IAC valve

[inoutinout]

Hi all
I have a gas/fuel problem that may be the IAC valve. To check the IAC I have followed the book instructions and started the car warmed it up and left it to idle. (950 RPM) The book then says to turn off the vehicle and disconnect the IAC valve and start the car with it disconnected. The RPM should climb noticeably. It didnt.
I did the same to my other VS commodore same year and model and the RPM went to nearly 1500 RPM so I assume the car is running right and the IAC is working correctly.
I changed IAC from the good car into the bad car and redid the test. There was still no noticeable change in the RPM.
I then checked the hoses and they were fine.
Have connected a voltmeter to the wires of the IAC and the wires on both cars have the same readings.
The RPM should change when the IAC is disconnected. Can anyone see anything I am missing.
Thanks for your time.

[Brett_jjj]

Hi,try checking for any logged error codes.---Checking error codes VR/VS (Revised)---

[t0bes]

Is the throttle body clean? the path to the IAC might be really gummed up preventing the good IAC from doing anything..?

[Cheap6]

With the IAC disconnected the idle will not change. It should change when reconnected as the PCM relearns the IAC motor position. You might try running the engine with the spare IAC valve/motor connected instead of the one in the car and watch what happens when the A/C (a load) is switched on. That will tell you if the IAC is being driven by the PCM.

It most likely is just a gummed up IAC port +/or throttle plate though.

[my03equipe]

Try removing IAC whilst connected to wiring and get some one to turn key to ON not START. IAC should move in or out, if movement occurs IAC ok. Whilst it's out clean it, Carby cleaner works well. Check Vac lines closely too, check air box and intake and make sure filter fitted properly. Consider getting your Air Flow meter checked and crank angle sensor but that may be worst case scenario. Commodore engines can be quite twitchy when it comes to O2 intake.