So I just opened and set up the TAZ 4 and found that the precut abs thats in the print head is stuck and I can’t pull it out. Should I just heat it and melt it out completely?
I managed to get it out but now when I put in PLA nothing extrudes out of the nozzle.
ABS melts at a higher temperature than PLA does. There is probably still ABS in the bore, and it’s not getting hot enough to flow out. you can either disassemble the nozzle entirely and remove the plug, or heat the nozzle to 230c, with the understanding that its probably going to burn some PLA and at that temperature extrude away until just scalding hot molten PLA comes out, then drop the temperature back down and continue to extrude until no discolored PLA is coming out.
Thanks! Got it to work. Should I be using blue tape with PLA? It doesn’t seem to want to stick to the bed at the beginning of the print.
I’ve heard good things about blue painters tape for PLA, but I don’t print with it very often so I don’t know for sure. If nothing else it’s inexpensive and non destructive to try out
Use a glue stick or a PVA glue (white glue) solution to treat the bed for PLA, and heat it to 55-60C.
Don’t use a gluestick/PVA glue if your going to switch between materials somewhat often and randomly. Cleaning it is a pain. Painters tape is the shite! You don’t need to heat the bed if you use painters tape either, so you can start printing sooner and faster(which is especially handy when your girlfriend wants to leave and you are trying to start a print before you go) 
When printing with heatbed off, i print the first layers at like 210-220 so they stick better.
for PLA I use hair spray. works great with heated bead. You can hear the parts POP off the bed when it vools., Just sopray over the area and print again.
You’ll find that people have their preferred method of treating the bed for part adhesion. The trick is settling on what works best for you, and allows for great part adhesion AND easy part release post print.
Yeah, I can also contribute to this!
Before everything please make sure that your bed is leveled fine. I was always looking for the solutions for prints to stick.
…That is, until I learned that a good bed level, and slower print for the first layer are essential
When I got that right, I never had problems with parts not sticking.
Now I can print on default Lulzbot bed, which is covered in PET sheet, and I don’t have to add any kind of ‘glue’
Temperature for bed is 65 for PLA and 110 for ABS ( I believe it can go even lower 5-10 degrees)
…seriously, level your bed! And level it so that you slide the piece of paper under the nozzle when it’s homed-Z axis. You need to have slight pressure when pulling the paper under it. And do that for all 4 corners of the printbed
For extra control, I do one level check in the middle of the bed, which has a bit higher pressure that the corners because the extruder is heavy and the rails bend (very slightly)… then if that middle pressure is too much, use the red Z endstop to move it away (very very little, don’t lose too much tension in the corners)