I have a 92 cx with an all motor b20v. I'm in the process of a custom body harness, deleting both oem fuse boxes. My question is, is the ELD in the under-hood fuse box necessary for alternator regulation? Will my alternator overcharge the battery without it?

thanks in advance

 

the ELD system is actually more for idle speed and a secondary injector compensation. If electrical load gets too high, it brings the idle up a little higher in order to get a little more current from the alt. It also adds a bit of fuel on top of what the injector latencies are already adding.

Technically you don't need it. But without it you'll need to spend more time tweaking injector voltage latencies in the tune, and your heater and headlights might go a little soft at idle depending on how high you set the base idle speed to.