Auxiliary Air Valve (Idle Speed): Testing and Inspection

Bypass Air Valve:

1. Remove air valve from intake manifold.

2. Immerse in ice water until valve is cold.

3. Check that air will flow between the two passages "B" & "C" (see illustration).

If not, replace valve.

4. Heat valve housing "A" with hot air blower (such as a hair dryer or industrial hot air blower) and check that the valve moves in the direction of the arrow (see illustration).

When valve is hot (above approx. 140° F/60° C), air passages should be closed. If not, replace valve.