Over head mileage accuracy?

[FlyFisha']

Hello all --



I'm curious how your computerized mileage readings are compared to your hand calculated mileage readings. I've only had my truck for two days and I'm still on my first tank so I haven't started the comparison my self yet.



Anyone know if these computers are truly tracking the amount of fuel sprayed through the injectors vs. mileage traveled or is it something much more basic?



BTW, this truck is amazing... my brother in law picked up a new Ford 6. 0l and I had a chance to drive it a few weeks ago. It's a very nice truck/transmission but this Cummins/Dodge setup takes the cake!



Next summer my family is having a "family camping trip" where there will be my uncles '02 HO, dad's '96 12valve, brother-in-laws '03 6. 0, and my '04 HO... should shake the woods of Idaho real good!!!



Jeff

 

[ttreibel]

Welcome to the TDR and you probably want to update your sig.



The overhead is fairly accurate I find I usually get better mileage than the computer states by at the most 1. 5mpg I have never had worse.



I reset the computer at each fill-up some say if you just leave it seems more accurate. I like the DTE setting works great even when pulling.

 

[Moterhead]

Originally posted by FlyFisha'

Hello all --





Next summer my family is having a "family camping trip" where there will be my uncles '02 HO, dad's '96 12valve, brother-in-laws '03 6. 0, and my '04 HO... should shake the woods of Idaho real good!!!



Jeff

Learned something new from your post. I thought the HO came out in '03, not '02.

 

[FlyFisha']

Actually, I believe the HO came out in '01 with the 6 speed.



Jeff

 

[Moterhead]

Was it the 305 hp, 555 torque spec? The quiet version came out in '03?

 

[FlyFisha']

Originally posted by Moterhead

Was it the 305 hp, 555 torque spec? The quiet version came out in '03?

No, the '01 and '02 models had lower specs on both hp and tq... although I can't remember them off the top of my head. It was not the same engine, but rather a 24valve often referred to as the second generation engine.



One of the major differences, though there are many more, is the switch from the VP44 injection pump to the new High Pressure Common Rail (HPCR).



Jeff

 

[wild4stangs]

Mine says 16. 1 consistantly (empty 70/30 highway/city), my actual mileage is running @ 17 mpg... .

 

[Prairie Dog]

Unfortunately mileage is calculated from a software program not from actual fuel flow readings like some cars are.

 

[Boonieman]

I've found that if I reset it at each fillup, it's reasonably accurate. If I let it go awhile between fillups, it tends to be less and less accurate... usually a little on the low side. After checking it for about 20 tanks or so, I decided the hell with it cause I'm keeping the truck anyway.

 

[McDaniel]

on my 03 2500 QC The computer shows an average of 23+ mpg when reset at every fill. However, when calculated by hand it comes out to roughly 17mpg.



This is with 17,000 miles, Edge Ez, Afe Air box with custom intake tubing, and open 5" exhaust

 

[Jengle]

I just got my 04 3500 HO/6spd. Mine seems to run about 2/10s lower than hand calculating the mileage. Not bad. Either resetting or letting it run totals. Seems pretty accurate.

 

[Tony T.]

My computer usually shows a greater number than when I hand calculate it, most of the time, any where from 1/10 to 2/10, has been off as much as 5/10's. It will go crazy when going down the road and I reach up and hit the reset just for kicks, up to about 30mpg and will drop down to about 25mpg stay there awhile, and then usually stops around 19 or 20 mpg. Let it set overnight, and next start up will show around 17. 1 or 17. 2. Fill up and hand calculate show about 16. 9 empty. (80% city-20% hwy). Best mileage (hand calculated) was 18. 8, but still not running interstate. Running US hwy through small towns, red lights, etc.

 

[DPelletier]

Moterhead,

2001 - 2002 ETH H. O. 245 hp, 505 ft lbs. S. O. = 235 hp, 460 ft lbs.

Dave

 

[JPM]

My computer is about 2mpg's optimistic. It's showing 19. 9mpg's now and I'll see real mileage in the low 18's or high 17's

 

[Summit]

mine is usually 1-1. 5 better than the comp.

 

[Prairie Dog]

Mines usually "optimistic" 1 to 2 MPG too.

 

[SLinse]

I don't have many miles on the truck so I am always cruising and resetting the overhead. boy is it unstable. I've seen a low of 12. 5 cruisng 80 and 23. 5 crusing 60. I haven't checked by hand yet. I'm still happy, that is almost double what I was getting with the 2500 HEMI I traded in!!

 

[FlyFisha']

Well, after running a quite a few tanks through my new truck it appears that the Computer reading is about spot on. Sometimes slightly over and sometimes slightly under.



I still do hand calcualtions though, because I enjoy it.



Jeff

 

[t6_man]

I took mine on a 3400 mile trip last July pulling my 5er. Hand calculation for the entire trip was 10. 8; the computer showed 11. 0. Fairly close...

 

[goodwid]

I have roughly 30000 Km's and am usually +/- 1% on every fill (hand calc vs. comp). That is hiway, 4x4, snow, rain, idling for long periods of time etc... ... . very consistant at 14 liters/100 km or 20 miles/imperial gallon.



I do notice from time to time that everything goes blank on the overhead, when it comes back to life everything is reset! Anyone else with this problem? If I take it to the dealer they wouldn't find the problem anyway unless it goes out and stays out!