I just finished installing my Mk II on my VR16...
Its probably the selector plate for the spectre, assuming you removed the cutoff lever when you did the install... If it only happens when you hold it left the selector plate is probably falling away from the microswitches on the back of the FET, switching it into SAFE mode. Try adding tape or heatshrink around the metal part. I also modified mine slightly with a dremmel, by removing 1-1.5mm from the leading edge of the tappet plate to make sure it isn't stopped from being pushed all the way forward when the fire selector is actually in safe mode.
edit: For future reference: To mod my selector plate I added heat shrink around the green part. I also removed 1-2mm from the blue edge to allow the selector to move all the way forward. I found adding the heat shrink alone prevented the plate from moving all the way forward and engaging safe mode. I also removed ~1mm from the red edge to prevent the selector plate from hitting the stock VFC bearings which stick out of the gearbox slightly. That is all.
