MSefi.com read only forum (Jan.15,2018)

The IAC valve is not designed to see positive pressure, and if you've plumbed it incorrectly, the boost can force it open even at a duty cycle where it would normally be closed. The IAC normally balances the force of the solenoid against a spring tension; adding boost changes the balance between ...

Matt Cramer wrote: Also, a DC value that's closed at idle may not be closed under boost.

ahhh i see. could you expand on this please?

right, but assuming you set the "closed dc" value to something which will close the valve (ie 0), the value will stay closed every time it was not in idle?

anyone?

does the IAC code close the valve when it is not in idle? assuming this is what the "closed dc" value is

Yeah, i've been thinking about this one too. I have mine hooked up to have one side of the valve going to the plenum and the other side going to the cooler piping after the turbo. I have a 1-way valve on the line between the IAC and the plenum (so air can only be sucked into the plenum from the ...