I have a 2002 3.0 flex engine. What is the actual advantage to these engines if there actualy is one? All engines as far as I know run on the methanol added fuel anyway as far as I know. I know they have bigger injectors to help keep the power up but how does it know one fuel from another in the first place and about all fuel nowdays has methanol in it and everything runs ok not being flex rated. And does the bigger injectors affect fuel mileage. Why did they only make it available in the 3.0 and not the 4 cyl. or the 4.0? I'm just curious about some of these things.

 

Standard gasoline has only up to 10% ethenol, flex fuel engines are designed to run on E85 which is 85% ethenol. BIG difference between the two types of fuel and you cannot run E85 in a non flex engine ( not well anyway ). The advantage is ethanol burns cleaner so the hippies get a boner for it... Thats it. Compared to standard gasoline however its a terrible fuel and is not as efficient. Hence the need for bigger injectors. And yes it does cause fairly drastic decreases in fuel mileage. The computer on a flex engine can tell the difference based on sensor readings. When burning ethenol the sensors will detect the leaner fuel mixture and adjust the injectors accordingly. The whole flex fuel thing is pretty much dead, around here you cant even buy e85 fuel anymore. It was a fad that will hopefully stay dead. My advice, use gasoline!

 

Well in fairness you need to go back a few years, late 1800's, lol

"1876 Otto Cycle was the first combustion engine designed to use alcohol and gasoline. 1896 Henry Ford built his first automobile, the quadricycle, to run on pure ethanol."
Alcohol is ethanol, methanol is basically "poisoned" ethanol so would make you sick if you drank it

The first "automobile engines" were designed to use ethanol and gasoline.
At that time gasoline was a by-product of oil production and dirt cheap.
But ethanol could be produced by anyone, farmers could make it to run their tractors or farm equipment so self reliant if they wanted to do that.
The production of Moonshine has been around since, well since forever, lol, but you don't have to use "good" organic material to make ethanol, pretty much any organic refuse can be fermented and made in to ethanol, not good for "sippin' liquor", lol, but can be burned in an engine.

Gasoline has a 14.7:1 air fuel ratio, that is a WEIGHT RATIO, 14.7 POUNDS of air to 1 POUND of Gasoline, nothing to do with volume

Ethanol has a 9:1 air:fuel ratio, so more ethanol is required if there is 14.7 pounds of air

This required larger jets in carburetors to run ethanol, but earlier carbs were setup so jets could be changed easily for the fuel being used
Also means MPG is less for ethanol

Gasoline has lower octane, I think 99 is highest but 93 is highest at the pump
Ethanol is 107
Gasoline is far more dangerous than ethanol, ignites much easier because of lower octane
And harder to put out gasoline fire with water
Because of the higher octane and safety many racing engines uses ethanol, they can run higher compression engines, which compensates for less power per gallon of fuel

This safety issues was not lost in the early years, ethanol proponents would show gasoline explosions happening much easier.

Because of the cost, gasoline won out over time, simply a cheaper fuel in the past.
As the cost of gasoline goes up ethanol becomes more viable, also as simple as that.
And since people can now make their own ethanol, Fuel Alcohol permit, it is possible to make your own fuel if you don't need alot.

Larger distillers still make more on human consumption ethanol than as a fuel so not really a good alternative for them, lol.

And electric power is becoming more viable as batteries do.
But extended trips with batteries is the problem
But IMO a smaller ethanol powered generator added to an electric vehicle would be a good solution to long term use.
It is a renewable resource and safer to store in a vehicle, emissions are much lower that gasoline as well.
Gasoline/oil is a finite resource, it absolutely will be gone at some point in the future, not even a debatable issue, lol, so if we want our cars and trucks then alternatives need to be explored, again, as simple as that.

Newest Flex Fuel engines didn't need fuel sensors, they used larger injectors for adding extra fuel as needed for ethanol(all Flex Fuel need this), and then computers were setup to allow for longer injector open time when using E85, so you didn't get Lean Codes.
You could use up to E40 or so in any computer controlled gasoline engine, you might get Lean code above E30 but thats just a computer code, it doesn't mean engine is actually running Lean.
E100 is not sold because people would drink it, lol.

And no I am not a tree hugger, I use gasoline like it will last forever, lol, just a realist

 

I guess what I'm trying to ask then is if my oxygen sensors on my 2002 3.0 Flex are working properly running standard Non-E85 fuel should I get about the same gas mileage as a standard 3.0 with the smaller injectors running the same standard fuel.
I'm getting this truck ready for a pretty good commute for work everyday and want to get it as efficient as possible. Already changed the plugs, wires, air filter, synthetic oil, changed trans fluid and filter, new tires and alignment and am adjusting the transmission bands this weekend. I will be checking the upstream oxygen sensors too to make sure they are switching like they should. I know these 3.0's aren't known for having much power but after driving a 81 VW Rabbit Diesel for years on this same commute it feels like a Corvette by comparison already.
I do miss the little Rabbit though but it was honestly ready to break in half because of rust so I got rid of it, even though it still ran 100%, 44 mpg with the Turbo-Diesel engine.

