Introduction, extruder question, HE3D Xi3

Hi everyone,
I inherited an HE3D Xi3 printer kit from an engineering student that totally botched the build.
In the last few months I've learned a lot about 3d printing and seem to have a lot more to go.
My Machine:
Prusa I3 acrylic frame
MK7 extruder
Arduino mega / RAMPS 1.4
Repetier firmware .92 and using Repetier host 1.6.2
I finally have it fixed and calibrated.
The last calibration was the extruder and that's where my questions start.
Before calibration I could print the standard cube and a few simple things but the x/y dimensions were off
and the layers were a little thick but it was basically doing what it was told to do.
Now, since I calibrated the extruder it does not extrude properly. Either it does not extrude at all or it's very
lite or chunky.
If I lift up the z-axis and extrude using the manual control on the software it works fine. A nice, even thread of melted
ABS comes out.
To be certain I disassembled the extruder, made sure it was clean with no obstructions or dirt on the gear.
The tension is tight but not so tight that it chews up the filiment. (1.75 mm ABS, it's what came with the printer)
I checked my calibration at both 10mm and 100mm. It pushes through and retracts the right length even after multiple tries.
I'm printing at 250c extruder temp and 95c bed temp.
It's an aluminum bed with blue masking tape and it seems to stick ok.

Any thoughts?

Also, I was thinking about replacing the extruder fan because it came with a pitiful piece of crap that wasn't even useful
as a 486 processor fan back in the day. Does adding a larger fan that weighs more make it necessary to make any changes
to compensate for the extra mass?

I attached a copy of my EPROM settings

Edited 1 time(s). Last edit at 01/07/2017 02:08PM by IchabodV.

The key to extrusion problems is to figure out what is happening when extrusion fails.

Does the motor keep turning or stop? If it stops, does it go completely still and quiet for a while (stepper driver over-heated and shut down, reduce the Vref) or does it jump back and forward making clicking noises (motor stalled due to lack of torque, increase the Vref unless things are already too hot, in which case reduce the extrusion rate)? If the motor keeps going, is the drive gear turning with the motor or slipping on the axle (tighten the set screw on the flat of the axle, add thread locker if necessary)? If the drive gear is turning has it chewed a chunk out of the filament (not enough idler pressure, tighten the tension screw), or has the filament escaped from the feed path, kinked and made a tangled mess in the extruder (make sure the throat is as close as possible to the drive gear, if it's already there, then slow down your extrusion rate by either slowing the feedrate or using thinner layers).

Thanks for answering my question.
I found out what the problem was. The slic3r settings were off. There is quite a learning curve with these things.

Quote
IchabodV
There is quite a learning curve with these things.

Oh, that's the truth for sure. It never ceases to amaze me how things I thought I understood keep turning out to be more complicated than I'd realised.

Glad to see it is resolved.
These puzzles can be quite frustrating.

Lykle