Postby 87 PathyOner » Sat Jul 18, 2009 9:05 am
The wax thermo unit controls the fast idle, via a cam that acts on the throttle plate. When the wax inside the unit gets gets hot (it's controlled by the coolant temp) it pushes on the cam which then rotates allowing the the throttle to close.
So whats happening here is a combination of events with several components, throttle position sensor,
Idle-up solenoid, and the thermo element.
Basically if the themo element doesn't rotate the cam, when its hot the computer thinks its cold, and opens the throttle up solenoid.
Its becomes an endless loop.