Okay, couple things you need to do before you start editing the effects. Make sure you have the SDK installed for your version of P3D, and then to make sure you have MCX
setup with the right tools in the SDK so you can export the MDL once you have edited the effects.
Once that is done a couple things to do in MCX is to turn off the Boundingbox. (bottom row, 6th tool from left "Display BoundingBox") Then click on the paperclip, (Same row
4th tool "Display Attached Objects". Then click on the "Wireframe Render Mode" (same row next to the camera). This way you can see where the effect is attached on the MDL.
Once you have the Attached Objects Editor open find the smoke effect (Left side) it will highlight in yellow on the model. In the "Position" under General the first set of numbers
is for left/right, 2nd is for back/forward, and last is for up/down.
left; back; up
(0.00; 0.00; 0.00)
right; forward; down
Remember that to move the effect left/back/down you will need to use the minus (-) in front of the number.
Joe