Gas mileage and Fuel Treatment

[peejman]

I currently drive a '95 Toyota 4Runner, no matter what "brand" of standard grade gas (83?) I get somewhere abouts 13-14 mpg. I've tried severly combos of standard grade gas and fuel treatments/additives and still in the same ball park mpg. What should I do to get the milage up? All my filters, sparks plugs, spark plug wires, are good and my oil and transmission fluid just got changed. My 4Runner currently running on 31 a.t.'s, but I can't afford to get small tires due to the area I live in (mountains, rough roads, bad snows, etc.). Please give some help. TY!

Honestly, there's nothing you can do to improve your mileage significantly in that vehicle.

The best thing you can do is buy the lowest octane you vehicle runs reasonably on. Using higher octane than necessary actually make mileage worse if anything.

Make sure your tires have an adequate amount of air pressure. The sticker in the door jamb should be the minimum air pressure. The tire side wall has the maximum. 5 psi in air pressure can make a significant difference in rolling resistance.

[Guest Lester Weevils]

Yeah ethanol gas causes some documented problems in small engines, as best I can tell. Was thinking if ethanol gas can mess up a boat motor or chainsaw, then MAYBE non-ethanol gas would be long-term better for an auto engine also, even if ethanol gas doesn't cause immediate problems with auto engines? But that may be flawed reasoning. Maybe big engines are so different from small engines that the fuel becomes a meaningless factor.

Perhaps different vehicle's onboard gas mileage computers integrate over different time periods? Maybe some of them even have two readouts, long-term and short-term? I only buy a vehicle every 20 years and the 2010 Wrangler is the only one I've had with the onboard MPG readout. The integration time is pretty short on the Jeep. Not long enough to measure the average MPG for an entire tank of fuel. If I do city driving one day and hiway the next day, the integration time is short enough that I get radically different MPG numbers on the two different days.

But if somebody "keeps an eye on" the meter every day, then it is easy to get a feel for the general range. Assuming the onboard odometer and the fuel-comsumption real-time metering is at all accurate, then if you drive a route one day on ethanol gas and drive the same route the next day on non-ethanol, then it ought to give valid comparative numbers (one MPG is better than the other or whatever) regardless whether the meter is "absolutely accurate" for a long-term mileage measurement?

Maybe a well-coded, bug-free GPS would be better than the odometer for measuring such stuff? Sometimes when I would drive with my old Garmin eTrex on the dash of my ancient old truck, it seemed to give more accurate speed readings than the speedometer. But in that case it was comparing an ancient GPS against an even more ancient truck.

[Guest 6.8 AR]

A car's computer takes a snapshot of what is there and estimates mileage, based on

all of its input devices. It does it continually and gets more accurate toward the end

of the trip. When it calculates "miles before running out" it is a joke until it is very close

to empty. An old vacuum gauge is a lot of help to increase mileage. It's all in how you

drive.

Occasionally I put pure acetone at 2oz/10 gallons of gas(real gas) and I have noticed a

slight increase in the mileage on my Fords. I will probably do it after the warranties

expire on the BMWs, but not until then. My wife and I have both noticed a change in

performance and a slight mileage increase in both the BMWs with pure gasoline and

we try to find pure gas for them.

This ethanol added crap has done nothing more than raise our taxes, raise our food

and make the little liberal children feel better about the climate.

Like I really care about them...

I don't remember the exact numbers, but, ethanol takes somewhere around four times

the caloric energy to produce and get to market and reduces the caloric energy contained

in every gallon of gas it is added to. So how is there a benefit? I don't see how you can get

better mileage from any amount of E10, E15, or especially E85 enhanced gas.

It is a political boondoggle and anyone who believes in the stuff should go out and design

the right type of internal combustion engine to run it in.

See it around long enough and people start believing it.

Sounds like something Goebbels did once, huh?

Edited December 9, 2011 by 6.8 AR

[Guest db99wj]

Yeah ethanol gas causes some documented problems in small engines, as best I can tell. Was thinking if ethanol gas can mess up a boat motor or chainsaw, then MAYBE non-ethanol gas would be long-term better for an auto engine also, even if ethanol gas doesn't cause immediate problems with auto engines? But that may be flawed reasoning. Maybe big engines are so different from small engines that the fuel becomes a meaningless factor.

