diff --git a/firmware/integration/rusefi_config.txt b/firmware/integration/rusefi_config.txt
index 3f9536e25b..73cf12f24c 100644
--- a/firmware/integration/rusefi_config.txt
+++ b/firmware/integration/rusefi_config.txt
@@ -1067,7 +1067,7 @@ custom maf_sensor_type_e 4 bits, S32, @OFFSET@, [0:1], @@maf_sensor_type_e_enum@
 	bit canWriteEnabled;enable can_write/disable can_write
 	bit useLinearIatSensor
 	bit useFSIO16ForTimingAdjustment;+See fsioTimingAdjustment
-	bit tachPulseDurationAsDutyCycle;+Treat milliseconds value as duty cycle value, i.e. 0.5ms would become 50%
+	bit tachPulseDurationAsDutyCycle,"Constant time","Duty cycle";+Treat milliseconds value as duty cycle value, i.e. 0.5ms would become 50%
 	bit isAlternatorControlEnabled;+This enables smart alternator control and activates the extra alternator settings.
 	bit invertPrimaryTriggerSignal;+This setting flips the signal from the primary engine speed sensor.
 	bit invertSecondaryTriggerSignal;+This setting flips the signal from the secondary engine speed sensor.
@@ -1174,7 +1174,8 @@ custom pin_mode_e 1 bits,    U08,   @OFFSET@, [0:6], @@pin_mode_e_enum@@
 	float[CRANKING_CURVE_SIZE] crankingTpsCoef;Cranking fuel correction coefficient based on TPS;"Ratio",      1,     0,      0.0,    700.0,   2
 	float[CRANKING_CURVE_SIZE] crankingTpsBins;;"%",        1,     0,    0.0,    100.0,  2
 	
-	float tachPulseDuractionMs;;"ms",        1,     0,    0.0,    100.0,  2
+! todo: rename field remove 'ms' since unusual case of dual-purpose field - it could be either ms or percent	
+	float tachPulseDuractionMs;;"",        1,     0,    0.0,    100.0,  2
 	int unused1708;;"units", 1, 0, -20, 100, 0
 	
 	float wwaeTau;+Length of time the deposited wall fuel takes to dissipate after the start of acceleration. ;"Seconds",        1,     0,    0.0,    3.0,  2
diff --git a/firmware/tunerstudio/rusefi.input b/firmware/tunerstudio/rusefi.input
index 0fe2067d03..c4cca87348 100644
--- a/firmware/tunerstudio/rusefi.input
+++ b/firmware/tunerstudio/rusefi.input
@@ -2901,7 +2901,7 @@ cmd_set_engine_type_default					= "@@TS_IO_TEST_COMMAND_char@@\x00\x31\x00\x00"
 	dialog = tachSettings, "Tachometer output"
 		field = "Pin",									tachOutputPin
 		field = "Pin mode",								tachOutputPinMode
-		field = "Pulse duration is duty cycle",			tachPulseDurationAsDutyCycle
+		field = "Pulse Mode",			                tachPulseDurationAsDutyCycle
 		field = "Pulse duration",						tachPulseDuractionMs
 		field = "Pulse per Rev",                        tachPulsePerRev