Difference between flex fuel model and non flex fuel model 3.0 engine.

[I support common sense]

Anybody got any knowledge in this area? I read that the flex model may be tougher in the long run because it has anti corrosive parts.

 

[pjtoledo]

the anti corrosive parts are in the fuel delivery system.
the pump and fuel injectors are larger to accommodate the increased flow needed for alcohol.
all other engine parts are the same.
about the time flex fuel happened the heads switched to a different chamber size/shape but that applied to all the 3.0 engines.

the first years of FF had a separate alcohol content sensor in the fuel line. VERY EXPENSIVE to replace.

 

[arse_sidewards]

There are no major differences to the fuel system beyond the presence of the sensor that tells the computer how much alcohol is in the gas.

The cylinder heads are going to be slightly higher compression (fraction of a point) on the flex fuel engine but it's an emissions thing not a performance thing, putting flex fuel heads won't increase power measurably if at all on a non flex fuel engine.

 

[stmitch]

Fuel injectors are the only meaningful difference on the engines. You need more flow to accommodate e85.

Early FFV trucks had the flex fuel sensor installed between the tank and engine, and had cylinder heads with a slightly different combustion chamber. Around 2001-2002, Ford decided none of that was necessary. They were able to determine fuel content with the O2s, and used the standard gas cylinder heads for all Vulcans.

You could theoretically convert a gas 3.0 to Flex Fuel pretty simply with properly sized injectors and the right software tune. There are also aftermarket options for Flex Fuel setups.

 

[I support common sense]

I’m running regular low grade gasoline right now, but I’ve got the check engine light on and it’s idling very rough often times even when it is warm. It’s actually got a multiple random cylinder misfire at all the way up to 1500 rpm. giving me a code that I don’t remember, but I looked up and was bank2 sensor 1(upstream) o2 sensor slow circuit response. So, I’ve blamed it on the o2 sensor. Is that why it misfires? Because the injectors are too large?

 

[pjtoledo]

misfires possibly yes. too large? no because they were built that way.
the O2 sensor should tell the computer to adjust the fuel mixture.
slow/incorrect response and the computer gives it the wrong fuel amount.

how many miles? oil consumption?

 

[I support common sense]

Mine is old enough that it uses a flex fuel sensor I think, and it is not consuming oil, however it has 289,xxx miles on it. However if it doesn’t have a flex fuel sensor and it uses the o2 sensor that would explain a bad idle.

 

[Brain75]

akranger also has a 99 I believe, and he definitely does have the sensor - we worked together to go through a stalling issue...

 

[stmitch]

Your 99 should definitely have the flex fuel sensor. It's going to be on the driver's side framerail under the cab. It looks like this:

Stock injectors in a FFV should have no problem running either gasoline or e85. The higher the ethanol content the better honestly. The ethanol is a great cleaner for injectors, combustion chambers, valves, etc.

Misfires due to an O2 sensor are probably unrelated to the fact that it's Flex Fuel, and more due to the fact that it's got 289k miles. Most places will tell you that O2 sensors start to slow down by 100k miles. If your O2s have 100k miles or more, then they're worth replacing. Since you have codes related to O2s, I'd start there before worrying about any of the Flex Fuel system.

 

[I support common sense]

Well, I never assumed it was because it was a flex model, I just posted to see if I could figure out what kind of differences my engine has compared to a standard 3.0. I still recall reading somewhere about having parts coated in corrosion resistant materials. Anyway, thank you.

I’m still not entirely sure of the vehicle’s background and it’s possible it had a swapped engine, how would I go about determining if the engine is a flex fuel model? It’s a rebuilt title and one of the previous owners said he didn’t think that it had the original engine.

 

[stmitch]

Most engines since the mid 90s have had parts and fuel systems that were resistant to alcohol since there's some alcohol in regular unleaded. I'm not aware of any special coatings or other hardware for the Flex Fuel engines.

The Flex Fuel 3.0 and Regular Gas 3.0 have no visual differences. The injectors are the only really important difference. Stock injectors were around 19lbs, and FFV injectors were 24lbs to handle the higher flow needed for e85. You could try to pull a part number off of one I suppose. No idea if that's realistic or not.

If a standard 3.0 were installed in place of a Flex Fuel 3.0, without swapping the fuel injectors, then it would have some drivability issues, and things like misfires. It would probably result in misfire fault codes for each bank or individual cylinders. I'd be surprised if that only triggered O2 sensor faults.

 

[nickname23]

Only difference I noticed is that the Flex-Fuel Pump doesn't necessarily work for the normal Gas Engine.

They aren't properly marked so you have to cross-reference between three companies to figure it out.

The sender units just don't keep up and burn out pretty quick especially if you have a lean condition where as the Gas version can apparently take a beating.

From a visual inspection both pumps really aren't that different at all just coloring (blue is Flex orange/brown is Gas)

Upgrade your injectors and Throttle-Body, that might not seem like much but it will be noticable the response time and building revs between gears will take less effort while not having to tear the motor apart if it's not necessary yet.

