diff --git a/firmware/controllers/algo/event_registry.h b/firmware/controllers/algo/event_registry.h
index 64af3a7989..ef93f825f6 100644
--- a/firmware/controllers/algo/event_registry.h
+++ b/firmware/controllers/algo/event_registry.h
@@ -70,10 +70,9 @@ public:
 	 */
 	angle_t sparkAngle = NAN;
 	floatms_t sparkDwell = 0;
-	/**
-	 * this timestamp allows us to measure actual dwell time
-	 */
-	uint32_t actualStartOfDwellNt = 0;
+
+	// this timer allows us to measure actual dwell time
+	Timer actualDwellTimer;
 
 	float dwellAngle = 0;
 
diff --git a/firmware/controllers/engine_cycle/spark_logic.cpp b/firmware/controllers/engine_cycle/spark_logic.cpp
index e0ea2b2586..7915bc9e3a 100644
--- a/firmware/controllers/engine_cycle/spark_logic.cpp
+++ b/firmware/controllers/engine_cycle/spark_logic.cpp
@@ -208,11 +208,12 @@ void fireSparkAndPrepareNextSchedule(IgnitionEvent *event) {
 #if !EFI_UNIT_TEST
 if (engineConfiguration->debugMode == DBG_DWELL_METRIC) {
 #if EFI_TUNER_STUDIO
-	uint32_t actualDwellDurationNt = getTimeNowLowerNt() - event->actualStartOfDwellNt;
+	float actualDwellMs = event->actualDwellTimer.getElapsedSeconds(nowNt) * 1e3;
+
 	/**
 	 * ratio of desired dwell duration to actual dwell duration gives us some idea of how good is input trigger jitter
 	 */
-	float ratio = NT2US(actualDwellDurationNt) / 1000.0 / event->sparkDwell;
+	float ratio = actualDwellMs / event->sparkDwell;
 
 	// todo: smarted solution for index to field mapping
 	switch (event->cylinderIndex) {