when does the valve open and close, when open does it blow into the intake of the turbo or does it suck air from the intake of the turbo straight into the intake pleinum
iac
- Thread starter MKIII TURBO60-1
- Start date
Cant see how as you would have a vac drop everytime you came to idle. maybe im over looking something jdub?
Vacuum is created by the interaction of the pistons, valves and cam...the ISCV has no effect on vac readings other than controlling engine RPM. Read this:
http://www.cygnusx1.net/supra/TechTips/vacuum_gauge_readings.aspx
At idle the TB plate is closed, metered air is pulled in (with vac) through the ISCV path...that is the main source of air for the engine at idle and the ISCV regulates it (by open/closing) to control idle speed.
Above idle, most air comes through the TB...the amount that comes through the ISCV is minor. In any case all air is metered, which is why you do not want to put a mini air filter on the ISCV with a stock ECU.
Under boost, the ISCV path is block by a check valve under the ISCV flange. This prevents a boost leak.
http://www.cygnusx1.net/supra/TechTips/vacuum_gauge_readings.aspx
At idle the TB plate is closed, metered air is pulled in (with vac) through the ISCV path...that is the main source of air for the engine at idle and the ISCV regulates it (by open/closing) to control idle speed.
Above idle, most air comes through the TB...the amount that comes through the ISCV is minor. In any case all air is metered, which is why you do not want to put a mini air filter on the ISCV with a stock ECU.
Under boost, the ISCV path is block by a check valve under the ISCV flange. This prevents a boost leak.
A new gasket should fix that. The valve plunger/seat might need a good cleaning too. Clean the check valve while your at it.