Name That Part

[discotech]

On the SHOforum image of the intake you can see a small cylindrical part with a wiring harness at one end. It sits between the throttle body and an intake runner at the far right. What is it? What does it do? Can it be damaged easily? I unscrewed the two screws holding it together and I have an uneasy feeling about it.

 

[shojuan]

It's the IAB (also called the IAC) Idle Air Bypass. Since the computer doesn't have control of the throttle body butterfly (your right foot does) it uses this solenoid controlled gizmo to bypass the throttle body butterfly so it can let a regulated quantity of air into the intake manifold for idle control. At least that's what I assume it does. Cleaning it out often helps with rough idle or constant throttle surging at highway speed. There's a procedure on shotimes.com under care and feeding -> engine control. I never felt like mine was going to break the numerous occasions I've had it off for cleaning.

Rick

 

[discotech]

thanks for the tip, I went right over and printed it out. The uneasy feeling is gone, thanks.

 

[Yamaha V6]

"Intake Air Circuit" is what the EEC error codes call it.