Are you using the same needle for both? If the little blue bobbles on the canvas are fabric ( I thought they were the top thread) then I'd suggest either your needle is blunt, pushing threads instead of piercing, or too big. I don't have any experience of sewing faux leather but I'd have guessed a 100. I've sewn heavy duty canvas, stitching transparent vinyl to it to repair a boat awning. I bought special needles for this & used a heavy duty thread. It was very successful, I don't remember needing to adjust tension on my old Pfaff.