Perhaps different vehicle's onboard gas mileage computers integrate over different time periods? Maybe some of them even have two readouts, long-term and short-term? I only buy a vehicle every 20 years and the 2010 Wrangler is the only one I've had with the onboard MPG readout. The integration time is pretty short on the Jeep. Not long enough to measure the average MPG for an entire tank of fuel. If I do city driving one day and hiway the next day, the integration time is short enough that I get radically different MPG numbers on the two different days.

But if somebody "keeps an eye on" the meter every day, then it is easy to get a feel for the general range. Assuming the onboard odometer and the fuel-comsumption real-time metering is at all accurate, then if you drive a route one day on ethanol gas and drive the same route the next day on non-ethanol, then it ought to give valid comparative numbers (one MPG is better than the other or whatever) regardless whether the meter is "absolutely accurate" for a long-term mileage measurement?

Maybe a well-coded, bug-free GPS would be better than the odometer for measuring such stuff? Sometimes when I would drive with my old Garmin eTrex on the dash of my ancient old truck, it seemed to give more accurate speed readings than the speedometer. But in that case it was comparing an ancient GPS against an even more ancient truck.

I have a 2009 JKU, with 33" tires that are heavy. My mileage on average, tank to tank, is about 13.2 MPG. How do I get that, most of my driving is in the city. I get about 250 miles per tank and I have to put in 19.111 gallons, it has a 22 gallon tank. The computer is not a good indication of what you get overall, it can give you immediate, I will reset it on a trip and see what I am getting at highway speeds, which is about 20 MPG. City driving kills MPG, especially in stop and go rush hour traffic. That's why I get bad MPG, and the tires, and the aerodynamics of the brick on wheels we drive! But then, I didn't buy the thing for the gas mileage! The computer thing, while I won't say it is junk, it is not really accurate. Also, I hate how the light will come on, it will give you the miles to empty until about 35 miles left, then go to "Lo Fuel". How many miles do I have left their mister fancy computer? I wish we could reprogram it to show miles all the way down, which is why I typically only put in 19.xx at fill ups. I think I have only put in 20 gallons a couple of times and once 21 gallons, and I was on a road trip in the near the TX/AR/LA border, late at night, and went miles without seeing any sign of life let along a gas station.

[Guest TAFKAP]

ONe gas station in Memphis that has it, would cost me a quarter tank to drive that far. Ethanol crap for me I guess. Ethanol has caused me problems in my small engines. I use Fuel Stabilizer in them and they have been working pretty good for the past year.

Supposedly, the only non-ethanol station is an Exxon terminal right by the refinery. I've driven by it numerous times, but it doesn't appear to be a "public" gas station.

But some FYI for all you West TN drivers: All fuel in the Memphis area comes from the Valero refinery. Exxon is the only exception, as they barge their fuel up the river. They have a terminal right at the "crotch" of the MS river where it diverts around President's Island. So regardless of the station you purchase your fuel from, it originates in the same location.

Can someone with some more knowhow explain the difference in gasoline brands, if the fuel originates at the same place? At what point are their special "additives" mixed in?

[Guest TAFKAP]

Yeah ethanol gas causes some documented problems in small engines, as best I can tell. Was thinking if ethanol gas can mess up a boat motor or chainsaw, then MAYBE non-ethanol gas would be long-term better for an auto engine also, even if ethanol gas doesn't cause immediate problems with auto engines? But that may be flawed reasoning. Maybe big engines are so different from small engines that the fuel becomes a meaningless factor.

Ethanol has a "shelf life" of about 3-6 weeks, depending on who you ask. Most daily drivers burn the ethanol before they have a chance to clog the engine. But if you think of the frequency of use in a small engine, the ethanol is generally left for longer periods in the tank, allowing it to gum up the system. Instead of just cutting off your mower now, shut the fuel off and let it run out of the lines, or just let it run until the tank is empty.

[Guest db99wj]

Supposedly, the only non-ethanol station is an Exxon terminal right by the refinery. I've driven by it numerous times, but it doesn't appear to be a "public" gas station.

