Repair 7

The EGR sensor is an automotive engine component designed to work with an exhaust gas recirculation system. Exhaust gas recirculation systems are part of many newer makes of automobiles, which must comply to more stringent environmental standards. The EGR sensor detects temperature and oxygen levels and determines whether the system is functioning properly.

Benefits

An EGR system offers two primary benefits to an automobile engine. The primary benefit is a reduced level of environmentally damaging emissions. The second benefit is a more efficient use of fuel, leading to better energy efficiency and more thorough combustion.

How EGR Systems Improve Engine Systems

An automotive engine without an EGR system releases gaseous emissions with hydrocarbon waste that has not been fully consumed by the combustion process. An EGR system recycles this partially combusted waste gas back into the combustion system to be used a second time for an overall cleaner emission.

EGR Sensor Warning

An EGR sensor fault warning on the vehicles indicator panel can indicate either that the sensor itself is damaged or that the exhaust gas recirculation system is not functioning within factory designated parameters. The best way to tell the difference between the two potential problems is to take the vehicle in for maintenance and have the sensor replaced.

The exhaust gas recirculation (EGR) system is used in car engines to reduce exhaust emissions. Though EGR problems are often blamed on the EGR valve, its the tube that can become clogged and will require cleaning.

How It Works

The EGR system works by allowing a small amount of exhaust to return to the combustion chamber. The gases cause a reduction in ignition temperature, which prevents the formation of NOx and other pollutants. The EGR system uses a valve that opens and closes to maintain the proper temperature.

Components

The primary component of the EGR system is the valve. Valves can be controlled either by vacuum pressure or electronics. When the gas is needed to cool combustion, the valve is opened. The exhaust gases move through the open valve and pass through a small tube or channel back to the intake manifold.

Tube Cleaning

The exhaust gases often carry small particles. These particles can become deposited inside the EGR valve or tube and clog the system causing it to fail. EGR tube cleaning simply ers to the process of cleaning this sediment from the tube. Most sediment will accumulate in the tube near the valve and can be removed with a small wire. Larger deposits will require the manifold to be removed for cleaning.

Although not essential, all modern gasoline automobile engines depend on exhaust gas recirculation or EGR valves to reduce toxic nitrogen oxides from emissions. The removal of EGR valves, while long debated, has not been shown to have any performance benefits.

Function

Dangerous nitrogen oxide gases form when gasoline combustion chambers reach temperatures in excess of 2500 degrees Fahrenheit. To combat this, the EGR valve was introduced in 1973 by General Motors to recirculate exhaust gases into the combustion chamber, drastically reducing temperatures and the formation of nitrogen oxides. EGR valves do not function at idle or wide open throttle and generally increase fuel economy and performance.

Disconnecting the EGR Valve

For some, the benefit of more engine bay space is enough to make removing the EGR valve worthwhile. In order to do so without interferring with engine operation, the engines electronic control module (ECM) must be set to never activate the missing EGR. Additionally, an EGR plate must be installed to cover the hole in the intake manifold where the EGR valve was installed.

Considerations

On most cars a missing EGR valve will cause the vehicle to fail emissions testing because of a tripped check engine code and the presence of heightened levels of nitrogen oxides.

The exhaust gas recirculation, or EGR, valve is a device attached to your intake manifold that recirculates approximately 10 percent of exhaust emission gases back into the intake manifold. This is supposed to lower the amount of nitrous oxide gases that are produced and emitted by your vehicle, while also minimizing overall emissions. EGR valves are installed on both gasoline and diesel engines. By improving your EGR valves performance, you may also be able to improve your vehicles overall performance.

Instructions

1

Use high quality fuel. Exhaust gas recirculation valves are most commonly damaged by debris, particles and carbon build up that occurs when fuels do not burn cleanly in the engine. These particles are then sent back through the EGR valve and into the engine. The better quality fuel you use, the fewer of these particles there will be, and the more efficiently you can expect your vehicles EGR valve to work.

2

Turn off your vehicle instead of allowing it to idle for long periods of time, especially if it is a diesel. Idling wastes fuel, and creates particles that will build up and clog your EGR valve in the process, shortening its lifespan.

3

Clean your EGR valve periodically so it does not become clogged and affect performance. The EGR valve becomes clogged by the particles that are created when fuel is used by the engine. A clogged EGR valve will negatively affect your engine and may cause a rough idle or stalling problems. You can unbolt your EGR valve from the intake manifold and clean it periodically. If the build up and debris is severe or the EGR valve is more than 10 years old, you may want to replace it.

