Raising Gas Mileage on a 2003

I know this topic has been beaten like a dead horse...

I've decided to go on a "increase fuel economy" crusade.



My first step was to setup ProScan on a laptop with a ELM 327 ODB/USB interface so I could monitor gas mileage.



My 2003 Sport Trac has about 83K miles. It is 4wd with an automatic.

A few things special... It has 3.73 gears, It has Lear bed cap, a K&N air filter, and it has a Gibson stainless exhaust.



My commute to work is about 9 miles each way and is pretty much crowded suburban driving through northeast Philadelphia suburbs.



Proscan pretty much indicates what I already knew. I get anywhere between 15.5-17 mpg on my commute. It pretty much depends on how thick traffic is.



One thing I have found is that the Trac does best when it can get over 45 mph to engage overdrive. It pays to alter your commute route if the change allows you spend more time up to that speed, even if it takes a longer distance. In addition, getting it to go into overdrive at around 45mph requires the lightest touch of the pedal. Your really have to focus to get the best out of it.



My real suprise was how well my Trac does on the highway. I recently went out to a junk yard in Elizabethtown, PA to pickup a high series console. It was about 100 miles each way.

I actually got 25.5 mpg on that trip. I kept the speed between 60-65mph. I tried to keep with traffic. If there was a semi, I got behind him (but i wouldn't say I drafted).



I really think the Lear cap and the Gibson exhaust makes a big difference on the highway fuel mileage.



I have planned the next steps in my quest to increase mpg:



1) Change rear axle to Mobile 1. (done 2 weeks ago)

2) Change transmission fluid to Mobile 1 ATF (this weekend).

3) Switch to 0-30W Mobile 1 Engine oil (this weekend or next).

4) Add molybdenum disulfide additive to engine oil (as soon as it arrives).

5) Convert to Ford Taurus electric radiator fan (some time this winter).



I think items 3.4 & 5 will be particularly helpful in raising my commute (around town) mileage.



I'll try to post some meaningful data in this thread as I make the mods.

Wish me luck...

best of luck to you. I have the same truck. a 2003 4x4 but with 120,000 miles(I just hit yesterday). would love to hear your findings. I live in central Pennsylvania myself and here its all hills/mountains and my gas tank suffers miserably:sad: anything to help my mileage would be phenomenal. again best of luck to you:supercool:

Dean,

Don't expect a big or noticeable improvement? It's the traffic that is killing your mileage. That kind of slow-down, speed-up, and stop and go driving is murder on gas mileage especially in a heavy vehicle like the Sport Trac.



Getting 25+ MPG on the highway is well above average for Sport Tracs and clearly indicates that your Sport Trac and your driving is about as good as it gets.



Yes, changing all your fluids to synthetic fluids can help MPG by reducing friction from the moving and rotating parts.



The electric fan can save MPG in highway driving, but had minimal effect in low speed, stop and go traffic because your fan will be running more frequently during low speed driving. I would also recommend that you install a by-pass switch so you can turn on the fan if the thermostatic sensor fails....I have own a lot of cars with electric cooling fans and never had a fan fail, but the thermostatic switches have always been a constant problem. With a by=pass switch, you can force the fan to come on and prevent overheating if the thermostatic switch fails and you will not be left stranded on the side of the road.



...Richard

Can you list your tire size and how you are measuring your MPG? Trust but verify....:grin:

ncstatewolfpacker is correct.

Your speedometer/odometer accuracy can be effected by different tire diameters and if you use those Odometer readings in calculating your gas mileage, you may be using inaccurate readings. That makes me suspicious when you claim you get 25.5 MPG on the highway, which is higher than most Sport Trac owners get. Your city MPG is also on the high side but within the expected range, but most owners get less MPG than you do in heavy, congested city/suburban driving.



I bought an UltraGauge that allows me to adjust the speed/odometer reading (on the guage) to correct for tire size, or simply factory speedometer errors.



