fast idle system on gas engine

[Tattooo]

Good to know

[redwngr]

Fast idle still works on my '14 1500. I think people hear fast idle and automatically think it's a diesel only thing, nope, just follow the directions in the manual and rpms jump up to 1200 rpm. Also read on here about a year ago for vehicles with no cruise to turn the key on but don't start, press gas pedal all the way to the floor and tap break pedal repeatadlly for 3 times within 8 seconds. Never tried that one though.

2014 and 2015 OM's both say:

cut and paste

Fast Idle System

If equipped, this feature is available

only with cruise control. The manual

fast idle switch is operated using the

cruise control buttons on the left

side of the steering wheel.

Of course undocumented features have been found in software before.

[Braaap60]

2014 and 2015 OM's both say:

 

cut and paste

 

Fast Idle System

If equipped, this feature is available

only with cruise control. The manual

fast idle switch is operated using the

cruise control buttons on the left

side of the steering wheel.

 

Of course undocumented features have been found in software before.

Here's a screen shot of the post I saw about a year or so ago.

[redwngr]

Elevated idle is a diesel only feature. (your pic is from the Duramax supplement)

 

Dmax trucks can have both the Elevated idle AND the Fast idle.

 

 

Elevated idle will engage/disengage automatically. It drags the torque converter to create load and also heat the Allision. It also adjusts the vane position on the turbo.

 

Fast idle, operated manually by the cruise buttons, simply raises the rpm. It is useful when higher engine rpm is desired for things like boosting another vehicle or operating pto driven devices that may be connected to the allison.

[redwngr]

From the 2014 diesel supplement, the Elevated Idle and Fast Idle explanations are one after the other starting on page 9-3.

 

cut and paste:

Elevated Idle

The engine has a cold temperature

high idle feature which elevates the

engine idle speed from base idle to

1050 rpm for pickup models or

1200 rpm for van models 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.

This feature can be turned on or off

using the DIC buttons. If the vehicle

is not equipped with DIC buttons, do

the following to turn this feature on

or off:

1. Turn the ignition to ON/RUN,

with the vehicle off.

2. Press the accelerator pedal to

the floor and hold while quickly

pressing the brake pedal three

times in less than eight seconds.

3. Release the accelerator pedal

and start the engine.

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.

Fast Idle Control

The vehicle may have this system

which can be used to increase the

engine idle speed.

Fast Idle control will be enabled

when the following conditions

are met:

. The parking brake is set.

. The transmission is in P (Park)

or N (Neutral).

. The vehicle speed is about

0 km/h (0 mph).

. The cruise control is in the On

position. See “Cruise Control” in

the owner manual.

. The cruise control Set switch is

pressed and released for Preset

Fast Idle Speed (1200 rpm).

Fast Idle control will be disabled

when one or more of the following

conditions occur:

. The cruise control is in the Off

position.

. The cruise control Set switch is

pressed and released. See

“Cruise Control” in the owner

manual.

. The cruise control Cancel switch

is pressed.

. The brake pedal is pressed.

. The transmission is shifted out

of P (Park) or N (Neutral).

. The parking brake is released.

. The vehicle speed is not

0 km/h (0 mph).

When Fast Idle is active, a

FAST IDLE ON message will be

displayed in the Driver Information

Center (DIC). See Starting the

Vehicle Messages on page 5-12

[tanner709]

I'll try it on my '14 1500 SLE tomorrow...

 

FYI the "possible" fire issue I've seen first hand, and it burnt the truck to the ground. It also nearly burned the house of the owner as well. Happened in my province - seemed to only be occuring in extremely cold climates but scary nonetheless.

[SMiller]

Fast idle is a $200 option on the HD trucks, it can be had with both gas and diesel. I ordered my gas 3500 with it.