Replaced fuel pump ecm and fuel pump regulator but it won't start. Checked fuses seems there are good. Car sat two yes fuel filter maybe? If ground not solid from ecm will that prevent starting?

Can you hear the fuel pump turn on 'for a couple seconds ' when the key is turned on? .. May need a helper to turn key while you listen at tank filler neck with gas cap removed... Have you checked for ignition spark 'from' plug wire(s) ?