But some FYI for all you West TN drivers: All fuel in the Memphis area comes from the Valero refinery. Exxon is the only exception, as they barge their fuel up the river. They have a terminal right at the "crotch" of the MS river where it diverts around President's Island. So regardless of the station you purchase your fuel from, it originates in the same location.

Can someone with some more knowhow explain the difference in gasoline brands, if the fuel originates at the same place? At what point are their special "additives" mixed in?

That website link above doesn't have that one, I know which one you are talking about, not sure either if it is a "public" station. The one that the website link has is Canale and Son's grocery at 10170 Raleigh Lagrange Rd East, which is way out east, not feasible for me living in the loop in all.

I've wondered that as well, I've seen the Valero trucks most of the gas stations. I'm not sure about Kroger gas though. I see the truck there, but for the life of me can't remember if it was Valero or Dupree, or something else. When Valero had the explosion/fire a few months ago, lots of stations, including BP here at Estate and Poplar, was out of gas for several days. Little lady said they were trying to get some from Nashville.

[strickj]

A car's computer takes a snapshot of what is there and estimates mileage, based on

all of its input devices. It does it continually and gets more accurate toward the end

of the trip. When it calculates "miles before running out" it is a joke until it is very close

to empty. An old vacuum gauge is a lot of help to increase mileage. It's all in how you

drive.

It also calculates by your driving habits. I drive consistently each time I go somewhere.

All three of my estimates (instant mpg, avg mpg and run out millage) are accurate. And yes, I have, umm... "tested" my run out millage. IIRC, it read 6 miles as I drifted off the side of the road. That's 1\3 of a gallon of accuracy.

Maybe you're inconsistent on the gas peddle?

Edited December 9, 2011 by strickj

[Will H]

It really is all in how you drive. I average 44.2 mpg combined city/hwy in a non-hybrid car EPA rated at 30 combined. This is pump verified, not just the display, and is on the 10% ethanol crap. I have done this with very slight modifications to the car. First of all the car is a 5 speed, which eliminates the power train loss in automatics. I have replaced the stock tires with Goodyear FuelMax tires running about 45 psi in the summer (The tires are rated at 50 psi cold, so it's safe). I also lowered the car about 2.5 inches to reduce the drag coefficient.

I do not use any fuel additives, as they are already in the fuel and not needed. I also run name brand gas only. My wife was a dispatcher for a company called Petroleum Traders, and she said "yes, there is a big difference in brands, and it's not really the gas, but the additives they put in it."

Oh, and car is a 2008 Chevy Cobalt XFE with 90,000 miles and never a problem. Yes, a Chevrolet, because if you actually look at the numbers they have been beating the "imports" in mpg for sometime now.

[Guest 6.8 AR]

It also calculates by your driving habits. I drive consistently each time I go somewhere.

All three of my estimates (instant mpg, avg mpg and run out millage) are accurate. And yes, I have, umm... "tested" my run out millage. IIRC, it read 6 miles as I drifted off the side of the road. That's 1\3 of a gallon of accuracy.

Maybe you're inconsistent on the gas peddle?

No, actually I have a life. If you

go up and down I24 and think you are consistent

every day and expect all variables to be consistent,

I have some swamp land you might be interested in.

I'll admit to only owning few brands of cars with

trip computers, but I have never seen them reach

the accuracy you mention, but pigs can fly, I guess.

The computer in a car doesn't really care what your

habits are, it just measures. Did you actually read

what I wrote? I said I use it to adjust my driving

habits, I think. There may be a system out there

that takes into account every wheeze, sniffle and

siphoning, but most cars don't have it. It calculates

the results of its input devices.

Sent from my iPhone using Tapatalk

[Motasyco]

My truck does not call for 93 octane but it runs better with it and gets better mpg enough to offset the cost.

That's because the "Force" is strong with you. If OS is riding with you, you probably have more gas when you arrive than you did when you left.

[strickj]

No, actually I have a life. If you

go up and down I24 and think you are consistent

every day and expect all variables to be consistent,

Yes, I am constant and "smooth" with my driving... and also have a life.

