Description

The EGR valve is mounted to the intake manifold.

Operation

The engines use Exhaust Gas Recirculation (EGR) systems. The EGR system reduces oxides of nitrogen (NOx) in engine exhaust and helps prevent detonation (engine knock). Under normal operating conditions, engine cylinder temperature can reach more than 1649ºC (3000ºF). Formation of NOx increases proportionally with combustion temperature. To reduce the emission of these oxides, the cylinder temperature must be lowered. The system allows a predetermined amount of hot exhaust gas to recirculate and dilute the incoming air/fuel mixture. The diluted air/fuel mixture reduces peak flame temperature during combustion.

Removal

Fig. 74: Air Inlet Duct

1. Remove air inlet duct (3).

2. Disconnect negative battery cable.

Fig. 75: ENGINE COVER-REMOVAL

3. Remove engine cover.

Fig. 76: Intake Manifold

4. Disconnect EGR valve vacuum line.

5. Disconnect EGR pipe (3) at EGR valve.

6. Remove air inlet tube from intake manifold flap motor (5).

7. Remove intake manifold flap motor (5).

8. Remove EGR valve retaining bolts and remove EGR valve (7).

Installation

Fig. 77: Intake Manifold

1. Inspect EGR and intake manifold flap motor o-rings (6,8) for damage. Replace as necessary.

2. Install EGR valve (7) to intake manifold. Torque retaining bolts to 10.m (88 lbs.in.).

3. Install intake manifold flap motor (5) to EGR valve (7). Torque retaining bolts to 10 N.m (88 lbs.in.).

4. Inspect EGR pipe gasket (4)for damage, replace as necessary.

5. Connect EGR pipe (3) to EGR valve. Torque retaining bolts to 20N.m (177 lbs.in.).

6. Connect EGR valve vacuum line.

Fig. 78: Engine Cover

7. Install engine cover.

Fig. 79: Air Inlet Duct

8. Connect negative battery cable.

9. Install air inlet duct (3).