So here is my question when i select tow haul should I lock out 6th or not. Here in good old flat illinois I have no issue pulling in 6th gear rarely downshifts to 5th. The eingine is running at about 1800 rpm and i am getting between 9 and 9.5 mpg. I have locked out 6th when we have been in the Ozarks and then the engine is running about 2200 rpm as a norm but haven't checked milage. I wonder if by locking out 6th gear and keeping the rpm up which is closer to the pwoer band if I would see better mpg? Also even though the rpm is lower is the engine lugging more? More of a curiosty issue than anything. Over all I am very happy with the prefomance. WE have about 1800 miles towing so far with no issue. But I would not go any larger that what we currently have.

Automatics are designed for folks who do not want to, or do not know HOW2 managethe gears vs situationWhy automatics now have that 'tow/haul' button...Since you have an automatic (it thinks for itself, removes the gear selectionoverhead from the driver, etc), why not use the 'tow/haul' button and leave itin the gear your manual says to when using 'tow/haul' and then enjoy the ride?Most 'tow/haul' functions will hold a lower gear longer and/or drop to a lowergear by itself to reduce the strain on the drive train when 'towing' or 'hauling'...

yes i do use the tow haul mode which does gear ratio but in doing so i have the option of locking out the 6th gear which is the highest od Also For information i do have 3.73 rear end my thought is that locking out sixth the engine would be in fifth and closer to the power band thus possibly improving preformance and mpg.

sele wrote:yes i do use the tow haul mode which does gear ratio but in doing so i have the option of locking out the 6th gear which is the highest od Also For information i do have 3.73 rear end my thought is that locking out sixth the engine would be in fifth and closer to the power band thus possibly improving preformance and mpg.If you are looking for mileage it's simple, just look at the boost gauge. The closer you are to vacuum the better. If you are in vacuum, the higher the vacuum the better. Anytime you're in boost your making your engine bigger and it will gulp more fuel. At full boost that little 3.5 thinks it's a 7.0 liter engine. You want it to think it's a 3.5 liter as much as you can.Try it in both gears and see which is better.

I suspect 5th gear will be slightly better with improved throttle response.

Great question. I have the same truck with 3.73 axle. My experience (though not scientific)is that I get better mileage at the lower RPMs in 6th gear, so if the truck will maintain 6th on its own, I let it do its thing. The exceptions would be a headwind, a slight uphill grade, or if I am travelling under 55 mph. In these cases the truck may tend to lug a bit, even though the low end torque maintains 6th gear. I then lock out 6th as it 'feels' better and the truck is more responsive and it's probably a little easier on the transmission. I don't think the difference in fuel economy would be significant in either case so I go with the most comfortable towing experience in each given situation. The Ecoboost is so quiet regardless of the gear.

mpg f150 ecoboost to lock out 6th or not | Good Sam Community

30 Replies

johndeerefarmer
Explorer III
Sep 21, 2013
Buck50HD wrote:
6th gear = 6-8psi boost at 1750RPM
5th gear = 1-3psi boost at 2150RPM

Both offer nearly identical mileage and quiet towing. I like 5th with less cylinder pressure and no downshifting on grades <5%.

My only exception is with a good tailwind, I'll kick it into 6th.

No you monitor CAT temps as well? If so what range do you see?

Are you tuned or running stock?
sele
Explorer
Aug 10, 2013
Knock on wood I have yet to experience this issue SO back to my original post we are headed home in the morning and having given it a week to think about how to handle this issue. I have decided to use tow haul mode and lock out sixth gear, 9mph on the way hear and response from vechile are enough to convince me plus that fact that we have gotten 18.5 when running around this week to make up my average mph. Will report when we get home on how the return trip home went.
brownieab
Explorer
Aug 07, 2013
Thanks Learjet......I did some looking around and found out what all the buzz was about. I presently have a Suburban with a 5.7. It's getting long in the tooth ( 1999 ) I am starting to look for a new tv with the thoughts of a larger trailer in the future. The Ecoboost sounded interesting. Maybe it will work out for Ford and all their customers, but for my time frame, I can't wait for Fords fix and testing protocol.
Buck50HD
Explorer
Aug 07, 2013
OK, back on the forum so I can explain. I knew about this issue before buying the truck (nearly anyone that researches a little would). Didn't care then and still don't care. The truck is awesome.

