Found out something interesting this morning (I think)
22° out this morning and I remote started the truck. When I walked out to it 5 or so minutes later, It had already gone to high idle. I got in and clicked the exhaust brake switch but noted no change in the engine tone. Pretty sure they have these set to automatically engage the exhaust brake when it’s cold out and you start the truck. On my 2017 CTD, I had to manually engage the exhaust brake. Love it!
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You're probably also aware, but for the benefit of others reading that may not, you can also manually idle up (to 1,500RPM) by pressing the Cruise, then Set button to engage, then pressing Accel repeatedly to raise + from 1,100 up to 1500 RPM. The ECU will limit this if the engine is too cold. Set - to lower.
Foot on the brake cancels it.
Your vehicle is equipped with an engine warm up protection feature that may limit engine performance after cold starting at low ambient temperatures. The length of time engine speed is limited is dependent upon engine coolant temperature. Engine speed may be briefly limited to 1000 RPM after starting with coolant temperature below freezing conditions, and may be limited to 1000 RPM for up to approximately 2 minutes under more severe cold conditions.
NOTE:
If ambient temperatures are low and the coolant temperature is below 180°F (82°C), the engine idle speed will slowly increase to 1,000 RPM after two minutes of idle, if the following conditions are met:
Foot is off brake pedal and throttle pedal.
Automatic transmission is in PARK.
Vehicle speed is 0 mph (0 km/h).
Applying the throttle will cancel fast idle.
Operating the exhaust brake at idle will greatly improve warm up rate and will help keep the engine close to operating temperature during extended idle.
Engine Idling
Avoid prolonged idling, long periods of idling may be harmful to your engine because combustion chamber temperatures can drop so low that the fuel may not burn completely. Incomplete combustion allows carbon and
varnish to form on piston rings, engine valves, and injector nozzles. Also, the unburned fuel can enter the crankcase, diluting the oil and causing rapid wear to the engine. If the engine is allowed to idle or the truck is driven on low engine speed drive cycles for more than 2 hours, the system will automatically enter an emissions operating mode that will increase the engine idle speed to 900 RPM.
While in this mode, which is designed to help maintain the diesel particulate filter, the engine idle speed will return to normal when the brake pedal is applied. A small change in engine tone or a slight change in engine performance while accelerating may also be noticeable at speeds below 20 mph (32 kmh). This operating mode may last for up to an hour of idle time, or around 20 minutes of driving time.
Your truck may have been ordered with an optional voltage monitoring idle up feature. If a load is placed on the electrical system while the truck is in park, this feature will attempt to maintain normal system voltage by automatically increasing engine idle speed. You may notice several consecutive increases in idle speed, up to a maximum of 1,450 RPM, as the system will attempt to utilize the smallest increase in idle speed necessary to maintain normal system voltage. The idle speed will return to normal when either the electrical load is removed, or when the brake pedal is applied.
Idle-Up Feature
The driver-controlled high idle speed feature will help increase cylinder temperatures and provide additional cab heat, however, excessive idling may still cause the exhaust aftertreatment system to not properly regenerate.
Extended periods of idle time should be avoided.
The Idle-Up feature uses the Speed Control switches to increase engine idle speed and quickly warm the vehicle's interior.
1. With the transmission in PARK, the parking brake applied, and the engine running, push the speed control switch to the ON position, then push the SET switch.
2. The engine RPM will go up to 1,100 RPM. To increase the RPM, push and hold the ACCEL/RESUME switch and the idle speed will increase to approximately 1,500 RPM.
To decrease the RPM, push and hold the DECEL switch and the idle speed will decrease to approximately 1,100 RPM.
3. To cancel the Idle–Up feature, either push the CANCEL switch, push the ON/OFF switch, or press the brake pedal.
