The injectors have a set pressure before they will start spraying. You maybe now getting fuel out of the top of the FD but is the pressure enough to operate the injectors?
How is your fuel pressure regulator? Have you changed that yet?
The EHA only regulates enough pressure between the upper and lower chamber of the FD to cause some enriching or less rich mixture during engine operation. Its operation is regulated by the ECU which in turn gets info from the heat sensors and O2 sensor to regulate the richness of the fuel mixture. If the OVP is blown the EHA has no effect. The injection system will work just fine - without regulation.