12V to the pump has been tested, but I'm not getting it through the relay. Not burning up pumps, the pump works perfectly fine when I put a 12V lead to the inertia switch. Inertia switch does pass voltage, I've tested all the leads and I'm getting continuity throughout the wiring harness to the pumps, both low and high pressure, right up to the fuel pump relay.
At this point, its either a broken ECM or a bad relay connector. Should be the only two options left.
To recap: with just my key, fuel pumps don't prime or run when engine is turning. When I connect 12V directly to the inertia switch, fuel pumps run. This indicates either a PCM or a connector issue, as I've replaced the relays. When fuel pumps run and engine is cranked, it doesn't fire. Could also be a spark issue with the distributor, but that could be a symptom of a failing ECU or a relay connector that doesn't pass voltage.