Hello everyone. I had recently watched a video described on the Forum on how to do this (Problem Solver Garage), and he uses a process similar to what the Tech Manual describes except he uses a target idle RPM during his iterative process with the Idle Air Valve and the wheel at the rear of the FIP. This is very similar to what our Tech Manual prescribes except our iterative process involves maximizing vacuum level and this same adjustment on the back of the FIP.
I would just like to understand the vacuum approach a little better. I would expect that the IAV ranges from a full open position to a full closed position. So I'm puzzled at how the max vacuum level can be attained at a point in the IAV adjustment between more open and less open? Seems like vacuum would always increase as the IAV is closed. That is, how can vacuum increase as we close the IAV, then begin to increase again as we continue to close the IAV? Would the maximum vacuum level not be when the IAV is fully closed?
Thanks,
Harry