THE INTAKE PIPE BETWEEN THE INTERCOOLER AND THE INLET MANIFOLD KEEPS PRESSURISING AND PARTING WHEN CAR IS REVVED.WHY?, THE EGR BODY AND VALVE ,MANIFOLD AND LINK PIPE ARE CLEAN.

The EGR valve is a device that reduces the emissions of the engine by recirculating some of the exhaust gas back into the intake manifold. The EGR valve is located in the engine compartment, near the firewall on the driver's side. It is attached to a metal pipe that connects to the exhaust manifold. To access the EGR valve, you will need to remove the air intake hose, the throttle body, and the EGR tube.

Fig. 4: Exploded view of the EGR system and related components for the 4.0L engine (click over pic for zoom)

REMOVAL & INSTALLATION

PFE/DPFE Sensor
This component is found on all engines, and is also referred to as the backpressure transducer.

1. Disconnect the negative battery cable.
2. Detach and label the wiring harness connector from the PFE/DPFE sensor.
3. Disconnect all of the hoses from the sensor.
4. Remove the mounting nuts, then separate the sensor from the mounting bracket.
5. If necessary, remove the EVR solenoid and the PFE/DPFE mounting bracket from the upper intake manifold.

To install:

1. If removed, install the EVR solenoid and mounting bracket onto the upper intake manifold.
2. If applicable, install the EGR tube heat shield.
3. Position the PFE/DPFE sensor on the mounting bracket, then install and tighten the mounting nuts until snug.
4. Attach all necessary hoses and wiring to the sensor.
5. Connect the negative battery cable.

EGR Vacuum Regulator (EVR) Solenoid
The EVR solenoid is mounted either on the same bracket as the PFE/DPFE sensor, attached to the upper intake manifold, or near the EGR valve on its own bracket.

1. Disconnect the negative battery cable.
2. Label and detach the wiring harness connector from the EVR solenoid.
3. Detach the main emission vacuum control connector from the solenoid.
4. Remove the retaining nuts, then separate the solenoid from the mounting bracket.

To install:

1. Position the solenoid on its mounting bracket and install the retaining nuts.
2. Attach the main emission vacuum control connector and the wiring harness connector to the EVR solenoid.
3. Connect the negative battery cable.

EGR Valve
See Figures 6 and 7

1. Disconnect the negative battery cable.
2. If necessary, remove the air inlet tube from the throttle body and air cleaner housing.
3. Label and detach all vacuum hoses from the EGR valve.
4. Label and detach any electrical wiring harness connectors from the EGR valve.
5. Disconnect the EGR valve-to-exhaust manifold tube from the EGR valve.
6. Remove the EGR valve mounting fasteners, then separate the valve from the upper intake manifold.
7. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
   

Fig. 6: Cutaway view of a base entry type EGR valve

Fig. 7: Cutaway view of a side entry type EGR valve

To install:

1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 4-22 ft. lbs. (20-30 Nm) on 3.8L engines, or to 106-49 inch lbs. (1-18 Nm) on 5.0L engines.
2. Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 30 ft. lbs. (41 Nm).
3. Connect all wiring or hoses to the EGR valve.
4. Install the air inlet tube.
5. Connect the negative battery cable.

Hope this helps, good luck (remember to rate this comments).

3.8L Engine (most common) Upper Intake Manifold To Remove:

1. Drain the cooling system.
2. Remove or disconnect the following:
   • Negative battery cable.
   • Fuel injector sight shield.
   • Air cleaner intake duct.
   • Right spark plug wires from the ignition control module and reposition.
3. Relieve the fuel pressure.
4. Remove or disconnect the following:
   • Fuel rail assembly.
   • Brake booster hose from the vacuum source manifold in the upper intake manifold.
   • Exhaust Gas Recirculation Valve (EGR) wiring harness heat shield nut, bolt and the EGR heat shield.
   • Throttle body support bracket upper bolt.
5. Disconnect the electrical connectors from the following:
   • EVAP purge solenoid
   • Throttle Position (T/P) sensor
   • Idle Air Control (IAC) valve
   • Manifold Absolute Pressure (MAP) sensor
   • Mass Air Flow (MAF) sensor
   • EVAP purge solenoid vacuum line from the throttle body.
   • Accelerator and the cruise control cables with the bracket from the throttle body.
6. Remove or disconnect the following:
   • Upper intake manifold bolts and stud.
   • Clean the upper intake manifold bolt threads.
7. Remove or disconnect the following:
   • Upper intake manifold by lifting the back of the intake and sliding the manifold forward from the throttle body support bracket.
   • Upper-to-lower intake manifold carrier gasket from the upper intake manifold.
8. If the upper intake manifold is being replaced, remove the following:
   • Throttle body assembly.
   • Manifold Absolute Pressure (MAP) sensor.
   • Positive Crankcase Ventilation (PCV) valve.
   • Vacuum source manifold.

