Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Air Injection System: Description
The Fiesta air injection system is designed to reduce unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. It does this by injecting fresh air into the exhaust ports to further the burning of hot exhaust gases. The air, which is pressurized by the air pump, enters the exhaust port either through an external supply tube or through internally-drilled passages. The system consists of an air pump, a bypass valve, a vacuum vent valve, exhaust check valve, idle vacuum valve, and vacuum delay valve.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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