diff --git a/firmware/controllers/algo/accel_enrichment.cpp b/firmware/controllers/algo/accel_enrichment.cpp
index 7c70af06a0..6d5de927df 100644
--- a/firmware/controllers/algo/accel_enrichment.cpp
+++ b/firmware/controllers/algo/accel_enrichment.cpp
@@ -48,6 +48,7 @@ void WallFuel::resetWF() {
 
 //
 floatms_t WallFuel::adjust(int injectorIndex, floatms_t desiredFuel DECLARE_ENGINE_PARAMETER_SUFFIX) {
+	invocationCounter++;
 	if (cisnan(desiredFuel)) {
 		return desiredFuel;
 	}
@@ -287,6 +288,8 @@ void TpsAccelEnrichment::onEngineCycleTps(DECLARE_ENGINE_PARAMETER_SIGNATURE) {
 	// we update values in handleFuel() directly
 	//onNewValue(getTPS(PASS_ENGINE_PARAMETER_SIGNATURE) PASS_ENGINE_PARAMETER_SUFFIX);
 
+	onUpdateInvocationCounter++;
+
 	// we used some extra fuel during the current cycle, so we "charge" our "acceleration pump" with it
 	accumulatedValue -= maxExtraPerPeriod;
 	maxExtraPerPeriod = maxF(maxExtraPerCycle, maxExtraPerPeriod);
diff --git a/firmware/controllers/algo/accel_enrichment.h b/firmware/controllers/algo/accel_enrichment.h
index 2020643010..5036345729 100644
--- a/firmware/controllers/algo/accel_enrichment.h
+++ b/firmware/controllers/algo/accel_enrichment.h
@@ -30,6 +30,7 @@ public:
 	void setLength(int length);
 	cyclic_buffer<float> cb;
 	void onNewValue(float currentValue DECLARE_ENGINE_PARAMETER_SUFFIX);
+	int onUpdateInvocationCounter = 0;
 };
 
 class LoadAccelEnrichment : public AccelEnrichment {
@@ -75,6 +76,7 @@ public:
 	floatms_t adjust(int injectorIndex, floatms_t target DECLARE_ENGINE_PARAMETER_SUFFIX);
 	floatms_t getWallFuel(int injectorIndex) const;
 	void resetWF();
+	int invocationCounter = 0;
 private:
 };
 
diff --git a/unit_tests/main.cpp b/unit_tests/main.cpp
index aa1b950b9a..9ca3b7160c 100644
--- a/unit_tests/main.cpp
+++ b/unit_tests/main.cpp
@@ -41,7 +41,7 @@ GTEST_API_ int main(int argc, char **argv) {
 //	printTriggerDebug = true;
 
 	//	resizeMap();
-	printf("Success 20191013\r\n");
+	printf("Success 20191016\r\n");
 	printAllTriggers();
 //	printConvertedTable();
 	testing::InitGoogleTest(&argc, argv);
diff --git a/unit_tests/tests/test_accel_enrichment.cpp b/unit_tests/tests/test_accel_enrichment.cpp
index 993b55a836..00f51cfbfe 100644
--- a/unit_tests/tests/test_accel_enrichment.cpp
+++ b/unit_tests/tests/test_accel_enrichment.cpp
@@ -1,6 +1,8 @@
 /**
  * @file	test_accel_enrichment.cpp
  *
+ * See also test_fuel_wall_wetting.cpp
+ *
  * @date Apr 29, 2014
  *  	Author: Dmitry Sidin
  *      Author: Andrey Belomutskiy, (c) 2012-2018
@@ -10,8 +12,9 @@
 #include "engine_configuration.h"
 #include "accel_enrichment.h"
 #include "engine_test_helper.h"
+#include "tps.h"
 
-TEST(fuel, testTpsAccelEnrichment) {
+TEST(fuel, testTpsAccelEnrichmentMath) {
 	printf("====================================================================================== testAccelEnrichment\r\n");
 
 	WITH_ENGINE_TEST_HELPER(FORD_ASPIRE_1996);
@@ -38,6 +41,40 @@ TEST(fuel, testTpsAccelEnrichment) {
 	ASSERT_EQ( 0,  engine->tpsAccelEnrichment.getMaxDelta(PASS_ENGINE_PARAMETER_SIGNATURE)) << "maxDelta";
 }
 
