Dic Accuracy?

[robertluongo]

It seems my DIC readings don't match my maual checks. My DIC says I am averaging 18.5MPG but a manual check (fill up before and fill up after) says I am geting 15.8 MPG. Also gallons used don't match actual gallons taken to fill up. I have a three gallon discrepancy. The DIC gives me very favorable numbers, Actual manual checks don't look so good. Anybody have an answer?

[Matt_]

first off... are your tires stock sized? That IS quite a discrepancy between the DIC and calculated (edit: now that i think about it, your tire size wouldnt matter because you're using your odometer to do the hand calc... so you'd be just as far off as the DIC in this case)

 

General concensus is that the DIC is more accurate than pump calculated mpgs for various reasons; biggest factor IMO being that you don't get the same amount of gas from each pump... it could easily be 1 gallon different between fill ups.

 

here's some discussion

 

http://www.gm-trucks.com/forums/index.php?...509&hl=pump

[robertluongo]

My tires are stock 245 70R17. I read the history posts thank you. My gap is pretty big 3 gallons on usage and over 2.5 on mileage. It's hard to believe there can be that be a difference.

[louie730]

I have checked mine about 3 or 4 times in the last year and it has never been off more than 2/10 of a gallon. It almost right on most of the time less than 1/10 of a gallon difference. For me it is very accurate. Maybe it's just mine but it is very accurate.

[Jsdirt]

Just my humble opinion here ...

 

I noticed this a week after my '07 NBS was delivered. The mileage on the DIC, along with the "oil life" monitor, is a fantasy ... not sure if it's to keep certain segments of our population generating that "warm, fuzzy feeling" .. or to genuinely deceive ...... but either way, neither is even close to the real world. With the technology available today, it should at least be in the ballpark I would think ...

 

Mine says I'm getting 16.2. In reality, I'm getting 14.4. I have some performance goodies, plus I have my foot in it constantly. If mileage was a concern to me, I'd ride my motorcycle in the snow ... but anyway ... the oil life monitor shows 50% oil life when the oil is one step above sludge stage. Just changed mine 2 days ago -- full synthetic, mind you -- with 4,300 and change. Looked horrendous. If this were regular dino oil I'd be downright scared to run this until the monitor said "0% oil life". Then again, it does GM's pocketbook no good for you to keep your truck for 10 years, instead of 4 ...

 

The tire monitor is another joke that our government decided to mandate ... I mean really, do we need the damn government telling GM that a light should turn on when our tires are low???? Don't most check their tires on a regular basis?? Don't most people know when a tire is low???

 

Life today defies logic sometimes ....

 

The next "new" vehicle I buy will be from the 60's or 70's. You can have your technology!

[redvett]

The TPS all goes back to Firestone/Ford a few years ago. People do not check there tire pressure and when a tire heats up from low pressure "Boom".

 

 

 

Just my humble opinion here ...

 

I noticed this a week after my '07 NBS was delivered. The mileage on the DIC, along with the "oil life" monitor, is a fantasy ... not sure if it's to keep certain segments of our population generating that "warm, fuzzy feeling" .. or to genuinely deceive ...... but either way, neither is even close to the real world. With the technology available today, it should at least be in the ballpark I would think ...

 

Mine says I'm getting 16.2. In reality, I'm getting 14.4. I have some performance goodies, plus I have my foot in it constantly. If mileage was a concern to me, I'd ride my motorcycle in the snow ... but anyway ... the oil life monitor shows 50% oil life when the oil is one step above sludge stage. Just changed mine 2 days ago -- full synthetic, mind you -- with 4,300 and change. Looked horrendous. If this were regular dino oil I'd be downright scared to run this until the monitor said "0% oil life". Then again, it does GM's pocketbook no good for you to keep your truck for 10 years, instead of 4 ...

 

The tire monitor is another joke that our government decided to mandate ... I mean really, do we need the damn government telling GM that a light should turn on when our tires are low???? Don't most check their tires on a regular basis?? Don't most people know when a tire is low???

 

Life today defies logic sometimes ....

 

The next "new" vehicle I buy will be from the 60's or 70's. You can have your technology!

