RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×


Reply
 
Thread Tools Display Modes
Old 10-19-2020, 11:35 PM   #1
Senior Member
 
EdandShelley's Avatar
 
Join Date: Nov 2019
Location: Frisco, TX
Posts: 364
Freightliner M2 Fuel Gauge Comparison

Has been quite a few comments and frustration about the Freightliner M2 fuel gauge not being accurate. We agree... so we logged some data on our recent trip. Here is how our 2018 XL reads compared to how many gallons the ScanD tracked as consumed and/or how many gallons it took to fill both tanks (topped off).

Dash Fuel Gauge.....ScanD TFC.....Fill Up Gallons

Approx 3/4..................25 gal..............25 gal
Approx 1/2..................40 gal..............40 gal
Approx 1/4...................62 gal..............61 gal

So.... we know there is reserve capacity in the 100 gallon rated tanks. Regardless, the dash gauge loses accuracy with progressive fuel burn while the ScanD is pretty darn accurate.
At a dash reading of 1/4 tank... we still had about 40 gallons of diesel remaining.

Am going to fill at the “red” below 1/4 on next trip to get that actual remaining fuel.

Are others seeing similar numbers?
EdandShelley is offline   Reply With Quote
Old 10-20-2020, 05:24 AM   #2
Senior Member
 
JC70's Avatar
 
Join Date: Jul 2018
Location: Concord, New Hampshire
Posts: 111
That's good work. At 1/4 tank on the dash, I pump in 41-42 gallons. I assume full tanks to be only 80 gallons, not 100. It would be nice to get a definitive answer about total actual fuel capacity as others on this forum say only 80 gallons as total capacity and Freightliner advertises 100 gallons.

I too use a Scangauge and I've found it to be quite accurate. I'll duplicate your methodology when we return to the road.
__________________
Sheila and Joe
2020 Force 34HDKD - XLRB next March
2016 Jeep Grand Cherokee
JC70 is offline   Reply With Quote
Old 10-20-2020, 08:38 AM   #3
Senior Member
 
MoJoe1003's Avatar
 
Join Date: Oct 2018
Posts: 431
I switched from a ScanGauge D to the BlueFire adapter about 6 months ago. Using an iPad to connect to the BlueFire allows me me to see everything at a glance without having to push buttons to cycle through. An example of the BlueFire dash I use is attached.
I have found that the fuel percentage and DEF percentage is pretty much right on. It takes the reading from the ECM. When the screen shows 50%, I usually am able to put in 42 to 45 gallons. I feel like my useable capacity is right at 90 gallons. According to everything I have read filling to 90% is about max capacity so on 100 gallons that works out. Also the DEF percentage is almost exact. At 50% I put in slightly less than 3 gallons.

Click image for larger version

Name:	IMG_0274.jpg
Views:	40
Size:	195.3 KB
ID:	241559
__________________
Joe & Cynthia
2018 Dynaquest XL 3801 TS Cindy 'B'
2018 Jeep Wrangler Unlimited Sahara
“Breathe in, Breathe out, Move on”
MoJoe1003 is offline   Reply With Quote
Old 10-20-2020, 09:28 AM   #4
Senior Member
 
Join Date: Mar 2012
Posts: 688
I would still like to know what happens if one tank is dry and the other tank has 20 gallons. Since these systems are dual feed dual return, can one tank ever run dry since fuel should always be returning?
__________________
DYNAMAX 2016 FORCE HD
houstonstroker is offline   Reply With Quote
Old 10-20-2020, 12:37 PM   #5
Member
 
duneviper's Avatar
 
Join Date: Apr 2014
Posts: 33
Quote:
Originally Posted by EdandShelley View Post
Has been quite a few comments and frustration about the Freightliner M2 fuel gauge not being accurate. We agree... so we logged some data on our recent trip. Here is how our 2018 XL reads compared to how many gallons the ScanD tracked as consumed and/or how many gallons it took to fill both tanks (topped off).

Dash Fuel Gauge.....ScanD TFC.....Fill Up Gallons

Approx 3/4..................25 gal..............25 gal
Approx 1/2..................40 gal..............40 gal
Approx 1/4...................62 gal..............61 gal

So.... we know there is reserve capacity in the 100 gallon rated tanks. Regardless, the dash gauge loses accuracy with progressive fuel burn while the ScanD is pretty darn accurate.
At a dash reading of 1/4 tank... we still had about 40 gallons of diesel remaining.

Am going to fill at the “red” below 1/4 on next trip to get that actual remaining fuel.

Are others seeing similar numbers?