The Exhaust Gas Recirculation (EGR) valve on the 2000 Ford Explorer is an important part of the engine emissions system. The EGR valve allows a precisely metered amount of exhaust gas to be circulated back to the combustion chamber. This introduction of exhaust gas into the cylinder allows the engine to achieve combustion at a lower temperature, leading to the creation of fewer smog-related emissions. If the EGR valve is not functioning properly, it can lead to misfires, rough idle, stalling, and failed emissions tests. Fortunately, the EGR valve is easily replaced using basic hand tools.

Instructions

1

Park the Explorer on flat, level ground with the parking brake fully engaged. Raise the hood by pulling the release handle located under the steering column and then pulling up on the lever located under the center of the hood while lifting the hood. Disconnect the negative battery cable with a pair of pliers or open-ended wrench. The EGR valve is located above, and slightly in front of, the exhaust manifold on the drivers side of the engine. The EGR valve is a flat metal disc with a small rubber hose attached to the top and a larger metal pipe running from the bottom of the valve to the exhaust manifold.

2

Remove the small rubber hose from the top of the EGR by gently pulling straight up on the rubber fitting. Unscrew the metal pipe from the bottom of the EGR using an open-ended or adjustable wrench. Remove the two bolts holding the EGR valve to the engine. Remove the valve from the engine.

3

Clean any remaining gasket material from the EGR valve mating surface using a plastic putty knife.

4

Install a new EGR gasket on the mating surface using gasket sealer to hold it in place. Attach the new EGR valve to the engine using new bolts and tighten the bolts to 15 foot-pounds. Reconnect and securely tighten the metal pipe to the bottom of the valve and slide the rubber fitting back onto the top of the valve.

5

Reconnect the negative battery terminal and close the hood.

A cars engine depends on a balanced ratio of fuel and air for proper combustion and sufficient horsepower. A faulty exhaust gas recirculation (EGR) valve affects the functioning of the mass air flow (MAF) sensor for an engines air flow.

Identification

The EGR valve allows a small quantity of exhaust gas from the combustion chamber into the engines intake manifold, resulting in a cooling of combustion fumes. The MAF sensor, also known as the air flow meter, calculates the amount of air entering the engine for balancing with the fuel.

Effects

Typically, a faulty EGR valve leaks more gas into the engines intake manifold, which has a direct effect on the MAFs functioning. The MAF detects more gas or air within the system and automatically adds more fuel to the mixture to balance the fuel-to-air ratio.

Significance

A faulty EGR valve requires immediate replacement. Aside from wasting excess fuel from an improper fuel-to-air ratio, a faulty EGR valve releases harmful emissions into the atmosphere.

The EGR valve of a Chrysler Sebring regulates the flow of air from the exhaust to the intake system in order to control the air temperature and the amount of nitrogen. A faulty EGR valve will result in poor combustion and engine knock, causing the car to rattle or misfire. Because they are calibrated together, the EGR valve and transducer are sold together and must be installed as a set. While the 1998 Sebring has two different locations for the EGR valve, depending on the type of engine, replacing it is a DIY job that will dramatically improve vehicle performance.

Instructions

1

Raise the car hood and disconnect the negative battery terminal. If your 1998 Sebring has a 2.0- or 2.4-liter engine, the EGR valve is located behind the cylinder head, so remove the large tube connecting the air intake to the air filter for added clearance. On the 2.5-liter engine, the EGR valve is to the left of the positive battery terminal, so remove the transmission control module (TCM) for clearance. The TCM is located to the left of the engine fuse box, and the positive battery terminal is secured by a central retainer and retaining screws.

2

Remove the vacuum tubes and electrical connections from both the EGR valve and electrical transducer, including the line to the solenoid, making sure to label where each tube goes for reinstallation. Remove the metal EGR tube leading to the intake manifold and clean its mounting surface. Unfasten the bolts holding the EGR valve and transducer. Carefully remove each component.

3

Loosely connect the EGR tube with the new EGR valve, using new gaskets. Install the new EGR valve and transducer. Once the components are in place, tighten the screws on the EGR tube and any remaining loose bolts. Reconnect all of the vacuum tubes connecting the EGR valve, transducer and solenoid as labeled.

4

Reinstall any components that you removed for access and reconnect the negative battery terminal. Start the engine and carefully listen for a hissing sound that would indicate a vacuum leak. Correct any vacuum leaks, if necessary, using a small amount of gasket-making compound to seal connections.