A good way to do a quick test is to drive to a mile-marker on a nearby interstate. Jot down your exact odometer reading (to the tenth of a mile). Now drive about 10+ miles (more miles = more accuracy) and pull up to the next Mile-marker and jot down the odometer reading. The difference between the actual miles traveled vs what the odometer reading, is a fairly accurate way to determine just how far off your speedometer/odometer is. This only gives you an approximate indication of the accuracy of your speedometer/odometer. The UltraGauge gives calculates the speedometer adjustment factor to a fraction of a percent. Now my UltraGauge speed exactly matches my GPS speed and the Interstate mile-markers, even though my vehicle speedo is several MPH off at most speeds.



Most speedometers read higher than the actual speed or distanced traveled so if you use those readings to calculate gas mileage, that will result in an inaccurately high MPG average.

Depending upon the actual tire diameter, you may be throwing the speedometer/odometer off by even more that the normal factory error.



...Rich

Try raising the tire pressure a few psi over spec. You commute is so short your ST barely has time to get to operating temp(better efficiency). But, letting it idle to warm up gets 0 mpg. Also, it's getting colder out now and running "winter gas" isn't helping.

Good luck. It sounds like your ST is doing just fine though.

My tire size is stock. 235/70-16. I just put on a new set of Khumo's from Tire Rack.

Sweet clearance deal..$61 dollars each! And they are nice tires. AA traction rated and A temperature rated. I am running them at 38 psi.



I have pretty good confidence in the Proscan ODB software and it's trip MPG reading.

The 25.5 highway reading is legit.



Keep in mind, I'm running 3.73 axle ratio, K&N air filter, and a Gibson exhaust already. However in my opinion I think the Lear cap has made the biggest improvement on highway fuel economy. That and a driver with light foot and good technique. Keep it below 65mph, look ahead and try to anticipate things etc.



I think an electric radiator fan would be more beneficial during my commute than on the highway. Here is why:

With the stock fan clutch, even when it is not engaged, still needlessly spins the fan and wastes fuel. Secondly, there is faster warm-up of the engine with the electric fan.

I think getting the engine up to temp quickly is important for fuel efficiency on a short commute.



I did change out the ATF today. I disconnected the top ATF return line on the radiator and slipped a clear hose over the line and into a bucket. Started the truck and put her in drive for a bit to pump out as much fluid as possible from the torque converter.



Pepboy's gave me the wrong trans filter. Had to tell the parts computer it was a 2001 and he then listed two types. He pulled them out we found one that matched my old one. They made good on the return exchange. BTW, I love Pepboys rewards program. Used 20% discount to buy the filter and Mobile 1 ATF (which usually goes $10 a quart).



BTW, I ditched the Purolator trans gasket and got a Felpro instead, much better, its thicker and it hold the bolts in place making re-installation a breeze.



There was quite a bit of fine sludge on the magnet and a bit on the surface of the trans pan. Made me wish I had pulled the pan back at 35K instead of having the dealer just do the flush with the Rotunda machine.



I did take the time to install the drain plug kit and I painted the exterior of the pan while I was at it. I have three quarts of ATF left over. I will probably drain & fill transfer case tomorrow.

A 100 mile trip is no where enough to check MPG's.



This weekend, 531 miles of that 480 at interstate speed, 21.3 total MPG. Thats a 2003 4.0 automatic 2wd with 3.73's. Mobile 1 oil, Valvoline synthetic tranny fluid and a K & N air filter with the cold air mod (Interesting fact, I routinly draw air that is 4 degrees lower than ambient) and a factory hard tonneau cover. All checked by HOBDrive.



I don't even consider that number correct, as I just cleared my HOBdrive program for the trip. I had reset it after 1200 miles. That total average was 19.5.



That's the number I assume is my real MPG.

Dean,

Yes, your aftermarket exhaust is probably giving you your biggest mileage boost.



