gen1 3sge throttle body info

[3sfe]

I'm wanting to know how the isc works, it looks like its got like a thermostat inside it which looks like it works off the water lines, does this work like went it is cold its wide open and then when its got up to running temp it closes? then theres the air intake the 5/8 pipe then there is 2 other smaller pipes what are these for?
Hope this makes sense.

[88FOUR]

this may be a silly question, ..but what is the isc?..........I recently rebuilt a 3sge, may be able to help.

[matt86sx]

ISC = Idle Speed Controller

[88FOUR]

I know what it is. I know that the little valve under the screw will ware out over time and probably need replacing if it hasnt been. Its a cheep part too from toyota....Dont know anything else about it.... ...sorry man.

[AndyTTR]

The ISC on the gen 1 is a float made of wax that sits in a chamber that has coolant flowing through it. The float is connected by a linkage to a valve that lets air bypass the throttle butterfly. When the coolant is cold the float sinks to the bottom of the chamber and the linkage opens the bypass, letting more air in past the throttle and hence raising the idle speed. As the coolant heats up, the wax starts to float upward in the chamber and the linkage starts to close the air bypass which lowers the idle speed.

It may be the other way around, but that's the basic concept that I had explained to me once. My gen 1 would never idle properly after changing the coolant because air got trapped in the chamber, used to take ages to bleed it out!

Hope this helps,
- Andy