Auxiliary Air Valve

1. Install a suitable tachometer onto engine as per manufacturer's instructions.
2. Using fingers or needle nose pliers, pinch hose connecting air intake duct and auxiliary air valve and check engine speed.
3. With engine cold, engine idle speed should drop when hose is pinched. With engine as normal operating temperature, reduction in engine speed should be 100 RPM or less.
4. With engine started and auxiliary air valve at normal operating temperature, engine speed should drop gradually until specified engine idle speed is obtained. If engine speed will not drop, proceed as follows:
a. Using a suitable ohmmeter, check resistance of auxiliary air valve.
b. Disconnect electrical connector from auxiliary air valve and measure the resistance between connector terminals.
c. If resistance obtained is zero or infinity, replace auxiliary air valve.
5. Check source voltage as follows:
a. Disconnect electrical connector from auxiliary air valve and check voltage on harness side.
b. With engine operating, voltage reading should be 12 volts or more.
c. If voltage reading is less than 12 volts, check harness and repair or replace as necessary.