[Xortex]

I also re-checked the voltage between the DRV8825 current adjustment pot and the 12v supply as explained in the wiki and it is 9.15V. This is the best value I could get in either direction. Is this a normal value?

[Xortex]

which is why it is only a temporary solution until I address the underlying stepper issue.

Do you know what else I can have a look at? I set the maximum current pot as explained in the wiki and fiddled around with several combinations of step time (ms) and cool time (ms) settings.

I removed the stepper from the IAC valve and it is moving in the correct direction for the less air and more air movements, as well as the home position. I also cleaned up the IAC valve to make sure that there is no dirt resisting stepper movement, but to no avail.

[ric355]

which is why it is only a temporary solution until I address the underlying stepper issue.

Do you know what else I can have a look at? I set the maximum current pot as explained in the wiki and fiddled around with several combinations of step time (ms) and cool time (ms) settings.

I removed the stepper from the IAC valve and it is moving in the correct direction for the less air and more air movements, as well as the home position. I also cleaned up the IAC valve to make sure that there is no dirt resisting stepper movement, but to no avail.

Sorry, didn't spot this question.

I can't really give you any other advice than to try a new valve if your existing one is old. I said in one of my earlier posts that I had been trying to find a moment to give a replacement valve a try on my engine, and I managed to do so the other day. So far it seems like it is working exactly as it should, such that I've even been able to switch on closed loop idle control and it hits the target pretty well. Oddly it seems to overshoot when the engine is cold but I may just be a bit lean during warmup as it was all tuned for open loop operation.

[Roverdog]

I found a better solution on my Rover V8 is to use the idle timing control,responds much faster than any IAC,
Easily & quickly compensates for load from the power steering and rad fan .just use a switched valve to compensate for the higher load from a/c.

[Xortex]

I found a better solution on my Rover V8 is to use the idle timing control,responds much faster than any IAC,
Easily & quickly compensates for load from the power steering and rad fan .just use a switched valve to compensate for the higher load from a/c.

What do you mean by idle timing control, is it the cells for low rpm on the spark table?

Thanks.

[Roverdog]

Look in the idle menu,fairly easy to setup,you will already have a target idle speed set.
I have also found it works great to improve off idle response.

http://wiki.speeduino.com/img/idle/idle_advance.png

Idle advance control
Idle speed can be controlled without the use of an idle valve (IACV) by adjustiming timing. This feature references the same idle RPM target curve that is used by the closed loop idle control and will then adjust the advance based on the error between current and target RPM.

[Xortex]

Cheers, I'll fiddle around with this table, it was not available on older firmware versions so my old tune never used it.