i got a mx-3 with a 93 j-spec bp with a ford escort gt ecu and harness and they car has been running fine(for 3 months now) and my vics was working but today i checked and it's not working anymore

before it used to close when i started the car then open at 5500 rpm, but now it dosn't close when i start the car and just stays open at all rpm

whats wrong?

 

could be a bad solenoid valve

a few things to check:
with the engine off, disconnect the vacuum hose from the shutter valve actuator ('dashpot') for VICS. check to be sure the rod moves smoothly back and forth....

now start the engine and check to see if there is a vacuum at that disconnected hose. if not, then *most likely* the problem is the solenoid valve that the vacuum hose is connected to....

but it *could* also be the ecu, wiring, or the vacuum chamber - the black cylinder that sits next to the shutter valve actuator.

remove the vacuum chamber and check it out by blowing through the top port; if its good, NO air will flow... blow through the bottom port; if good, air WILL flow.

so.... if its OK - and the actuator was OK - you have it narrowed down to the solenoid valve, the ecu, or the wiring.

 

i looked today and i think it's the solenoid valve, so i'm going to the junkyard tommorrow
thanks