Surprisingly, surveys done years ago on this website show that there is little difference in MPG between the 3.73 and the 4.11 rear axles.



It's not tires size as much as tire diameter that effects speedometer/odometer readings. You can have the stock tire size, but all tires of that size are not always the same diameter. It might only be 1/2" difference, but it does make difference that accumulates over the miles driven. Also, remember that over-inflating tires to reduce their roll resistance also increases their diameter and leads to more inaccuracy.n



I'm sure your ProScan gauge is good, however if it is not calibrated to correct for speedometer/odometer error it cannot give you an accurate reading because it is using the OEM Speed sensor which are know to be inaccurate and coupled with a possible difference in tire diameter.



You theory on the electric fan is totally wrong. The electric fan does nothing to make your car warm up faster....that is controlled by the thermostat and engine load. That is why most car makers recommend that you not let your vehicle warm up...just start your vehicle and drive off. You are wasting gas idling, and it takes longer to warm up. Yes, the conventional belt driven fan does impart drag that takes some power, and is most significant when the fan is not needed...on the highway, when speeds are above 30 MPH. In town, the fan is needed because the vehicle is not going fast enough to get sufficient air flow to cool the engine. When the electric fan is on, it requires the alternator to do more work and that puts extra load on the engine. So an electric fan in city traffic is not going to save you much gas if at all. But get out on the highway and the fan shuts off and there is not parasitic drag, and now you are saving some gas. The more highway driving you do, the more gas you will save.





If you are accurately getting 25+ MPG on the highway, you are getting well above the average MPG for a Sport Trac. Your city/suburban MPG average is also better than most people get with their Sport Tracs...some get as low as 11 MPG or less in city driving.



As doctorcad said, 100 miles certainly is not enough the calculate MPG. It is only slightly better than an instantaneous MPG reading. Traffic and road conditions very so widely from day to day that all the little things you have done to improve mileage get lost in the overall average



...Rich

That was a 200 mile trip, 100 each way. That is plenty of miles to determine highway MPG via OBD. doctorcad - How fast were you going when you got 23mpg? How good is your ecomodding driving technique? I'm pretty good at it!



Rich, I'll agree the warm-up is dependent on the thermostat. But I'll bet once I get the electric fan setup it will rarely ever kick on, even on my commute. I've owned cars in the past that had them and they hardly ever kicked on. I'm expecting A 2-3% increase with the efan, but we'll see.



Also, It would be very strange if my Kuhmo 235/70-16 diameters were significantly different than the stock Cross terrains 235/70-16's. But you know what? I have a stock Cross terrain as a spare. I'll go measure it if it makes you feel any better.



I'm not here to argue. Here's what I'm going to do. I'm going to collect some data, establish a commute baseline mpg. Over the next year I'm expecting some long trips up to lake Wanpaupack (250 miles round trip) I'll use those for the highway measure. That and maybe some trips out to Downingtown to the Victory Brewery.



Along the way I'm going to do the mods and record the data right here in this thread.

And then we will just look at the percentage improvements rather than the absolute magnitude, OK?



But I still stand by the 25.5 highway mpg reading!

You claim to be getting the gas mileage that many brand new sedans are getting. How much better do you really think you can do with a 10 year old 2+ ton truck with the aerodynamics of brick?



I'm really not trying to be a jerk or argumentative; I just think you've reached (or are extremely near) any possible maximum. You are certainly claiming the highest numbers I've ever seen anyone claim in a Gen1 ST.



For related info about a guy that was able to get 30mpg from his 4 door Explorer, search the ExplorerForum.com site for posts by the late Aldive. Many of his methods have been lost since his passing since he did not spill all of his secrets but his mission is well documented. Consider the advantages his truck had over the ST from the factory, though.

