injectors 2 and 4 not firing?????????

[wardept]

Any one know what sends the signal to the ECM to tell it when to send the ground signal to the injectors? I found a bad/corroded connection from the ECU to the injectors. Fixed that, still no good. I have a real weak ground signal comming from the white and wite/red wire's from the ECM to the injectors. Any help would be great. This thing is about ti drive me nuts!!!!!!!!
Thanks
Bill