When we left the house that day, towing our 5th to a campground, the ambient temp was almost 90F with about 90%RH, thunderstorms brewing. Right as we got going, it started to downpour and did so for the next 1/2 hour of our trip. Temp on the dash showed 70's during the rain and you can be sure the actual temp of the rain was lower yet. When you compress saturated air (around 2-3psi in my case) and cool it back to the initial temp or even lower, water will fall out and collect in the intercooler/CAC. Then, when you hammer on it, the water gets sucked in, causes mis-firing and kills the catalytic converter with the raw fuel and moisture going into the exhaust. It just so happens that the left bank gets the brunt of it.

In my case, I suspected it was going to happen and let off almost immediately when I noticed the power drop off. I stayed off the gas for few seconds, trying to feather the throttle once or twice and finally got a response after about 10-15 seconds. Right back to normal, no codes at the time. Then, I was dumb enough to try it again... and it happened the second time. Let it clear out, then drove the rest of the way without a problem (1.5hrs)

Then, after a few restarts and driving empty after we got to the campground, it sensed the catalytic converter was not operating efficiently and threw the code (PO430).

Made an appointment at the dealer. New left bank catalytic converter, reflash, new version CAC, a few hours, no charge. Don't notice any difference in power. The new CAC has the same shield on top that the old one had.

Like I said, I was aware of this issue before buying the truck and knew it was a possibility. Although I knew it was physically possible, I was skeptical about how easy it would be to create the problem. Well, given the perfect conditions, it happens, quite predictably. Thinking it cannot happen on these trucks is like thinking a dog will never bite.

Now I know what not to do after warranty is up, unless I want to pay for a new left bank converter:)
EcoBullet
Explorer
Aug 06, 2013
brownieab wrote:
OK I'll bite.....What is the condensation club all about. Did you guys get hats and t-shirts upon application or a bill from the dealer ???

Under very damp conditions, some of the Ecoboosts will start missing out and go into limp mode when you suddenly accelerate rapidly (put your foot to the floor) after driving at a steady speed for a good while. At least that is what mine did once, but I've never been able to repeat it after the dealer reflashed the computer. I'm no mechanic, but I understand this is due to a buildup of condensation in the intercooler that pushes in too much water all of a sudden.
Learjet
Explorer
Aug 06, 2013
brownieab wrote:
OK I'll bite.....What is the condensation club all about. Did you guys get hats and t-shirts upon application or a bill from the dealer ???

No one talks about condensation club, just like fight club ;)

If you had an EcoBoost or looked around the internet...you can find out.
brownieab
Explorer
Aug 06, 2013
OK I'll bite.....What is the condensation club all about. Did you guys get hats and t-shirts upon application or a bill from the dealer ???
sele
Explorer
Aug 06, 2013
Shadow_Grey wrote:
Buck50HD wrote:
My phone isn't very smart so I had to get the scangaugeII. Nice to be able to read codes as well, especially after towing in thunderstorms for 1/2 hour and stomping on it:S Yep, I'm an official member of the condensation club as of a few weeks ago. Couldn't resist trying it, even though I knew it was going to happen in those conditions.

I drove in rain from upper state NY to Mid Ohio and my truck didn't stumble one time...at times it rained so hard cars were pulled off to the side. I had the wipers on full speed with a good coating of Rain-X applied too...I just don't see what you guys are experiencing...I don't know???
Our first trip with this TV was to St Francis State Park this spring and the ranger came around that second morning and advised us to leave as the creek would be out of its banks soon. So we pulled back into Illinois around Litchfield and found a spot for the rest of the weekend. Driving rain as hard as I have ever pulled in and not a single problem.
oxygen
Explorer II
Aug 06, 2013
Buck50HD wrote:
My phone isn't very smart so I had to get the scangaugeII. Nice to be able to read codes as well, especially after towing in thunderstorms for 1/2 hour and stomping on it:S Yep, I'm an official member of the condensation club as of a few weeks ago. Couldn't resist trying it, even though I knew it was going to happen in those conditions.

what code came up during the condensation club experience?
Shadow_Grey
Explorer
Aug 06, 2013
Buck50HD wrote:
My phone isn't very smart so I had to get the scangaugeII. Nice to be able to read codes as well, especially after towing in thunderstorms for 1/2 hour and stomping on it:S Yep, I'm an official member of the condensation club as of a few weeks ago. Couldn't resist trying it, even though I knew it was going to happen in those conditions.

I drove in rain from upper state NY to Mid Ohio and my truck didn't stumble one time...at times it rained so hard cars were pulled off to the side. I had the wipers on full speed with a good coating of Rain-X applied too...I just don't see what you guys are experiencing...I don't know???