Dean,

I agree with Hugh. If your MPG calculations are accurate, you are getting far better gas mileage than most Sport Trac owners in both city and highway driving...probably in the top 1%. It's not likely that you are going to get much better mileage and the more you spend to get better mileage, the more money you stand to lose.



My point about needing to calibrate your ProScan still stands....If it cannot be calibrated, or you have not calibrated it to correct for your OEM Speedometer/Odometer error and recalibrate it when you change tires, you may actually be getting less MPG than your ProScan is telling you. And even though the errors may appear to be small, they do add up to a lot of accumulated error.



Traffic conditions from day to day can cause significant MPG variances. Just getting caught at a traffic light that you did not catch yesterday could cost you MPG. The wind and the direction can make a big difference in mileage...I know I can see my instantaneous MPG reading drop when I am driving into a head wind...even a small head wind on a truck that is as aerodynamic as a brick will show up on your ProScan gauge.



Also, the simple fact that you are using a 200 mile trip as proof of your gas mileage is not realistic. That is not even a 1/2 tank of gas at 25+ MPG ??? You simply don't really know exactly how much gas you used...only what you pumped back into the tank when you filled up. There is no accurate way to measure exactly how much gas was in the tank before the trip, and unless you can fill the tank to exactly the same point after the trip, the gas consumed will not be accurate. I don't believe you can get an accurate MPG for any vehicle unless you put 1500-2000 miles on it, and fill up the tank at least 4-5 times to average out the accumulated error. MPG is an average....so the more miles you drive, the more accurate that average will be, as long as you are accurate in your measurements.



A lot of people drop the tenths of a mile on their Odometer, and some even round off the tenths or 100ths off the pump reading when calculating their MPG. Sounds small but it does add up to be a very large inaccurate results.



If you want to run a short test of 200 miles, you must first fill your tank to the brim, where you can see gasoline in the filler pipe at the restrictor plate. Then drive 200 miles or so and fill the tank to the brim again....that way you know that what you put in the tank is what was the amount of gas consumed. If you just go by the pump's auto shut-off, you don't have any idea how much gas is actually in the tank. If you fill your tank very slowly to the brim, you can actually put 2-3 gallons more gas in than the tank's rated capacity.



I don't recommend overfilling your tank all the time, but it works fine for an short MPG test once in a while.



...Rich

Who cares about MPG anyway? I have found that at best I can save $20-30 a month by purposely fudging with inputs that affect gas mileage. That's not a big enough savings to even worry about it.



Dean, have you tried non-ethanol gas? If you're truly seeing 25 hwy, I bet you'd find you can get 27-28 with E0. I currently pay $3.99/gal (down from $4.18/gal all summer) with the average price around here at little over $3/gal. I don't use it for the purpose of increasing MPG though, it's just a nice additional benefit.

Hugh,

I agree that non-ethanol gas would show some improvement in gas mileage...I just don't believe it would be that much of an improvement. We can't get E0 where I live, so I have never tried it. but pure E-100 will yield about 25% less gas mileage so if Dean is getting 25 MPG now on E-10 then the most he could expect to get would be slightly less than 0.6 MPG improvement....and that would not justify the extra cost for E0 gasoline unless all you were trying to do is get the highest possible MPG without regards to cost.



I also find it kind of foolish to spend $300+ for an AutoMeter ProScan to just monitor fuel mileage, when Dean could have bought a $59 (plus shipping), Ultra Gauge that does everything he probably needs, and can easily be changed from vehicle to vehicle regardless of brand. The ProScan requires you to order the device for specific vehicles like GM, Ford, Chrysler, etc??? Then you have to hook it up to a laptop to use it. The UltraGauge is truly a gauge with a small display module that can display up to 3 screens of up to 6 separate readouts each. I switched my Ultra Gauge from my 2002 Toyota Highlander to my 2013 Hyundai Tucsan and only had to re-calibrate the Speedometer/Odometer settings.



...Rich

What is wrong with me trying to do a few things to increase MPG and documenting them here? sorry, I'm on a quest and there is no stopping me..



