Ok here is the sitiuation, its a '93 Civic CX w/ a JDM B18C w/ a JDM ECU, the car has ran fine for months then all of a sudden it wont start, wont turn over or anything. Had the Battery tested, it was fine, even put a new battery in, the lights and everything dont work either, the dome light comes on like barely when you open the door. I've checked all the grounds, fuses, andeverything. Does anyone have any idea. I thought it might be a bad ECU but i wouldn't think it would throw these symptoms.

 

From your description, you definately have a voltage supply problem. If you've got jumper cables, use one half of the set and connect between the battery negative and a good solid ground point on the engine and see what happens. If that fixes it, then your ground cable or it's contact point is bad. Check the positive cable where it goes into the clamp. Corrosion can build up in there and limit the current, even though the clamp itself and the battery post are clean. After all that checks out, look at the main fuses in the under hood fuse box. Make sure all connections are clean and tight. BTW, your ECU will not cause the symptoms you describe.

 

I had the same problem.... open the FUSE box under your hood. there are ground wires in there. some times the screws come lose.. check that. thats what was wrong with mine.