F 250 4WD Super Duty V10-6.8L VIN Z CNG (2003)
Air Injection: Description and Operation
SECONDARY AIR INJECTION (AIR) SYSTEMS
Overview
The Secondary Air Injection (AIR) system controls emissions during the first 20 to 120 seconds of engine operation by forcing air downstream into
the exhaust manifolds to oxidize the hydrocarbons and carbon monoxide created by running rich at start up.
Electric Secondary Air Injection System
Dual Or Single AIRD Valve Electric Secondary Air Injection (AIR)
The Electric Secondary Air Injection (AIR) system consists of an Electric AIR Pump (EAP), single or dual combination check air injection diverter
(AIR diverter) valve(s), an AIR bypass solenoid, a solid state relay, Powertrain Control Module (PCM) and connecting wires and vacuum hoses.
1. The PCM requires Engine Coolant Temperature (ECT), Intake Air Temperature (IAT) and Crankshaft Position (CKP) inputs to initiate
Secondary Air Injection function.
2. When the engine is started, the strategy will determine when to enable the EAP. The PCM signals the solid state relay and the AIR bypass
solenoid, after a (5 to 10) second delay, to begin system operation. Once the catalyst is lit-off, the PCM then signals the solid state relay to
stop AIR pump operation and to close the AIR bypass solenoid from supplying vacuum to the AIR diverter valve(s).
3. The solid state relay provides the start-up signal and will switch the high current required to operate the AIR pump.
4. The AIR bypass solenoid applies a vacuum to the AIR diverter valve(s) causing it to open and to allow air to flow into the exhaust manifolds.
5. The vacuum check valve controls vacuum bleed-off to solenoid.
6. The function of the splash cap if equipped is to provide the AIR pump with a source of dry air.
7. The electric AIR pump delivers the required amount of air to control emissions during engine operation. Air is forced into the exhaust
manifolds to oxidize the hydrocarbons and carbon monoxide created by running rich at start up.
Hardware
Electric AIR Pump
