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Is it possible, High Idle Modification using 0411pcm
Posted: Sat Dec 18, 2021 7:13 pm
by NoInfo
Is it possible to have a high idle modification done using an unused input for the 0411 pcm?
Or maybe using the LS1 Boost OS?
viewtopic.php?f=42&t=7482
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Sat Dec 18, 2021 11:04 pm
by B52Bombardier1
How high of an idle RPM do you wish to go? As you go higher, you will also need to also give it more air. I've gone as high as 800 RPM on both an 0896 and a 0411 PCM with little difficulty - up from the stock RPM of 550 - but my leg got a bit of a workout holding the brake pedal at that RPM.
So, how high is "high"?
Rick
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Sat Dec 18, 2021 11:36 pm
by NoInfo
Is that a limit of the IAC valve?
I would like it to be adjustable up to about 1100rpm.
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Sat Dec 18, 2021 11:39 pm
by In-Tech
It's more like a PTO(Power Take Off) mode and is available mode in many GM controllers. I have not researched in the later controllers but it was for external water pumps as well as higher output from the alternator so they could drive external welders in the field.
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Sun Dec 19, 2021 12:05 am
by NoInfo
I see that some of the trucks have:
Blue Connector
pin 22 PTO Switch Enable Signal
pin 52 PTO Status Signal
pin 78 PTO Engaged Signal
On the Express and Astro it looks like none of those are populated/used.
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Sun Dec 19, 2021 1:25 am
by turbo_bu
Yes, PTO is what your looking for. It was on some pickups and Kodiaks. I believe that it used the cruise control switches.
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Mon Dec 20, 2021 7:38 am
by NSFW
Please tell us more about your scenario.
When I was struggling with return-to-idle tuning, I set the idle to be 1200 RPM when AC was on (normally 750 RPM). So when I was out tinkering with idle settings, if I made a change that didn't work out, I would just turn on AC to band-aid the problem. It was a little weird but at least the engine wouldn't sputter and die at random intersections while I drove back home for another reflash.
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Fri Dec 24, 2021 9:29 am
by NoInfo
That is a great idea while working on tunes, TY!
I want to increase the idle for faster charging a battery bank.
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Sat Dec 25, 2021 10:14 am
by NSFW
That sounds very similar to what the Power To Off mode was for.
I don't know whether any 411/P01 operating systems support it, but PTO is definitely a feature in the 12587603 OS for the P59 PCM.
Re: Is it possible, High Idle Modification using 0411pcm
Posted: Wed Dec 29, 2021 12:59 am
by turbo_bu
I'm pretty sure that the code for the PTO is in each OS since there is a place for the PTO option in the vehicle platform table under the system segment. I do know that there are quite a few parameters for the PTO under the engine segment. If you are starting with an OS which didn't have the PTO enabled, those parameters might be zeroed out. You would just have to copy over that section of code from a truck that had PTO enabled.