Either the gains will be so little as to be lost in the measurement noise or they MIGHT be significant. We'll just wait and see.



Proscan and other OBD2 readers use the techniques described here to measure MPG:

http://www.mp3car.com/engine-management-obd-ii-engine-diagnostics-etc/75138-calculating-mpg-from-vss-and-maf-from-obd2.html



If you scroll down on that page you will read..

"In fact, the accuracy of this method has been proven in literally tens of thousands of gasoline-powered vehicles. Accuracy within a few percent is typical, often limited by the accuracy of the vehicle speed reading (i.e., VSS)."



Sorry, I won't be measuring at the tank, pump or the odometer, just with Proscan.



And Rich... Proscan software for Windows $59 here http://www.myscantool.com/store/

Bought the ELM-327 OBD2 USB interface from China a few years ago for about $20. I didn't buy it for MPG measuring. This is my code reader solution.



BTW, My tire diameter looks to be about 29 inches. The spare OEM tire measures the same.

My speedometer reading is in agreement with GPS speed reading.



I think you guys are correct regarding the highway mileage. I'm probably close to the limit.

It's my daily commute mpg that I'm really interested in improving.

Nothing wrong with this mission at all. I'll enjoy reading your findings. I won't likely put them to use but I appreciate it nonetheless.



We get greater than a 10% increase in highway MPG in our Edge using E0. I never drive the Edge in city driving so I have never calculated the difference there. I have a thread about the highway results in the off-topic board.

Dean,

I take it from your answer that you did not or cannot calibrate your speedometer/odometer reading on the ProScan? You cannot rely on just the ProScan since it is only getting it's information from the OEM sensors, which have their own variables. It sounds like your ProScan is simply an Error code diagnostic tool. The reason I question this is because it does not appear that there is anyway to calibrate for Speedometer/Odometer errors and connects to a PC for diagnostics while driving, which is not convenient for normal day to day driving and checking your gas mileage.



The OEM VSS are known to be inaccurate and your ProScan is making its calculations based on what the VSS tells it. The formula may be very accurate, but if the data from the VSS going in is inaccurate, you will get an inaccurate calculation. The VSS on all vehicles is know to be inaccurate and cannot compensate for its own inaccuracy much less compensate for different tire diameters.



The formula used by your ProScan (in your link) shows that it is getting the distance numbers from the VSS (Vehicle Speed Sensor)...The factory VSS are notoriously inaccurate (up to +/- 5% error?), and all appear to give significantly higher readings, so the Distance Traveled recorded by the VSS is most likely too high and your uncalculated ProScan calculations are highly suspicious. You cannot state that your VSS is accurate if you have not tested it's accuracy and you cannot just rely on a GPS...they can be inaccurate too. That's why I recommend that you do an actual measured test of at least 10 miles...the more miles the more accurate the results will be



You also have not answered my question: 'Can the ProScan be calibrated for VSS errors'?? You never answered that question so my only assumption is that you did not calibrate it, or it cannot be calibrated.



You said: 'Tire diameter looks to be about 29' ??? That simply speaks volumes about the accuracy of your measurements and calculations. It's those little, 'Close-enough',

guess-timations that you make that can add up to big errors. A half inch in tire size diameter can lead to 1.5? difference in rolling distance per revolution and with a tire rotating about 700 times per mile, that will induce an error of 87.5? per mile?now multiply that times your 200 mile test and your mileage will be off by about 1460 feet, or more than a ? mile.



That may not sound like much, but your inaccurate measurements would indicate that you are making a lot of other inaccurate assumptions....One being that you ProScan is accurate without calibration. Your ProScan coupled to an inaccurate VSS cannot give you an accurate MPG calculation unless it is calibrated to compensate for the VSS error (that also compensates for tire diameter variations)



I think your MPG claims are inaccurate and more suspect now than when you made your original post. I think they are about 10-15% higher than the true MPG if measured with a calibrated gauge.



