Toyota Repair: 93 camry 3.0 no injection pulse, intake plenum, installed alarm

Question
the car is a 93 camry 3.0 v6 with approx. 125k on the clock. the car originally was brought in for a draw. diagnosed problem to be within the brain of the aftermarket installed alarm. the alarm was disconnected, all wires were soldered and heat shrinked. while i dont believe the customer on this one but here it goes, once done with the repair, the car intermittently will not start. it has good, strong spark and perfect fuel pressure, it loses its ground pulse to all injectors. after trying known good e.c.m.,distributor,ignitor,and ignition switch, ive all but given up. i know for sure that there is no output pulse from e.c.m to injectors and input is good, thats why the e.c.m. was a sure fix i thought, but didnt do it. any help would be greatly appreciated. thanks eddie

Answer
Check the injector and computer ground wires to body ground, there are some ground connections on the intake plenum on the passenger side make sure they are clean and tight, check the computer ground connections in both the left and right side kick panels,check all computer ground wires at the computer connectors to body ground, all ground wires are brown/black,or white/black, if you have a wiring diagram that show ground points it would help, it sounds to me you are losing ground somewhere because of a loose ground point. Just an afterthought, when losing injector pulse do you still have a constant voltage to one wire of the injectors?