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: Operation
The air pump is a low pressure unit, belt driven by the engine, which uses vanes on its drive pulley as a centrifugal filter. The air delivery line is connected to the check valve. The check valve prevents hot exhaust gases from flowing out through the delivery line and pump in case the pump fails or exhaust gas pressure becomes excessive.
A relief valve, mounted on the air pump on Strada and X1/9 or on the air cleaner on Brava and Spider, is used to vent excess pump pressure. See Figure and Figure. Pump output which passes through the check valve enters the cylinder head passages and is delivered to the exhaust ports.
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.