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PID Idle Closed Loop Idle settings in MSII
https://mail.slantsix.org/forum/viewtopic.php?t=68424
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Author:  Greg Ondayko [ Wed Nov 12, 2025 4:39 pm ]
Post subject:  PID Idle Closed Loop Idle settings in MSII

Since my original install of MSII (2008) it works well for my needs (batch fired multi-port injection) and full (single) coil control by the MS II via a OE type Slant 6 Distributor.

I updated the firmware from 2008 to ~2019 I think about 6 years ago. The firmware update added so much more functionality in tuner studio / MSII.

The CL Idle control works well except for some hunting issues on a ~ medium warm restart.. It will hunt and oscillate for a few seconds; however if i give it just a bit foot throttle angle, the hunting vanishes when CL Idle shuts off.

What I am asking here is without blindly playing with the P, I, D settings, (as every other idle situation is very good - not 2020 OE new car good, but good enough for me) how to I tune out the "hunt/oscillate" in the P, I, D Settings?


Thank you,
Greg

Author:  Rick Covalt [ Wed Nov 12, 2025 5:01 pm ]
Post subject:  Re: PID Idle Closed Loop Idle settings in MSII

Replace fuel injection with BBD. :mrgreen:

Author:  Greg Ondayko [ Wed Nov 12, 2025 6:18 pm ]
Post subject:  Re: PID Idle Closed Loop Idle settings in MSII

Quote:
Replace fuel injection with BBD. :mrgreen:
I did it the other way 'round sir!

This is the fuel injection sub-forum 'ya know!

Author:  Rick Covalt [ Fri Nov 14, 2025 4:01 am ]
Post subject:  Re: PID Idle Closed Loop Idle settings in MSII

I knew I got lost somehow! :D

Author:  DadTruck [ Sun Nov 16, 2025 1:15 pm ]
Post subject:  Re: PID Idle Closed Loop Idle settings in MSII

Greg,
Check the ignition advance table to verify that the idle oscillation is not due to the ignition advance table adding advance and causing the RPM run up, having the rpm too high the ecm cuts fuel dragging the rpm down, the ignition then advanced causing the oscillation.

I too have my slant powered ms controlled 68 Barracuda starting and driving like a modern car.
Just turn the key, no throttle added and it starts, idles down as it warms.

I ‘messed’ with the PID to get where I am.
And messed with is basically what I did.
1) made one adjustment at a time and then took the time to determine if there was a difference
2) kept good notes on what was changed so I could go back and not run myself in circles.

I don’t currently have access to my notes or the car so I can’t be more exact on what I did.


There are You Tube videos that provide guidance of what each element of PID does that were helpful.

Author:  Greg Ondayko [ Mon Nov 17, 2025 4:45 am ]
Post subject:  Re: PID Idle Closed Loop Idle settings in MSII

I am pretty sure the Ign advance is not the issue, but a good thought to check. I will have to do that and keep the Ign advance gauge open when I observe hunting, which is not often. Sometimes it starts and idles down just superb.

I have seen some videos, but I was looking for specific guidance on how it applies to the CL Loop. There is also a slider in the settings window that seems to scale all of the settings for the PID CL Idle.

I guess I wanted a more pinpointed approach instead of fussing and doing trial and error testing, as I know how to do that.

Author:  Dart270 [ Mon Nov 17, 2025 5:58 am ]
Post subject:  Re: PID Idle Closed Loop Idle settings in MSII

You could try moving the slider to the "faster" or "higher gain" setting and see if that helps. Often when a feedback system oscillates, it is because the feedback timing (time constant) is too slow for to compensate for the effect that is causing the changes to the system.

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