Fuel question
 

I was just bought a 2003 f150 from my dad. We've had it for over 10 years and they've always run e85 fuel in it. i know the recommended fuel is 87 and want to start running it but before i did wanted to see if i needed to do anything to it before hand or fill it up with 87 and be on my way. any help is appreciated

what i would do is either run the truck till it runs out of the e85 or drain it out of the tank. it is not good to mix the two fuels

how many miles on the truck?

E85 is 51-83% ethanol vs the what, 10% or 15% in regular gas? So what is the issue in switching? It seems to me that the E85 is more corrosive on the rubber and plastics, but might gives a higher octane number rating. So regular gas would be less corrosive on the fuel system but might be more prone to the light pinging a lot of us get.

Wouldn't the real concern be in going from regular gas to E85? And since most pump gas already has 10-15% ethanol why wouldn't it blend ok with E85?

the truck isn't a flex fuel and shouldn't have ran on e85 to begin with

To my knowledge Ford did not start producing the flex fuel capable F-150 models until late 2005. There are however aftermarket flex fuel systems that can be added to some models that didn't come from the factory FFV capable to add that capability. On vehicles that are truly flex fuel capable, they are usually able to adjust on the fly as needed for changes in ethanol content. So most all truly flex fuel setups can adjust on the fly as needed when you are switching over from one type of fuel to another. However some vehicles that have aftermarket calibrations for E85 are setup specific for only E85 in which case you would want to try to run all of the fuel out first before switching back / fourth to the other type of fuel. Do you know if the truck has an aftermarket flex fuel system that was added to the truck before you owned it possibly? I would definitely double check to see the specifics before changing to a different type of fuel just to be on the safe side.

Hopefully the e85 has not damaged the fuel system. ethanol is corrosive to rubber and certain metals.
As said, it was not designed for it, but if you have been using it for 10 years and no problems, maybe you got lucky.
Surprised you have not been having drivability issues, these trucks are not mapped to run on the e-85 so it would be running lean and get horrible fuel mileage.

yeah that will be fine

I'd run it empty... just fill up a 5gal tank of 87 and keep it with you, when you run dry of the e85 pour in the 87 and then head to a gas station.

If you're nervous about running out of gas, wait till the low fuel light comes on, then drive a few miles (I know I can get at least 40miles when mine comes on) then when you're really low just do laps around the neighborhood till you run out. That way you can run out in a safe area and fill up.

Why run it empty? That will just be a bigger shock. Start using plain old 87 octane E10 now and as the blend changes more toward E10, less ethanol, it will either start running worse and you know you have a problem or it will run fine.

There's no "shock," because the EEC was never designed for different fuel types to begin with. It doesn't know the difference between E85, E10 87, E10 93, or anything in between. It uses the preset tables it's programmed with.

2100 has it right, except the in-tank fuel pumps in these things don't like being run totally dry (or for long periods with minimal fuel), since it's the fuel that cools them. I'd run it until the light comes on, drive it another 20 miles, fill it with 87 octane, and enjoy it another ten years or so.

Yeah I was hesitant to change my wording because yeah technically really nothing should be ran completely dry lol. I was figuring when it started stuttering he'd shut it down and fill it up. But I also know people run out of gas all the time and it doesn't necessarily mean you're gunna destroy the truck. So yes OP you don't need to run it till its bone dry but get as much out as you can.

Edit* also not a bad time to find out what your low fuel light means. Like I said I know I have at least 40 miles once my light kicks on. (Stuck on a barren stretch of interstate and was hoping a gas station was coming up.... it did 42miles later) I've got 35s and cant recall my gear lol so your light estimation will probably differ. But it's always good to know how dire your gas needs are when the light shows up. I've not dared push it farther because I'm rarely 40+ miles from a gas station.

True. It's just a safer bet to leave a little in there. :)

That's why I added the last sentence :thumbsup: I agree lol

The PCM settings will probably change with E10 versus E85. Call it a shock, call it a change, whatever. You might get some funky idle behavior or a code.

But, it really doesn't matter much. There's no reason to drain the E85 down before filling up with E10. What is the rationale? There isn't any.

Even the user manuals for flex fuel vehicles say to run the tank low and fill it up with as much 87 as you can. Granted they say half a tank is do able; even FORD recommends using as much as you can before switching and not to switch often.

Also these trucks weren't supposed to be running on E85 so best to run it low and fill up with 87 and not mix the two.

Why does FORD recommend you run it lower than at least half but preferably lower? There isn't any reason to argue with FORD unless you just like to argue.

Edit* link if you want to read. Last paragraph is what I am paraphrasing from FORD
http://www.fordservicecontent.com/Fo...ngEnabled=True

The PCM will *not* change anything, since it has no way to know that a different fuel is/was being used in the first place.

As to the second part of your post, mixing the existing fuel with E10 will simply prolong the existence of higher levels of alcohol than should have been there in the first place.

OP, if you really wanted to, you could remove the Schrader valve from the fuel rail, run a hose to a bucket, then run the truck using the fuel pump to drain the tank. That would actually be the *quickest* way to eliminate the E85. After ten years, though it probably won't make much difference any way you slice it.

Thanks for the link. Looks like they anticipate you'll get 5 miles of weird behavior after every blend change so they want to minimize that. If you want to follow the instructions exactly you have to add in the "drive 5 miles immediately" part. Maybe he can just drive 4 miles since he'll be using E10, probably.

His 2003 isn't a flex-fuel vehicle though. It's just been using the "wrong" fuel for years.

"Switching Between E85 and Gasoline
We do not recommend repeatedly alternating between E85 and gasoline. If you switch from using E85 to gasoline, or from gasoline to E85, add as much fuel as possible, at least half a tank. Drive your vehicle immediately for a minimum of 5 mi (8 km) to allow it to adapt to the change in ethanol concentration. If you use E85 exclusively, we recommend that you fill the fuel tank with regular unleaded gasoline at each scheduled oil change."

Idle speed parameters are part of PCM memory, and idle speed will most likely change with E10 versus E85 due to different energy values for the fuels. It won't know anything it will just do what it does all the time based on what it measures, idle speed and O2 sensor values.

And, if nothing is changing then why the big deal. Nothing is different. We're kind of going in circles here. Like magic is going to happen.

Well, I guess I haven't learned *anything* having owned Ford vehicles for the last 29 years. :unsure:

How about a description of what will happen if he just starts filling with 87 E10? That's what he really wants to know. I'd like to know too. Will something get damaged, will it run poorly? If there's a benefit to running the tank dry first, then there must be a detriment to not doing that.

Still very interesting that a person can apparently run E85 in a 2003 truck spec'ed to E15, with no apparent issues. Besides the conversation about how to get back to normal.

Clear codes or disconnect battery when refill.
It should resort to default and learn over again thru drive cycle.

These trucks arent even meant for e-10.

Not meant but still "allowed". If E85 didn't damage it, E10 isn't going to.

https://afdc.energy.gov/fuels/ethanol_e15.html

https://afdc.energy.gov/fuels/ethanol_fuel_basics.html