Hi I have a 92 civic and my number three injector is not working, I have checked to see if there is 12v, which there is, I have continuity from the injector to the Ecu, replaces the Ecu and injector and switch it with another from a good cylinder also checked all the grounds on the Ecu not sure what else it could be... any help would be great full.

 

Check injector drive with a "noid light" or simply a 194 bulb with the pins straightened down and pushed into the injector plug. You can't tell very well with a voltmeter. If you do have injector drive there could be some other reason for dead cylinder. You could also try pulling the wires over from #2 or #4 and plug onto the #3 injector. Though out of sequence, some fuel will go in and the cylinder should fire.

If there really is no injector drive, could be a bad pin in the ECU plug. Take ECU covers off and measure continuity from inside the ECU where the plug attaches to the circuit board all the way through the injector.

 

Alright thank you

 

....So you swapped injectors and the problem is still there? If so, you have a bad cylinder.
Check compression. If #2 and #4 cylinders are higher than #3, one of the valves is bad/bent. More than likely, exhaust valve(s).

 

Just fixed it turned out to be a bad connector on the Ecu thank y’all for the help!