3.0 Duramax High Idle Setting

[Time2gofishing1980]

Question on the high Idle setting.  I couldn't find the info in the diesel supplement manual or normal manual.  

 

I'm assuming if I turn the high idle setting on it will be ECM controlled conditionally based on external temp?  We're in a cold stretch and the truck was still cold after I let it run for 10 min before getting in.  I'm thinking high idle will help

[redwngr]

On 6.6L diesel there is an elevated idle function that is automatic -- so it will engage after remote start.  It is a standard item.  

It will warm both engine and trans.. Does things like dragging torque converter and engine fan to create more load/heat.   

 

There is also an optional 'high idle' function available that is manually operated. Gives higher speed, but does not do the heat generating extras. It appears that the high idle option (UF3) is available on both 6.6's. 

 

6.6L dmax has a bunch of info about the 'elevated idle' function.  If it's not in the 3.0 supplement, perhaps it's not available -- or they have made it automatic and it cannot be disabled.

 

On 6.6 it will run the idle up to about 1100rpm.  It will only function below 32*F ambient and below about 160*F coolant.  (also requires not throttle or brake. zero speed and transmission not in gear) There is a menu item to disable/enable.  Most leave it enabled, since it only kicks in the cold anyway. 

 

 

Does your 3.0 idle up on a cold start at below freezing temps?

 

 

[Time2gofishing1980]

It doesn't appear to change idle speed below freezing.  The high idle option is turned off in the vehicle customization settings by default.  I guess I'll turn it on and test the functionality by seeing how it reacts with different ambient temps.   I'll report back!

[redwngr]

9 hours ago, Time2gofishing1980 said:

It doesn't appear to change idle speed below freezing.  The high idle option is turned off in the vehicle customization settings by default.  I guess I'll turn it on and test the functionality by seeing how it reacts with different ambient temps.   I'll report back!

I didn't see reference to it  (did I miss it? page number?) in the 3.0L diesel supplement I downloaded, so wondered it  was automatic.

 

May or may not be useful to you, but this is the what the (2020) supplement for the 6.6L  says about the 'elevated idle' uses:  (earlier 6.6's were similar) 

This 'elevated idle' is standard on 6.6L duramax. 

 

Elevated Idle

The engine has a cold temperature high idle feature which elevates the engine idle speed from base idle to 1050 to 1100 rpm when outside temperatures are below 0 °C (32 °F), and the engine coolant temperature is below 65 °C (150 °F). This feature enhances heater performance by raising the engine coolant temperature faster.

 

To turn this feature on or off, see Vehicle Personalization 0 13.

 

When the engine is started, it will slowly ramp up to the high idle speed after a delay of a few seconds up to approximately two minutes. For this method to work properly there must be no throttle or brake pedal faults.

 

The engine idle speed will return to normal once the following conditions are met: 

 

. Engine coolant temperature reaches 65 °C (150 °F).

. Air intake temperature reaches 0 °C (32 °F).

 

The high idle speed will be temporarily interrupted and the engine speed will return to normal if any of the following conditions occur:
. The brake pedal is applied.
. The accelerator pedal is pressed.
. The transmission is shifted out of P (Park) or N (Neutral).
. Vehicle speed is detected.

 

Once these inputs are removed, the engine idle speed will slowly ramp back up to high idle after the normal delay, if the conditions for engine coolant temperature and air intake temperature are still met.

 

 

There are separate instructions for the optional Fast Idle system -- but basically, if ordered, it is run by the cruise buttons.  

(I haven't seen any mention in the order guide about a Fast Idle option on a 1500)

 

2020 6.6 dmax shows this extra entry to the climate and air quality section::

 

Climate and Air Quality

Select and the following may display:

. Rapid Heat-Elevated Idle Rapid Heat-Elevated Idle

This allows the feature to be turned on and off. See “Elevated Idle” in Starting the Diesel Engine pg 15.
Select Off or On.

 

 

Interested to hear if this setting is available on the 3.0 and what the setting change does for you! 

 

(I don't see the setting and instructions in the 3.0 supplement or main OM for 2020 )

 

[redwngr]

9 hours ago, Time2gofishing1980 said:

It doesn't appear to change idle speed below freezing.  The high idle option is turned off in the vehicle customization settings by default.  I guess I'll turn it on and test the functionality by seeing how it reacts with different ambient temps.   I'll report back!

I didn't see reference to it  (did I miss it? page number?) in the 3.0L diesel supplement I downloaded, so wondered it  was automatic.

