ScanGauge and Gas Mileage...

[Gotta_P]

I have my ScanGauge set up to show average gas mileage per trip and per tank, and so far it seems to be fairly accurate. Does anyone know if it knows when the generator is running and does it take into account the fuel consumed by the generator when calculating fuel mileage?

Just curious, on our way back from Murphy, NC this past Sunday, I averaged 8.3 mpg with the generator running! Not sure if that is accurate or not because I don't know if the ScanGauge was just showing fuel mileage for the engine or if it was taking into account fuel used by the generator. Anyone know how it calculates fuel economy and if it showing fuel consumed by the coach engine, or fuel consumed from the tank (i.e. coach engine and generator engine)? Thanks...

[DriVer]

Quote:

Originally Posted by Gotta_P I have my ScanGauge set up to show average gas mileage per trip and per tank, and so far it seems to be fairly accurate. Does anyone know if it knows when the generator is running and does it take into account the fuel consumed by the generator when calculating fuel mileage?

Hi Paul! The Scan Gauge is connected to the OBDII port under your dash and only reads the fuel performance of the engine from the ECM.

There isn't any connectivity between the generator fuel consumption and the engine fuel consumption.

The pickup tube on the generator set is totally independent from the fuel pump and that's why the gen set will shut down when you get to about the 25% of fuel remaining in the tank. It is frustrating sometimes because my generator won't run in the late afternoons if I haven't filled up in the morning.

[dieselclacker]

Quote:

Originally Posted by Gotta_P I have my ScanGauge set up to show average gas mileage per trip and per tank, and so far it seems to be fairly accurate. Does anyone know if it knows when the generator is running and does it take into account the fuel consumed by the generator when calculating fuel mileage? Just curious, on our way back from Murphy, NC this past Sunday, I averaged 8.3 mpg with the generator running! Not sure if that is accurate or not because I don't know if the ScanGauge was just showing fuel mileage for the engine or if it was taking into account fuel used by the generator. Anyone know how it calculates fuel economy and if it showing fuel consumed by the coach engine, or fuel consumed from the tank (i.e. coach engine and generator engine)? Thanks...

I don't believe the Scan Gage takes into consideration if the generator is running or not. It only knows how much fuel is being used, and how many miles have been covered. The gen on my motorhome uses less than a gallon per hour with both AC units working. Best way (most accurate) to figure mileage is still with pencil and paper. I often get over 8 mpg, even with generator running, all depends on driving conditions, terrain, headwinds etc. Now if I could find out a way to get all those 6.3 mpg fill ups to come to 8 consistantly-------

Dieselclacker

[Gotta_P]

Thanks guys, but I'm still a little confused. Being as the generator does pull fuel from the same tank as the engine, figuring mileage the old fashion way (pencil and paper) should give me the milage with combined fuel consumption for that tank. So, if the ScanGauge is only figuring mileage based on engine consumption, I should see a pretty significant difference next time I top off the tank and figure my gas mileage, correct? Or, is the calculation shown on the ScanGauge based on input to the ECM from the fuel tank, i.e. actual fuel remaining and number of miles driven.

This brings up another concern... Another display parameter on on my ScanGauge is Distance till Empty! If the ScanGauge does not take into account fuel consumed by the generator, than I probably have way less range tan is being displayed by the ScanGauge! Yikes!

Off Topic: My 4th parameter displayed is HP, how accurate do you think that is, and will it show an increase when I finally get the UP upgrade?

[TrekPR]

Paul,

Your ScanGauge does not know your generator is running and does not compute the fuel used by it. The EMC meters the fuel used by the engine computes it against the milage, it is then read by the ScanGauge and displayed. If you are running the generator the ScanGauge miles till empty will be in error however the fuel line for the generator does not reach the bottom of the tank so the generator will shut down and still have about a quarter of a tank. As Dieselclacker states your generator will use about a gallon per hour.

[motohomer]

After getting UP, my scangauge HP goes to all 9's after about 350.
The MPG's also go all 9's during this time.

I've been meaning to ask somebody about that but never got around to it.

[DriVer]

Quote:

Originally Posted by Gotta_P Thanks guys, but I'm still a little confused. Being as the generator does pull fuel from the same tank as the engine, figuring mileage the old fashion way (pencil and paper) should give me the mileage with combined fuel consumption for that tank.

√ Yes that's correct. Paper and pencil will give you real world data in regard to the combined fuel consumption if you were running the Gen set all day long BUT it's not going to give you a true idea of what your MPG is "unless" you factor in the 1 GPH (under full load by the way) that you've consumed during your run. If you ran the set for 5 hours add 5 gallons and then do the math. This will give you a "horse shoes" MPG rating. The only way to get it as accurate as possible is to not run the set and then do the math.

Quote:

So, if the Scan Gauge is only figuring mileage based on engine consumption, I should see a pretty significant difference next time I top off the tank and figure my gas mileage, correct? Or, is the calculation shown on the Scan Gauge based on input to the ECM from the fuel tank, i.e. actual fuel remaining and number of miles driven.

The data from the scan gauge is based on tables, algorithms, calculations and direct circuit monitoring. Neither the on-board IP based MPG computations or the ScanGuage display will agree as to what the MPGs really are. The only true method to monitor fuel consumption would be pressurize the tanks and have transducers monitor volume and weight like an aircraft. Our instruments are only designed to give us a "Good" idea of what's going on and these tools are useful.

If you were to do paper and pencil say over the course of say 6 fill-ups and compare that to the instruments over the same time at the end of that cycle you would be able to "fair" in a curve and your Butt MPG Meter (BMM) would be able to tell you what your performance is based on observation over several cycles plus time in the seat observation. It might take a couple of years but you will get very familiar with the performance characteristics of your vehicle and will be able to predict a great many things. A butt is a wonderful thing and it learns just like the ECM.

Quote:

This brings up another concern... Another display parameter on on my Scan Gauge is Distance till Empty! If the Scan Gauge does not take into account fuel consumed by the generator, than I probably have way less range tan is being displayed by the Scan Gauge! Yikes!

The DTE will be effective in the later stages of fuel consumption after the gen set stops running and drawing fuel. When I get a "Bingo" fuel chime and IP prompt in the Command Center, I know that I have about 3-5 gallons of fuel remaining and that translates to 15 to 25 miles depending on terrain (RPM) and speed. I will occasionally Russian Roulette this thing and wait for the Bingo BUT that said I am usually in a dense fuel station corridor like on I-95 or other densely populated state roads. Once the Bingo goes off and the longer I go the more my palms begin to sweat! Fortunately over the many years of motorhome ownership, we have never ran out of fuel.

Quote:

Off Topic: My 4th parameter displayed is HP, how accurate do you think that is, and will it show an increase when I finally get the UP upgrade?

There isn't any guarantee that MPGs will go up using UP however I don't expect that they will go down either.

[DriVer]

Quote:

Originally Posted by motohomer I've been meaning to ask somebody about that but never got around to it.

Call Brazels RV and ask for Steve.

[motohomer]

Thanks Driver,
I was going to ask them at the Winnebago GNR next month, but I see they wont be there this year.
Guess I'll have to call.

[DriVer]

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Originally Posted by motohomer Thanks Driver, I was going to ask them at the Winnebago GNR next month, but I see they wont be there this year....

We won't be going to GNR this year. I have a WCC Rally that we're doing on Cape Hatteras and then I have the iRV2 Rally in Myrtle Beach.

[motohomer]

See you in Cape Hatteras!