[brad black]

the idle switch range when read by the gt1 is from around 325 to 390mv from memory. so anywhere in that range will activate the idle switch. that's the only setting procedure from bmw, so if it's within that range it's considered ok.

if you change the idle stop screw setting you should check the balance with the air bleeds wound in on both sides as you'll probably have unbalanced idle stop settings. most of them are out from the factory anyway.

when you do a zero = zero this idle stop balancing is important as the rh one will be open quite a bit more than the lh one - which is now open less due to the tps baseline being higher with the same / similar idle voltage setting. this is also why the zero = zero makes them a little richer - the throttle is open less for the same tps reading.

doing the 'air bleed in' idle stop balance can often make them that little bit nicer at idle and low throttle openings.