Check fuel flow at the lower chamber fitting; remove the line, connect a piece of hose that you can direct into a container. Flow should be approx. 140-150 cc per minute. There is a restrictor in the lower chamber outflow circuit; if that restrictor is clogged the flow will be low, the lower chamber pressures will be too high (as you observed), and injector flow will be cut off.

You ask about turning the EHA; I am not familiar with any adjustment provisions in or on the EHA.