RPM's Go Up While Idling
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More Turbo
Joined: Aug 2010
Posts: 630
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From: Green Acres, Ca.
RPM's Go Up While Idling
Sorry if this has been answered before but I couldn't find anything on the pages. I have a 2019 F350 dually with the 6.7 diesel motor with almost 12k miles. I'm retired. This has happened twice now in the last 4 months. I start my truck in the morning and after about 5 minutes of idling while I'm loading things the RPM's of the motor will go up to about 1,000RPM's. If I press the gas pedal down the RPM's will lower back down to normal only to raise back up. I'm sort of figuring that it's going into "regen" mode. What do you all think it is before I have it looked at? Is this normal or not normal? Thanks.
Mountain Pass
Joined: Jul 2019
Posts: 175
Likes: 7
From: NW Suburban Chicago
Not regen, it's idling up based on engine parameters and ambient temps. This is to keep the fuel from getting past the rings and getting in the oil. The technical name of this condition is escaping me at the moment.
Cargo Master
Joined: Feb 2020
Posts: 2,277
Likes: 949
I think the term you're looking for is wet stacking.
Cold Idle Kicker
The cold idle kicker strategy provides an increase in idle speed during cold engine warm up. The PCM uses the engine
coolant temperature (ECT) sensor and transmission position as primary inputs, and in certain conditions the PCM uses the
ambient air temperature input to adjust the cold idle RPM up to a maximum of 1,200 RPM (Transit) or 1,175 RPM (all
others).
The cold idle kicker strategy provides an increase in idle speed during cold engine warm up. The PCM uses the engine
coolant temperature (ECT) sensor and transmission position as primary inputs, and in certain conditions the PCM uses the
ambient air temperature input to adjust the cold idle RPM up to a maximum of 1,200 RPM (Transit) or 1,175 RPM (all
others).
Mountain Pass
Joined: Dec 2021
Posts: 107
Likes: 47
Sorry if this has been answered before but I couldn't find anything on the pages. I have a 2019 F350 dually with the 6.7 diesel motor with almost 12k miles. I'm retired. This has happened twice now in the last 4 months. I start my truck in the morning and after about 5 minutes of idling while I'm loading things the RPM's of the motor will go up to about 1,000RPM's. If I press the gas pedal down the RPM's will lower back down to normal only to raise back up. I'm sort of figuring that it's going into "regen" mode. What do you all think it is before I have it looked at? Is this normal or not normal? Thanks.
mine will also do it when it’s hot. It does it at all random times. From what I understand it is normal. The truck could be doing it for a number of reasons. I believe mine currently is doing it because of low voltage possibly. I will need new batteries soon it looks like and has been a while.
FTE Legend
Joined: Mar 2017
Posts: 31,874
Likes: 9,170
From: Western NY
I've only seen my truck do it when it's below 30 degrees. When it's really cold for here, under 10 degrees, it goes slightly over 1000 RPMs. It doesn't do it once it's fully hot unless some here are towing and their trucks are real hot. Maybe its kicking it up to cool things down.
Super Moderator
Joined: Aug 2008
Posts: 37,379
Likes: 1,863
From: Frederick, MD
Usually this occurs due to cold temps. But if it happens and you hit the brake pedal and it idles down then there is nothing to worry about . the PCM commanded it due to a number of reasons.
DPF regen is not one of them, unless you are running a stationary regen.
DPF regen is not one of them, unless you are running a stationary regen.
Lead Driver
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And there won't be any uncertainty about that process!
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Hotshot
Joined: Jul 2013
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Sorry if this has been answered before but I couldn't find anything on the pages. I have a 2019 F350 dually with the 6.7 diesel motor with almost 12k miles. I'm retired. This has happened twice now in the last 4 months. I start my truck in the morning and after about 5 minutes of idling while I'm loading things the RPM's of the motor will go up to about 1,000RPM's. If I press the gas pedal down the RPM's will lower back down to normal only to raise back up. I'm sort of figuring that it's going into "regen" mode. What do you all think it is before I have it looked at? Is this normal or not normal? Thanks.
now, there is another reflash for folks who were flashed recently...apparently...the recent reflash disables the feature that puts your truck into limp mode if you have a nox sensor problem...so ow ford was to reflash us..so that upon a nox sensor calibration problem...our trucks will go into limp mode. AND, the notice says if you dont get the second reflash...your emissions warranty is voided.
