My MPG gauge is very accurate

Post by **rmmagow** » 31 Oct 2013, 07:08

My gauge is also pretty accurate, within .3 of real measured mileage. My car's got 205K on it now, original fuel pump but I fill almost all the time once the gauge reads "6" for the whole immersed in fuel idea. Seems to be working!

bob850 · Post by **bob850** » 31 Oct 2013, 08:43

The pump on my wife's car failed at 160K, but she tends to let the tank get close to empty more often.

Post by **rspi** » 31 Oct 2013, 09:54

I don't get gas unless my light is on. On average my Miles To Empty is about 45 miles. This behavior has been going on since I purchased the car 3 years ago and 50,000+ miles. I'm not bragging by no means, it's just the facts for my situation.

I do know that running a car out of gas and trying to start it over and over again will burn the pump out in a few minutes, but I thing it will be fine as long as fuel is going through the pump. I also use Lucas fuel injector cleaner, they claim that lubricates the pump.

I ran one of my 850's out of gas just to see how accurate the Miles To Empty was and it started coughing at 5 miles. I immediately pulled over and added some gas I had in the trunk.

Post by **abscate** » 31 Oct 2013, 10:33

I ran one of my 850's out of gas just to see how accurate the Miles To Empty was and it started coughing at 5 miles. I immediately pulled over and added some gas I had in the trunk.

We need more people like Robert in the world....

Post by **jblackburn** » 01 Nov 2013, 10:16

I ran one of my 850's out of gas just to see how accurate the Miles To Empty was and it started coughing at 5 miles. I immediately pulled over and added some gas I had in the trunk.

Don't trust that thing. Mine started coughing at 25 to E (granted, it sat around 25-35 forever). At that rate, there should have still been a gallon or mre in the 18.5 gallon tank. It took 18.2 gallons...

I do miss how accurate the Volvo's MPG meter was...mine was almost always dead-on, and I tracked every fillup with a phone app. The Camry/Cruze are always 1-2 MPG off.

To my understanding, the injector pulse width method of tracking MPG was laid claim to by some manufacturer in the late 90's and other auto manufacturers had to find another method to calculate fuel used.

Post by **matthew1** » 01 Nov 2013, 11:45

+1 on distance to empty calculation error.

Just don't trust it. It's not that it's flawed, it's simply predicting future DTE on past throttle/speed/distance data. It's literally trying its best to predict the future based on how you've been driving.

Scenario
You pull off the highway with 30 miles to empty. Ok, 30 miles, no problem. But that's at say 30 mpg for hundreds of miles. Now you're in town, getting half that. I don't know how far back in time or distance the prediction math goes (5 miles? 10 miles? Jimmy might know this), but the estimate is going to take some time (distance since highway) to "catch up" with the new driving reality.

Can you see where this is going?

In the first 2 miles of navigating stop-and-go traffic in a city you don't know, the DTE suddenly shows 20 miles. Whoa! Then a mile later, 15 miles DTE. Uh oh.

Granted, this is an extreme example, but it's how you can go dry with 10 or 20 miles showing.

instarx · Post by **instarx** » 01 Nov 2013, 17:54

abscate wrote:3 mpg for an air dam seems really high. Same fuel, temperature. warp core properly aligned?

It seemed high to me too, as I said. But those were the numbers and I take my mpg measurements seriously. That post was 4 years ago so I barely remember the trips, but there were no huge differences. I do know it was the same time of year, same time of day, same traffic level, same tire pressure, same speed, etc. If anyone else had posted those numbers I would be skeptical myself.

Post by **jblackburn** » 01 Nov 2013, 18:16

instarx wrote:
abscate wrote:3 mpg for an air dam seems really high. Same fuel, temperature. warp core properly aligned?
It seemed high to me too, as I said. But those were the numbers. That post was 4 years ago so I barely remember the trips, but there were no huge differences. Same time of year, same time of day, same traffic level, same tire pressure, etc. The only significant difference I remember was the NY ends of the trips used different gas stations.

The 30.2 mpg turned out to be my all-time highest mileage for a tank. It was also the only time I used that air dam on a long trip. Anecdotal, I know. If anyone else had posted those numbers I would be skeptical too.

I do remember a noticeable drop in FE when mine broke as well - you're not alone.

Post by **rspi** » 01 Nov 2013, 19:16

abscate wrote:We need more people like Robert in the world....

There are some experiments that I am not willing to test myself. LOL

My MPG gauge is very accurate

Re: My MPG gauge is very accurate