You don't have to drive like granny to do this.

The computer in a car doesn't really care what your

habits are, it just measures.

Actually, they do. Even says so in my manual. Did you read your manual?

And it's not just for MPG calculations, either.

A vehicle will even adjust engine and transmission performance based on your driving habits. I think GM started this in 2000.

Though the info is only stored over a few dozen driving cycles, but there is software available that will allow you to download this info to your laptop via OBD. There are also modules available that you leave plugged into your OBD that will record the info for longer periods.

[Will H]

No, actually I have a life. If you

go up and down I24 and think you are consistent

every day and expect all variables to be consistent,

I have some swamp land you might be interested in.

I'll admit to only owning few brands of cars with

trip computers, but I have never seen them reach

the accuracy you mention, but pigs can fly, I guess.

The computer in a car doesn't really care what your

habits are, it just measures. Did you actually read

what I wrote? I said I use it to adjust my driving

habits, I think. There may be a system out there

that takes into account every wheeze, sniffle and

siphoning, but most cars don't have it. It calculates

the results of its input devices.

This is incorrect.

Actually, they do. Even says so in my manual. Did you read your manual?

And it's not just for MPG calculations, either.

A vehicle will even adjust engine and transmission performance based on your driving habits. I think GM started this in 2000.

Though the info is only stored over a few dozen driving cycles, but there is software available that will allow you to download this info to your laptop via OBD. There are also modules available that you leave plugged into your OBD that will record the info for longer periods.

This is correct, except that's OBD II instead of OBD.

Here is some very simple proof.

This is a pic of my miles to empty right after filling up one day...

It says I can drive 608 miles on this tank of gas.

The car is a 2008 Chevy cobalt XFE.

The EPA rating is 25 city, 36 hwy for a combined 29 mpg* Source: Fuel Economy of the 2008 Chevrolet Cobalt XFE

This car has a 13 gallon tank.

29 avg mpg * 13 gallons = 377 miles.

My MPG during this time (summer) figured from the pump was 51.1 mpg

51.1 my average pervious tank * 13 gallons= 664.3

Obviously the car is re figuring the miles to empty based on my recent driving habits. A lot of newer cars include this type of AI.

Edited December 10, 2011 by Will H

[Guest 6.8 AR]

Did I say the car does not adjust for conditions?

I said the trip computer makes calculations based

on the input devices. I never said anything about

OBDII. Was only referring to the trip computer.

OBDII definitely adjusts according to any change

in throttle, barometric, humidity, octane and many

other variables. I guess I must be wrong every time

I reset and recheck my trip computer, because it

has never gotten so close as your cars do.

Been checking the numbers since the early nineties.

Sent from my iPhone using Tapatalk

[ls3_kid]

Once or twice a year I run 110 octane. Other than that it is BP, Shell, or Texaco/Chevron "Hi-Test" as my dad still calls it lol. Also I believe GM's OBD is your last 20 key starts. I can't remember exactly...

Edited December 10, 2011 by ls3_kid

[Guest Lester Weevils]

or Texaco/Chevron "Hi-Test" as my dad still calls it lol.

I recall when "hi-test" was the new hip name for spensive gasoline.

Before that, they called the best stuff Ethyl (or possibly Ethel [as in Merman]).

Tetraethyllead - Wikipedia, the free encyclopedia

"Gimme two bits worth of that thar Ethel, and check the tares and earl."

Edited December 10, 2011 by Lester Weevils

[strickj]

Did I say the car does not adjust for conditions?

I said the trip computer makes calculations based

on the input devices. I never said anything about

OBDII. Was only referring to the trip computer.

OBDII definitely adjusts according to any change

in throttle, barometric, humidity, octane and many

other variables. I guess I must be wrong every time

I reset and recheck my trip computer, because it

has never gotten so close as your cars do.

Been checking the numbers since the early nineties.

Sent from my iPhone using Tapatalk

OBD II is the connector for your ECM.

I think I might not be saying this clearly 'nuff.

What I'm trying to say is, if you constantly change your driving habits (one trip you're driving like John Force, the next trip like the Clampetts), then your OBC can not accurately estimate your MPG.

