Engine/Transmission (1994 - 1998) Mileage drop when fueling at wal mart?

[FFeiller]

something that makes no sense to me is my truck gets 1mpg better mileage when the tank is from 1/2 to full than it does when 1/4 or less. it's a 52 gal tank. every time i check it it proves out the same.

 

[HBarlow]

HBarlow,

How do you account for it then, beyond the things that you mentioned in your first post? I am curious?

I'm not sure if I understand your question but I'll try to answer.

As my friend Gary Ames wisely wrote above, true fuel mileage can actually vary due to slight variations in wind speed and direction, road speed, terrain, load, ambient temperature, humidity, cleanliness of truck, tire inflation pressures, and other factors. So-called "calculated" fuel mileage will always vary slightly because it depends upon the accuracy of the pumps it is purchased from and the fill level of subsequent tanks of fuel. Unless all these factors are controlled by laboratory-like conditions they are, at best, an estimate.

Fuel mileage and performance are often a matter of perception as well. Scientists and physicians call this perception syndrome the "placebo effect. " Give a man a "pill" and tell him it will make him feel better and he often feels better. It is human nature. Laboratory testing of new medicines involves "blind testing" where a controlled number of patients are given actual medications, and others are given a placebo (sugar pill) to eliminate this factor of human nature. The recipients and test administrators don't know which of the test patients received which medication. The placebo effect occurs when we put a new set of tires on a vehicle. We "feel" and "sense" the new tires and often imagine that our vehicle rides and drives better.

There is also bias that enters in to the analysis. Just as Ferd owners are certain of the superiority of their 6. 0 junkers, even when sitting on the shoulder broken down (saw another yesterday evening when my wife and I drove to the next small town for dinner. I picked the guy up and brought him home out of the cold to wait for his buddies to come rescue him), some folks believe that certain gasoline or diesel fuel brands are better. Sometimes the grandfather, father, and other male relatives are absolutely convinced of the same false truth.

Again, I emphasize that I am not a petroleum engineer and don't know or understand much about fuel, but I would say that there could be variations in the energy contained in a gallon of diesel fuel among the various refiners. The difference could result from the different source of the raw crude, possibly from the refining process itself, I honestly don't know. But Wal-Mart fuel is not inherently different from the fuel sold by branded retailers in the same area except it may not be dyed the same color and may not have certain additives added. I don't believe the additive packages effect fuel mileage. Diesel fuel is diesel fuel. Just like you and I can't eat a serving of corn and tell which farm, which region, or which state the corn was grown in, we can't identify the source or refiner of a gallon of diesel fuel. Corn, rice, gasoline, diesel fuel, and many other consumables are commodities.

My point in this discussion is Wal-Mart doesn't refine fuel, they simply sell the same fuel that is sold by fuel jobbers in any given large city or less populated region that is sold by name brand retailers.

A careful investigation in your area would reveal that the retail vendor who actually operates the fuel station at your Wal-Mart buys the fuel from a regional jobber and it is the same fuel that is sold at other branded stations in your area. Wal-Mart sells it a few cents cheaper following the model of Sam Walton: "sell as cheaply as possible and sell a lot of the item".

As a guy who has lived a long time, lived all over the USA, and who is an amateur student of politics, I know that in some regions of the country where labor unions are very strong and influential or where the politically correct/liberal point of view is the prevaling culture, there is a very strong bias against Wal-Mart stores. In IL, for example, many people hate Wal-Mart. Oddly enough, wherever a Wal-Mart store is built, thousands of people apply for jobs there and happily work there and hundreds of thousands of customers buy from that Wal-Mart store.

I believe that the additive packages that make the fuel sold by different retailers different are added at the wholesale pump before the fuel is pumped into the transport truck for delivery to the retailer.

 

[CBloom]

my 2 cents

every retailer buys fuel from a refinary that mixes the batch as required by season, regulations and customer requirements. I'm not a engineer just a truck driver of 26yrs. pilot+ flying j get full truck loads of fuel mixed to their standards, walmart may not,depends on how much they sell. Of bigger concern is calibration and temperature. A few years back some truckstop owners cranked up the heat on their pumps [installed to prevent gelling or freezing] hot fuel is thinner yet takes up the same volume. Became apparent when road drivers had to where gloves to hold on to hot nozzles. govt became involved some where shut down others fined some went out of business as word spread. calibration of the pump can easily be off, on purpose or most likely accident. I now run heavy haul and sometimes use over 200 gallons per day. Quality does vary alot! on pilot fuel power drops temps raise milage drops. Down . 2 [1. 9 from 2. 1] LOL Flying j fuel does much better as does most co-op fuel can't say about walmart can't get rig in there. wife does fuel there some but prefers fuel from ambest 30miles away. She sometimes goes to that town just to fuel i think?lol

 

[HBarlow]

Fuel truck drivers don't pick up fuel from the refinery, they pick up tanker loads from fuel jobbers ie wholesalers who supply fuel to retailers.

