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Truck idling around 1k

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Captn

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Hello everyone, I am new here so please just point me to the right thread if this has already been solved.

I’ve had a 2022 6.7 for about a year. The truck currently has 45k. It’s pretty much stock other than lift. A few days ago I started it and noticed the idle seemed higher than normal. It was staying at 1k from the moment it was started and in park. When pressing the brake it lowers to a normal idle but when I let go it goes right back up. This only happens in park and not any other gear at Idle.

Is this something these trucks just do? I’ve seen some stuff about the regen but I always thought that happened while driving and at normal operating temps.

Any help is appreciated and thanks in advance
 
Fast idle can be commanded for too cold or too high of coolant temp. Are your gauges indicating correctly?
 
AH64ID said:
Fast idle can be commanded for too cold or too high of coolant temp. Are your gauges indicating correctly?
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Just checked, started and drove around for about 20 minutes, everything came up to temp and when I put it in park it still continued to increase idle
 
My 22 idles up to around 800 at various times and I can’t get anything on why. It’s a little harder to stop when it tries to keep pulling. I checked to see if the Torque Converter was staying locked but it doesn’t appear to be. Does it mostly during hot weather but all of the temps are good. Idk
 
Are you running the A/C when noting the higher idle?
 
If it’s the ac doing it, why doesn’t it do it all of the time? It didn’t do it at all today when I drove it and it was 97* with the AC on doing all it could do.
 
OLEJOE said:
If it’s the ac doing it, why doesn’t it do it all of the time? It didn’t do it at all today when I drove it and it was 97* with the AC on doing all it could do.
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Have you tried scanning it? Have you looked for vacuum leaks?
 
I have a ScanGauge that runs all of the time. I monitor 27 different pids for just about everything and I can’t find anything out of the ordinary. I thought it might be the torque converter staying locked but no. I thought it might’ve been injector timing no. I thought it might be fuel pressure no. Can’t find anything that is out of spec causing this.
Other than that, I have had zero issues with the truck for the last year and a half. No fuel in oil, only time based regens and everything is working like it’s supposed to except the intermittent higher than normal idle.
 
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I noticed today that if I had the EB on, when it did the high idle, if I turned the EB off it would idle back to normal. Going to have to do some more testing.
 
Captn said:
Hello everyone, I am new here so please just point me to the right thread if this has already been solved.

I’ve had a 2022 6.7 for about a year. The truck currently has 45k. It’s pretty much stock other than lift. A few days ago I started it and noticed the idle seemed higher than normal. It was staying at 1k from the moment it was started and in park. When pressing the brake it lowers to a normal idle but when I let go it goes right back up. This only happens in park and not any other gear at Idle.

Is this something these trucks just do? I’ve seen some stuff about the regen but I always thought that happened while driving and at normal operating temps.

Any help is appreciated and thanks in advance
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Sounds like your truck was engaging an operation mode known as “hydrocarbon desorption mode”. If you accumulate about 2 hours of collective engine idle time within a certain period, the truck will automatically increase engine idle speed to 900 rpm and hold it there. The idea is to protect the emissions system from absorbing too much partially combusted fuel since in-cylinder temperature is lower when idling (especially if it’s cold outside). This mode also increases the temperature in the exhaust system, which protects sensitive emissions-based sensors from damage caused by excessive condensation when idling. The system will maintain HCD mode for up to an hour of additional idling, or roughly 20 minutes of driving.
 
mbarber84 said:
Sounds like your truck was engaging an operation mode known as “hydrocarbon desorption mode”. If you accumulate about 2 hours of collective engine idle time within a certain period, the truck will automatically increase engine idle speed to 900 rpm and hold it there. The idea is to protect the emissions system from absorbing too much partially combusted fuel since in-cylinder temperature is lower when idling (especially if it’s cold outside). This mode also increases the temperature in the exhaust system, which protects sensitive emissions-based sensors from damage caused by excessive condensation when idling. The system will maintain HCD mode for up to an hour of additional idling, or roughly 20 minutes of driving.
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Mine does it on the get off ramp getting off of the highway after being run for 20-30 minutes at 75 mph. I don’t idle my truck except in stop and go traffic. The last time it did it, it dropped back to normal when I turned the exhaust brake off. ?
 
OLEJOE said:
Mine does it on the get off ramp getting off of the highway after being run for 20-30 minutes at 75 mph. I don’t idle my truck except in stop and go traffic. The last time it did it, it dropped back to normal when I turned the exhaust brake off. ?
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Somethings up there. The exhaust brake should have no bearing on the engine’s idle speed.
 
I agree something isn’t right about that but I sure am not going to take it to the dealership for them to diddle stick around in looking for something. My truck is doing perfectly regen wise even during the hot weather. Admittedly running the Archoil every tank but the last one and it still isn’t showing anything on EVIC DPF gauge. I’ll just have to push the brake pedal a little harder.
 
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