I just put in my Ls-Vtec using a chipped PW0 ECU. Chip is from Xenocron and the ECU was sourced from Ebay and socketed by me. I accidentally wired the Vtec pressure switch using the Ignitor wire from the ECU. The engine cranked just fine but I had no spark, which is from cutting the ignitor wire. I rewired it to the proper pin and resoldered everything back together and triple checked everything was correct. Now it wont even crank. Here are my symptoms and parts that I've tested.

*At the "ON" position on the ignition everything lights up just fine and the fuel pump primes.

*When trying to start the lights go dim and there seems to be another faint "beep" sound coming from somewhere other than the beep box above the rear view. Pretty odd.

*When I turn the ignition back to the "ON" position the Main Relay starts going crazy. It clicks very fast. Going to the first spot on the ignition and back to the on position the relay goes crazy again. But if I turn it all the way off and go back to the on position everything acts normal again.

*MAP and TPS gets 5V

*Everything in the distributor gets proper voltage and continuity. It's also brand new.

*Starter cranked over just fine before the rewire so I'm quite sure it's working fine.

*Main Relay was also working just fine before the swap and it worked up until the rewire.

 

Verify all grounds are good and that you didn't pop the 15a ecu fuse in the engine bay fuse box.

 

My bets are all in on the thermostat grounds not secured properly.

... Unless the battery is in need of a charge.