Intake Air Distribution and Filtering (v8 5.0l Gasoline) Land Rover Range Rover L322

Scheme 538

INTRODUCTION

The intake air distribution and cleaning system comprises

1. Dual air intakes, air cleaners and air ducts.
2. An intake manifold.

Scheme 539

Air is supplied to the air cleaners, from under the sides of the hood, through the air intakes, the front fender aprons and the dirty air ducts.

The air cleaners are located in the engine compartment, forward of the suspension housings. Three isolators locate each air cleaner to a bracket on the related front side member and front fender apron. Each air cleaner consists of an air cleaner element installed in a tray and enclosed with a cover secured by six screws. Air inlet and outlet connections are incorporated into the tray and cover respectively. The bottom of the tray incorporates a drain valve to prevent the accumulation of water in the air cleaner. The air outlet connection incorporates a MAFT (mass air flow and temperature) sensor.

The clean air convolutes and the clean air duct direct the air from the air cleaners into the electric throttle. Hose clamps connect the clean air convolutes and the clean air duct together, and to the air cleaners and the electric throttle.

The clean air duct also incorporates the following

1. Resonators, to reduce air induction noise.
2. A connector stub for the engine full load breather pipe.

INTAKE MANIFOLD

The intake manifold is installed between the cylinder heads and directs air from the electric throttle to the individual cylinders. The inlet port connects to a central chamber in the intake manifold. Eight separate tracts connect the central chamber to the outlet ports. A cover plate seals the rear of the intake manifold.

The intake manifold incorporates

1. A stub pipe for connection of the part load breather.
2. A stub pipe for connection of the evaporative emissions system.
3. A MAP (manifold absolute pressure) sensor.
4. A vacuum connection for the brake booster.
5. Threaded inserts to provide attachment points for the electric throttle, fuel crossover tube, engine cover and an engine harness shield.
6. Compression limiters in the cylinder head attachment points.
7. Seals in the inlet and outlet ports.
8. A VIS (variable intake system).

The VIS changes the length of the tracts in the intake manifold to improve the air flow to the cylinders, which improves the engine power and torque.

A cassette in the intake manifold contains eight flap valves, each located in an opening part-way along one of the tracts. Two drive shafts connect the flap valves together in two groups of four. Each drive shaft is connected to a pneumatic actuator installed on the cover plate of the intake manifold.

A tuning valve, also installed on the cover plate, controls the application of vacuum pressure to the pneumatic actuators. The tuning valve is a normally-closed solenoid-operated valve installed in the vacuum line between the cover plate and the pneumatic actuators. A vent cap on the tuning valve allows atmospheric pressure into the vacuum line to the pneumatic actuators when the tuning valve is closed.

The ECM (engine control module) controls the operation of the tuning valve.

Scheme 540

Note. A = Hardwired

VARIABLE INTAKE SYSTEM

The flap valves can be set to one of two positions, to produce short or long intake tracts in the intake manifold. Short intake tracts are produced with the flap valves closed. Long intake tracts are produced with the flap valves open. The flap valves are closed at engine speeds up to 4700 rev/min and open at engine speeds of 4700 rev/min and above, with a hysteresis of 50 rev/min.

The tuning valve receives a power feed from the EMS relay in the EJB (engine junction box), and is connected to ground through the ECM. To close the flap valves, the ECM connects the tuning valve to ground. The energized tuning valve blanks off the atmospheric vent and opens the vacuum line between the cover plate and the pneumatic actuators. The depression in the intake manifold is sensed at the pneumatic actuators, which turn the drive shafts and move the flap valves to the closed position.

To open the flap valves, the ECM disconnects the ground connection and the tuning valve is de-energized closed. Atmospheric pressure is sensed at the pneumatic actuators through the vent cap on the intake manifold tuning valve and the flap valves move to the open position.

PRINCIPLES OF OPERATION

For a detailed description of the intake air distribution and filtering system and operation, refer to the relevant Description and Operation instructions in the Workshop Manual.

INSPECTION AND VERIFICATION

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage. VISUAL INSPECTION Mechanical Electrical Hoses and ducts: condition and installation Air cleaner element condition and installation Restricted air intake Vacuum hoses condition and installation Fuse(s) Wiring harness(es) Loose or corroded electrical connector(s) Mass air flow (MAF) sensors Manifold absolute pressure/temperature (MAPT) sensors Intake air temperature (IAT) sensor The IAT sensor is built into the right-hand MAF sensor
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.

SYMPTOM CHART

DTC INDEX

For a list of Diagnostic Trouble Codes (DTCs) that could be logged on this vehicle, please refer to Diagnostic Trouble Code (DTC) Index - 5.0L, DTC: Module Name: Engine Control Module .

See also:
• Diagnostic Trouble Code (DTC) Index - 5.0L, DTC: Module Name: Engine Control Module