Continental 2000-2002

Exhaust Gas Recirculation (EGR) System

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Description & Operation



The Exhaust Gas Recirculation (EGR) system is designed to reintroduce exhaust gas into the combustion cycle, thereby lowering combustion temperatures and reducing the formation of nitrous oxide. This is accomplished by the use of an EGR valve that opens under specific engine operating conditions, to admit a small amount of exhaust gas into the intake manifold, below the throttle plate. The exhaust gas mixes with the incoming air charge and displaces a portion of the oxygen in the air/fuel mixture entering the combustion chamber. The exhaust gas does not support combustion, but it takes up volume, the net effect is to lower the temperature of the combustion chamber. There are a few different EGR systems used.

The most commonly used system is the Pressure Feedback Electronic (PFE) system. The PFE is a subsonic closed loop EGR system that controls EGR flow rate by monitoring the pressure drop across a remotely located sharp-edged orifice. The system uses a pressure transducer as the feedback device and controlled pressure is varied by valve modulation using vacuum output of the EGR Vacuum Regulator (EVR) solenoid. With the PFE system, the EGR valve only serves as a pressure regulator rather than a flow-metering device.

The Differential Pressure Feedback Electronic (DPFE) EGR system operates in the same manner except it directly monitors the pressure drop across the metering orifice. This allows for a more accurate assessment of EGR flow requirements.



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Fig. Pressure Feedback Electronic (PFE) EGR system schematic



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Fig. Differential Pressure Feedback Electronic (DPFE) EGR system schematic

The Electronic EGR (EEGR) valve system is used on some vehicles equipped with the 5.0L engine. An electronic EGR valve is required in EEC systems where EGR flow is controlled according to computer demands by means of an EGR Valve Position (EVP) sensor attached to the valve. The valve is operated by a vacuum signal from the electronic vacuum regulator that actuates the valve diaphragm. As supply vacuum overcomes the spring load, the diaphragm is actuated. This lifts the pintle off of its seat allowing exhaust gas to recirculate. The amount of flow is proportional to the pintle position. The EVP sensor mounted on the valve sends an electrical signal of its position to the PCM.



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Fig. Electronic EGR (EEGR) system schematic

The Pressure Feedback Electronic (PFE) EGR Transducer converts a varying exhaust pressure signal into a proportional analog voltage that is digitized by the PCM. The PCM uses the signal received from the PFE transducer to compute the optimum EGR flow.

The EGR Vacuum Regulator (EVR) is an electromagnetic device that controls vacuum output to the EGR valve. The EVR replaces the EGR solenoid vacuum vent valve assembly. An electric current in the coil induces a magnetic field in the armature. The magnetic field pulls the disk back, closing the vent and increasing the vacuum level. The vacuum source is either manifold or ported vacuum. As the duty cycle is increased, an increased vacuum signal goes to the EGR valve.



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Fig. View of the EGR system components-late model 3.8L engine shown

Removal & Installation



DPFE Sensor


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Fig. Detach the connector for the DPFE sensor



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Fig. Matchmark and remove the vacuum hoses for the DPFE sensor and . . .



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Fig. . . . remove the retaining nuts from the DPFE sensor and . . .



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Fig. . . . remove the DPFE sensor from the intake manifold



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Fig. Location of PFE sensor. Also note the EGR valve behind it. Lubricating the fasteners before removal

  1. Disconnect the negative battery cable.
  2.  
  3. Label and disconnect the wiring harness from the DPFE sensor.
  4.  
  5. Label and disconnect the vacuum hoses.
  6.  
  7. Remove the mounting screws and remove the DPFE sensor.
  8.  

To install:

  1. Position the DPFE sensor and tighten the mounting screws.
  2.  
  3. Attach all necessary hoses and wiring to the sensor.
  4.  
  5. Connect the negative battery cable.
  6.  

EGR Valve
3.8L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Detach the vacuum line(s) and/or electrical connector(s) from the EGR valve.
  4.  
  5. Remove the mounting bolts, then remove the EGR valve. Remove all old gasket material.
  6.  

To install:

  1. Using a new gasket, install the EGR valve, then secure using the retaining bolts.
  2.  
  3. Attach any vacuum lines or electrical connectors disengaged during removal.
  4.  
  5. Connect the negative battery cable.
  6.  

4.6L Engines


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Fig. Remove the vacuum hose from the EGR valve



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Fig. On the 4.6L engine, remove the nut and the brake booster bracket from the EGR mounting stud



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Fig. Using a suitable size wrench, loosen the EGR valve-to-exhaust manifold tube and . . .



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Fig. . . . remove the tube from the EGR valve



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Fig. Remove the EGR valve mounting bolts and . . .



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Fig. . . . remove the EGR valve from the intake manifold



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Fig. Remove the EGR valve gasket and . . .



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Fig. . . . thoroughly clean the EGR valve mounting surface

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the vacuum hose from the EGR valve.
  4.  
  5. On the 4.6L engine, remove the nut and the brake booster bracket.
  6.  
  7. Disconnect the EGR valve-to-exhaust manifold tube from the EGR valve.
  8.  
  9. Remove the EGR valve mounting bolts, then separate the valve from the intake manifold.
  10.  
  11. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
  12.  

