16 Scat Pack desired idle issues

[totalengine]

I have a 2016 Scat Pack Charger here that we just installed a 426 in, and im having issues with the desired idle not commanding what the idle rpm is actually set to in the tune. In the tune (see attached) i have the idle set to 704 RPM in park and drive, which the car idles at perfectly, EXCEPT immediately after coming to a stop. In the attached log, you will see that as soon as i come to a stop, the desired idle goes to 550 RPM for a second or two, and then jumps back up to what its supposed to be, 704 RPM. As you can imagine, the car stumbles and almost dies during those couple seconds, but once the desired idle goes back up to 704 the car will idle perfectly. I cannot see anywhere in the tune where its telling the car to idle at 550 RPM at any time, Is there something i am missing? Does anyone have any ideas why it would desire an idle Rpm that is less than what is commanded in the tune for those couple seconds after coming to a stop?

What is even weirder is that it does not do it every time. If i come to a stop extremely slowly, the desired idle wont dip down to 550, and will stay at 704, but if i come to a stop at a normal rate to a fast rate, the desired idle will drop down to the 550 rpm for a couple seconds.

[wrc]

I have a 2016 Scat Pack Charger here that we just installed a 426 in, and im having issues with the desired idle not commanding what the idle rpm is actually set to in the tune. In the tune (see attached) i have the idle set to 704 RPM in park and drive, which the car idles at perfectly, EXCEPT immediately after coming to a stop. In the attached log, you will see that as soon as i come to a stop, the desired idle goes to 550 RPM for a second or two, and then jumps back up to what its supposed to be, 704 RPM. As you can imagine, the car stumbles and almost dies during those couple seconds, but once the desired idle goes back up to 704 the car will idle perfectly. I cannot see anywhere in the tune where its telling the car to idle at 550 RPM at any time, Is there something i am missing? Does anyone have any ideas why it would desire an idle Rpm that is less than what is commanded in the tune for those couple seconds after coming to a stop?

What is even weirder is that it does not do it every time. If i come to a stop extremely slowly, the desired idle wont dip down to 550, and will stay at 704, but if i come to a stop at a normal rate to a fast rate, the desired idle will drop down to the 550 rpm for a couple seconds.

I think you have to look at the Idle Torque Throttle PID settings for drive, you should make some minor changes to compensate for the intermittent dipping. Try bringing in the adjustments a little sooner and see what works. Of course it is always trial and error.

[Hemituna]

It is the 'low idle mode' setting.
Adjust it closer to your idle target or if you don't have such a setting in your OS, HPt support can add it for you.
It seems the low idle mode is used as a TB cal type feature so when you flash a vehicle it will check it a few times to make sure that the idle can be controlled.
If you have a vacuum leak etc, it will then usually pop a cel.
After a few run cycles, you will rarely see it occur anymore.
Even stock vehicles do this occasionally.
If you can adjust this setting, it stops this annoying behaviour especially when tuning and flashing often.

[JoshCP527]

Looks like some of the minimums go bellow 704. Vehicle speed is set down to 1? I thought raising this to 5 helps with transitioning into idle control sooner. Enable rpm error is 600 does that mean it has to drop below 600 before taking over confused?

[totalengine]

It is the 'low idle mode' setting.
Adjust it closer to your idle target or if you don't have such a setting in your OS, HPt support can add it for you.
It seems the low idle mode is used as a TB cal type feature so when you flash a vehicle it will check it a few times to make sure that the idle can be controlled.
If you have a vacuum leak etc, it will then usually pop a cel.
After a few run cycles, you will rarely see it occur anymore.
Even stock vehicles do this occasionally.
If you can adjust this setting, it stops this annoying behaviour especially when tuning and flashing often.

I dont see a "low idle mode" anywhere in the tune. Where would this normally be located in the tune file so i can make sure i am not over looking it and also so i can ask HPT to add it?

So to make sure i understand correctly, you're saying that it should stop doing the low idle mode check after a few key/run cycles as long as i dont flash a tune? If thats the case then i will do some more driving with it and not flash another tune and see if it stops.

Ive run into this same problem recently on a 14' WK2 426 also, and never figured out why it was desiring such a low idle for a few seconds after coming to a stop, but it wasnt as noticeable as that motor had a relatively smooth idle so it would idle at that low rpm without issue. I also just looked at that tune file, and did not see a "low idle mode" in that file either.

[totalengine]

Looks like some of the minimums go bellow 704. Vehicle speed is set down to 1? I thought raising this to 5 helps with transitioning into idle control sooner. Enable rpm error is 600 does that mean it has to drop below 600 before taking over confused?

I should of added earlier that i changed every idle table that is available to a minimum of 704, and that didnt work either. It still desired an idle speed of 550 for a couple seconds immediately after coming to a stop, and then jumped back to 704 desired. The vehicle speed set at 1 is how the tune is stock, but i also upped that to 3MPH and it didnt change anything. I will give 5MPH a try also and see what happens.
,
The enable rpm error at 600, as far as i understand it, means that 600 rpm above the idle rpm is where the Idle torque spark will begin to start making corrections. So for example, in my case, idle speed is 704, and enable rpm error is 600, 704+600=1304RPM. Below 1304 RPM is where the idle torque spark will begin making corrections, if i understand it correctly.

[Hemituna]

I've had to have it added to a few OS's.
It should be in the idle section on 2012+ VVT's, so have support add it for you.

It will go low idle mode only occasionally once the tune has been in for a while.
But can be real annoying when you are tuning or if your mods need a higher idle.

I idle a lot of the big hemis at 600 rpm, so if they drop to 550 it is not very noticeable.
But I still lift low idle mode to the idle speed or close if the table is available to eliminate the drop in rpm.

I dont see a "low idle mode" anywhere in the tune. Where would this normally be located in the tune file so i can make sure i am not over looking it and also so i can ask HPT to add it?

So to make sure i understand correctly, you're saying that it should stop doing the low idle mode check after a few key/run cycles as long as i dont flash a tune? If thats the case then i will do some more driving with it and not flash another tune and see if it stops.

Ive run into this same problem recently on a 14' WK2 426 also, and never figured out why it was desiring such a low idle for a few seconds after coming to a stop, but it wasnt as noticeable as that motor had a relatively smooth idle so it would idle at that low rpm without issue. I also just looked at that tune file, and did not see a "low idle mode" in that file either.

[totalengine]

Thanks Hemituna, i had HPT add the low idle rpm tables and raised the low idle rpm to match the idle rpm and that took care of the issue.

[Hemituna]

Glad you got it sorted