diff --git a/firmware/controllers/algo/fuel/fuel_computer.cpp b/firmware/controllers/algo/fuel/fuel_computer.cpp
index 0f290566fa..4048ac1db2 100644
--- a/firmware/controllers/algo/fuel/fuel_computer.cpp
+++ b/firmware/controllers/algo/fuel/fuel_computer.cpp
@@ -28,11 +28,11 @@ mass_t FuelComputerBase::getCycleFuel(mass_t airmass, float rpm, float load) {
 float FuelComputer::getStoichiometricRatio() const {
 	float primary = engineConfiguration->stoichRatioPrimary;
 
-	// Config compatibility: this field may be zero on ECUs with old defaults
+
 	if (primary < 5) {
-		// todo: fatal in July of 2023
-		// 14.7 = E0 gasoline AFR
-		engineConfiguration->stoichRatioPrimary = primary = STOICH_RATIO;
+   	// Config compatibility: this field may be zero on ECUs with very old defaults
+		criticalError("Please set stoichRatioPrimary");
+		return 0;
 	}
 
 	// Without an ethanol/flex sensor, return primary configured stoich ratio
@@ -42,11 +42,10 @@ float FuelComputer::getStoichiometricRatio() const {
 
 	float secondary = engineConfiguration->stoichRatioSecondary;
 
-	// Config compatibility: this field may be zero on ECUs with old defaults
 	if (secondary < 5) {
-		// 9.0 = E100 ethanol AFR
-		// todo: fatal in July of 2023
-		engineConfiguration->stoichRatioSecondary = secondary = 9.0f;
+	  // Config compatibility: this field may be zero on ECUs with very old defaults
+		criticalError("Please set stoichRatioSecondary");
+		return 0;
 	}
 
 	auto flex = Sensor::get(SensorType::FuelEthanolPercent);