You will have to figure out if there are any sensors that detect alcohol in the fuel system and if they need to be transplanted or if they even work with your computer (damn planned obsolescence).

From what I understand about fuel E85 is pointless and can actually the cost either evens out or the savings are pointless compared to the engine upgrade and the fact that the fuel system will eventuality corrode other internal components over time.
Don't believe for a second that the Flex-Fuel is 100% ethanol proofed against corrosion.

Ethanol is a problem regardless and from a perspective of performance and longevity, it isn't something you want inside a fuel system that runs on Gasoline period.
It's in your non-flex gas tank right now.. and that's not even 100% gasoline it's still mixed along with additives.

Performance? Gasoline is better than Ethanol so having bigger injectors, a gas motor will actually still have more power than the Flex even though the injectors are slightly smaller.

This is because of the different fuel mixture, E85 also develops even worse mileage so you will be filling up more often.

 

[stmitch]

Only difference I noticed is that the Flex-Fuel Pump doesn't necessarily work for the normal Gas Engine.

They aren't properly marked so you have to cross-reference between three companies to figure it out.

The sender units just don't keep up and burn out pretty quick especially if you have a lean condition where as the Gas version can apparently take a beating.

From a visual inspection both pumps really aren't that different at all just coloring (blue is Flex orange/brown is Gas)

Upgrade your injectors and Throttle-Body, that might not seem like much but it will be noticable the response time and building revs between gears will take less effort while not having to tear the motor apart if it's not necessary yet.

You will have to figure out if there are any sensors that detect alcohol in the fuel system and if they need to be transplanted or if they even work with your computer (damn planned obsolescence).

From what I understand about fuel E85 is pointless and can actually the cost either evens out or the savings are pointless compared to the engine upgrade and the fact that the fuel system will eventuality corrode other internal components over time.
Don't believe for a second that the Flex-Fuel is 100% ethanol proofed against corrosion.

Ethanol is a problem regardless and from a perspective of performance and longevity, it isn't something you want inside a fuel system that runs on Gasoline period.
It's in your non-flex gas tank right now.. and that's not even 100% gasoline it's still mixed along with additives.

Performance? Gasoline is better than Ethanol so having bigger injectors, a gas motor will actually still have more power than the Flex even though the injectors are slightly smaller.

This is because of the different fuel mixture, E85 also develops even worse mileage so you will be filling up more often.

This is the owner's manual for a 99 Ranger. Check out the power ratings between gas and E85:

Alcohol cleans better than gasoline. It runs cooler than gasoline. And it's higher octane means that there's more resistance to knock (which the 3.0 is known for) and the ability to increase timing if the vehicle is truly flex fuel. Fuel efficiency does drop with e85, but the cost/benefit vary depending on your location and needs.

I live in the corn belt, and my truck would require premium thanks to the supercharger. E85 is typically ~$1/gal less than Premium unleaded, and means I can run more timing/make more power than I might otherwise. It's cheap race gas.

 

[Brain75]

I haven't seen it myself, but I understand the hard line portions of the flex are a higher amount stainless steel, and there are more hard lines (since all the soft lines are viton instead of rubber which costs more.... like 90% of the fuel line is hard), which makes the whole fuel line system more $$$. And yeah in helping AK Ranger out we discovered just how gawd awfully pricey the flex fuel sending unit is (Like $300 instead of the normal average $100). All the parts of the pump look pretty much the same except they run off AC instead of DC, and there is a converter in the sending unit power feed line just before the pump - little grey box.

Congrats on finding cheap E85.. Here in Colorado (Denver and the eastern plains) E85 is on average $0.15/ gal cheaper or even more expensive depending on size of town and how close to the tourist roads you are - zero benefit to buying it when the fuel economy is so terrible, have to be at least $1/gal cheaper to break even I figured (when gas was $3/gal).
(and while we aren't IL, eastern Colorado is every bit as much corn belt as western NE - 90% of the fields around here are corn, the "hard land" that wont grow anything gets planted dryland wheat, and there is a little rotation of pinto and soy but you can drive for miles and miles without seeing one of those)

 

[I support common sense]

This is the owner's manual for a 99 Ranger. Check out the power ratings between gas and E85:

Alcohol cleans better than gasoline. It runs cooler than gasoline. And it's higher octane means that there's more resistance to knock (which the 3.0 is known for) and the ability to increase timing if the vehicle is truly flex fuel. Fuel efficiency does drop with e85, but the cost/benefit vary depending on your location and needs.

I live in the corn belt, and my truck would require premium thanks to the supercharger. E85 is typically ~$1/gal less than Premium unleaded, and means I can run more timing/make more power than I might otherwise. It's cheap race gas.

Now, if I were to run regular low grade gas in my truck I might not be reaching that horsepower? And I’m assuming that the reason for the extra horsepower is because of the different head size?

Not sure how a supercharger requires a better grade of fuel, after all gas is gas, but the grade is determined by the amount of pure gasoline right?