I have no problem with you being on a quest to get better gas mileage, but I just think you should be doing it accurately, and you certainly have not convinced me, and others here that your MPG calculations are accurate. If you do conduct an accurate mileage tests, you might be disappointed that you are not getting the MPG you think you are.



I also think that MPG variations of less than 1 MPG are variations that you often have no control over. They are based on traffic conditions at that moment in time, wind speed, wind direction, temperature, wet or dry pavement, weight of the vehicle (including fuel), speed, and then number of times you need to slow down or speed up for traffic conditions. The best you can hope for is the best MPG for that particular time under those particular conditions and a good overall average.



It always amazes me that people ask for help or opinions here and when they don't like the answer or someone disagrees with them, they immediately go on the defensive and into denial.



...Rich

Rich, your concerns are duly noted, but unwarranted. Let's say my setup is "off" with respect to VSS. Let's say I really am getting 23mpg when if fact the unit reports 25mpg. Fine.



What I'm going to attempt to do here is gather some highway and commute mpg data, to establish a baseline, and then perform some mods to see if there is an improvement.



So, you have now found yourself in the position of having to argue that the unit is not repeatable in it's method of measurement. I happily await your response in this regard for it is based on a well accepted formula and the consistency of the speed and mass air flow sensors.



The fact of the matter is that my tires are well within 1% of the diameter of the stock tires. I also highly doubt the vehicle speed sensor is off by 5%.



I'm sorry you have no confidence in the readings with Proscan. I know that 25.5 sounds high but I think it is a real number. In early October I drove up to Lake Wanpaupak on a 252 mile round trip. Unfortunately I did not have Proscan running on this trip. But I do know that the fuel gauge still read over half a tank left over when I got back home.

Go for it, Dean!!

I agree with Richard L on most points, however, I will say that my experience with GPS units have been that they are very accurate compared to other distance or speed measurement methods (odo, mile markers, speedometer, etc.)



Dean - I also encourage you to not be defensive at Richard L's quest for accuracy. You're posting numbers that have not been seen here in 13 years of a truck model'l life. Richard L is just questioning them because they're hard to believe. Remember what Abe Lincoln said, "Don't trust everything you read on the internet."



You said "Sorry, I won't be measuring at the tank, pump or the odometer, just with Proscan." Richard is pointing out that proscan reads the same sensors that you're odo and speedo are. You said, "I also highly doubt the vehicle speed sensor is off by 5%." I know mine can be because it reads 53 mph when several GPS units are reading 50 mph. That's 6%.



If you don't want to ensure accuracy, then fine, but you argue with us and then say, "The 25.5 highway reading is legit." and "But I still stand by the 25.5 highway mpg reading!" Now you just said you're OK if you're reading 25 but getting 23. Richard L is just trying to say accuracy is in question if you're posting MPH values.



Finally, you stated, "My tire diameter looks to be about 29 inches. The spare OEM tire measures the same." and then later, "The fact of the matter is that my tires are well within 1% of the diameter of the stock tires." These are very different statements. Eyeballing in the former, and getting to within 1/100th of an inch in the latter.



This topic came up a few months ago. To get true gas mileage, drain your fuel, put in 10 gallons, drive until you stall, divide your GPS-measured distance by 10 and you're as accurate as you can get without spending any extra money on gadgets and calibrations. Refilling to full doesn't work because you're simply relying on the accuracy of a gas stations pump.



I'm interested in more power myself. If I post initial readings of 330 hp and 360 ft-lbs from a stock 4.6L, then people are gonna want to see accurate numbers from a calibrated dino, not my phone sitting on the passenger seat running an app. I know, not the same as a proscan, but just making a point.



Good luck with your improvements. I'm interested in seeing them myself. You're new tires probably might handicap you. AA traction ratings generally result in lower fuel economy.