The car drives strangely, consumption increased, but diagnostics show everything is clean? Most likely, your control unit is quietly fighting with a dying neutralizer. It changes the fuel mixture, trying to compensate for the drop in cleaning system efficiency, but in a way that a regular scanner won’t show anything. But you feel the changes every day behind the wheel.
How the System Tries to Deceive Oxygen Sensors
The electronic brain constantly analyzes lambda sensor readings before and after the ceramic gas cleaning block. When honeycombs get clogged or platinum coating degrades, the difference between readings decreases. The ECU perceives this as a signal: mixture is too lean. In response, it increases fuel supply, trying to “fix” the situation.
By the way, if the neutralizer is no longer coping, it’s not necessary to just throw it away. There are used catalytic converter for sale through platforms like Autocatalyst, where old elements are bought for extracting precious metals. There, you can also check approximate prices and understand how much you can realistically get for a worn-out component.
Signs of an Invisible Battle Between Sensors and Processor
The first thing attentive drivers notice is the floating idle speed. The engine either reaches 900, then drops to 650, as if searching for a stable point. The system constantly corrects the mixture, reacting to distorted data from the second lambda sensor.
Here’s what else reveals the hidden conflict:
- Hesitation during acceleration in a narrow RPM range — usually between 2000 and 3000, when the ECU sharply leans the mixture, thinking the neutralizer is overloaded, although it’s simply clogged.
- Increased fuel consumption without visible reasons — the computer pours more gasoline, trying to raise the temperature in the cleaning system and “revive” chemical reactions that no longer occur.
- Hydrogen sulfide smell during warm-up — when the ceramic is destroyed, unburned sulfur particles pass further and give a characteristic rotten aroma.
These symptoms appear long before the Check Engine light comes on. The system can work in compensation mode for months before registering an error.
Consequences for the Engine
Constant operation on an over-enriched mixture kills spark plugs faster. Electrodes become covered with black carbon, and after 15-20 thousand kilometers, misfires begin. Piston rings also suffer — excess fuel washes away the oil film from cylinder walls.
If you’ve noticed such oddities, it’s worth checking the neutralizer, even if diagnostics are silent. Sometimes the problem is visible only through an oscilloscope when you look at the lambda sensor voltage in real time.
