2004.5 Overhead computer MPG error

[klenger]

I've fueled the new ride 3 times now, and each time the overhead computer is reading considerably lower than the caluclated milage. I realize that the overhead computers are never real accurate, but this one is so far off that it's basically useless. Here are the numbers:



1) 183 miles, Computer 14. 4. MPG, Actual 15. 88



2) 476 miles, Computer 15. 6 MPG, Actual 17. 64



3) 446 miles, Computer 14. 6 MPG, Actual 15. 88



I am wondering if all the 3rd gens are like this, or if maybe this is something with the CTD 600, like maybe they haven't programmed the overhead computer to match the 600 specs. Can I expect the numbers to become more accurate with more miles?



I've got to go to bed. Drove from Denver to Tucson, 900 miles in 14 hours, and got in at 3:30 this morning. Then I spend all day washing the truck, and installing the new brake controller and 5th wheel 7 pin plug in the bed. Hitch goes in next.

 

[Fireman]

Ken,



When mine was new the computer was 1-2 mpg lower than actual. When I had the reflash for the problem of not returning to idle after extended cruse control use the computer started being very acurate. Within 2/10 s mpg and it was that way untill I added a Turbo Air Guide. Now it reads about 1 mpg higher than actual. As long as it is consistant I don't care, but it was nice when it worked properly.



Fireman

 

[PJ]

Mine is a 2004 305 hp and my first tank was 21mpg on the meter yet I got 21. 5. That between Grants Pass Oregon and Chico Calif. . A 250 mile drive. Alot of the trip was down hill. When I returned home, i got 19 mpg and the meter read 17. 5. It was mostly up hill on that leg of the trip. It would be nice if it was correct but, I had a 97 Lincolm Mark IIIV and it was NEVER even close, but hey, that was a FURD!

Im happy with anything above 15mpg! I love my new 04 that is not legal in Calif! What a great feeling.

Almost forgot. This is off topic but yesterday, I bought a "back pack type" leif blower to use in my yard. I just tried it out today and saw a sticker on it that read "NOT LEGAL IN CALIF" . Ya gotta love it. Lawn equipment has smog devices in Calif!

 

[jungledave]

My 04 actually reads about 1 MPG better than it actually gets. My last tank was almost com;letely highway miles and the computor showed 19. 4 and it actually got 18. 1. The good part is I actually made 500 miles on less than 28 gallons and that is all above 6500 ft. altitude. My 02 usually averaged about a mile per gallon more than the trip computor showed, but i never did much better than 16 with it.

 

[bish777]

Mine reads low also, about 1. 5 to 2 mpg low. Must not have adjusted it for the 600.

 

[Gary - K7GLD]

You can at least establish a baseline with them, and then guesstimate pretty close to true MPG on the average - hey, it's NOT lab equipment!



I hear the 3rd generation trucks no longer provide the instantaneous MPG like the older ones did? If not, that's a shame, since I get more use/entertainment watching THAT one in changing circumstances than the overall MPG...

 

[klenger]

TTT

 

[Jengle]

Mine seems to be running within a few tenths of actual since new. I do get an update on the average of the readings. It will change more often when you just reset it, rather than letting it average over tank fillings. Mine seems to be pretty accurate either letting it run for more than one tank, or resetting it with each fill-up.

 

[slo-ryde]

klenger, I sure hope your fuel economy improves! I'm still debating the move up to the 600/325 but like the solid 20-22 mpg I'm getting on my '02.