CM870 ROUGH IDLE

[preacherboy24]

Do a bank cutout. Cut the front three and then the back three. If the engine runs better on the front or back bank then you have isolated it to either those three injectors or the actuators running those three injectors. I did the bubble test and after swapping in injectors (used from another engine) I had no bubbles. Took all 6 to an injector shop and had three blowing air and one wouldnt fire on the stand. Dont rule out bad injectors because your not blowing bubbles.
Another thing you can do is get a laser temp gun and check your exhaust manifold ports. If you have a bad injector you should see a temperature difference in the exhaust manifold port.