injectors voltage

[dadmomcat]

What is the voltage range at the fuel injector ??
I have a problem of running only on 5 cylinders, ran it down to #4 injector, no reading with volt meter or test light. new wire harness from casper, car has been running really strong, then one day, running like S$&T, check every thing, came down to this one injector. Took wire apart and hook every thing back, running better, but still no reading at #4 injector. Any idea ???
Thanks

 

[WarpSpeed]

Welp, one side is a constant 12v+, the other side is the signal, (-) from the ecm and is not constant, of course. On a volt meter it'll show about 3v (negative probe), although it doesn't mean much except there's a signal.

 

[dadmomcat]

After some more reading, the ecm grounds the injector when firing, so warpspeed is correct on the constant 12V+ and ground, just would like to know that they are all working. i had to reverse the + & - on my volt meter leads to read any voltage, plug has one black wire going to all of the injector ( must be 12V + ) and six other colors ( must be the - side ) will have to think this one over.
thanks for the info