I've got the Ramps 1.4, off of gadgets 3d. I'm running the latest Marlin on it, and I've got that all set up. The problem lies with KISSlicer, my slicing software, I suppose. The temperature works, the commands work fine, everything's bright and shiny. Including the extruder, when it's manually controlled. The problem comes in actual prints.

The three steppers for the Cartesian robot work just fine, and trace the path that it would take if it was printing. Without fail, however, the extuder's motor refuses to activate from the Gcode's command (although I can control it manually just fine, through the RAMPS). It's not Marlin, the Minimum extrusion temperature is well below the one at which it reaches during a print. I haven't a clue how to get it going, though, and I think the problem lies in the Gcode.

The prefix-Gcode:

G28
M109 S155
M103
M227 P1600 S1600
M108 S600.0
M113 S1.0
M101

Is kisslicer set to use relative extruder values? I'm not an expert on it but I know there are 2 different ways to control an extruder. One is relative one is absolute vales, if your slicer is set to one and the firmware set to the other you will have problems,

I know I haven't given a solution but I hope I've helped poi t you in the right direction.

You were right, I found the answer on the forums fifty seconds after I posted this. Had to switch it from BFB to 5D Absolute E. Got the motor running, at least, but the newest problem is that it's slow. It's only pulling one or two revolutions a minute, except when it's retracting filament. The BFB original Rapmen would retract and then re-extrude when it had to make a lengthy jump in the model, to prevent stringing, and in its current state, the printer only hits the specified speed during that process. Any ideas?