General description
1. The EGR system is designed to return a small portion of the exhaust gas to the combustion cycle, thereby reducing nitrotoxins in emissions. The amount of exhaust gas reburned and the cycle time depend on various factors - engine speed, altitude, manifold vacuum, exhaust back pressure, coolant temperature and throttle angle. All EGR valves are vacuum actuated - a diagram of the vacuum lines for a specific vehicle is shown on the emission control information label in the engine compartment.
2. Tauras/Sables use two types of EGR valves: an electronic type used on four-cylinder engines, and an electronic pressure feed back (PFE) valve used on the California 3.0LV6 and 3.8LV6 engines.
Electronic EGR valve for four-cylinder engine
3. The electronic EGR valve controls the flow of exhaust gas using the EVP sensing element located at the top of the valve. The valve is actuated by a vacuum signal from the dual valves - EGR solenoids or an electronic vacuum regulator acting on the valve diaphragm. As soon as the vacuum suction overcomes the spring force, the diaphragm is activated, which lifts the valve from its seat and allows the exhaust gas to recirculate. The amount of gas released depends on the position of the valve. From the EVP sensing element, an electrical signal is transmitted to the ECA system indicating the position of the valve.
Electronic Pressure Feed EGR Valve (PFE)
4. PFE valve - same as EGR, only a sensitive back pressure tube is connected to it. The valve is used together with a pressure converter, which provides pressure feedback to the EEC-IV processor. The flow through the valve is proportional to the pressure drop at the outermost, sharp-edged holes.
5. Make sure all vacuum hoses are properly connected and securely fastened. Replace cracked, broken or deformed hoses.
6. Make sure that there is no vacuum at the EGR valve when idling and the engine is at normal operating temperature.
Note: The EVR solenoid on four cylinder engines has a constant internal leak. You will find a negligible vacuum signal (it will be less than 2 1/2 inches of mercury at idle).
7. Install the tachometer in accordance with the manufacturer's instructions.
8. If the vehicle has a V6 engine, remove the electrical connector from the bypass valve (see chapter 4).
9. Disconnect the vacuum supply hose from the lower EGR valve. Install a plug in the hose.
10. Set the gearbox to neutral, start the engine, warm it up and let it run at idle speed.
Note: Do not increase the engine idle speed. If it is too high or too low, it should be adjusted.
11. Attach a hand vacuum pump to the EGR valve vacuum nipple and slowly apply vacuum to 5-10 inHg.
12. The valve will need to be replaced if any of the following occurs when creating a vacuum in the EGR valve:
a) the engine will stall.
b) idle speed will drop by more than 100 rpm.
v) idle speed will not return to normal (±25 rpm) after the vacuum line is connected.
14. Disconnect the vacuum pump and connect the EGR valve vacuum line.
Replacement of elements
15. Disconnect the wire from the negative terminal of the battery.
16. On four-cylinder engines, remove the electrical connector from the EVR sensor socket in the EGR valve.
17. Using a wrench, unscrew the threaded tip connecting the tube and the EGR valve (see figure).
18. Unscrew the EGR valve mounting bolts (see pictures) and disconnect the valve and gasket from the intake manifold. Discard the old gasket.
19. If you are going to replace the EGR valve without replacing the EVR sensor on a four-cylinder engine, remove the sensor from the old valve (see section 2) and install it on the new valve.
20. Installation is carried out in the reverse order of disassembly. Make sure that the mating surfaces of the gasket are clean; use a new gasket for the valve.
Note: Apply anti-stick compound to the threaded surfaces of the EGR pipe.
[The material was copied from an information website FordBook.ru]