egr Archives - UnderhoodService
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.

Diagnosing Driveability Problems

Understanding what comes out through the exhaust valve is critical to solving any emissions or driveability problem.

Chasing The Perfect Combustion Event

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

VIDEO: Why Do Diesel Engines Need EGR?

Doug Kaufman discusses diesel engines and why even modern engines need an EGR system. Sponsored by Blue Streak.

EGR And Secondary Air Injection And Emissions Management

The perfect internal combustion vehicle would be able to put the exact amount of fuel and air into the combustion chamber. If the perfect combustion event were to occur, you would get nothing more than water and carbon dioxide as byproduct. There would not be any unburned fuel or oxygen. Combustion would occur at the right temperature so oxides would not combine with nitrogen and carbon to form nitric oxides (NOx) and carbon monoxide (CO). This perfect car would not need a catalytic converter or any other emission-control device.

VIDEO: 3 Tips For A Leak-Free EGR Valve Gasket Installation

Learn how to achieve a leak-free EGR Valve Gasket with 3 simple tips! Watch Andrew Markel in this week’s Maintenance Minute as he stresses cleanliness during the replacement of the gasket. Sponsored by MAHLE.

Evaporative Vapor Emissions Control

These EVAP monitors can be run in two different ways. Ford, GM and some Asian imports use a vacuum to run the monitor. Chrysler, most European and a few Asian products use pressure to run the monitors.

Diesel Exhaust Particulate Filters: How Do They Work, What Do They Do?

The Diesel Particulate Filter (DPF) is a ceramic filter that has thousands of tiny channels or honeycomb-shaped openings that trap the soot onto the channel walls and prevent the particulate matter (down to 1 micron) from exiting out the tailpipe. The honeycombed inner structure is covered with a layer of a chemical catalyst that contains small amounts of precious metals, usually platinum or palladium.

GM: Exhaust Smell in Cabin: Codes P0299 and P2263

Some owners may complain of an exhaust smell in the cabin and reduced engine power. Under acceleration, a hissing or whistling noise can be heard coming from under the hood. Also, codes P0299 and/or P2263 are present.

VIDEO: Lean Codes On EGR Valves

Andrew Markel discusses a diagnostic solution when a vacuum leak appears that can’t be pinned down. Sponsored by Auto Value and Bumper to Bumper.

Ford EGR-ESM Diagnosis

The EGR system module (ESM) is one of Ford’s latest EGR system for gasoline engines. It is an EGR valve, EVR, MAP and DPFE sensor rolled into one package. Though the DPFE sensor on an ESM is referred to as “DPFE” by the scan tool and also wiring diagrams, it is not a traditional DPFE sensor as used on the older EGR system. It is actually two separate MAP sensors.

egr esm 2