Dual extruder retraction at start of print is excessive

[CoreXYZ]

I have installed a Chimera on my D-Bot and am trying to dial it in.

At the start of the print the T0 extruder retracts an excessive amount (10cm or so) which then jams the extruder.

Where should I be looking? I have each tool retracting at 1.75mm under the extruder tab and 3.00mm for tool change retraction under "Other" for both.

[brian442]

Those are the only settings that cause a retraction during the print, but if it's happening at the very beginning, the problem may be in your starting script.

[CoreXYZ]

Thanks for the insight.

The odd thing is only T0 is doing the retracting at the start (I've double checked settings for T0 and T1 and they are identical).

The starting script is simply G28 (home all)...nothing else.

On a single extruder setup the retraction does not happen.

[brian442]

Well you might want to actually look through the gcode for the first hundred lines of your print to see if you see any big "G1 E-XXX" commands that would be causing a big retraction. I know I have used firmwares in the past that did big retractions automatically when starting a print, usually because they had some type of 3-in-1 nozzle or something like that where it was required, but it's possible your firmware settings are causing the retraction too if you don't see anything in the gcode.