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.
Federal Models
The air switching valve (ASV) is designed to redirect air flow from the air pump to the check valve or to the atmosphere. When manifold pressure is higher than specified, the valve allows air to flow to the check valve.
When manifold pressure is lower than specified, the air valve shuts air flow to the check valve, and at the same time vents pressure to the atmosphere.
The ASV is operated by air pump pressure and by intake manifold vacuum through the vacuum switching valve. The ASV redirects air flow from the air pump to either the check valve or to the atmosphere.
When manifold vacuum is applied to pipe 1, the ASV allows air to flow from air pump to the check valve. When the vacuum switching valve directs air pump pressure to pipe 1, the ASV shuts air flow to air injection manifold, and at the same time vents pressure to the atmosphere (air cleaner).
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.