What my truck does really doesn't line up with any of the other posts I've been reading but it seems like a nice feature for a diesel. It seems odd because it's like an auto-throttle. On the big diesels I used to drive a very long time ago I would always use the hand throttle or a stick to to increase the idle speed to 1000 when idling for a while.

I have a "new to me" 2019 F-350 Lariat with 6.7 L. I may be able to add a signature after this, my 5th post.

I don't do much with the truck yet and slowly learning about it. Still under 400 miles since I got it three months ago. I did some slow speed driving today, moving the old 5th wheel to it's new home on our property. All told, I drove maybe a half mile to actually move it 75 yards to the back side of the pole barn we like to call our garage.

I never have simply let the truck idle. Today, while doing things like opening/closing gates, moving the horse around. surveying my progress into the new parking spot, etc. I noticed it would increase the idle speed while I was out of the truck. Touching the brake to put it in gear stops it. After I got done and parked I paid closer attention. The increase starts after about 55 seconds of idling. It goes from what looks like 650 to 1000 over a period of around 15 seconds. It was around 75° this afternoon. I went out tonight to check it again when it's 55°. Same thing. Run for almost a minute and then slowly increase. Tap either pedal to stop it. The second elevated idle cycle began again right on time but this time I let it go on for 5 minutes.

So, the first stop this afternoon was reading the monster of a manual and found nothing to explain this. Most of this seems to relate to cold cold temps but I found this.

"Your vehicle may have a factory option for a stationary elevated idle control through the upfitter switches in the overhead console." and this "For extended idle times use an approved idle speed increase device"

Nice thought but all of my upfitter switches are always off. The dealer told me none are connected.

Any ideas why this high idle happens like clockwork?

 

The upper boot to the turbo has a split , mine did this too and found two small splits in the rubber, after I replaced ( very simple task ) the high recirculating pump stopped trying to recirculate. Hope this helps

 

Wow, thank you for that amazing information. I'll have a look this morning.

Is this something that would throw a code? I recently got a new scan tool with lifetime updates for our truck and my wife's Escape PHEV. First one ever so I'm clueless. I haven't tried it on them yet. It does seem to work well in my Santa Fe.

 

It may be doing a a regen. That will make it idle higher also. It doesn’t sound like you’ve driven it enough to complete one while driving.

Most of the high idle mods I’ve heard of are manually controlled. I don’t have one mine only high idles when it cold and in cold weather.

 

I have the same truck, 2019 F350 Lariat 6.7. I get the same high idle issue you have seems like it kicks in way to soon and to often. I will check the turbo boot but if not that what else to look for? Can this idle issue be adjusted via FORScan?

Mike

 

I don’t think it can be manipulated, it burns the carbon from unspent diesel, before it gets to the maf mass air flow sensor and then to the turbo , it’s supposed to regenerate every so often , with mine it would do it all the time and I lost turbo response with the splits ,
mare you seeing oil on the hood ? Or a oily mess in a general area on the engine?

 

It sounds like the PCM programming that elevates the idle speed to help with unburned hydrocarbons in the SCR. Ford has a service bulletin describing this. It's usually associated with extended idle time, but your low speed/low RPM use isn't much different than idling.

https://www.ford-trucks.com/forums/1...le-idling.html

 

It might also be idling up to charge the batteries. There are several things that command higher idle speed including climate control demands. I wouldn't sweat it.

 

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 elevated idle can happen at operating temperature and during warm ambient temps as well. The OP mentioned 75 and 55 degree ambient.

 

Correct. The PCM programming looks at the coolant temperature.

 

@

@04badford I checked the turbo hoses this morning. Not sure which one is the upper boot to the turbo but searches for that product name always to lead to the one marked as 1 in the picture. I couldn't find any splits in #1 or #2. Both are in great condition.. Everything in the entire area very clean.

I've checked this high idle thing twice today at 60 and 75. The spin up to 1000 is like clockwork again today.

@4wd6.7L That service bulletin SSM 50636 is one thing I found last night. It makes sense but doesn't seem to be the same thing my truck is doing. I suppose it could be applicable but wouldn't that mean my truck has an unsatisfactory amount amount of unburned hydrocarbons after 55 seconds of idle? Or maybe the previous owner had somebody figure out how to modify the PCM for an automatic high idle? I understand he's a bigtime contractor who used it for his mobile office. People down here in Lower Alabama love our AC.

Anyways, for the other ideas on cause of this, the climate control was turned off and I very rarely let any automotive battery go down below 70% SOC. Although the temps were down in the teens the week before last, the cold is long gone for a while.

I did pull the codes today. Nothing but:these.

SCM-E (Seat Control Module E) 1 problems exist
1.B2486-20 Left Side Repeater Lamp Output Circuit Fault
Continuous Memory DTCs

TCU1 (Telematic Control Unit Module) 1 problems exist
1.B1246:13-0A GSM (Group System For Mobile) Antenna
Continuous Memory DTCs

 

I'll have to check this out during typical use. The usage yesterday was very atypical. A drive is usually at least 50 miles. It doesn't matter which of three way we go, it's 25 miles to any town.

 

It’s the center hose you have a red dot on , check it when the engine is on , if there’s a split you’ll feel the blow by.

 

No red dots, there are two numbers on different hoses.