tb connections

cre · 04-11-2008, 12:32 AM

They're for coolant lines. The hoses run from the coolant hardpipe which wraps around the block from the exhaust side then goes up into the TB at the rear. The coolant then exits the TB at the front and the hose runs then to the Idle speed controller. The final length of this route is from the bottom of the ISC to a nipple in the lower side of the bottom intake manifold's flange.

As for why.... it's to ensure that the TB and ISC stay warm enough in high humidity situations where the incoming airflow may permit not only condensation but freezing on critical components... or more simply put, it's there to make sure no ice keeps the throttle plate open when ya want to stop.

It's not uncommon to find it's been bypassed by former owners.

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04-11-2008, 12:32 AM	#1
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	They're for coolant lines. The hoses run from the coolant hardpipe which wraps around the block from the exhaust side then goes up into the TB at the rear. The coolant then exits the TB at the front and the hose runs then to the Idle speed controller. The final length of this route is from the bottom of the ISC to a nipple in the lower side of the bottom intake manifold's flange. As for why.... it's to ensure that the TB and ISC stay warm enough in high humidity situations where the incoming airflow may permit not only condensation but freezing on critical components... or more simply put, it's there to make sure no ice keeps the throttle plate open when ya want to stop. It's not uncommon to find it's been bypassed by former owners.