Accuracy of DICs average MPG

[mzodarg]

I bought this car in April, have 14K on the ODO. Manually calculated MPG is consistently off by 4 MPG.

Just completed a 2900 mile trip and the DIC stated My Average was 39 MPG, manually calculated it was actually 34.4.

Just curious what others are seeing.

Tre'

[DrivenDaily]

I have had mine be off by less than a 10th (26.2 DIC vs 26.294 manual) and over 3 mpg. Just depends on what's going on with the driving.

[Richard]

Originally Posted by DrivenDaily

I have had mine be off by less than a 10th (26.2 DIC vs 26.294 manual) and over 3 mpg. Just depends on what's going on with the driving.

I agree, I find the Accuracy of the DIC Average MPG to be spot on. If I want to see my true Highway MPG, I reset the Average MPG as I enter the highway and I see what I'm averaging as I'm exiting.

The reason you might have calculated less than the DIC MPG is there was probably some city driving involved there as well. So you didn't calculate true highway MPG. If you reset the Average MPG when you were on the highway, then the computer was only calculating those MPG's which would be higher than the true MPG of mixed city and highway driving.

If you want to see your overall Average MPG, reset the computer when you fill up. Then see what you get with mixed city and highway driving. My car advertises 26 MPG in the City, and 38 on the highway. With mixed driving, I generally get around 29 MPG. When I divide the number of miles traveled by the fuel used since my last fillup, the average mpg is very accurate.

[Steve_AZ]

My DIC is always off - usually reads a couple MPG too high. The readout in my Caravan is also optimistic by a couple mpg nearly every time.

I use a spreadsheet I created to keep track of my lifetime average, and now also http://www.fuelly.com so that I am able to share with others.

[mzodarg]

I always reset the DIC Avg MPG when I fill up. Like I stated earlier, had a business trip last week, 2900 miles, left on a Saturday, was back home on Tuesday. Drove 10 miles at my destination and left the following morning. I did'nt re-set anything as I wanted to see what the total trip MPGs came out to.

I was just curious if anyone else has experienced this. My wife has a 2011 Honda exl V6 with nav and that car is always within 10ths of manually calculations. It also gets very similiar mileage to the Malibu ( +/- 1 gallon) on the highway, little less in town.

Tre'

[cp-the-nerd]

Originally Posted by mzodarg

I always reset the DIC Avg MPG when I fill up. Like I stated earlier, had a business trip last week, 2900 miles, left on a Saturday, was back home on Tuesday. Drove 10 miles at my destination and left the following morning. I did'nt re-set anything as I wanted to see what the total trip MPGs came out to.

I was just curious if anyone else has experienced this. My wife has a 2011 Honda exl V6 with nav and that car is always within 10ths of manually calculations. It also gets very similiar mileage to the Malibu ( +/- 1 gallon) on the highway, little less in town.

Tre'

Your average fuel economy read out does not record 2900 miles. If it's like the one in the 2008-12 Malibu, it records about 1000 miles and throws out the old data. Reset the average FE for every tank of gas and compare those readings. 39 mpg was the result of the final stretch of high way driving, and I bet you were pretty close to that in real life.

[cp-the-nerd]

Also, there's no way on God's green earth that a '11 Accord V6 gets "very similiar mileage" to the Malibu Eco. I don't know why you have such a beef with the car you chose to buy, but such exaggerations are just going to kill your credibility or make you look biased.

[nutcrunch]

I wondered bout the accuracy myself. When I first got the car it seemed 2-3 mpg off. I started this thread http://www.chevymalibuforum.com/foru...ad.php?t=10772 and went through 4 fillups to check the accuracy and found it to be within 1mpg of actual findings.

As for the Eco getting about the same mpg as an 2011 V6 Accord, well like I said in another thread, you may want to get that Eco checked out as it doesn't sound like it is operating properly or it could just be the driver
The 2013 malibu Eco is rated at 25 city and 37 highway while the 2011 Accord V6 is rated at 19 city 29 highway.

[cp-the-nerd]

I don't think there's anything wrong with his car at all. Achieving 34.4 mpg over 2900 miles is pretty much where it should be. We don't know his driving habits or the breakdown of those miles. Even if it was as much as 90% pure highway, he's just about dead on the EPA estimate.

[nutcrunch]

Ok yea, I forgot the part where he said he got 34.4 which is about what I got on my approximately 3300 mile trip to Oklahoma and back a few months ago. I was focusing on the comparison to the Accord part.

Here was the breakdown
Leaving Virginia enroute to Oklahoma
Miles / Gas / MPG
300.9 / 7.8 / 38.5 (a lot of this was 65 mph and below highway)
245.7 / 7.94 / 30.95
144.6 / 2.99 / 48.36
264.6 / 8.311 / 31.84
245.8 / 6.895 / 35.649
412.6 / 13.0 / 31.738
Total
1614.2 / 46.936 / 34.392


Leaving Oklahoma enroute to Virginia
Miles / Gas / MPG
308.5/10.593/29.123 (about half of this mileage was city driving)
269.1 / 7.8 / 34.5
222.1 / 5.32 / 41.748
175.3 / 5.114 / 34.278
391.5 / 11.375 / 34.4175
333 / 8.9 / 37.4517 (a lot of this was 65 mph and below highway)
Total
1699.5 / 49.102 / 34.611

Trip Totals
Miles / Gas / MPG
3313.7 / 96.038/ 34.5

Traveled around 70 mph most of the way, through some mountains. Trunk packed with luggage, 2 adults 2 kids and air conditioner on the whole trip. The car had about 1164 miles on it when we started the trip so it was still getting broken in.