GM style IACV control frustration.

[craigkenyon]

Using TS MS v2.0.4 with MS2/Extra release 2.1.0 controller
The IACV is wired IAW the manuals available at the time ( MS@ Extra Quick Guide, MegaTune) and IAW JAmes Murray's Hardware manual for the 3.57 board page 36 IAC1a, IAC1b, IAC2b, IAC2a looking at the IACV. The IACV is working in open loop where the start value drives the valve fully Open. This is IAW with the old manuals. I can't get the closed loop to function or go into CL. James Murray's current manuals imply that homing steps and wide open steps are for initially driving the valve fully Closed on start up. The earlier tune file is for the CL, the later is when I went back to open loop. log of the open loop is also attached. TR6 straight 6 with EDIS ignition and bespoke manifold, GM throttle body, port bank injection, speed density.

[billr]

Try "always on" instead of "moving only".

[jsmcortina]

If possible, update to the current firmware. There are many years of tweaks and bug-fixes to idle control since that old code you are using.

James

[craigkenyon]

Didn't work with always moving either. My main question is when and why did the standard go from fully open on start up to fully closed on start up.

[billr]

You set the homing direction in TS. Study the "Start/Idle" tab options some more.

Edit: You said "always moving" didn't work, but that isn't a valid option. Did you mean "always on"? There is also now a "holding current between steps" option that probably works as well without as much heating of the stepper windings.

[jsmcortina]

My main question is when and why did the standard go from fully open on start up to fully closed on start up.

In around 2006 I think, when we first created MS2/Extra.

James

[craigkenyon]

James. thank you. I am going to delay the firmware update while I sort some other issues. I will assume that with the update TS will then display the homing direction (not available on the older firmware). Now the question is, will the current TS with the current firmware operate the GM IACV in closed loop even though it is currently wired in accordance with the older documentation?

[jsmcortina]

I'm not aware of any changes in the wiring of the GM 4-wire stepper idle valve?

James

[Matt Cramer]

With the latest firmware, you can specify either direction as the homing direction.

[craigkenyon]

James and Matt, thank you for the info. I will update the post when I update the firmware. Currently working through issues with my LC-1 widebands. They are 4 years old and developing "issues".