The total voltage change is not what the ECU is looking for. For a Hall input the signal must cross 2v AND 3v or vice versa. There is a 1v split between the levels to give a bit of a "no mans land" so only the signals that go all the wya are counted. You could have a signal that went from 0-5v or 3.5v to 1.5v and both would work.
Don't solder anything on to anything, just send me the captures.
All of you must now watch ALL of my ref/sync webinars as home work.