[drbob11]

i never have trusted anything electronic.. heck... how stable is your desktop computer? to me electronic stuff is just ONE more thing to break alto fun to play with. I think the DIC is more of a GO-BY than anything else... at least thats just my opinion. so i wanted to see how accurate my DIC was so i did a little test. mind you my truck is all factory since i just bought it a couple months ago. I ran the truck until it was empty then i ran 10 gals of gas and drove like usual until it ran out. (i carried 10 gals can in back... so not to strand myself) here are my results.. DIC says i am getting 17.2 mpg average but my hand calcs give me 15.8 mpg.. so when the "fuel remaining" says i have 447 miles of fuel (based on 17.2mpg) when it is full and my hand calcs say i can go 325 (based on 15.8mpg) i just do like i used to do... LOOK at the NEEDLE ON THE GAUGE and see how much i have left. so in a nut shell (too late) DIC is just a fun toy to mess with and is kind of in the ball park

[Zembonez]

The DIC on my truck has proven pretty accurate (but not right on) since I bought it. The few times I have checked it agaionst actual pump amounts, it was within a few tenths of one mpg.

 

I don't use OLM to change my oil. I still use mileage.

[redvett]

The only way you can accurately calculate fuel mileage is to fill the tank write down odo mileage, drive until around 1/4 tank and refill divide the miles driven by the gallons used. Do not run until pump runs dry or damage will result to pump running dry.

The method you used is poor at best as the distance driven is too short for accuracy.

 

i never have trusted anything electronic.. heck... how stable is your desktop computer? to me electronic stuff is just ONE more thing to break alto fun to play with. I think the DIC is more of a GO-BY than anything else... at least thats just my opinion. so i wanted to see how accurate my DIC was so i did a little test. mind you my truck is all factory since i just bought it a couple months ago. I ran the truck until it was empty then i ran 10 gals of gas and drove like usual until it ran out. (i carried 10 gals can in back... so not to strand myself) here are my results.. DIC says i am getting 17.2 mpg average but my hand calcs give me 15.8 mpg.. so when the "fuel remaining" says i have 447 miles of fuel (based on 17.2mpg) when it is full and my hand calcs say i can go 325 (based on 15.8mpg) i just do like i used to do... LOOK at the NEEDLE ON THE GAUGE and see how much i have left. so in a nut shell (too late) DIC is just a fun toy to mess with and is kind of in the ball park

[drbob11]

i seriously think that driving 150+/- miles is to short for accuracy??? we have already established the miles/gal method. everyone knows that. we are talking about why the DIC gives one mpg number and doing the hand calc gives a diff mpg number.

 

The only way you can accurately calculate fuel mileage is to fill the tank write down odo mileage, drive until around 1/4 tank and refill divide the miles driven by the gallons used. Do not run until pump runs dry or damage will result to pump running dry.

The method you used is poor at best as the distance driven is too short for accuracy.

 

i never have trusted anything electronic.. heck... how stable is your desktop computer? to me electronic stuff is just ONE more thing to break alto fun to play with. I think the DIC is more of a GO-BY than anything else... at least thats just my opinion. so i wanted to see how accurate my DIC was so i did a little test. mind you my truck is all factory since i just bought it a couple months ago. I ran the truck until it was empty then i ran 10 gals of gas and drove like usual until it ran out. (i carried 10 gals can in back... so not to strand myself) here are my results.. DIC says i am getting 17.2 mpg average but my hand calcs give me 15.8 mpg.. so when the "fuel remaining" says i have 447 miles of fuel (based on 17.2mpg) when it is full and my hand calcs say i can go 325 (based on 15.8mpg) i just do like i used to do... LOOK at the NEEDLE ON THE GAUGE and see how much i have left. so in a nut shell (too late) DIC is just a fun toy to mess with and is kind of in the ball park

 

 

[redvett]

Your method of fuel calculation is poor at best. The GM system uses miles driven by injector pulse duration and since the PCM in modern vehicles is faster and more powerful it is better than the home PC as all it has to do is certain functions related to the vehicle. The PC on the other hand can do many operations along with getting a virus and crash.