I want to retire soon...but with all these electrical and module things going one...getting to be a nervous nelly and am thinking of getting rid of my 6.7 and getting a pre-2006 gas truck.
but yes...we now have that rise to 1000 at idle feature and I dont know if you get the second reflash if it keeps the rise to idle feature.
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FTE Legend
Joined: Mar 2017
Posts: 31,874
Likes: 9,170
From: Western NY
my 2019 f-450 did not do this prior to going into service for charging circuit work in march of 2020. while it was in for charging work, they reflashed the PCM with out my approval. since that reflash, my 6.7 does the same thing.
now, there is another reflash for folks who were flashed recently...apparently...the recent reflash disables the feature that puts your truck into limp mode if you have a nox sensor problem...so ow ford was to reflash us..so that upon a nox sensor calibration problem...our trucks will go into limp mode. AND, the notice says if you dont get the second reflash...your emissions warranty is voided.
I want to retire soon...but with all these electrical and module things going one...getting to be a nervous nelly and am thinking of getting rid of my 6.7 and getting a pre-2006 gas truck.
but yes...we now have that rise to 1000 at idle feature and I dont know if you get the second reflash if it keeps the rise to idle feature.
now, there is another reflash for folks who were flashed recently...apparently...the recent reflash disables the feature that puts your truck into limp mode if you have a nox sensor problem...so ow ford was to reflash us..so that upon a nox sensor calibration problem...our trucks will go into limp mode. AND, the notice says if you dont get the second reflash...your emissions warranty is voided.
I want to retire soon...but with all these electrical and module things going one...getting to be a nervous nelly and am thinking of getting rid of my 6.7 and getting a pre-2006 gas truck.
but yes...we now have that rise to 1000 at idle feature and I dont know if you get the second reflash if it keeps the rise to idle feature.
Are you saying that this recent recall, 21E01, disables the limp mode for a NOx sensor fault?
3rd Gear
Joined: Dec 2023
Posts: 1
Likes: 0
Real answer
The real answer is that diesel engines do not do well idling, they are made to run. The reason the RPMs goes up during excessive idling is to prevent what is called "wet stacking" which will wear the engine excessively.
link to wiki explaining wet stacking. https://en.m.wikipedia.org/wiki/Wet_stacking
link to wiki explaining wet stacking. https://en.m.wikipedia.org/wiki/Wet_stacking
Sorry if this has been answered before but I couldn't find anything on the pages. I have a 2019 F350 dually with the 6.7 diesel motor with almost 12k miles. I'm retired. This has happened twice now in the last 4 months. I start my truck in the morning and after about 5 minutes of idling while I'm loading things the RPM's of the motor will go up to about 1,000RPM's. If I press the gas pedal down the RPM's will lower back down to normal only to raise back up. I'm sort of figuring that it's going into "regen" mode. What do you all think it is before I have it looked at? Is this normal or not normal? Thanks.
Lead Driver
Joined: Dec 2020
Posts: 8,639
Likes: 2,433
The real answer is that diesel engines do not do well idling, they are made to run. The reason the RPMs goes up during excessive idling is to prevent what is called "wet stacking" which will wear the engine excessively.
link to wiki explaining wet stacking. https://en.m.wikipedia.org/wiki/Wet_stacking
link to wiki explaining wet stacking. https://en.m.wikipedia.org/wiki/Wet_stacking
Lead Driver
Joined: Dec 2020
Posts: 8,639
Likes: 2,433
Tuned
Joined: Jul 2021
Posts: 372
Likes: 199
From: NE Oklahoma
Dave, are you aware you don't have to buy a high idle kit to idle the truck up? You only need a $2 resistor and a couple butt splice connectors to use an upfitter switch to idle it up. Have a read here for all the info > https://www.ford-trucks.com/forums/1...-pictures.html
Cargo Master
Joined: Feb 2010
Posts: 2,298
Likes: 94
From: Delta, CO
Dave, are you aware you don't have to buy a high idle kit to idle the truck up? You only need a $2 resistor and a couple butt splice connectors to use an upfitter switch to idle it up. Have a read here for all the info > https://www.ford-trucks.com/forums/1...-pictures.html
