Tried pics but this new ipad when set to smallest widgets has a .HEIR and our Forum wont accept.
But after reading 6E3... I now see its a stepper motor, which is reasonable since it allows the ECM to count the steps and remember what the setting is. All the way closed is "0" - at engine off it closes, engine on it counts out to the remembered idle setting.
It does not go too deep but I would assume it is only adjusting idle when under a 1000rpm.
"A scan tool will read IAC position in steps (counts). "0" steps indicates the ECM is commanding the IAC to be driven all the way in, to the fully seated position, and this is usually caused by a vacuum leak. The higher the amount of counts the more air being allowed to pass the IAC valve. Chart C-2C can be used to diagnose the IAC valve. Also refer to "Rough, Unstable, or Incorrect Idle, Stalling" in Symptoms Section B".
There does not appear to be a test voltage, they only say that coil is more than 20ohms each coil, no opens, shorts, grounds, but always do these checks with ECM disconnected.
And did notice whilst reading last nite before I spat the dummy trying to upload pics, that the pipe you mentioned has vac from under the middle of the runners via metal tube, then 90° rubber hose into 90° PVC valve into rocker cover. The other side is similar but my pic not so good, I'll have a look on the Blue.
Also if you attempt to read the pulses with digital voltmetre - it will try to average out the pulses and display an equivalent DC voltage reading, whilst not accurate it is indicative that one coil is being driven continuously - and upon reflection I cant find the magic 4.2Vdc we spoke about - I think that voltage is to do with the TPS setting.
Ummmm you could actually look at the voltage, since if its a pulse, a CRO would display it, now just where that CRO is, umm the killer chickens amd mice live on that side of the garage......... bugga !!!!!!!
