loccomoffo

Can someone please enlighten me to what this part on the throttle body of my MY95 1.8L engine is? The hoses going to/from it contain engine coolant.

Also can you tell me at what time this system comes into play and how it performs it's job? The image was taken directly overhead of the throttle body, looking downwards.

Thanks in advance




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loccomoffo

OK the quiz is over I found what the device is in a Subaru Fuel Injection and Engine Management Manual. Its an idle air control valve (IAC) which increases idle speed in cold engine conditions. It is also sometimes known as an idle air bypass.

From the manual:

"during cold engine operation the throttle is assisted by a coolant sensitive device that contains a wax pellet. The wax pellet contracts when it is cold and expands when it is heated. During cold operation a spring loaded lever resting on the end of the pellet moves toward the pellet. The opposite
end of the lever is cam shaped. As it moves upward it pushes on the throttle shaft, mechanically increasing the idle speed. Increasing coolant temperature expands the pellet relaxing the force applied to the throttle shaft."

There is also an air-conditioning IAC which is a black valve which is solenoid controlled and picks up air just after the MAF and inputs it just after the throttle:

"The A/C IAC allows additional air flow to by pass the throttle plate to compensate for load the air conditioner places on the engine."


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