Manipulating calibration factor

[joe2006]

I have done a search & couldn't find the answere hence this inaugural post  .

I have found that there is approx 5% error in fuel consumption figures provided by my UG. Probably not surprising as I intend to change tyre size & therefore have not done a distance calibration.

The question is... can I manipulate the calibration figure manually in order to get closer to actual fuel usage?

I figure that as my consumption figure is out 5%, I could adjust the calibration figure 5%. If that makes to great a change, I could half or quarter the adjustment I made to the calibration figure & should eventually get it very close to the real consumption figure.

Although my fear is doing so will result in unexpected changes to other measurements.

Any ideas.

Thanks

[lildaddym]

That's a good question!  I've calibrated mine over a 5 mile course, and the trip odometer is still of more than half a mile in 50...so the MPG is off, too...

[joe2006]

I will reply to my own question & say that I have started manipulating the calibration figure & will let you know how it goes. It might however take a couple of months as the vehicle doesn't travel great distances.

[lildaddym]

Hey, sir,

What have you done so far, and how?  I was thinking that I could change the distance after calibration...my UG is a bit optimistic, showing an extra tenth for every 15 miles or so.  Right now, the car trip odo is showing 45.6, and the UG is showing 45.9...

[joe2006]

Howdy,

What have I done?

Firstly as I have said, I have not done the distance calibration so no doubt "distance to empty" figures will be wrong.

The UG fuel consumption figure was about 5% optimistic (using 5% less than actual). By that stage I had probably filled up about 5 times & did not keep a tally of the litres/gallons pumped into the vehicle over the 5 fills.

Lets say the UG said I used 500 litres/110 gallons over those 5 fills, I manually increased the number of litres/gallons by about 5%. To do this I did the following:

1. After filling the tank, held the up key to recognise fill up.
2. Zeroed the average. Select MPG. Menu   -   Gauge/Page Menu   -   Zero Ave MPG,G/H
3. Increased the total number of litres/gallons pumped. Select Menu   -   Vehicle Set Up   -   Calibration  -  Calibrate MPG/Fuel and increased my 500 litres/110 gallons to 525lt/115.5 gallons.

This increased my calibration figure. Say from 5.1 to 5.8 (I have them written down but not handy at the moment)

Unfortunately the adjustment was too much & the UG was then reading about 8% high.

At the next fill I went through the process again but this time reducing the total amount of fuel used. This decreased the calibration figure to say 5.4. Now UG reads about 2.5% high.
Today I filled up again & again reduced the total fuel used but only by a very small amount & the calibration figure is say 5.35.

I just made sure to write down the original calibration figure & if all goes pear shaped, I can revert back to the original figure (by adjusting the fuel used as per the above).
 

     

[lildaddym]

Hey, sir,

Sounds like you thought this out pretty well!  Based on what you've got here, my UG could be almost exact compared to the car if I could get the calibration (miles) right, then make sure that the gallons used matches what I put into the car...had no clue I could do that!

Michael

Howdy,

What have I done?

Firstly as I have said, I have not done the distance calibration so no doubt "distance to empty" figures will be wrong.

The UG fuel consumption figure was about 5% optimistic (using 5% less than actual). By that stage I had probably filled up about 5 times & did not keep a tally of the litres/gallons pumped into the vehicle over the 5 fills.

Lets say the UG said I used 500 litres/110 gallons over those 5 fills, I manually increased the number of litres/gallons by about 5%. To do this I did the following:

1. After filling the tank, held the up key to recognise fill up.
2. Zeroed the average. Select MPG. Menu   -   Gauge/Page Menu   -   Zero Ave MPG,G/H
3. Increased the total number of litres/gallons pumped. Select Menu   -   Vehicle Set Up   -   Calibration  -  Calibrate MPG/Fuel and increased my 500 litres/110 gallons to 525lt/115.5 gallons.

This increased my calibration figure. Say from 5.1 to 5.8 (I have them written down but not handy at the moment)

Unfortunately the adjustment was too much & the UG was then reading about 8% high.

At the next fill I went through the process again but this time reducing the total amount of fuel used. This decreased the calibration figure to say 5.4. Now UG reads about 2.5% high.
Today I filled up again & again reduced the total fuel used but only by a very small amount & the calibration figure is say 5.35.

I just made sure to write down the original calibration figure & if all goes pear shaped, I can revert back to the original figure (by adjusting the fuel used as per the above).