are good and I'm getting spark. I checked camshaft and crankshaft sensors, they are good and sending a signal to ECM. Checked for common ground on sensor wiring and ground is good. Car starts with starter fluid when sprayed into throttle body. At this point I'm assuming the injectors aren't firing and I'm thinking it's the ECM. Do you think my findings are right? Or I still need to further troubleshooting?