To install:

  1. Install the EGR valve, along with a new gasket, on the intake manifold, then install and tighten the mounting bolts.
  2.  
  3. Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 25-35 ft. lbs. (34-47 Nm).
  4.  
  5. Connect the vacuum hose to the EGR valve.
  6.  
  7. On the 4.6L engine install the brake booster bracket and the retaining nut.
  8.  
  9. Connect the negative battery cable.
  10.  

5.0L Engine
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner outlet tube.
  4.  
  5. Detach the EVP sensor connector.
  6.  
  7. Disconnect the EGR valve-to-exhaust manifold tube from the EGR valve.
  8.  
  9. Remove the vacuum hose from the EGR valve.
  10.  
  11. Remove the EGR valve mounting bolts, then separate the valve from the intake manifold.
  12.  
  13. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
  14.  

To install:


NOTE
If replacing the EGR valve, transfer the EVP sensor onto the new valve.

  1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts.
  2.  
  3. Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 25-35 ft. lbs. (34-47 Nm).
  4.  
  5. Connect the vacuum hose to the EGR valve.
  6.  
  7. Attach the EVP sensor connector.
  8.  
  9. Install the air cleaner outlet tube.
  10.  
  11. Connect the negative battery cable.
  12.  

EGR Valve Control Solenoid


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Fig. Detach the connector for the EVR solenoid



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Fig. Match mark the vacuum hoses for the EVR solenoid and . . .



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Fig. . . . remove the vacuum hoses from the EVR solenoid



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Fig. Remove the retaining nut for the solenoid and . . .



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Fig. . . . remove the solenoid from the intake manifold

  1. Disconnect the negative battery cable.
  2.  
  3. Label and detach the vacuum hoses from the EVR solenoid.
  4.  
  5. Detach the electrical connector from the solenoid.
  6.  
  7. Remove the retaining hardware, and remove the solenoid.
  8.  

To install:

  1. Position the solenoid and install the retaining hardware.
  2.  
  3. Attach the main emission vacuum control connector and the wiring harness connector to the EVR solenoid.
  4.  
  5. Connect the negative battery cable.
  6.  

Testing




NOTE
Many of the following testing procedures require the use of a breakout box tool for EEC systems diagnosis. SUPER STAR II tester or NEW GENERATION STAR (NGS) tester or equivalent scan tools.

DPFE Sensor
  1. Disconnect the pressure hoses at the DPFE sensor.
  2.  
  3. Connect a hand vacuum pump to the downstream pickup marked REF on the sensor.
  4.  
  5. Using a multimeter, backprobe the SIG RTN circuit at the DPFE connector.
  6.  
  7. With the ignition ON , signal voltage should be 0.20-0.70 volts.
  8.  
  9. Apply 8-9 in. Hg of vacuum to the sensor. Voltage should be greater than 4 volts.
  10.  
  11. Quickly release the vacuum from the sensor. Voltage should drop to less than 1 volt in 3 seconds.
  12.  
  13. If the sensor does not respond as specified, check the power and ground circuits.
  14.  
  15. If power and ground circuits are functional, the sensor is faulty.
  16.  

EGR Valve
  1. Install a tachometer on the engine, following the manufacturer's instructions.
  2.  
  3. Detach the engine wiring harness connector from the Idle Air Control (IAC) solenoid.
  4.  
  5. Disconnect and plug the vacuum supply hose from the EGR valve.
  6.  
  7. Start the engine, then apply the parking brake, block the rear wheels and position the transmission in Neutral.
  8.  
  9. Observe and note the idle speed.
  10.  


NOTE
If the engine will not idle with the IAC solenoid disconnected, provide an air bypass to the engine by slightly opening the throttle plate or by creating an intake vacuum leak. Do not allow the idle speed to exceed typical idle rpm.

  1. Using a hand-held vacuum pump, slowly apply 5-10 in. Hg (17-34 kPa) of vacuum to the EGR valve nipple.
    1. If the idle speed drops more than 100 rpm with the vacuum applied and returns to normal after the vacuum is removed, the EGR valve is OK.
    2.  
    3. If the idle speed does not drop more than 100 rpm with the vacuum applied and return to normal after the vacuum is removed, inspect the EGR valve for a blockage; clean it if a blockage is found. Replace the EGR valve if no blockage is found, or if cleaning the valve does not remedy the malfunction.
    4.  

  2.  

EGR Valve Control Solenoid
  1. Remove the EVR solenoid.
  2.  
  3. Attempt to lightly blow air into the EVR solenoid.
    1. If air blows through the solenoid, replace the solenoid with a new one.
    2.  
    3. If air does not pass freely through the solenoid, continue with the test.
    4.  

  4.  
  5. Apply battery voltage (approximately 12 volts) and a ground to the EVR solenoid electrical terminals. Attempt to lightly blow air, once again, through the solenoid.
    1. If air does not pass through the solenoid, replace the solenoid with a new one.
    2.  
    3. If air does not flow through the solenoid, the solenoid is OK.
    4.  

  6.  
  7. If the solenoid is functional but the problem still exists, check the power and ground circuits.
  8.  

 
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