Your OBC will estimate your MPG by using both sensors and your driving habits.

If you constantly drive like John Force, then your OBC will give an accurate MPG reading, as it knows what to expect based on this learned given.

If you constantly change your driving habits, then your OBC can not give an accurate reading because there is no given.

To make an analogy; imagine for a moment that you are a hind catcher in baseball. If your pitcher always throws the ball between 90-95 MPH and 12 inches above the plate, then you will always know where to put your glove and how hard to squeeze it so you don't drop the ball. But if he randomly throws the ball at different speeds and in different locations, then your guess on how and where to put your glove will always be wrong.

Same thing here. There has to be a given before you can get an accurate reading on you MPG.

In addition, you will get much better gas millage by having a consistent driving habit. Your car will learn and temporally store your driving habits in order to adjust engine and trans performance.

If you drive fast and hard all the time, then you will get better gas millage then if you drive fast and hard half of the time.

If you have ever heard an old married couple say that their shared car doesn't get good gas millage, this is why. Hubby probably drives hard and fast while the wife drives soft and slow. The car's computer will be confused and will feed too much fuel at the wrong times.

This is what I meant earlier when I said I drive consistently.

[Guest 6.8 AR]

I understand about consistency and I also understand about the computer adapting to your driving habits. But I was referring to the trip computer on your dash board. It can only make assumptions based on historical data: Data which can change with the driving habits and with the total trip. that same computer is going to have a fit when you decide to floor it because of whatever reason, and it will change all the assumptions at some point. It can only be so accurate unless you drive the same way day in and day out. I don't drive that erratically either, but conditions do change. I do know that many BMW's transmissions adapt like you refer and I have understood the computer's role in the Ford vehicles for years.

Hey, call a spade a spade. Your condition doesn't fit everyone else. The computer's role in the car is to increase efficiency, driveability and comfort, but it didn't take over your input, yet. That's called the gas pedal and everyone drives differently. When you fill your tank with gas, the computer estimates based on historical data. Then it samples all the variables all the time and re-estimates enroute. The more consistent your driving habits are, the more consistent the original calculation is, but, when you say the computer is totally accurate all the time, try qualifying your statement before you do it, because the math can lie very fast if the variables aren't yours. I have never bought a car based on it's EPA estimate of pigeon dung it consumes. One example is a 92 Taurus SHO. The one with the Yamahammer engine. It was the best of both worlds to me. It would fly and handle well in the curves. And on the highway, it would get 30 mpgs on cruise all day long. I only mention that car because it was an extremely well designed engine in an otherwise drab car. The efficiency of the design of the engine has a lot to do with economy, also. Back then, it was just OBD and a very efficient fuel and spark delivery system. Now, with OBDII, or whatever you want to call it, adaptive computing, it will attain a higher level of accuracy. No doubt! But, until that computer starts penalizing you for your driving changes, there will always be what's called an estimation. It would have to control every aspect of your driving, not just most. It's getting very good. No doubt. I think we may be having difficulty in what we are trying to accomplish unless we specify all the variables, don't you?

Edited December 15, 2011 by 6.8 AR

[Guest 6.8 AR]

BTW, most of my driving is up and down I-24, between Clarksville and Nashville. I go to work at different

times. Traffic is different every time I go to work. In the morning, it's like rush hour starts in Clarksville for

the Nashville slow downs. another variable is the type of music I'm listening to. If it's classical, I'm serene

and passive. If I'm listening to Blood, Sweat&Tears, get out of my way I do like that kind of jazz. My best

mileage is with strings, though. I could drive on past my exit with it.

Edited December 10, 2011 by 6.8 AR

[Lumber_Jack]

Note: if you're running a late model vehicle like the OP, and also have oversized tires (anything over what the door tag states) and have not had your odometer/speedometer adjusted, you may not be getting accurate MPG data.

I have a 08 GMC Seirra 5.7L V8, that drops to 4 cyl when coasting or going downhill. I still get 17 mpg maximum on the interstate. Average about 15.5, as low as 13, depending on 4wd use.

