5.9L V-8 and 8.0L V-10 engines with HDC packages are equipped with an air injection system.
The system consists of:
The air injection system adds a controlled amount of air to the exhaust gases aiding oxidation of hydrocarbons and carbon monoxide in the exhaust stream.
On the 5.9L HDC engine air is drawn into the pump through a rubber tube that is connected to a fitting on the air cleaner housing.
On the 8.0L engine, air is drawn into the pump through a rubber tube that is connected to a fitting on the air injection pump filter housing. Air is drawn into the filter housing from the front of the vehicle with rubber tube. This tube is used as a silencer to help prevent air intake noise at the opening to the pump filter housing.
Air is then compressed by the air injector pump. It is expelled from the pump and routed into a rubber tube where it reaches the air pressure relief valve. Pressure relief holes in the relief valve will prevent excess downstream pressure. If excess downstream pressure occurs at the relief valve, it will be vented to the atmosphere.
Air is then routed from the relief valve, through a tube, down to a "Y" connector, through the two, one-way check valves and injected at both of the catalytic converters.
The two one-way check valves protect the hoses, pump and tubes from hot exhaust gases backing up into the system. Air is allowed to flow through these valves in one direction only (towards the catalytic converters).
Downstream airflow assists the oxidation process in the catalyst, but does not interfere with EGR operation (if fitted).
- The air injection system and pump is not completely noiseless. Under normal conditions, noise rises in pitch as engine speed increase.
- To determine if excessive noise is at fault, disconnect the accessory drive belt and temporarily run the engine.
- Run the engine to normal operating temperature and let it idle.
- Disconnect the output hose.
- If the pump is operating properly, airflow should be felt at the pump outlet. The flow should increase as you increase the engine speed. The pump is not serviceable and should be replaced if it is not functioning properly.
One-Way Check Valves
- Remove the rubber air tube from the inlet side of each check valve.
- Start the engine.
- If exhaust gas is escaping through the inlet side of the check valve, it must be replaced. Valves are not repairable.
REMOVAL & INSTALLATION
Air Injection Pump
- The AIR pump does not have any internal serviceable parts.
- Disconnect both hoses at the pump.
- Loosen, but Do NOT remove yet, the three pump pulley mounting bolts.
- Relax the accessory belt tension and remove the accessory belt.
- Remove the pulley bolts and remove the pulley.
- Remove the two air pump mounting bolts and remove the pump from the mounting bracket.
- Reverse the removal procedure.
- Tighten the pump mounting bolts to 30 ft. lbs. (40 Nm).
- tighten the pulley bolts to 8 ft. lbs. (11 Nm).
On 8.0L engines, the air filter for the pump is located inside a housing located in the right front side of the engine compartment. Connection is via a rubber hose.
The filter should be replaced every 24,000 miles/24 months under normal operating conditions.
- Remove the rubber tubes at the filter housing.
- Remove the housing mounting nut and remove the housing.
- Remove the housing lid that snaps off.
- Remove the filter.
- Clean the inside of the housing.
- Tighten the mounting nut to 8 ft. lbs. (11 Nm).
- The reset of the procedure is the reverse of removal.
- Remove the hose clamp at the inlet side of the valve.
- Remove the hose from the valve.
- Unscrew the valve from the catalyst tube. To prevent damage, use a backup wrench on the tube.
- Reverse the removal procedure.
- Tighten the valve in the catalyst tube to 25 ft. lbs. (33 Nm).