 

i seriously think that driving 150+/- miles is to short for accuracy??? we have already established the miles/gal method. everyone knows that. we are talking about why the DIC gives one mpg number and doing the hand calc gives a diff mpg number.

 

The only way you can accurately calculate fuel mileage is to fill the tank write down odo mileage, drive until around 1/4 tank and refill divide the miles driven by the gallons used. Do not run until pump runs dry or damage will result to pump running dry.

The method you used is poor at best as the distance driven is too short for accuracy.

 

i never have trusted anything electronic.. heck... how stable is your desktop computer? to me electronic stuff is just ONE more thing to break alto fun to play with. I think the DIC is more of a GO-BY than anything else... at least thats just my opinion. so i wanted to see how accurate my DIC was so i did a little test. mind you my truck is all factory since i just bought it a couple months ago. I ran the truck until it was empty then i ran 10 gals of gas and drove like usual until it ran out. (i carried 10 gals can in back... so not to strand myself) here are my results.. DIC says i am getting 17.2 mpg average but my hand calcs give me 15.8 mpg.. so when the "fuel remaining" says i have 447 miles of fuel (based on 17.2mpg) when it is full and my hand calcs say i can go 325 (based on 15.8mpg) i just do like i used to do... LOOK at the NEEDLE ON THE GAUGE and see how much i have left. so in a nut shell (too late) DIC is just a fun toy to mess with and is kind of in the ball park

 

 

 

[Zembonez]

[drbob11]

i use the same method you use??? so your telling me your "method of fuel calculation is poor at best" as well?? whether you run it until bone dry empty or to a 1/4 tank it is still the same method. miles/gals - how many miles driven divided by how many gallons used. DIC is just another gizmo in the car.. its not the space shuttle. if it were so accurate as you described are you going to bet your life on the thing? the point of this thread is why the difference between DIC computer mpg vs basic math mpg.... not a debate on how to calc mpg.

 

Your method of fuel calculation is poor at best. The GM system uses miles driven by injector pulse duration and since the PCM in modern vehicles is faster and more powerful it is better than the home PC as all it has to do is certain functions related to the vehicle. The PC on the other hand can do many operations along with getting a virus and crash.

 

i seriously think that driving 150+/- miles is to short for accuracy??? we have already established the miles/gal method. everyone knows that. we are talking about why the DIC gives one mpg number and doing the hand calc gives a diff mpg number.

 

The only way you can accurately calculate fuel mileage is to fill the tank write down odo mileage, drive until around 1/4 tank and refill divide the miles driven by the gallons used. Do not run until pump runs dry or damage will result to pump running dry.

The method you used is poor at best as the distance driven is too short for accuracy.

 

i never have trusted anything electronic.. heck... how stable is your desktop computer? to me electronic stuff is just ONE more thing to break alto fun to play with. I think the DIC is more of a GO-BY than anything else... at least thats just my opinion. so i wanted to see how accurate my DIC was so i did a little test. mind you my truck is all factory since i just bought it a couple months ago. I ran the truck until it was empty then i ran 10 gals of gas and drove like usual until it ran out. (i carried 10 gals can in back... so not to strand myself) here are my results.. DIC says i am getting 17.2 mpg average but my hand calcs give me 15.8 mpg.. so when the "fuel remaining" says i have 447 miles of fuel (based on 17.2mpg) when it is full and my hand calcs say i can go 325 (based on 15.8mpg) i just do like i used to do... LOOK at the NEEDLE ON THE GAUGE and see how much i have left. so in a nut shell (too late) DIC is just a fun toy to mess with and is kind of in the ball park

 

 

 

 

 

[brims]

DIC is pretty close to my mileage. Over the last 2 years it has deviated little.

 

No one checks their tire pressures, hence the TREAD act that mandates TPMS.

 

For all of you who hate electronics, why do you own a house without gas lamps, why are you driving vehicles instead of riding horses. I don't get you Amish wannabes that still own tons of electronic stuff.

[redvett]

All the people that hate electronics better get off the computer,INTERNET,cell phone,television,ATM's and much more. Life would certainly be more difficult but than again simple.