[kieefer]

FYI - Ethanol-free gas stations in TN

[Guest Lester Weevils]

I have a 2009 JKU, with 33" tires that are heavy. My mileage on average, tank to tank, is about 13.2 MPG. How do I get that, most of my driving is in the city. I get about 250 miles per tank and I have to put in 19.111 gallons, it has a 22 gallon tank. The computer is not a good indication of what you get overall, it can give you immediate, I will reset it on a trip and see what I am getting at highway speeds, which is about 20 MPG. City driving kills MPG, especially in stop and go rush hour traffic. That's why I get bad MPG, and the tires, and the aerodynamics of the brick on wheels we drive! But then, I didn't buy the thing for the gas mileage! The computer thing, while I won't say it is junk, it is not really accurate. Also, I hate how the light will come on, it will give you the miles to empty until about 35 miles left, then go to "Lo Fuel". How many miles do I have left their mister fancy computer? I wish we could reprogram it to show miles all the way down, which is why I typically only put in 19.xx at fill ups. I think I have only put in 20 gallons a couple of times and once 21 gallons, and I was on a road trip in the near the TX/AR/LA border, late at night, and went miles without seeing any sign of life let along a gas station.

Haven't noticed the lo fuel light yet. I try to refill at the half-tank point, just in case there is an emergency that might need plenty of gas.

I don't drive much. The JK is a year old and just now tipped over 3000 miles. If one doesn't drive much then the fuel economy is not important. Though I do refuel the JK more often than the 18 year old Astro van, which is bigger, has the aerodynamics of a brick, and has at least as big an engine as the JK. Maybe the astro has a slightly larger fuel tank.

The JK is more fun to drive and has a better ride. The old Astro rides as rough as a buckboard, which long ago didn't bother me as much as lately.

[Guest TAFKAP]

Once or twice a year I run 110 octane. Other than that it is BP, Shell, or Texaco/Chevron "Hi-Test" as my dad still calls it lol. Also I believe GM's OBD is your last 20 key starts. I can't remember exactly...

Are you filling up at the race track or the airport?!?!?!?!

[daddyo]

FYI - Ethanol-free gas stations in TN

Can't trust that website. The ones I have driven to personally do NOT have ethanol-free fuel.

[Guest nicemac]

First,

10% Ethanol mixed in your fuel is bad for several reasons, and it will decrease your mileage slightly. But unless you have a 2,500 mile range on a tank of fuel, it will not decrease the range of a tank of fuel 100 miles. Ethanol only has 66% of the energy (BTUs) of gasoline. (.66 * 10%) + (1.00 * 90%) = 96.6% as much energy from a gallon of gas with 10% ethanol added. You would expect power and mileage to be down 3.4%. So a car that gets 25mpg with real gas will get 24mpg (or more) with 10% ethanol mixed in and the engine will produce 96.6% as much power as it would with 100% gasoline (all other factors being equal, which they are not, as the on-board system will make adjustments to compensate–hence the theoretical 24mpg car will get better than 24…).

Second,

Running 93 octane gasoline in an engine designed for 87 will actually cause it to be harder to start (especially on colder days) and, contrary to popular belief, it can not and will not run better. Read up on what the octane rating means and you will see why. 93 octane does not burn cleaner, will not get you better mileage, is not magic and will not fix anything on your car, despite the cool signage at the gas station. Btw, many times when you fill up with (what you think is) 93 octane, all you get is 87 octane anyway.

Third,

Fuel filters only need to be replaced when they start getting restricted. Any sooner is a waste of money. Same with air filters–only on most cars you can simply blow those out and be fine. For. Years.

Fourth,

Much like changing fuel filters, injectors that are not clogged do not benefit from any type of cleaning solutions added to the tank. At all.

Finally,

A car with a 29 mpg EPA estimate is not going to get 51 miles per gallon under anywhere near normal driving conditions. Maybe after filling up at the top and coasting off of Monteagle you can get the trip computer to read that way, but that is just fooling the system… Hyper-milers have to drive in a very unorthodox manner to achieve the mileage numbers they get.

Kevin

ASE-Certified Master Technician

Ford-Certified Master Technician

12 years dealership driveability experience