Mileage - Computer vs. Actual

[SLVRBLT]

Every time I have filled the truck with fuel since it was new, I have figured the actual mileage and compared it to the computer. Without fail, the actual and the computer agree perfectly. I now have a 90 gal. tank in the bed and it still is matching perfectly. Last fill-up, I had gone 1500 plus miles and the computer matched exactly what I figured with the calculator. This includes winter, summer, towing, empty, fast, slow, etc. Don't get me wrong, I'm not complaining, it's just that I didn't think the computer would ever be that accurate. Is everyone's that accurate? Just curious about this.
Dave

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2001 2500 HO 6spd QC LB 4x4 SLTPLUS All options except Snow Plow and Clearance Lights - Rhino Liner,Straight Exhaust, 90 Gal. American Toolbox/Tank Combo
'95 Harley Low Rider, Crane cam, S&S Super E, Samson 2" drag pipes

 

[Bad340fish]

Mine is about . 1 high every time on the dot. I just added an EZ box(which Is cool!) And haven't run a tank through it yet to see if its still accurate. I did notice an increase in mileage by about 2. 5MPG with it according to the computer.
Clark

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Clark
1999 2500 QC SB 5spd, EZ, Flowmaster 3 chamber, K&N Re-0880
1968 Barracuda Formula S Viper Blue 11. 98@112 Currently scattered all over the garage

 

[work2muchplay2little]

Mine used to be spot on prior to BOMBing, now reads 5. 1mpg high everytime. I suspect the mileage computer is keyed off the throttle position sensor as I don't have to push the go pedal down as far anymore just cruising #ad


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Kurt Voss
********* 1999 2500 24VCTD AUTO 4x4 QC LB Laramie SLT, Luverne stainless steel nerf bars, 3 piece bug deflector, mopar mud flaps, Line-X bedliner, Blue Chip Fuel Management System (Premium), Psychotty Air, DD3's,TTPM, DD 4" exhaust, HX40, DTT VB/TC(91%) , Mag-Hytec transmission pan... YEEEEEHAAAA!!

 

[klenger]

My actual milage is about 8% higher than the computer. I filled it up about 4 times since new.

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Ken Lenger
2001. 5 2500 QC 4X4 SWB SLT, ETC/DDX 5 Speed, 3. 54 (no LSD), camper group, trailer folding mirrors, RBR CD/Radio, LT265/75R16E AT OWL tires, trailer tow group, Patroit Blue / Agate, Westin CPS Step Bars, Jordan Utlima Brake Controller, Weather_Guard 664 tool box
Trailite 21' Travel Trailer, ~4000 lbs loaded.

 

[Archive]

I have found that the more I BOMB, the worse that little MPG computer works! As above, while stock it was almost dead on with each fillup. Now, it shows high by about 2. 5mpg when I use the calculator.

 

[waterbrain]

I've seen the same thing Rob. After adding the EZ and 275's I thought I was getting 25 mpg on a highway trip (that's what the comp showed). Turns out I was really getting 20. Still pretty good, but not 25. Pre-BOMB numbers were almost always right on.

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2001. 5 2500, QuadCab, 4X4, LB, Auto, 3. 55, SLT+. Mods: EZ, 275's, Rhino Liner.

 

[SmokinJoe]

Originally posted by klenger:
My actual milage is about 8% higher than the computer. I filled it up about 4 times since new.

Mine too is off. I am 100% stock. I have just added a ARE Z Series cap and I am getting improved fuel economy. The computer would say 17 mpg and I would actually get 18. 48 mpg.

I only have 2,500 on my truck. Maybe after breaking the computer and calculated mileage will match.

I think the computer gets the mpg based on vehicle speed, fuel injector pulse width and RPM. Possibly the retarded timing is causing our ETC's computer to lie!


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2001. 5 QC 2500 White Sport 4x4 LWB ETC 5-Speed Anti-Spin 3. 54 Trailer Tow 241HD SLT+ Tan Leather(Mad Cow Disease) LT265/75R16E ARE Z Series Cap Bedrug ICI Nerfbars

 

[Idaho Native]

Ditto what work2muchplay2little said...computer was within . 2 pre BOMB... now about 4-5 high with EZ only. No real drop in actual mileage... maybe . 5 -1 MPG, but that's my own fault for having a heavy foot #ad




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1999 24V 2500 QC HD,5 Spd, Luverne Steps, Predator Topper
1995 Impala SS, Dark Cherry Metallic
1995 Dutchmen 26 foot travel trailer (the "excuse" for the diesel!!)
1997 Honda Shadow ACE 1100
(Too Many Toys)

 

[Pine Sap]

my computer has been . 4 to . 6 mpg lower than the actual math method. I am going to check it again on next fill, its been a while since I've validated it #ad


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2001. 5, QC, 2500, 2wd, auto, 3. 54, 4 disc, long-bed, all the stuff, heated leather, patriot blue over silver, Brolin CB Bracket, stock4now!

the Blue Angel is a real "country cadilac"

 

[John Berger]

My computer is anywhere from 1 to 3 miles high. I haven't had the time to baseline it with the EZ yet. The computer is definitely not accurate, however. Is there a solution to this problem?

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1999 Dodge Ram 3500 Quad Cab 2wd; 5 spd; 4:10 LSD rear; Mag-Hytec differential cover; US Gear EGT and Boost gauges. Stewart Warner Fuel Pressure Gauge with dual senders, Westach Oil Temp Gauge for differential. Amsoil foam air filter and synthetics in the motor and differential. Cummins Power, don't leave home without it

 

[jdkenyon]

My computer has never been accurate and I am totally stock. At least it is consistently wrong. In town driving it reads about . 2 mpg low and on the highway as much as 1. 5 mpg low. I have tracked every tank and what the computer has read since new. With 16,000 miles it has averaged . 8 mpg low.

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'01 2500 QC SB 4x4 ETH/DEE 3. 54LSD

 

[jwgary]

Mine is usually dead on. After driving 545 miles the computer was only off by half a mile. That is easily just part of the limits of the display's precision. Again, bone stock... for now.

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B I G O R A N G E AMBER-FIRE (BURNT ORANGE) / BRITE SILVER 2001(. 5), 2500, SLT, Q-CAB 4x4, SWB, AUTO, 3. 55, LSD, TOWING PACKAGE
ADD-ON'S: LINE-X, 1/4" STEEL LONGHORN HITCH COVER, WESTIN NERF BARS, YELLOW-TOP OPTIMAS

 

[tron1959]

After 11,000 miles and checking every tank, The computer has averaged 0. 8 lower than actual. Last fill up was 22. 3 mpg, best yet. 4 previous fill ups averaged 21. 5 mpg. If it keeps getting better it will surpass my previous 94 single cab. The 2001 is a 6sp HO QC, The 94 was a 5 spd.

The 2001 started at barely 18 mpg and has slowly crept up to where it is now. I was disappointed at first but am very pleased with mileage now.