Upper intake manifold bolt torque sequence (3.8L engine)

To Install:

1. If the manifold was replaced, install or connect the following:
   • Vacuum source manifold.
   • Positive Crankcase Ventilation (PCV) valve.
   • Manifold Absolute Pressure (MAP) sensor.
   • Throttle body assembly.
   • Upper-to-lower intake manifold carrier gasket to the upper intake manifold.
2. Carefully place the upper intake manifold onto the lower intake manifold. Ensure that the alignment pins in the upper intake manifold align with the holes in the lower intake manifold. NOTE: Apply thread lock compound, to the bolt threads before assembly.
   
3. Install or connect the following:
   • Upper intake manifold. Tighten the upper intake manifold bolts in sequence to 89 in lbs (10 Nm)
   • Accelerator and the cruise control cables with the bracket to the throttle body.
   • EVAP purge solenoid vacuum line to the throttle body.
4. Connect the electrical connectors to the following:
   • Mass Air Flow (MAF) sensor
   • Manifold Absolute Pressure (MAP) sensor
   • Idle Air Control (IAC) valve
   • Throttle Position (T/P) sensor
   • EVAP purge solenoid
5. Install or connect the following:
   • Throttle body upper support bracket bolt. Tighten the bolt to 89 in lbs (10 Nm)
   • EGR valve wiring harness heat shield, nut and the bolt. Tighten the nut and the bolt to 89 in lbs (10 Nm)
   • Brake booster hose to the vacuum source manifold.
   • Fuel rail assembly.
   • Right spark plug wires.
   • Air cleaner intake duct.
   • Fuel injector sight shield.
6. Connect the negative battery cable.
7. Fill the cooling system.
8. Inspect for fluid or vacuum leaks.

Lower Intake Manifold (W/O Supercharger) To Remove:

1. Remove or disconnect the following:
   • Upper intake manifold.
   • Generator brace.
   • Drive belt tensioner with the mounting bracket and the heater water bypass inlet pipe.
   • Exhaust gas recirculation EGR outlet pipe bolt from the lower intake manifold.
   • Radiator inlet hose from the water outlet housing.
   • ECT sensor electrical connector.
   • Right upper engine mount strut bracket.
   • Generator brace bracket bolts.
   • Generator brace bracket.
   • Lower intake manifold bolts.
   • Lower intake manifold.
   • Lower intake manifold seals.
   • Lower intake manifold gaskets.
2. If replacing the lower intake manifold, Remove or disconnect:
   • Water outlet housing bolt and stud
   • Water outlet housing
   • Gasket and the thermostat.
   • ECT sensor.
3. Inspect the flatness of inlet flanges.
4. Clean the intake manifold mating surfaces.
5. Clean the intake manifold bolts and bolt holes of adhesive compound.

To Install:

1. If removed, install the ECT sensor.
   • Tighten the ECT sensor to 18 ft. lbs. (25 Nm)
2. If removed, install the thermostat, the gasket, and the water outlet housing.
3. If removed, install the water outlet housing bolt and the stud.
   • Tighten the bolt and stud to 20 ft. lbs. (27 Nm)
4. Install or connect the following:
   • Lower intake manifold gaskets. NOTE: Apply sealer GM P/N 12346286 (Canadian P/N 10953472) or equivalent to the ends of the intake manifold seals.
     
   • Lower intake manifold seals.
   • Lower intake manifold.
   • Lower intake manifold bolts.
   NOTE: Apply thread lock compound GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the two hidden bolts and ensure they are installed.
   
5. Tighten the lower intake manifold bolts in sequence to 11 ft. lbs. (15 Nm)
   
   
6. Install or connect the following:
   • Generator brace bracket.
   • Generator brace bracket bolts. Tighten the bolts to 37 ft. lbs. (50 Nm)
   • Right upper engine mount strut bracket.
   • ECT sensor electrical connector.
   • Radiator inlet hose to the water outlet housing.
   • EGR outlet pipe to the lower intake manifold.
   • EGR outlet pipe bolt to the lower intake manifold. Tighten the bolt to 21 ft. lbs. (29 Nm)
   • Drive belt tensioner.
   • Generator brace.
   • Upper intake manifold.
7. Inspect for leaks.

Lower Intake Manifold (W/ Supercharger) To Remove:

1. Disconnect the negative battery cable.
2. Drain the cooling system.
3. Remove the supercharger.
4. Remove the thermostat housing.
5. Remove the EGR pipe at the intake manifold.
6. Disconnect the electrical connection at the temperature sensor.
7. Remove the intake manifold and gaskets.