+TEST(fuel, testTpsAccelEnrichmentScheduling) {
+	WITH_ENGINE_TEST_HELPER(FORD_ASPIRE_1996);
+
+	setOperationMode(engineConfiguration, FOUR_STROKE_CRANK_SENSOR);
+	engineConfiguration->useOnlyRisingEdgeForTrigger = true;
+
+	eth.setTriggerType(TT_ONE PASS_ENGINE_PARAMETER_SUFFIX);
+
+	setMockTpsValue(7 PASS_ENGINE_PARAMETER_SUFFIX);
+
+	eth.fireTriggerEvents2(/* count */ 5, 25 /* ms */);
+	ASSERT_EQ( 1200,  GET_RPM()) << "RPM";
+	int expectedInvocationCounter = 1;
+	ASSERT_EQ(expectedInvocationCounter, ENGINE(tpsAccelEnrichment).onUpdateInvocationCounter);
+
+	setMockTpsValue(70 PASS_ENGINE_PARAMETER_SUFFIX);
+	eth.fireTriggerEvents2(/* count */ 1, 25 /* ms */);
+
+	float expectedAEValue = 29.2;
+	// it does not matter how many times we invoke 'getTpsEnrichment' - state does not change
+	for (int i = 0; i <20;i++) {
+		ASSERT_NEAR(expectedAEValue, ENGINE(tpsAccelEnrichment.getTpsEnrichment(PASS_ENGINE_PARAMETER_SIGNATURE)), EPS4D);
+	}
+
+	expectedInvocationCounter++;
+	ASSERT_EQ(expectedInvocationCounter, ENGINE(tpsAccelEnrichment).onUpdateInvocationCounter);
+
+	eth.engine.periodicFastCallback(PASS_ENGINE_PARAMETER_SIGNATURE);
+	eth.engine.periodicFastCallback(PASS_ENGINE_PARAMETER_SIGNATURE);
+	eth.engine.periodicFastCallback(PASS_ENGINE_PARAMETER_SIGNATURE);
+
+	ASSERT_EQ(expectedInvocationCounter, ENGINE(tpsAccelEnrichment).onUpdateInvocationCounter);
+}
+
 static void doFractionalTpsIteration(int period, int divisor, int numCycles, std::vector<floatms_t> &tpsEnrich DECLARE_ENGINE_PARAMETER_SUFFIX) {
 	// every cycle
 	engineConfiguration->tpsAccelFractionPeriod = period;
@@ -53,7 +90,7 @@ static void doFractionalTpsIteration(int period, int divisor, int numCycles, std
 	}
 }
 
-TEST(big, testAccelEnrichmentFractionalTps) {
+TEST(fuel, testAccelEnrichmentFractionalTps) {
 	printf("====================================================================================== testAccelEnrichmentFractionalTps\r\n");
 
 	WITH_ENGINE_TEST_HELPER(FORD_ASPIRE_1996);
diff --git a/unit_tests/tests/test_fuel_wall_wetting.cpp b/unit_tests/tests/test_fuel_wall_wetting.cpp
index 810960c9f5..1d2aad8e73 100644
--- a/unit_tests/tests/test_fuel_wall_wetting.cpp
+++ b/unit_tests/tests/test_fuel_wall_wetting.cpp
@@ -11,7 +11,7 @@
 #include "engine_test_helper.h"
 
 
-TEST(fuel, testWallWettingEnrichment) {
+TEST(fuel, testWallWettingEnrichmentMath) {
 	WITH_ENGINE_TEST_HELPER(FORD_ASPIRE_1996);
 
 	engineConfiguration->wwaeTau = 1.0f;
@@ -19,10 +19,31 @@ TEST(fuel, testWallWettingEnrichment) {
 
 	engine->rpmCalculator.setRpmValue(3000 PASS_ENGINE_PARAMETER_SUFFIX);
 
+	// each invocation of 'adjust' changes WallWetting internal state
 	ASSERT_NEAR(16.6666, ENGINE(wallFuel).adjust(0, 10.0 PASS_ENGINE_PARAMETER_SUFFIX), EPS4D);
-
-
 	ASSERT_NEAR(16.198, ENGINE(wallFuel).adjust(0, 10.0 PASS_ENGINE_PARAMETER_SUFFIX), EPS4D);
-
-
+}
+
+TEST(fuel, testWallWettingEnrichmentScheduling) {
+
+	WITH_ENGINE_TEST_HELPER(FORD_ASPIRE_1996);
+
+	setOperationMode(engineConfiguration, FOUR_STROKE_CRANK_SENSOR);
+	engineConfiguration->useOnlyRisingEdgeForTrigger = true;
+
+	eth.setTriggerType(TT_ONE PASS_ENGINE_PARAMETER_SUFFIX);
+
+
+	eth.fireTriggerEvents2(/* count */ 5, 25 /* ms */);
+	ASSERT_EQ( 1200,  GET_RPM()) << "RPM";
+
+	int expectedInvocationCounter = 4;
+	ASSERT_EQ(expectedInvocationCounter, ENGINE(wallFuel).invocationCounter);
+
+	eth.engine.periodicFastCallback(PASS_ENGINE_PARAMETER_SIGNATURE);
+	eth.engine.periodicFastCallback(PASS_ENGINE_PARAMETER_SIGNATURE);
+	eth.engine.periodicFastCallback(PASS_ENGINE_PARAMETER_SIGNATURE);
+
+	// still same 4 - wall wetting is NOT invoked from 'periodicFastCallback'
+	ASSERT_EQ(expectedInvocationCounter, ENGINE(wallFuel).invocationCounter);
 }