Fiav?

[DSM "BISH"]

i have quite a few questions regarding the FIAV gasket or whatever iti s that people are talking about. what exactly is FIAV? and where is it located? i know its somewhere on the throttle body.

 

[steve]

The FIAV (Fast Idle Air Valve) is located in the bottom of the throttle body next to the ISC (Idle Speed Control) motor where the coolant lines attach.

It's a wax pellet operated air bypass valve that expands and contracts based on the temp of the engine coolant that surrounds it. When the engine is cold the pellet shrinks and opens up the bypass allowing more air to enter the intake manifold and the engine speed to increase. As the coolant heats up the pellet expands and closes down the bypass lowering the engine speed. At normal operating temps (about 187F) the FIAV should be closed and only the ISC and BISS should be allowing air to bypass the throttle plate.

Some people call the whole lower part of the throttle body the FIAV but the lower casting supports both the FIAV in the coolant passages and the ISC. There is a gasket between the top and bottom of the TB to keep the coolant contained called the FIAV gasket. When the gasket fails it floods the throttle body.

 

[DSM "BISH"]

so if the gasket was bad i would kno. there would be coolant in font of my throttle plate if i took the intake pipe off?