Been running E85 in my 02 5.4L for quite a while. Decided to switch back to gasoline. The 25 gal tank had 8 gals left in it so I was gonna switch tunes back to gas and fill up. I switched to the gas tune and ran the truck on the remaining E85 to the gas station. I filled up with premium and drove back home. It ran good and since I still had 27.2% alcohol I kept an eye on the fuel trims. Runs a little rich but not bad.

 

I've heard that a STOCK non-flex engine without a tune can handle up to about 35% alcohol without throwing a lean CEL.

 

Doesn't surprise me. I think I might have got up to 30% E85 with no problems IIRC.

 

I a dozen or so tanks of half and half E85 and regular (E10 here in Colorado) in my 2003 non-flex 4.6L. That works out to 47-48% ethanol and somewhere around 90-95 octane

I bought a handheld tuner but turns out I wasn't smart/patient enough to tune it to run on E85 exclusively.

Truck ran great but mileage dropped from 13.5 to about 10.5.

It made sense when e85 was much cheaper than gas even with the mileage penalty, now not so much since the price of e85 is only a bit cheaper than unleaded.

 

I would be leary of running e85 in a vehicle that was not set up for it. Many of the rubber parts (hoses, seals, o-rings) are not meant to handle that much ethanol in the fuel. You may be asking for premature failure of those parts.

 

I ran E85 straight for a year. No problems occured at all. The only thing I didn't like is when the price rose to the point it wasn't worth running it. I buy premium now and make almost the same power. Oh ya my gas mileage went back up to former amounts.

 

Your problems will come later as the rubber parts deteriorate and crack. It's not an instant thing. That is the difference of a flex fuel engine and one that is not. The flex fuel gaskets and seals are different materials.

 

Not saying you're right or wrong but I love changing things on my truck to the way I want it to be. I've put a lot of replacement items in my truck because it didn't want to work with my plans. The fuel system is one of them.

 

You also run a serious risk of running too lean unless you have widebands and a programmer.

 

I looked into this a bit... and discovered that most of the fuel system components were identical part numbers, comparing the 4.6L non-flex-fuel and the 5.4L flex-fuel trucks (2005-newer). I didn't do an exhaustive search, but most major components like the fuel tank, pump, fuel lines, etc were the same.

Just sayin', if I were a car manufacturer, I would just make all the components alcohol-tolerant since most markets have up to 10% ethanol already. Plus it doesn't make sense to stock 2 sets of fuel system components (one for gas, one for ethanol).

My old Saab 9-3 turbo (daily commuter) runs like a scalded cat on e85. That particular car is able to detect the higher octane and create more power without any mileage penalty.

My 'effie is 10 years old, and I worried myself sick thinking of all the hoses and gaskets that would be dissolved by the ethanol but it just didn't happen. That said, I'm back to using gasoline because the there is no benefit (truck runs like crap even with a 93 octane tune, no extra power, less range, no cost savings, limited availability, etc).

 

SCT LiveWire programmer and an Innovate LM-1. Data logging capability.

 

The oil companies had to have told the car companies of what they were planning to do with the alcohol content of the fuel they sell.