From 61591fd23369a03063a42f57a174c51f995c7efb Mon Sep 17 00:00:00 2001
From: studiodyne <42887851+studiodyne@users.noreply.github.com>
Date: Tue, 10 Oct 2023 00:50:09 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20Fix=20tool-change=20E=20prime=20?=
 =?UTF-8?q?(#26237)?=
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Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>
---
 Marlin/src/module/tool_change.cpp | 35 +++++++++++++++++++------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/Marlin/src/module/tool_change.cpp b/Marlin/src/module/tool_change.cpp
index 622877667d..b33b642966 100644
--- a/Marlin/src/module/tool_change.cpp
+++ b/Marlin/src/module/tool_change.cpp
@@ -940,19 +940,20 @@ void fast_line_to_current(const AxisEnum fr_axis) { _line_to_current(fr_axis, 0.
    *  sync_plan_position_e();
    */
   void extruder_cutting_recover(const_float_t e) {
-    if (!too_cold(active_extruder)) {
-      const float dist = toolchange_settings.extra_resume + toolchange_settings.wipe_retract;
-      FS_DEBUG("Performing Cutting Recover | Distance: ", dist, " | Speed: ", MMM_TO_MMS(toolchange_settings.unretract_speed), "mm/s");
-      unscaled_e_move(dist, MMM_TO_MMS(toolchange_settings.unretract_speed));
-      planner.synchronize();
-      FS_DEBUG("Set position to: ", e);
-      current_position.e = e;
-      sync_plan_position_e(); // Resume new E Position
-    }
+    if (too_cold(active_extruder)) return;
+
+    const float dist = toolchange_settings.extra_resume + toolchange_settings.wipe_retract;
+    FS_DEBUG("Performing Cutting Recover | Distance: ", dist, " | Speed: ", MMM_TO_MMS(toolchange_settings.unretract_speed), "mm/s");
+    unscaled_e_move(dist, MMM_TO_MMS(toolchange_settings.unretract_speed));
+
+    FS_DEBUG("Set E position: ", e);
+    current_position.e = e;
+    sync_plan_position_e(); // Resume new E Position
   }
 
   /**
    * Prime the currently selected extruder (Filament loading only)
+   * Leave the E position unchanged so subsequent extrusion works properly.
    *
    * If too_cold(toolID) returns TRUE -> returns without moving extruder.
    * Extruders filament = swap_length + extra prime, then performs cutting retraction if enabled.
@@ -966,6 +967,8 @@ void fast_line_to_current(const AxisEnum fr_axis) { _line_to_current(fr_axis, 0.
 
     feedRate_t fr_mm_s = MMM_TO_MMS(toolchange_settings.unretract_speed); // Set default speed for unretract
 
+    const float resume_current_e = current_position.e;
+
     #if ENABLED(TOOLCHANGE_FS_SLOW_FIRST_PRIME)
       /**
        * Perform first unretract movement at the slower Prime_Speed to avoid breakage on first prime
@@ -1010,6 +1013,10 @@ void fast_line_to_current(const AxisEnum fr_axis) { _line_to_current(fr_axis, 0.
       unscaled_e_move(-toolchange_settings.wipe_retract, MMM_TO_MMS(toolchange_settings.retract_speed));
     #endif
 
+    // Leave E unchanged when priming
+    current_position.e = resume_current_e;
+    sync_plan_position_e();
+
     // Cool down with fan
     filament_swap_cooling();
   }
@@ -1061,17 +1068,19 @@ void fast_line_to_current(const AxisEnum fr_axis) { _line_to_current(fr_axis, 0.
         }
       #endif
 
+      // Prime without changing E
       extruder_prime();
 
       // Move back
       #if ENABLED(TOOLCHANGE_PARK)
         if (ok) {
           #if ENABLED(TOOLCHANGE_NO_RETURN)
-            const float temp = destination.z;
-            destination = current_position;
-            destination.z = temp;
+            destination.x = current_position.x;
+            destination.y = current_position.y;
           #endif
-          prepare_internal_move_to_destination(TERN(TOOLCHANGE_NO_RETURN, planner.settings.max_feedrate_mm_s[Z_AXIS], MMM_TO_MMS(TOOLCHANGE_PARK_XY_FEEDRATE)));
+          do_blocking_move_to_xy(destination, MMM_TO_MMS(TOOLCHANGE_PARK_XY_FEEDRATE));
+          do_blocking_move_to_z(destination.z, planner.settings.max_feedrate_mm_s[Z_AXIS]);
+          planner.synchronize();
         }
       #endif