Dashboard computer

[dcamisi]

My dash computer is very inaccurate when determining my gallons of diesel fuel consumed and mpg. It’s about 15 percent off. Telling me I’m getting 10mpg when it’s actually about 8.5mpg.
Is there a way to recalibrate it? Does anyone else have the same problem?
I have a Forrest River Berkshire XL 40BH with a 8.9l engine.

[Fiesta48]

None that I know of. Bought a Scan Gauge D that you can calibrate for accurate MPG.

[Lt Dan]

Ditto the ScanGauge D. I find that our average MPG on it is fairly close to what I get in actual usage results.

[530ktm]

On board computers always favor the high side of mileage, in all my cars and trucks too. Best way to see what you are getting is the good old fashion way of dividing mileage by gallons at fill up time.

[chuckftboy]

I don't know about calibrating the fuel computer but 8.5 mpg would be great for me if I can get it. I just bought an 8.9, 450 HP and was thinking I would get 7 or 7.5. My first trip is in a few weeks to the Perry Rally. I traded up from a 6.7, 340 HP that always got better than 9 mpg.

[Fiesta48]

Knowing the LBCU reads 10% high just take 10% off. 10 mpg reading is actually 9. Same for gal used, add 10%. 40 gal reading is actually 44.

[Crabby Mike]

On my two past DPs with 8.9 Cummins on Freightliner chassis, I found the LBCU MPG calculation to be very reasonable, once I adjusted for generator and/or Aqua-Hot use. I kept a spreadsheet, recording the LBCU figures for miles, fuel, MPG, and odometer at each fillup (resetting the trip data each time) and comparing the computer's MPG calculation to the old-school miles/gallons. The difference usually equated to only a few gallons, explainable by generator or AH use.

[gatorcq]

People, the milage is a calculated value. There is no turbine flow meter in the fuel line.
What does the calculation ? The ECU (Engine Control Computer).
I have found on mine to be within 2%, based on generator usage.