ecu fuse blows when key is turned

[Pedal]

ok so here is the deal. i have a 93 civic dx with a 95 gsr swap. i have had 2 ls swaps in the past few years with no issues. so i have put about 500 miles on the grs swap and the other night i was driving at about 40 mph and the car just lost all power (lihgts still work but no power). i have the car towed to the house, checked the fuel main (just in case) and the coil and igniter (i have 2 of each of these). all good! after closer inspection i found the 15 amp ecu fuse blown under the hood, replaced and the car stated and ran fine for i would say about 10 miles but also about 2 hours worth or just sitting and running. then tonight i am driving down the road and the exact same thing happens. i replace the fuse and try and start the car but all it does is spin over, by this time a friend has driven by and stops to help. i replace the ecu fuse again and turn the key and he tells me that the fuse is blowing right when i am turning the key in the ignition around the 2nd click when all the dash light and stuff come on. so i disconnect the battery and change out the ecu to the ls ecu just for shits and giggles well same thing.

so anyone with any ideas or does the nonsense above make and sense to anyone other than me.

[NAIZBST]

I wouls check to make sure everything is bolted down correctly in the fuse box and also the grounds are grounding correctly

[AnthonyF]

a wire might be exposed somewhere after the numerous swaps and could be shorting out. trace the wire back and see if it split anywhere. Might be rubbing on something sharp and after a few miles just finally wore through and shorting.

[Jordanmd88]

You have a short.. What does the suspect fuse control and theres where you will find your problem..

[Sammich]

You have a short..

x2

[RBS]

i bet you were messing with your ecu before all this started happenening, look around your ecu and its harness

[iEvo]

yea deff sounds like there is an exposed wire somwhere and its grounding out which is blowing the fuse