Which way should the butterfly valve go in the throttle body?
When I first got my focus a family friend fiddled around (without permission - trying to fix the LPG idle revs) and snapped part of the throttle body. We went to a scrapyard and bought a new one but things haven't been right since...
Under light throttle there's a whistle coming from the throttle body. It's very predictable and you can even hold the pedal to make it whistle. It's 100% the throttle, and it's so very annoying to hear it squeak when going from no throttle to light throttle. When I first bought the part I did some cleaning with warm soapy water on the butterfly to get rid of all the gunk, and am 99% sure it went back in the same way. What could be causing this whistle? I was thinking of checking its position again and giving a good clean with carburetor cleaner and a toothbrush. The butterfly valve seems quite weird in the focus....one side of it is far bulkier than the other, and there's a very obvious front and back to the butterfly itself. When depressing the accelerator, should the 'thick' part of the valve be coming upwards? And should the front be facing inside the body or towards me?