If the refinery refines to a particular customer spec how do they deliver it direct to that customer only?

 

[AStrand]

I used to be a transport driver. Blending is mostly done at the terminal as the fuel is being loaded. Any additives would be injected in the fuel as it is being loaded into the tanker. If you are loading for a certain company then thier additive package would be loaded with the fuel.

 

[bmoeller]

Doesn't matter where I get it, but I ALWAYS get between . 3-. 5mpg better in the KW on the LSD, as apposed to the ULSD. I fill up on it whenever I can find it.

The new biomass made diesel sucks. Some places I consistently lose up to 1mpg!

 

[GAmes]

Some have reported getting bad mpg from flying j, mostly due to their quick switch to ultra low sulfur diesel, which we supply in unmarked trucks, but chevron here in california, has not made the switch in all stations yet, so i pay a lil more to get the good stuff while it lasts. I hope that helps a little

I was with you until the last sentence, then you blew your credibility. CA went to exclusive ULSD a year before the rest of the states started the switchover. Because of that, the rest of your post is suspect.

 

[bmoeller]

I never question anyones credibility that is trying to help others.

Not safe to assume you're not ever being fed a line of bull.

 

[tgordon]

Suspect the pump calibration is off. Easy to prove if you've got an AUX tank set-up that lets you completely empty the tank. Mine takes exactly 32. 333 gallons to the fill neck like clockwork, proven on multiple honest pumps across our great land over the past 12 yrs and logged faithfully into my book. Which makes it immediately obvious when I've been charged for more fuel than will physically fit into this tank -- and easy to argue for a refund for the difference with the station manager (especially when I start writing down the pump certification number for my complaint to the state Dept of Agriculture:-laf)



FYI: I've noticed a significantly increasing problem with pump calibrations over the past 18-20 months. The pump calibrations at filling stations out front of the Kroger stores in my area are off by as much as 10%. My better value is the Shell station across the street charging 5 cents more a gallon.

I am going to suspect that this is the case, intentional or not I think the pervedial nail was hit on the head.

something that makes no sense to me is my truck gets 1mpg better mileage when the tank is from 1/2 to full than it does when 1/4 or less. it's a 52 gal tank. every time i check it it proves out the same.

If you are going by the gauge on the dash they are programmed to drop faster on the "lower Half" than from full to half if I recall correctly. Suppose t be some sort of deal about getting your attention. I am not sure of your set-up but could also be how exact your gauge is. Some farm tractors will give you the number of gallons in the tank not just the level on the gauge and that would be much more exact.

every retailer buys fuel from a refinary that mixes the batch as required by season, regulations and customer requirements. I'm not a engineer just a truck driver of 26yrs. pilot+ flying j get full truck loads of fuel mixed to their standards, walmart may not,depends on how much they sell. Of bigger concern is calibration and temperature. A few years back some truckstop owners cranked up the heat on their pumps [installed to prevent gelling or freezing] hot fuel is thinner yet takes up the same volume. Became apparent when road drivers had to where gloves to hold on to hot nozzles. govt became involved some where shut down others fined some went out of business as word spread. calibration of the pump can easily be off, on purpose or most likely accident. I now run heavy haul and sometimes use over 200 gallons per day. Quality does vary alot! on pilot fuel power drops temps raise milage drops. Down . 2 [1. 9 from 2. 1] LOL Flying j fuel does much better as does most co-op fuel can't say about walmart can't get rig in there. wife does fuel there some but prefers fuel from ambest 30miles away. She sometimes goes to that town just to fuel i think?lol

I actually saw a fuel pump warning that the fuel was not metered in a temperature compensating meter. I belive it was at the Love's station in LaSalle, IL. The part that blows me away is they say it would cost to much to install the equipment, yet they are all over in Canada, where the fuel company would be getting the screw, unlike say Texas or Florida#@$%!