Driver Information Center - accurate?

[dciarnie]

I agree, you need to check mileage over multiple fills.

 

And just to clarify, by gauge, I meant tire pressure gauge, not fuel gauge.

[fbachman]

On my 2007 Sierra, the DIC was approx 5% "optimistic" on mpg reporting when compared with hand calcs and actual gallons filled. Interestingly, the "Gallons Used" (which was available in the '07 DIC, and apparently not in the 2016 DIC of my new Sierra) was 5% optimistic. Unless I am missing it, there is no screen that any longer provides gallons consumed.

 

I concluded that the "bias" in mpg reported was due to the inaccuracy of the "fuel consumed" measurement of the vehicle computer. Odometers are extremely accurate anymore, and have been for a long time.

 

The 5% optimistic number was an average deviation of fill-ups over a period of 9 years, i.e. literally hundreds of fill-ups (I just entered my fuel receipt in an automated spreadsheet and let it do its thing). Sometimes it was dead nuts, other times (especially in winter for some reason) it could be waaaaay off.

 

I also came to the conclusion on the '07, that the fuel used reported by that '07 DIC apparently was NOT measuring if you performed a remote start, and began measuring when the ignition key was inserted and turned to the run condition. This conclusion was drawn after numerous informal surveillance tests.

 

WHy, might you ask, did I give a c___? Well, when i was into tuning, injector pulses go into the long term and short term fuel trim adjustments of the ECU, and therefore I had a need at the time to do some snooping. I am an engineer by profession and do get intruiged with stuff like this (pity me, I know).

 

On my 2016 SIerra, I only have one fill up thus far, so I can't draw any conclusions yet. After a few months, I can post my results.

[dciarnie]

Not counting fuel consumed before the key's inserted on remote start? That's nuts. I hope that's been fixed.

 

In any case, I'm only on my third fill up but I haven't been keeping track of anything. Maybe I'll start on my next fill.

[oburgtiger]

If you want to compare dic and hand calc, then check every fill up 10 or more times in a row. This will help to average out any differences in fuel level when the tank was filled.

 

dic doesn't know (or care) how much fuel was added, it just measures the flow through the injectors.

 

(the fuel gauge is NOT what the dic uses to calculate fuel mileage)

 

 

Been comparing it for the last 6 months. Mine is ALWAYS 1.0 MPG higher than by manual. The truck is a bone-stock '14 Sierra CC 4x4 3.08 gear w/ 18" Goodyear FuelMax tires. I rarely use the remote start (but I have been this week since it's 101 here).