Thanks BP and David, got it all sorted out. I think my brain was still fried from wiring and whatnot to comprehend what the Gcode was doing. Ive gotten it all working great now. Even added in a wipe in my startup script for priming the print. Learned a bunch with this and I really do appreciate your help!

Now, on to print that bracket for the bltouch!

Thanks BP and David, got it all sorted out. I think my brain was still fried from wiring and whatnot to comprehend what the Gcode was doing. Ive gotten it all working great now. Even added in a wipe in my startup script for priming the print. Learned a bunch with this and I really do appreciate your help!

Now, on to print that bracket for the bltouch!

Ah I see..
So in my home files I use relative to get to the stops. My Z hits the stop which should bottom me out and I should be able to level at this point as this should be the Z0 absolute. I then set the Z but tell at an offset of 2.5mm lower than where my Z stop was triggered.
Then when my print starts, it tries to go to Z0 which is now actually Z0+2.5mm+first layer print height?
Is it best to get the home on Z to be 1mm above the print surface, then set the layer height for the first layer off that in the software?

homeall.g

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool on Sat Apr 07 2018 15:34:24 GMT-0600 (Mountain Daylight 
Time)
G91                     ; relative positioning
G1 Z5 F6000 S2          ; lift Z relative to current position
G1 S1 X-205 Y-205 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 X5 Y5 F6000          ; go back a few mm
G1 S1 X-205 Y-205 F360  ; move slowly to X and Y axis endstops once more (second pass)
G1 S1 Z-185 F1800 S1    ; move Z down stopping at the endstop
G90                     ; absolute positioning
G92 Z2.5                ; set new Z position
;G1 Z5 F100 S2          ; uncomment this line to lift the nozzle after homing

Here is the homez.g

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool on Sat Apr 07 2018 15:34:24 GMT-0600 (Mountain Daylight 
Time)
G91               ; relative positioning
G1 Z5 F6000 S2    ; lift Z relative to current position
G1 S1 Z-185 F1800 ; move Z down until the switch triggers
G92 Z2.5          ; set Z position to trigger height

; Uncomment the following lines to lift Z after probing
;G91              ; relative positioning
;G1 Z5 F100 S2    ; lift Z relative to current position
;G90              ; absolute positioning

OK, sorry for the noob question. Ive dug through thread after thread but gcodes are escaping me at the moment.
I have a wanhao I3 that I tore apart and kept only the frame, lead screws, belts, E motor, end stops and power supply. I replaced the rest with 4 17HS16-2004S motors (X/Y/Z) and the DuetWifi. I also re-wired it from head to toe to make sure the gauge is correct etc. Now that I finally have it all back together it fires up and moves around. The problem is that I can home it, level the bed (no z probe yet till I can print the mount) and everything looks great… but as soon as I go to print anything from Cura using the previous printer settings (which Z height etc should be the same) or from Simplify3D, as soon as it goes to print it seems to dive lower than the homed Z setting and has unfortunately dug some nasty scratches into the bed.
Is there a gcode I am missing somewhere or a config somewhere I did wrong? My motor settings are:

; Drives
M569 P0 S1                                                                 ; Drive 0 goes forwards
M569 P1 S1                                                                 ; Drive 1 goes forwards
M569 P2 S0                                                                 ; Drive 2 goes backwards
M569 P3 S0                                                                 ; Drive 3 goes backwards
M350 E16 I0                                                                ; Configure microstepping without interpolation
M350 X16 Y16 Z16 I1                                                        ; Configure microstepping with interpolation
M92 X80 Y80 Z400 E100                                                      ; Set steps per mm
M566 X900 Y900 Z12 E120                                                    ; Set maximum instantaneous speed changes (mm/min)
M203 X12000 Y12000 Z1200 E3000                                             ; Set maximum speeds (mm/min)
M201 X1000 Y1000 Z100 E5000                                                ; Set accelerations (mm/s^2)
M906 X1800 Y1800 Z1800 E855 I30                                            ; Set motor currents (mA) and motor idle factor in per cent
M84 S30                                                                    ; Set idle timeout

; Axis Limits
M208 X0 Y0 Z0 S1                                                           ; Set axis minima
M208 X200 Y200 Z180 S0                                                     ; Set axis maxima

; Endstops
M574 X1 Y1 Z1 S0                                                           ; Set active low endstops

; Z-Probe
M558 P0 H5 F120 T6000                                                      ; Set Z probe type to switch and the dive height + speeds
G31 P500 X0 Y0 Z2.5                                                        ; Set Z probe trigger value, offset and trigger height
M557 X25:175 Y25:175 S20                                                   ; Define mesh grid

I know the lead screws are a TR8x8 so I got 400 for my steps/mm. Belt pulley is a 20T 2mm pitch. Am I missing something?

