Overhead reads about 3 mpg high

[ACF]

I have an 05, my overhead computer is reading about 3 mpg too high, does anyone else have this issue? It was built after the TSB for the reflash, and it runs fine in any case. Any suggestions? My old 04's computer was reading just about right on most of the time.

 

[DPKetchum]

How often to you reset it?

 

[DavidBurt]

My 05 reads about 1mpg higher than hand numbers. I reset it every fill up. 10,000 miles on truck.

 

[Truckie]

Mine reads 2 mpg higher than what IM really getting. Right now it says IM getting 14. 2 mpg and in all reality In only getting 12 mpg. I also reset the over head every fill up.

 

[RankRam]

My 05 reads 1mpg higher than hand calculations, this is if I'm towing or empty.



11,505 miles and running very strong. Oo.

 

[HEMI®Dart]

They are probably designed that way.

 

[AGrubbs]

mpgs

Mine seems to read low most of the time.



Read out said 23. 2 and hand calc came up at 24. 1 on a 627 mile tank, then the tank before the R. O. said 22. 7 and calc at 23. 1, on a 560 mile tank.



Been between . 5 and 1. 1 MPG low on the readout for as long as I can remember. I have about 37K miles on my -03 2500 4x4 QC 6 speed now, and it

just seems to be getting better all the time!



I suspect that the differences are mostly just variations in the sensors in the different trucks. A little different hi pressure readout will mean that the

computer will calculate a different fuel flow rate thru the nozzles.



Of course adding computer fueling (fooling) mod's will always give an actual mpg lower than the readout, because thats how it gets more power. . adding fuel the ECU doesn't know about! The way fuel prices are going, I dont think I will be adding any fueling mods any time soon! (maybe after I win the power ball ?? )

 

[SRubenstein]

I'll chime in w/ a yep me too! Reset every fill up overhead reads 15. 5 actual is about 14. 5. Currently 6k miles. Truck was born 5/05. Way past TSB I believe.

 

[JVolpe]

I had the TSB last year. Mine was always about 1 mpg low before the TSB and always about 1. 5 mpg high after the TSB. After the HOT Juice and EZ stack it is a constent 3. 4 mpg high. Too bad what it reads is not accurate, sure could use the extra mpg.

 

[Alan Reagan]

Mine was way off before the reflash. After resetting it a few times it got closer (2 mpg). Then I ran the fuel down till the chime came on so that I would know how many gallons I had left at that point.



I reset when I fueled up and since then it has been within +/- . 5 mpg.

 

[DHerzog]

My is generally 1. 5 mpg too low... . reads 18. 2 and I hand calc 19. 6

 

[TSpecht]

Mine tends to be +/- 1mpg compared with hand calculations. I don't use it for anything serious except a relative indication of how it's doing. In fact I can't remember the last time I looked at the MPG screen, I usually have the DTE displayed instead.

 

[MSLiechty]

I'm with TSpecht I usually have the distance to empty shown. Don't want to know I suppose,but I get close to 18 most of the time, but I do check it and reset at fill- up. I'm more concerned how many miles I can get out of each tank!





Michael

 

[JHardwick]

My OH reads at least 5 and sometimes 6MPG high. Doesn't seem to be affected all that much by resetting it, as long as I run at least a tank after doing so.

 

[jwduke]

Mine runs 2 mpg low. 16. 4 is actually 18. 4

 

[abdiver]

I have never reset mine Is this a recommended procdure?

 

[TSpecht]

For best accuracy you should probably reset it once per tank of fuel. Basically it keeps a running average and if you don't reset it, the accuracy will likely diminish. For example if you run a full tank or two through it running steady 65-70 down the expressway, you're less likely to notice a difference when you're in town running stoplight to stoplight against anything that steps up to challenge you. Likewise if you normally drive such that your display reads low, and you operate in conditions on another tank that should yield good mileage, it may not show it.

At least that's my understanding of the programming of the system.

 

[EEdmondson]

Mine reads about 1. 5 high (OH 18. 3, hand calc 16. 8 on last tank). It was more accurate before the TSB. I'm driving like the old man I am trying to keep it under 2000 RPM on the frwy . I think the 305/555 gets better mileage but wasn't available in Calif.

 

[smartineau]

For the first 10,000 miles or so I would compare overhead to calculator numbers they were always within . 1 mpg, either high or low. Then occasionally I would use the calcutlator to double check always within . 1 mpg.



now I am at 50,000 miles and the overhead is now reading . 5-4 mpg low.



steve

 

[abdiver]

Mine reads about 1. 5 high (OH 18. 3, hand calc 16. 8 on last tank). It was more accurate before the TSB. I'm driving like the old man I am trying to keep it under 2000 RPM on the frwy . I think the 305/555 gets better mileage but wasn't available in Calif.

When I first drove my truck on the dealers lot (Carson City Dodge in Nv) I was driving freeways over the Sierras my overhead was reading 19 mpg I thought wow great for engine with only 200 miles on it. Then it was 18. 3 I normally drive rural roads that are windy most of the time the 6 spd is in 5th as not long enough straight stretchs to run in 6 th gear. Anyway overhead now has slowly fallen gradually to15. 3 mpg and my calculations at top off tell me I am actually getting 12. 8 mpg engine only had 1100 miles at time. I have never reset overhead perhaps this would explain the slow decent of the overhead read out ?? Figured the better read out from dealership might have been do to Nv fuel ??



I would hope to get better mileage as I near 40K miles on truck



Bill