Emissions Archives - UnderhoodService
Domestic Gasoline Engine Oil Specifications

If it’s been more than a year since last oil change, the IOLM will display a reminder message, regardless of mileage.

Do Oxygen Sensors Generate Electricity?

They are made of zirconium oxide, a chemical compound used to form the sensor’s thermal-driven electrochemical fuel cell.

Talking To Customers About Oxygen Sensors

One of the toughest components to sell as a maintenance item, or even a replacement item, is an oxygen sensor.

Exhaust Gas Recirculation Operation and Diagnostics

Since exhaust gas does not burn, this lowers the combustion temperatures and reduces NOx emissions from the engine.

EGR, Secondary Air Injection And Emissions Management

EGR systems put a small amount of inert gas into the combustion chamber to control the temperatures.

EPA vs California Emissions Packages (VIDEO)

What’s the difference between EPA and California emissions packages? This video is sponsored by AP Emissions.

Checking Your Fuel (Video)

Fuel systems can have many possible issues to diagnose. This video is sponsored by AP Emissions.

Making Sure You Get A Strong Spark (Video)

Complete combustion requires strong spark at the right time with the right compression. Sponsored by AP Emissions.

VIDEO: Why Do Spark Plugs Have A Smaller Gap?

A tighter spark plug gap can increase power and reduce emissions. This video is sponsored by NGK and NTK.

Diesel Exhaust Fluid (DEF) Changes

Modern diesel exhaust systems are complex and they include multiple sub systems to keep exhaust clean.

Chasing The Perfect Combustion Event

The perfect internal combustion engine would put the exact amount of fuel and air into the combustion chamber.

Oxygen Sensor And Catalyst Efficiency

The catalyst efficiency monitor verifies that the catalytic converter is operating at a high enough efficiency rating to keep exhaust emissions within predetermined values. The PCM compares the signals from the upstream and downstream oxygen sensors to determine the state of the converter. These “tests” are called the readiness monitors.