Those are good too. In fact even though the shaft is a little longer than what I have for the stock gantry they should work too.. I'll order some! Thanks DC!

Thanks dc42, your assistance in this forum has been fantastic!

I like to build my stuff better than worse, so the fans are being built with the future in mind. Hoping that when I go to the CoreXY it will be an easy move, just a change to the mounting plate. The case will also have slots for the WiFi antenna, SD card and reset button.
Since the original printer is a 24V, its been funky with finding many who have done this conversion if any while keeping the stock parts. With my eye on the future, what are your favorite motors to pair with the DuetWifi? I may just replace the Z's now if they can stay the same size and fit into the gantry. I was thinking of 2 JK42HS40-1704 which would have 1.7A per motor and should fit into the next printer easily.

Hi all… newbie here. Got my first printer a couple weeks back and have been hooked on modifying it ever since. Talked the wife into letting me buy the Maker Select Plus and i dont think she knew I would start tearing into it like I have been. Hoping to get some validation on some ideas from the great folks here as well to make sure I am not going down the wrong path.
Original printer: Maker Select Plus 3D
Thoughts: Good printer but not great. After lots of non stop printing the print bed became warped with a wicked frown. This led me to try and figure out ways of leveling it. I also felt like the extruder was lacking so I replaced it with a Flexion. In my extended research I came across lots of praise of the Duet products and my brain started going crazy. I saw they also worked with a BLTouch and I just had to have one.

Path going forward:
I am stripping the electronics out of the 3P and replacing the controller with the DuetWifi. I also ordered and will be using the PanelDue 7i since I couldnt find much in the way of keeping the existing touch LCD without writing firmware, which felt like more work than it was worth. I will be adding some drag chain guides as well for cable management and as mentioned the BLTouch for the Z.
Eventually I would like to build a CoreXY box with a bigger print area and some better motors, but for the time being this is what I have.

So.. question 1 should be easy. Will these steppers work ok? Ive seen documentation about the steppers being a minimum of 1.2a and these seem shy of that.
E/X/Y - C17HD40102-01N - 1.02a?
Z - C17HD6039-06N - .39a? (seems really low)

Also I came up with the vref (using the duet's .051 resistors) as:
E/X/Y - .41616
Z - .15912

Now with the DuetWifi its recommended to run the Z in series with the plugs which I plan to do. Other systems they double the voltage to Z so i am guessing that with them being in serial I can just leave it at the 90% of .15912.

As for the BLTouch I have seen a couple threads on hooking them up so I should be OK there. I will run the wire ahead of time and just not connect them till I have the mount printed. The mount I have chosen will be mounted to the back side of the extruder bearing guide. Id rather have it as close as possible to the nozzle but with the fans and motor, this seems best. Otherwise I have to build a mount for the second blower to mount to the back of the bearing guide and do the BLTouch to the front but that may push it too far forward on the Y.

Second question is about the speed of the motors after this upgrade. With stock they claimed 150mms which was way too fast for their controller it seemed. I had run normally at:
Print: 40
Infill: 50
Travel: 80
Initial: 20
Would the upgraded controller and drivers allow a faster yet still quality print?
Any other suggestions? I am hoping to start wiring it all up starting next week. I need to get some wire connectors still.

Oh and I am going to start also designing a "case" for the LCD and DuetWifi. I am thinking I can build it to fit the front of the 3P and mount to the two screws in the faceplate. It will have 2x25mm fans to blow down the back of the Duet for cooling and hopefully it should be only about 70-80mm thick in total, depending on clearance for the LCD so not terrible.