Volvo Penta 5.7 Cranks but won't fire-All spark components check out OK

2000 292, Twin 5.7 TBI Engines. Cranks but won't fire. 5 different shops, including the local Cobalt dealer have tested/replaced, all components, Distributor, Coil, ECM, Plugs, Wires, Relays. All good. Last I ran it, under power got 2 beeps indicating either overheat or low pressure problem. Shut it down immediately. 15 minutes later restarted it. Ran fine for 5 minutes or so. Got 2 beeps and shut it down. Hasn't run since then. Key on, get fuel pump wine and 2 beeps. Crank it and in bbout 10 seconds get 2 beeps again.