http://civic-eg.com/viewtopic.php?t=1558
for a list of the codes and what they mean.
43 = Fuel Supply, 20 = Electrical Load Detector
You should really get the right ECU for your engine before you start troubleshooting. If you're using the lx ecu then the air/fuel maps will be incorrect for the z6.
The ELD in located in the underhood fuse box. Last time I checked, Honda doesn't sell just the ELD so you would have to buy the whole fuse box from the junk yard. Often the ELD will be fine, and the code can be caused by another problem in the electrical system. Are your headlights flickering at night? (common symptom of problem)
For the Fuel supply, how old is the fuel filter?