Not sure but I believe it allows the pcv to control the fuelling accross the full range rather than WOT
You can get to the lambda sensor plug without taking the tank off, there is two plugs attached to the left hand frame beam, It's the one at the front out of the two as shown in the previous pics. The Eliminator plug only fits one of them so you can't get the wrong one. Choose a map close to your spec, but it won't be a perfect match to your set-up as a Custom map is the only way to go.
