Average Mpg On The Dic

[Phillipjon]

Anyone else hand calc the numbers only to find that the DIC is incorrect? Mine is off by one whole MPG, if it says that i am getting 18.8 I am really only getting 17.8. Anybody else?

[trucc_boi]

mine is different with the # of gallons used so i guess it throws it off.

 

i take all that with a grain of salt anyways, it's a truck, crappy mpg, etc..

 

on a similar note, how big is my gas tank anyone know?

 

24 gallon? maybe a little more? truck info in sig.

[knipper_03]

I honestly think its got to be more accurate than the refilling till the fuel pump clicks off method. The computer tracks mileage and has got to have a flow meter or pulse monitor for the fuel injectors to be accurate. I think the old method we've always done it by is probably the least accurate way.

[Matt_]

Anyone else hand calc the numbers only to find that the DIC is incorrect? Mine is off by one whole MPG, if it says that i am getting 18.8 I am really only getting 17.8. Anybody else?

 

I found that if I average my hand calcs over a long period of time they're about the same as the DIC.

 

Every time you fill up your tank the "full" point changes. So when you fill up your ODO may say 200 miles and the gas pump may say 11.75 gallons... so you'd divide 200 by 11.75 and get 17mpg. But if the trigger in that gas pump was 1/2 gallon more sensitive to the "full" point, you'd only put in 11.25 gallons and then get a calculated ~17.75 mpg. So how do you know how much gas you actually used in that 200 miles? Hell a 1 gallon difference in this example would give you a mpg swing of 17 to 18.6 mpg.

 

Also remember that your DIC is calculating your mileage based on tire size... which is not very accurate either. So did you really travel 200 miles? Or is it 205?

 

Moral of the story... if you're hand calculation is 1mpg off of the DIC, don't sweat it... they're both equally as wrong. Take the average of the two, so your gas mileage is probably around 18.3. Not that big of a deal.

 

Now if you calculated a 3-4 mpg swing then thats something to question!

[66nova]

I'm with Matt here. I have calculated it over a long run and my DIC has been very accurate. I think it is more accurate then people give it credit. I have seen a few things that will screw up the numbers that people a lot of time...

 

1. The first problem is when most people reset their DIC. In order for it to truly be accurate, it should be reset before you even start the truck after refueling.

2. It has been shown time and again that gas pumps are very commonly not calibrated exactly. So you may have only put 10 gallons in when it says you put 10.5 gallons in.

3. Just as previously mentioned by Matt, every gas nozzle is different. You can't be sure where you are "topping the tank off" at is the same spot every time.

 

I actually trust the DIC more then calculations.

[Visegrip117]

mine is different with the # of gallons used so i guess it throws it off.

 

i take all that with a grain of salt anyways, it's a truck, crappy mpg, etc..

 

on a similar note, how big is my gas tank anyone know?

 

24 gallon? maybe a little more? truck info in sig.

 

 

It's a 26 gallon tank I believe

[Visegrip117]

mine is different with the # of gallons used so i guess it throws it off.

 

i take all that with a grain of salt anyways, it's a truck, crappy mpg, etc..

 

on a similar note, how big is my gas tank anyone know?

 

24 gallon? maybe a little more? truck info in sig.

 

 

It's a 26 gallon tank I believe

[Wires]

I've found mine to be pretty much bang on. The ECU knows how much fuel it sprayed down to 0.1ms of injection pulse, so it should be able to get you pretty accurate.

 

I think the biggest issue is filling the tank. No two gas pumps are the same. Case and point, my local pump the other day kicked out when the tank was filled right to the top of the fill nozzle, and was starting to run out!

 

Only way to accurately do it manually would be to fill the tank with a jerry can or something so you know exactly what went into the tank.

 

I basically use mine as reference when driving. If it drops rapidly then something is up.

[bluesrefugee]

Mine us usually within .2 mpg +/- of the old method of doing it at the gas pump.

[KMGZ400]

my 2003 suburban says im getting 14.8 MPG... idk how accurate it is its 145k miles old