my car is a 1990 civic s1 with a b16a. first it started out in limp mode then it went and started blowing the ecu fuse. the fuel pump dosnt prime. and im sure the ecu wiring is ok. could it be a bad ecu or a short somewhere?

 

Check your grounds at the thermostat housing, valve cover, and transmission. Then check the main relay. Check the grounding to the interior fuse box and the one under the hood. I'm sure there is a bad cable somewhere. That or there is an issue with your fuel pump ground which is shorting it out and blowing the fuse.

 

Blown fuses are usually signs of a ground problem.

 

It has to be a short to ground. You're drawing too much current through the ECM fuse, so whatever the ECM is triggering at the time it happens is likely to part that is shorted. You can start unplugging various electrical components like the fuel pump or main relay and see which no longer causes the fuse to blow. Better buy a big box of fuses. It might take a while.

Your only other choice is to put a foil-wrapped fuse in there and see what starts smoking. Not recommended but I did find a short like this on a dually I used to own. I had a wire that rubbed up against the engine block, behind where I could see. I followed the smoke and found it.

 

that was pretty funny made me smile.