Ford D5FZ-9D473-B Valve Assy - EGR Vacuum Control

For fuel economy purposes designers make adjustments to air/fuel ratios in cruise mode. When people mix lean, the combustion temperatures become high and generate pollutants like NOx. To control NOx during lean cruise modes, the EGR system reintroduces small quantities of exhaust gas into the intake manifold. It is the EGR valve that joins the exhaust system to the intake manifold, which is controlled by a vacuum-activated diaphragm. The F-series and Bronco vehicles have three different types of EGR systems, conventional ported vacuum, integral backpressure valve, and Electronic EGR (EEGR) system. The early non-U.S models used ported vacuum valves while early U.S carbureted models used integral backpressure valves.

The valves and components in the emission control system control exhaust gas recirculation (EGR) in vehicles. Its operation is based on a ported vacuum, which provides an ideal EGR signal during part-throttle and cruise conditions. BP valve modulates the flow of EGR using ported vacuum and exhaust back pressure. An electronic EGR valve controlled by a position sensor is used for EEGR. Troubleshooting entails dealing with issues affecting drivability, failed smog certifications or warning lights on the dashboard. The self-check function generates Diagnostic Trouble Codes (DTCs) to facilitate diagnosis. Vacuum testing, leakage tests, functional tests, and resistance measurements constitute some of the checks that need to be done on these systems.

The EGR valve is located on the intake manifold, adjacent to the carburetor. The majority of the time, when a fault develops in this emissions system it is due to a stuck or corroded EGR valve. With the engine cold to prevent burns, remove the EGR valve. Using moderate pressure, manually push the valve diaphragm up and down within the housing. If the diaphragm does not move or moves only with much effort, replace the EGR valve with a new one. If you are in doubt about the condition of the valve, obtain a new valve and compare the free movement between the two. Further information on EGR system can be found in the related materials.

The EGR valve is located on the intake manifold, adjacent to the carburetor. The majority of the time, when a fault develops in this emissions system it is due to a stuck or corroded EGR valve. With the engine cold to prevent burns, remove the EGR valve. Using moderate pressure, manually push the valve diaphragm up and down within the housing. If the diaphragm does not move or moves only with much effort, replace the EGR valve with a new one. If you are in doubt about the condition of the valve, obtain a new valve and compare the free movement between the two. Further information on EGR system can be found in the related materials.

Monitor idle speed with the IAC solenoid disconnected and apply vacuum to the EGR valve. If idle speed drops significantly, the EGR valve is functional. Otherwise, inspect for blockages or replace the valve.

The three types of EGR valves are the ported valve, the integral backpressure valve, and the electronic type.