 

As far as I know, when running on standard gasoline the 3.0 and 3.0 flex should run indentical and get identical mileage. Even though the injectors are larger on the flex the computer still tells the injector how much fuel to deliver and that would be the same between both engines regardless if using gasoline.

 

+1, ^^^

Injectors size, within reason doesn't effect MPG......or Power

3.0l Vulcan engine is a High RPM engine, makes best torque/power at 3,400RPM
Most engines are at 2,400rpm for best torque
People think they may be over REVing the engine, they are not, it was designed for higher RPMs.
So drive it like a "rented mule" for best power and best MPG, lugging an engine to get up to speed wastes fuel

 

very good response! Yes Henry himself envisioned the future running purely on ethanol. E10 has been around for decades (since 20's-30's) - tired of hearing all these people complain about this "new gas".

Isnt the Chevy volt setup like a diesel locomotive? Has a electric motor driving everything but an on board gas engine (not connected to the wheels) that kicks in once the batteries get low solely to charge the batteries.

 

Must be one hell of a generator to be able to do that. Todays technology is amazing.

 

I just filled it up today to be able to check the gas mileage in about a week. I have it running perfect but haven't had the emission test done yet. I'll more than likely be changing the 2 upstream o2 sensors before then since it just turned over 150,000 today.

 

If they are original upstream O2s then changing them WILL improve MPG, not much if it is OK now but will improve

O2 sensors use a chemical reaction to detect Oxygen in the exhaust, and the chemical gets used up, which causes O2 to read a little Lean, so computer runs engine slightly Rich, and MPG goes down.

Just like car batteries use a chemical reaction, and they work fine for 5 or 6 years, but toward the end they just start to fade out and one cold day.............click, click, click

 

This truck had so many problems when I got it I've been working mostly on those issues and since it ran pretty smooth at that time I figured I would wait and do the engine last if I even got that far. I know it's running a little rich by looking at the inside the tailpipe, doesn't really smell rich though and it's not oil for sure. I do have a slight exhaust leak on the pass. exhaust manifold and I imagine it's probably telling the oxygen sensor some bad stuff making it a little richer.
Or the sensors might be weak too besides. I bought a new Actron scanner {next to the best one} from Advance hoping it would read the airbags and abs problems I had, {it didn't} but I know it does engine live data fine so I will be using it now to check the o2 sensors out pretty close and try to learn how to read fuel trims ect.
I more than likely have some other vacuum leaks too but I'll get it straightened out now since the big stuff us finally behind me. I hope I can get that broken manifold stud out and not break anymore in the process but if the heads have to come off so be it and I can lap the valves and give it new head gaskets and intakes at the same time and be able to inspect the vacuum lines a little better if it comes to that. Done all those kinds of things many times over the years.
It has turned out to be a pretty nice truck after all and just enough little blemish's here and there so you don't have be so particular with it while till looking pretty good. One good thing about these little Rangers is that things are pretty easy to get too which is a nice relief from the newer cars.
It's been a fun project so far and learned so much here, especialy about the GEM and all the problems {which I had most of} it can cause when they go bad. I'd never figured out that mess without this forum.
So thanks again for everyone's help so far on this project.

 

Exhaust manifold leak "sucks" IN air from the outside when driving
Besides have Cold Air Intakes Rangers also came with scavenging exhaust manifolds.

Scavenging exhaust creates a lower pressure at the exhaust ports in a specific RPM band.
Factory manifolds are tuned for mid-range band, on the 3.0l that would be 3,000-3,600rpm
3rd party Headers are usually tuned for Lower band for more "get up and go" from stopped.
This lower pressure means exhaust is sucked out of a cylinder when exhaust valve opens, and this leaves more power on the crank because it doesn't have to push out the exhaust, so more power for the rear wheels.
If there is a manifold leak then Air is sucked in when pressure is lower, and that does two things, air pressure is not as low as it should be so less power left on crank, and O2 sensors sees that extra air(oxygen) so report Lean exhaust and computer runs that bank Richer than it should, as you said

Exhaust leaks past the upstream O2 sensors do not have the same effect, they are just a pain to repair, lol.

 

still need to change the factory O2's with 205K on it... working out all the other kinks first and not looking forward to trying to get them stuck in there bastards out...