cruise control
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New User
Joined: Dec 2012
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cruise control
I noticed while drivingmy 2012 F-250 with the cruise control on, the turbo goes up and down almost surging as if it can't find a happy medium. It happends at all different speeds. The highway was flat and no wind and no load. Is this normal? Also the truck was not in regen.
Mountain Pass
Joined: Feb 2010
Posts: 113
Likes: 6
From: Pacific Northwest
Turbo boost is the one indicator that you have that shows what the engine is doing when at a constant speed on cruise. It's constantly making small adjustments to maintain speed close to your desired speed. I noticed mine does it, but not to the extent that you can really feel or hear it.
Lead Driver
Joined: Jan 2010
Posts: 6,600
Likes: 84
Without the truck in an active regen, that doesn't seem normal (since you feel it).
However, my truck has this exact behavior in regen with cruse on.
Always has. You can see the boost gauge surging and sometimes feel it.
However, my truck has this exact behavior in regen with cruse on.
Always has. You can see the boost gauge surging and sometimes feel it.
Logistics Pro
Joined: Mar 2005
Posts: 3,533
Likes: 2,498
From: West Michigan
I've noticed this behavior too.
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Senior User
Joined: Jan 2013
Posts: 238
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From: Northern New Mexico
Cruise and Turbo Surge
Yep. I have seen it also, but infrequently. Cruise, straight, flat, no wind, not in regen at about 65 mph, I have seen a repeating oscillation about every 5-10 seconds from about 5 psi to about 11-12 psi. This lasts for maybe 5-7 minutes. I can feel a slight power surge. This happens infrequently and usually the power surge is what draws my attention to the boost pressure.
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Postmaster
Joined: Aug 2011
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From: Roll Tide, Roll
Ditto. Same here. I just cancel it for awhile then good to go.
Logistics Pro
Joined: Mar 2005
Posts: 3,533
Likes: 2,498
From: West Michigan
The odd thing is, is that if you just cancel cruise, and reset it, then it seems to stop doing it. I always just assumed a "programming problem", but never felt strongly enough to try to get Ford to fix.
Lead Driver
Joined: Nov 2005
Posts: 5,225
Likes: 4,239
From: Kaysville Utah
The Passive Regen is just excess heat burning off the soot in the DPF. It takes place when you have EGTs above 572°. Most freeway driving on flat roads will produce EGTS around 470-490°. So unless you are towing or climbing a pretty steep grade, your are not getting Passive Regens during normal freeway driving.
Lead Driver
Joined: Jan 2010
Posts: 6,600
Likes: 84
It actually gets my attention more on the Instant Fuel Mileage display because you see that going up/down pretty regular., along with the seat of the pants feel.
The odd thing is, is that if you just cancel cruise, and reset it, then it seems to stop doing it. I always just assumed a "programming problem", but never felt strongly enough to try to get Ford to fix.
The odd thing is, is that if you just cancel cruise, and reset it, then it seems to stop doing it. I always just assumed a "programming problem", but never felt strongly enough to try to get Ford to fix.
This addresses false DTC's about the turbo (along with many things included in previous TSB's), which I found out can simply disable the turbo while you are driving down the highway and not spin up again.
It also addresses low speed turbo surge.
This, in my mind, was a coding issue.
Otherwise the PCM should have never "thought" there was an issue.
Even if it did think there was an issue, I didn't get a CEL which it should have thrown as soon as the truck lost boost.
Maybe someone will experiment and discuss with their dealer if this could be a fix for the non-AR highway speed surge.
Lead Driver
Joined: Mar 2013
Posts: 8,865
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From: Central Vermont
Just a thought since I don't have my diesel truck yet but with my gas job, when I run the cruise control the computer constantly hunts to try to maintain the set speed. I've observed this on several different vehicles, Ford and otherwise. Its my opinion that computers, as digital devices, aren't real good at mimicing real world inputs on speed. Where you or I might allow the speed to drift down a little on a small rise, the computer will apply more accelerator to try to maintain the set speed. I find that, while I use cruise a lot on the highway just so I don't worry about losing track of my speed and earn a performance award from the local cops, I also don't get as good gas mileage as I can if I focus on managing my speed manually. And I think that is because the cruise is constantly adding a little more throttle to try to maintain the set speed.
But I could be all wet too.
But I could be all wet too.