NOTE: The coolant bypass tube will release from the intake manifold when the manifold is removed.
To Install:

1. Clean the gasket sealing surfaces.
2. Install the intake manifold gaskets.
3. Align the coolant bypass tube with the opening in the intake manifold and install the manifold. Tighten the bolts to 11 lb ft (15 Nm).
4. Install the electrical connector to the temperature sensor.
5. Install the EGR pipe to the intake manifold.
6. Install the thermostat housing.
7. Install the supercharger.
8. Fill the cooling system.
9. Connect the negative battery cable.

Fig. 11: EGR valve and component mounting-3.0L engine




Fig. 12: EGR valve and component mounting-3.8L engine

Removal:

1. Disconnect the negative battery cable.
2. If necessary, remove the air inlet tube from the throttle body and air cleaner housing.
3. Label and detach all vacuum hoses from the EGR valve.
4. Label and detach any electrical wiring harness connectors from the EGR valve.
5. Disconnect the EGR valve-to-exhaust manifold tube from the EGR valve.
6. Remove the EGR valve mounting fasteners, then separate the valve from the upper intake manifold.
7. Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
   

To install:

1. Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts to 15-22 ft. lbs. (20-30 Nm) on 3.8L engines, or to 106-159 inch lbs. (12-18 Nm) on 5.0L engines.
2. Connect the EGR valve-to-exhaust manifold tube to the valve, then tighten the tube nut to 30 ft. lbs. (41 Nm).
3. Connect all wiring or hoses to the EGR valve.
4. Install the air inlet tube.
5. Connect the negative battery cable.

Hope this helps (remember comment and rated this).

The EGR (exhaust gas recirculation) valve

What is it? This is a device that reduces engine emissions of nitric oxides by allowing a measured amount of exhaust gas to re-enter the intake manifold and mix with the air prior to entering the cylinders. The EGR can be vacuum or electrically driven or a combination of both.

Where is it located? The EGR is most often associated with the intake manifold. The EGR will be sited at a point of contact with both the exhaust and intake manifolds. If the exhaust manifold is remote, for example on the other side of the engine to the intake manifold, there will often be an exhaust feed pipe leading from the exhaust manifold to the EGR sited on the intake manifold.

How does it work? Generally intake manifold vacuum acting on a diaphragm draws up on a valve to open a connection between an entry port from the exhaust gases and an exit port to the intake manifold. An open EGR port makes starting difficult so the valve operation is often impeded by an electrical over-ride until the engine has warmed up, as signaled to the ECU by the coolant temperature sender. In some cases, a differential pressure feedback exhaust (DPFE) sensor fed by pipes from the exhaust feed to the EGR informs the ECU when and by how much the EGR should be open.

Symptoms of faulty EGR

The EGR has two possible fault modes either it is a) open when it should be closed or b) closed when it should be open. (some EGR faults are in fact more likely to be DPFE related)

• Poor idling: ‘hunts’ at idle and generally rough engine performance. This is due to the air ingress through the split diaphragm or the EGR valve being left open, either event compromises the intake manifold vacuum and in turn this interferes with the ECU’s ability to deliver accurate fuel to air ratio for a given engine speed.
• Misfire and ‘pinking’: if the EGR is jammed closed or the exhaust feed pipe is blocked (e.g. gummed up with baked carbon) the engine ignition runs lean and very hot, so hot in fact that the fuel air mix can spontaneously ignite causing a misfire. The misfire if pronounced can, in turn, be detected by the engine knock sensors and this gives the appropriate on board diagnostic error codes along with the check engine light. Due to the diesel engines creating more soot in the exhaust a blocked EGR is a much more common complaint in diesels than petrol cars.
• Surging: A sticking EGR valve can lead to an effect of rhythmic surging a bit like the MAF fault, especially in turbo charged engines. Normally on a warmed up engine the vacuum from the inlet manifold opens the EGR. If the EGR fails to open promptly the turbo can be subject to a slight boost. Extra fuel/air mix is pushed into the inlet manifold as a result, increasing pressure (decreasing the vacuum). Without vacuum in the inlet manifold the EGR closes again but if sticky does so only slowly. This may allow inlet gases to flow through the EGR into the exhaust manifold for a split second. There is a time lag in the sequence of these events leading the engine to surge in cyclical manner.

How to check? With the engine running it may be possible to force the EGR valve open by pressing on the diaphragm with one’s fingers. Failing that pulling off the vacuum line to the EGR, blocking the pipe on the inlet manifold and applying vacuum to the EGR to monitor function will determine if the diaphragm is split. Removal of the EGR assembly and examination of the ports and valve mechanism will reveal any carbon build up.

