Hi first post (Woo). Just got an 89 4Runner 3vz. Have a quick question: how does this thing idle? There is no IAC to speak of. Also, how is fast idle accomplished? This old EFI stuff is foreign territory to me.

Thank you

 

There is a IAC valve, kinda. Its located under the TB, its called the wax valve.. It uses wax, heated/cooled by the coolant bypass that flows through the TB. This regulates the idle.

 

Thanks Jay

So the computer has no control over idle? That raises another question: how does the compy compensate for AC or steering input?

 

Im not sure for A/C, but for steering there are two vacuum lines that come from the pump to the upper intake. These provide the idle up function when you turning while stopped...