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 supplies air under pressure through a diverter valve, check valve and air rails to the exhaust ports just above exhaust valve heads. The air combines with exhaust gases to further the burning process. Check valve prevents flow in air rails when exhaust pressure exceeds air supply pressure.
Diverter valve operates in response to abrupt fall in manifold pressure and diverts secondary air to atmosphere for 2-3 seconds. This reduces air/fuel ratio which otherwise would be too rich to burn and would pass through engine to mix with secondary air and become combustible, creating backfire. The diverter valve is actuated by manifold pressure via a rubber tube connected to intake manifold.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.