Hot Idle COMPENSATOR

When engine is cold or air temperature is normal, detach air hose from intake manifold and try to pull air through with vacuum pump. No air should pass through compensator. Using a heat lamp, heat valve to temperature above 155°F (69°C) and try to pull air through hose. Air should pass through compensator. If not, replace compensator.

Fig 1: Mazda Hot Idle Compensator Valve

Courtesy of MAZDA MOTORS CORP.