In Reply to: Crankcase Vent Hose & Idle Speed Control Hose ??? posted by Smokey on June 29, 1999 at 13:27:03:
First, both are easy to change....so do it yourself. The CC vent hose allows CC vapors from blow-by to be drawn into the engine's intake tract and burned. Hose goes from valve cover to just upstream of the throttle body (between airflow meter and throttle body). The ISC hose: when the throttle valve is closed it allows very little air to pass so incoming air at idle is routed around the throttle valve to the intake manifold via the ISC hose. This air passes through the idle control valve which itself is like a small throttle, regulating the amount air going into the engine at idle.
Cracks/leaks in either of these hoses can contribute to a lumpy/erratic idle.
: Technician advised me that these two hoses need to be replaced. What specific jobs do the two perform?
: '90 535