ISC valve hose routing.

[stew_7mgte]

The isc valve on the intake manifold apparently has coolant lines run to it probably to adjust the amount of air at idle depending on engine temp? Anyways i can see kinda how its hooked up through the tsrm but if anybody cant paint me a better picture i would be grateful.

 

[Mrbaboon]

The coolant lines are literally to stop them freezing in (really) cold climates. They also run to the throttle body of I remember rightly.

This diagram might help: http://www.cygnusx1.net/Supra/Library/EPC/291420/catalog.aspx?F=1603&P=2

Edit: Also this page: http://www.cygnusx1.net/Supra/Library/EPC/291420/catalog.aspx?F=2211&P=2

They run from the coolant pipe, up towards the TB/ISC then to a coolant nipple on the bottom of the lower intake manifold (between cylinders 1 & 2).

Although, since it rarely gets too far below freezing where I live, I'm bypassing the ISC/TB all together.

 

[stew_7mgte]

Yea i ended up bypassing them as well with somehelp advice from driftmotion.

 

[3p141592654]

Did you know that when the air passes through the ISC at idle its pressure drops about 12psi. Guess what happens to the air temp when it makes that journey from high pressure to low pressure. The answer is the same thing that happens to freon in your A/C evaporator at the expansion valve, its temperature drops. So, any humidity in the air can freeze out. Key point, ambient temp doesn't have to be below freezing for ice to form at the ISCV.

 

[jetjock]

^ This. Same thing with carburetors. It's why aircraft engines so equipped all have carb heat. Heating the air also aids in vaporization.