I have read the articles you have on the main relay, but have been unable to find the main relay in my 89 Civic hatchback. I found a relay close to the location where you said it should be but after replacing that relay I still do not have power to the fuel pump and the ecu still reads a code 16.
The relay I found only has 4 prongs not 8 as the ones you show in other answers. Am I messing with the wrong relay? My civic is a 89 model 1.5 liter 16 valve, with the engine code D16B and it has dual point injection.

1. Here's what your main relay should look like:

Zip Code Entry at PartsAmerica.com (http://www.partsamerica.com/ProductList.aspx?PartType=598&PTSet=A&SearchFor=Fuel+Injection+Relay)

What stamping no. was on the relay you removed?

2. Test all under-dash and under-hood fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-honda-civics-46563-3.html#post252145

3. Remove BACKUP fuse in under-hood fuse box for 10 seconds to reset the ECM; otherwise, disconnect the negative battery cable for 10 seconds.

Your main relay is tucked way up on the left kick panel to the upper left of your fuse box. Kind of hard to get to but not impossible. Take the four screws out of fuse panel, pull down and use swivel 10mm to take off relay.