I'd always been told that a b18c1 is a direct bolt in for a 5G Civic. All articles, all DIYs I've been able to find agree that is the case.

Apparently not with my car. I have a 1994 Civic CX Hatch, and it is completely missing a 6 (3 in use) pin connector to match a connector on my engine harness. This connector wires the evaporative emissions and crankshaft speed fluctuation sensor, neither of which the Civic have.

So what's the deal? Do I need to swap out my main harness (At the moment I'm assuming that that is what will be required) or what?

If I do swap out my main harness, will it still connect properly to my ECU subharness? It is ESSENTIAL that I retain the stock Civic subharness.