Also, do you have spark at the coils and fuel pressure.
Now put the clip of the test light on positive battery terminal and check the other injector wire while cranking engine. Injector still unplugged. The test light should pulse if ground circuit is ok.
To save some time if it fails the above ground test. There is a connector (c123) according to the Kia manuel. This is a white connector wrapped in foam material under the passenger side carpet near the ECU. (may also be behind the passenger kick panel. This connector will have a wire for for both the green 12 volt and the ground wire for each of the injectors. Make sure the contacts there are good. It is also a launching place to continue to ohm the ground wires either to the injector or to the ECU depending on what you find there using the same tests as above for the injector grounds except now do them at this connector.
If you dont see the c123 connector.Did you check behind the kick panel by the door? Sometimes these kia manuels are not 100%. Use the colors of the wires that are on the injector itself and recheck for c123 again.
In some cases its direct connection and the colors go directly int the ecm.
Unplug the ecm and injectors then ohm the wires to see if you have continuity. If not then there still has to be a inline connector somewhere breaking the circut.
Another thought, run a jumper wire from battery negative to a good spot on the engine, then run another jumper wire from the engine to a good spot on the chassis. Make sure the spots are clean and good bare metal.
There is also a ground wire from the battery tray to the intake manifold. Make sure "eye" connectors are good and the metal they attach to is clean and bare.
if you ohmed all the wires from the injectors to the ecm and there is good continuity. then cam sensor or crank sensor signal to computer is problem.The computer need signal from this sensors to see to fire the injectors.
Check connectors 123 and 124. They are near the firewall on the passenger side under the intake plenum. These connectors are right near the knock sensor connector. You may have to remove the mixing chamber if your arm isn't double jointed. Kia had a bulletin on these 2 connectors to unplug and clean them plus install special retaining clips. They are 2 black square type connectors next to a small black knock sensor connector. Very hard to get to even with the mixing chamber off.
If you pull out the harness a little bit in front of the mixing chamber right by the fuel pressure regulator and unwrap the insulation there is a 5 green wire splice which has to be resoldered and rewraped. This however is the 12 volt source but have given many injector problems. If you have the mixing chamber off this will be very easy to do.
If that is checked ok, then There are 3 ground bolts behind the right kick panel. Remove them and scuff up the painted area. Solder the eye connectors if possible.