My gauge was on E with the warning light on and I was only able to put 56 gallons in the tanks.
duneviper is offline   Reply With Quote
Old 10-20-2020, 12:52 PM   #6
Member
 
Join Date: Feb 2020
Location: Ohio
Posts: 65
One thing to be careful about / aware of is generator use. The ScanGauge is very accurate at determining fuel burn through the motor, but it can't track any fuel used by the genny.
__________________
Ty & Deb Montag
2020 Berkshire XLT 45A
2014 Honda CR-V toad
anaviator is offline   Reply With Quote
Old 10-20-2020, 01:05 PM   #7
Junior Member
 
M T Pockets's Avatar
 
Join Date: Dec 2018
Location: Niagara-on-the-Lake, Ontario
Posts: 19
I have run mine on E with the light on for 52 miles before I fueled up. Scan gauge showed 17 gallons of remaining fuel. I filled both tanks to the neck and managed 78.6 gallons.
__________________
Gary & Janet
18 Force HD 37TS
18 Buick Envision
M T Pockets is offline   Reply With Quote
Old 10-20-2020, 01:09 PM   #8
Junior Member
 
M T Pockets's Avatar
 
Join Date: Dec 2018
Location: Niagara-on-the-Lake, Ontario
Posts: 19
Quote:
Originally Posted by M T Pockets View Post
I have run mine on E with the light on for 52 miles before I fueled up. Scan gauge showed 17 gallons of remaining fuel. I filled both tanks to the neck and managed 78.6 gallons.
I actually dipped the tanks before I fueled. The drivers showed about 3" on the stick. The passenger side was about 2.5 "
__________________
Gary & Janet
18 Force HD 37TS
18 Buick Envision
M T Pockets is offline   Reply With Quote
Old 10-20-2020, 01:16 PM   #9
Member
 
Join Date: Apr 2015
Location: Arlington, Texas
Posts: 48
M2 Fuel gauge

My 2015 Force has similar issues with fuel gauges. When the low fuel light comes on when on level roads I have 27 gallons left. The owners manual says it should illuminate at 10% remaining. It has been this way since I bought it new in 2015.The only other issue with the fuel tanks is the vents. There is a green vent tube for each tank easily accessible from underneath. If the mud daubers get into those tubes you will pull a vacuum until the fuel pump can’t pull fuel against it...then the engine will die, you will be 90 miles from a Cummins dealer, they will send a flatbed to haul your rig into the shop, the tech will come out to the waiting area with a hardened mud cylinder in his hand which will have been extracted from a fuel tank vent and you will pay a large fee to the towing company. 🙁🙁🙁. The moral of the story? Get under your rig and blow into those vents! Takes about a minute, not as ghastly as it sounds and produces one less potential issue on the road. If the vent is plugged you will know it instantly and it is an easy fix.
Jetjockey6 is offline   Reply With Quote
Old 10-20-2020, 04:17 PM   #10
Senior Member
 
FOURWHL's Avatar
 
Join Date: Mar 2016
Posts: 2,580
Quote:
Originally Posted by JC70 View Post
That's good work. At 1/4 tank on the dash, I pump in 41-42 gallons. I assume full tanks to be only 80 gallons, not 100. It would be nice to get a definitive answer about total actual fuel capacity as others on this forum say only 80 gallons as total capacity and Freightliner advertises 100 gallons.

I too use a Scangauge and I've found it to be quite accurate. I'll duplicate your methodology when we return to the road.
The tanks also say leave 10% for air/temp expansion. Which is my theory why the fill necks are positioned where they're at. So if you take that off you're at 90 gal.

Comparing this to several fill ups I believe it to be an accurate assumption. I've never ran it dry, most I've put in was 84 gal, but at that level there was only an inch or two of fuel left. I CBA to actually measure depth but I probably should've.
__________________
2016 Dynamax DX3 - Big Blue

https://fourwhl.com - Traveling the country in our DX3 for the next year
FOURWHL is offline   Reply With Quote
Old 10-20-2020, 04:44 PM   #11
Senior Member
 
JC70's Avatar
 
Join Date: Jul 2018
Location: Concord, New Hampshire
Posts: 111
Quote:
Originally Posted by FOURWHL View Post
The tanks also say leave 10% for air/temp expansion. Which is my theory why the fill necks are positioned where they're at. So if you take that off you're at 90 gal.

Comparing this to several fill ups I believe it to be an accurate assumption. I've never ran it dry, most I've put in was 84 gal, but at that level there was only an inch or two of fuel left. I CBA to actually measure depth but I probably should've.

Excellent. 90 gallons is what I will work with. Thanks.
__________________
Sheila and Joe
2020 Force 34HDKD - XLRB next March
2016 Jeep Grand Cherokee
JC70 is offline   Reply With Quote
Old 10-23-2020, 03:14 PM   #12
Junior Member
 
Join Date: Jun 2020
Posts: 2
My experience with the Freightliner fuel gauge is similar to the other posts. In my M2, with rectangular 40 gallon saddle tanks and a 70 gallon useable fill, I went analogue - - a wooden stick with markings every 10 gallons or (2" in depth). As the gauge arrives on E, I have 30 gallons remaining and set my trip odometer knowing I have approximately 330 miles left.

When boondocking I know exactly where my 1/4 tank mark is relative to remaining fuel available for the generator and getting back on the road.

Not sexy - - but it works.
RedScooter is offline   Reply With Quote
Reply

Tags
fuel

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 02:00 AM.