is the iab ecu controlled or vaccuum controlled.

Does it stay closed untill the ecu opens it at a certain rpm,

or is it always open unless you have an ecu that deals with iab and that closes.

i ask this because my h22a makes peak power at 5000 rpms.
please help.

 

idle air bypass solenoid = IAB..... read it here... http://www.promustangs.com/tbclean.html

 

The iab system is controlled by the ecu and vacuum pressure.Impretty sure for a h22a,there supposed to open at 4600 rpms.

 

so if you don't have the right ecu for the iab. it just stays open the whole time.

 

Actually the IAB is Intake air Bypass and it's the butterflies that open and close in the second runners of the intake manifold. The Idle Air Control Valve is called an IACV on Honda's, which controls idle speed.

The IAB is actually turned on at low rpms and turns off at high rpms. If you disconnect the vacuum line or disconnect the wire to the ECU the butterfly valves will stay open all the time, so unless they're stuck, they should be open and cause low end power loss, not high end power loss.

The ECU sends a signal to the IAB solenoid which uses vacuum to hold the butterfly plates closed until 4900 rpm when it turns the solenoid off, letting the plates open up.

 

oops


[Modified by 94GSRRacer2, 3:33 PM 5/15/2002]