ABS is difficult than PLA for printing because: ABS is more slippery than PLA, so need more force(more friction) at the hobbed bolt to get the same pressure at the extruder. ABS is more flexible than PLA, so can deform easily and be smashed than PLA at the hobbed bolt. If the filament is smashed at the hobbed bolt, then it can clog in the PTFE when colling(after some layers). ABS doesn't have a temperature of transition from solid to liquid like the PLA, is always viscous and gradually become less viscous with high temperature. So it need more pressure to get the same output rate. If the ABS is printed at low speed and with low extruder diameter(<0.5mm), then it need a little more temperature to stick at the lower printed layers. PLA doesn't have this problem, because PLA need to change from liquid to solid, and this change need a lot cold. you may need to change some parts of your extruder to be printing with ABS. See the extruder diameter, if is too small, you may consider feeding with 1.75mm filament(expensive) or change to 0.5mm or get a good hobbed bold(cheaper). See if your hobbed bold works good, home made hobbed bold have less quality than some available at stores. See if the ABS gets a lot of pressure and is smashed at the hobbed bolt. if so, it can be clog at the PTFE part. I don't know what pressure does Erik's Bowden Extruder need to extrude ABS, but i know is less than normal the common version extruder(Wade's Geared Extruder). Erik's Bowden Extruder can work for you.