 

May or may not be useful to you, but this is the what the (2020) supplement for the 6.6L  says about the 'elevated idle' uses:  (earlier 6.6's were similar) 

This 'elevated idle' is standard on 6.6L duramax. 

 

Elevated Idle

The engine has a cold temperature high idle feature which elevates the engine idle speed from base idle to 1050 to 1100 rpm when outside temperatures are below 0 °C (32 °F), and the engine coolant temperature is below 65 °C (150 °F). This feature enhances heater performance by raising the engine coolant temperature faster.

 

To turn this feature on or off, see Vehicle Personalization 0 13.

 

When the engine is started, it will slowly ramp up to the high idle speed after a delay of a few seconds up to approximately two minutes. For this method to work properly there must be no throttle or brake pedal faults.

 

The engine idle speed will return to normal once the following conditions are met: 

 

. Engine coolant temperature reaches 65 °C (150 °F).

. Air intake temperature reaches 0 °C (32 °F).

 

The high idle speed will be temporarily interrupted and the engine speed will return to normal if any of the following conditions occur:
. The brake pedal is applied.
. The accelerator pedal is pressed.
. The transmission is shifted out of P (Park) or N (Neutral).
. Vehicle speed is detected.

 

Once these inputs are removed, the engine idle speed will slowly ramp back up to high idle after the normal delay, if the conditions for engine coolant temperature and air intake temperature are still met.

 

 

There are separate instructions for the optional Fast Idle system -- but basically, if ordered, it is run by the cruise buttons.  

(I haven't seen any mention in the order guide about a Fast Idle option on a 1500)

 

2020 6.6 dmax shows this extra entry to the climate and air quality section::

 

Climate and Air Quality

Select and the following may display:

. Rapid Heat-Elevated Idle Rapid Heat-Elevated Idle

This allows the feature to be turned on and off. See “Elevated Idle” in Starting the Diesel Engine pg 15.
Select Off or On.

 

 

Interested to hear if this setting is available on the 3.0 and what the setting change does for you! 

 

(I don't see the setting and instructions in the 3.0 supplement or main OM for 2020 )

 

[pewterliftedz]

On one of the reviews I watched the engineer stated that, there is no high idle switch or exhaust brake switch on the 3.0L Dmax.

[Time2gofishing1980]

21 hours ago, pewterliftedz said:

On one of the reviews I watched the engineer stated that, there is no high idle switch or exhaust brake switch on the 3.0L Dmax.

It's in the climate control options in the settings menu.  It only appears when the vehicle is started.  

 

 

[redwngr]

4 hours ago, Time2gofishing1980 said:

It's in the climate control options in the settings menu.  It only appears when the vehicle is started.  

 

Thanks for verifying that it does 'elevated idle''. 

I expect it doesn't do the other one -- the 'high idle'.

 

Did you have to turn it on or was it on already?

Have you done a 'below freezing' start (or remote start) with it on?

Did it ramp up the idle?

And then kick off if/when the throttle, brake or gearshift was moved?

[Time2gofishing1980]

1 hour ago, redwngr said:

Thanks for verifying that it does 'elevated idle''. 

I expect it doesn't do the other one -- the 'high idle'.

 

Did you have to turn it on or was it on already?

Have you done a 'below freezing' start (or remote start) with it on?

Did it ramp up the idle?

And then kick off if/when the throttle, brake or gearshift was moved?

So whether elevated idle is on or off it seems to idle at about 1k when the weather is cold.  I couldn't get it to change rpm by toggling off or on after start.  I also didn't notice any difference in starting via push button or remote start.

 

I'm really stumped on what it does...

[1500Duramax]

So I’ll share my high idle story only because i never thought this would happen to me. After power washing my floor mats I put the mat over the gas pedal. The pressure was enough to idle at 1200. Not sure how that happened. I wear cowboy boots and I honestly couldn’t feel the difference. So there’s that. 

[ReZpawN]

On 1/22/2020 at 8:13 AM, Time2gofishing1980 said:

It's in the climate control options in the settings menu.  It only appears when the vehicle is started.  

 

 

Which trim and year is your 3.0? I got a 2022 ltd ltz 3.0 and mine doesn't have the last option in settingd menu.

[mjonesjr84]

53 minutes ago, ReZpawN said:

Which trim and year is your 3.0? I got a 2022 ltd ltz 3.0 and mine doesn't have the last option in settingd menu.

 

It was removed somewhere in the mid 2021 model year. I know my 2022 refresh does it automatically. You can hear the RPM ramp up if you are setting with the AC or heat on and when the truck is remote started.