When the car turns off does the ISCV close? You should be able to hear it move if you get someone else to turn the engine off, The ISCV is located at the rear of the inlet manifold on the engine side, it has a black metal cover and connects to the manifold with two nuts.
The ISCV is a valve that the ECU uses to let more / less air past the throttle to control the engines idle RPM.
When you turn the engine off the ECU should move the ISCV to the fully open position, it does this so that it knows where it is for next time! ISCV should be powered by a relay which is controlled via the ECU via the M-REL output. Having the ECU switch the M-REL allows the ISCV to keep power after the ignition has been removed (the ecu senses this and then moves the ISCV and then cuts power to the M-REL). Depending on how your car has been wired up this may not be the case?
My suggestion would be to first remove the ISCV and check that it isn't gummed up and dirty (stopping it from moving). If it is dirty try and clean it with something like carby cleaner. If it looks fine then I would check that there is voltage at B1/B2 after ign has been switched off for a moment. If there isn't then you may have to search through the wiring and sort it out!.
A guide to test the 7M-GTE (MA70) ISCV is here
http://www.cygnusx1.net/supra/librar...fi/FI_106.html
1JZ-GTE should be very similar!
Cheers
Wilbo
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