the aux air valve allows air through to help the car tickover when its started from cold, all the multiplug does is tell it that the engine is getting warm and the disc inside the valve will slowly close until its shut. If you unplug the black multiplug from the valve the car should start, the only difference you will notice is that the revs will stay higher for longer as now the valve is relying on purely engine heat to shut it. If the car struggles to idle you may have a problem with the actual valve, try spraying some carb cleaner inside it, run the car, then spray wd40 in it to stop the disc sticking, then see how it runs. If it still runs shite then I suggest you try another valve.

Duncan