How to fix? If the diaphragm is split then the EGR needs to be replaced. Most EGR problems are linked to carbon soot build up and this can be cleaned using a cloth, brush and carburetor choke cleaner spray. If the exhaust feeder pipe is blocked this can be cleaned using a piece of frayed hand brake cable as an internal brush. This makeshift brush can be further enhanced by mounting it in a drill to sweep dirt from the interior of lengths of pipe. Some cars (Hondas are a good example) have an elaborate passage way system to provide exhaust gas to each inlet pipe runner. The only way to clean these out is by removing the blanking plugs (no easy task) and then using the makeshift rotary wire brush and carburetor choke spray. New blanking plugs have to be reinstated to make good the passage ways assembly.

change your egr valve on the car and the problem should be rectified.
the egr valve exhaust gas recirculation valve send exhaust gase back to the inlet manifold to keep the air fuel fuel mixture at the right temp and the exhaust manifold from over pressurising.
if this fail seizes shut it stop the recirculation from happening yuo cant just clean them though they have to be replaced

Bonneville, LeSabre, Park Avenue 2000-2005 Intake Manifold - Removal & Installation

3.8L Engine
VIN 1 Engine

1. Before servicing the vehicle, refer to the Precautions section.
2. Relieve the fuel system pressure.
3. Drain the cooling system.
4. Remove or disconnect the following:
   Negative battery cable Supercharger Thermostat housing Exhaust Gas Recirculation (EGR) tube at the intake manifold Engine Control Temperature (ECT) sensor Intake manifold

To install:

1. Install or connect the following:
   Intake manifold with new gaskets. Torque the bolts, working from the center out, to 11 ft. lbs. (15 Nm). ECT sensor connector EGR tube to the intake manifold Thermostat housing Supercharger Negative battery cable
2. Refill and bleed the cooling system.
3. Run the engine and check for leaks and proper engine operation.

VIN K Engine

1. Before servicing the vehicle, refer to the Precautions section.
2. Disconnect the negative battery cable.
3. Drain the cooling system.
4. Relieve the fuel system pressure.
5. Remove or disconnect the following:
   Fuel injector sight shield Air inlet duct Spark plug wires from the right side Manifold Absolute Pressure (MAP) sensor Vacuum lines from the intake manifold Fuel lines Fuel injector electrical connectors Fuel regulator vacuum line Fuel rail from the intake manifold Exhaust Gas Recirculation (EGR) heat shield Throttle cable bracket from the cylinder head mounting bracket and the throttle body cables Throttle body support bracket Upper intake plenum and gasket Thermostat housing Electrical connector from the Engine Coolant Temperature (ECT) sensor Drive belt tensioner assembly EGR valve outlet pipe Lower intake manifold
   
   
   Fig. Exploded view of the intake manifold and related components-3.8L (VIN K) engine
   

To install:



Fig. Upper intake manifold torque sequence-3.8L (VIN K) engine



Fig. Lower intake manifold torque sequence-3.8L (VIN K) engine

1. Install or connect the following:
   Intake manifold using new manifold gaskets. Torque the bolts in sequence to 11 ft. lbs. (15 Nm); then, re-torque to 11 ft. lbs. (15 Nm). EGR valve outlet pipe Drive belt tensioner assembly. Torque the tensioner bolts to 37 ft. lbs. (50 Nm). Electrical connector to the ECT sensor Thermostat housing Upper intake plenum. Torque the intake plenum bolts to 88 inch. lbs. (10 Nm). Throttle body support bracket Throttle cable bracket to the cylinder head mounting bracket and the cables to the throttle body lever EGR heat shield Fuel rail. Torque the fuel rail bolts to 88 inch. lbs. (10 Nm). Fuel lines Fuel regulator vacuum line Fuel injector electrical connectors Vacuum lines to the intake manifold MAP sensor Spark plug wires Fuel injector sight shield and air inlet duct Negative battery cable
2. Refill and bleed the cooling system.
3. Run the engine and check for leaks and proper engine operation.

Hope this help (remember rated this).

REMOVAL PROCEDURE

1. Turn OFF the ignition.
2. Disconnect the EGR valve electrical connector.
3. Remove the bolt retaining the pipe assembly from the EGR valve and carefully pull the pipe assembly back.
4. Remove the EGR valve retaining bolts.
5. Remove EGR valve assembly.
6. Remove the gasket.

INSTALLATION PROCEDURE

1. Install the EGR valve with a new gasket to the intake manifold. NOTE: Refer to Fastener Notice in Service Precautions.
2. Reinstall the bolts through the EGR valve into the intake manifold. Tighten Tighten the EGR bolts to 30 N.m (22 lb ft).
3. Connect the exhaust pipe assembly to the EGR valve.
4. Reinstall the exhaust pipe bolt. Tighten Tighten the nuts to 30 N.m (22 lb ft).
5. Connect the EGR valve electrical connector