All injectors ground out at key on

[SPOOLIN]

I recently popped an engine...and the car was running fine. I just put my engine back in and now when i flip the key all 4 injectors ground out and would spray if i had the injectors installed. I can meter at the injector plug putting the probes on both pins at the same time and get 12v passing through the clip.....obviously one wire has 12v when the key is on...but its grounding through to the ecu. What in the HELL would trigger an ECU to ground all 4 injectors simultaneously at key on....ive checked injector ground continuity and the only way they make a connection is through the ecu pins on the A plug. Im thinking its a wire because ive swapped out the ecu for another s300 box, and ive swapped dizzy's. What sensor tells the ECU to ground each injector....i have no CEL's and S300 works fine, lets me edit, upload, etc.

[SPOOLIN]

i think i figured out that it will always let you read 12volts as it always slightly grounds the injectors but its when it fires the injector that it fully grounds it. am i correct...seems the injectors arent on at key on, now that ive tried injectors that work.

[Spunkster]

so there is no problem?