Idle Adjustment Procedure

[imtb]

I reviewed some of the post but want to make sure I am adjusting idle correctly.

My 2.2 idle lows 750 or so and its in a heavy vw van so, I just adjusted the idle screw on TB, not much and it jumped to 850 seems better. I had the diagnostic running on the computer and it seemed like the IAC value went down, need to confirm this.

Shuld I follow this procedure.

Warm up to operating temp.

Set RPMs with TB adjustment screw

Check IAC value duty to 35%, Do I loosen 2 screws on top of IAC and adjsut to if needed? I can watch with scan tool to make it set correctly.

Let me know if I missed something.

thanks

[Legacy777]

The ECU wants to run at programmed RPM, so if you adjust the idle stop screw, the IAC valve is going to decrease duty % to maintain the programmed RPM.

There really is no proper way to adjust the idle other than changing the ECU programming. However, with that said, I think you would have better luck rotating the head on top of the IAC valve slightly to get you a little more idle speed.

[imtb]

I adjusted idle screw on TB 800rpms and was waiting to hear how to adjust IAC before I messed up it. Went ahead and check the IAC and it was 25.4 on computer. Loosed to screws and I could hear idle go down but computer wasnt changing. Moved IAC other way idle went up to 825, 850 and I could hear good vacuum thru intake filter, IAC stay same 25.4 wouldnt move. Idles good 825-850 left it there and test run was good. Left as is. Not sure why IAV value wasnt changeing.
I will check again tomorrow.