No ecu power after locking the brakes.....

[Florida240sx]

Swapped and engine last night along with full wiring harness of the car, because we were unsure of the car swapping into. Car has been driivng around town for about 2hrs. Roasting tires through 3rd gear Comign up to a stop sign lock up the brakes testing thme out... Car dies and then won't start. No spark and no ecu power.... What could it be. Ground issue with battery or IGN relay? anything else?

[180fan]

probably a ground, or something didn't get tightened down enough like a distributor or cas. I'd start poking around the fuse box for more clues first, then start pushing/turning of parts and then clean up grounds with a small wire brush and tighten em down.

not exactly sure what you mean by "brakes testing thme out" though.

[Florida240sx]

Driving 40mph and then going to neutral and pushing the brake pedal to the floorboard.Turns out somehow to ecu got fried. Added to more grounds to the car one more from battery and another from the enigne.