Inaccurate fuel readings

[Harbour35]

I have a 2018 M2 that is not even close on fuel gauge readings.

I have a Scangauge that I moved from my previous MH that had to be upgraded for the new connector so that will help. I am aware of the 400 mi. standard referenced in other posts but I would like the gauge to at least be close.
Currently at 1/4 tank I can only put 32 - 36 gallons in. I fill the tanks to the top of the filler neck so I know they are full.
I do not understand exactly how the equalization works between the 2 tanks but it seems ok and the quantities seem appropriate for a lt. 30 gal and a rt. 34 gal. tanks.
I plan to pump both tanks out and then add the appropriate fuel for 1/4 and then 1/2 gauge readings.
I am going to pull the sending unit and see if I can bend the float wire to improve the reading accuracy.
Freightliner checked the gauge and checked the resistance in the sending unit and said there was nothing more they could do.
Questions:
At what fuel level does the low fuel light come on ?
At what fuel level does the generator run out of fuel ?

Any thoughts/suggestions appreciated.

[Robbbyr]

I have a unit that seems somewhat better than some others based on lots of previous discussion here. But like most others, mine does read artificially low which I suppose is better than the alternative. Some others have had issues where it seems they only had 40 or so gallons of usable fuel. One run I made I put 65 gallons or so back in when I fueled it. But the gauge was buried on E and the low fuel light on for quite some time.

Some have been to Freightliner and had their sending unit replaced with (apparently) little success. If you are able to figure yours out and make it more reliable you will be revered here by other M2 owners!

[ronsimmmons41]

yes. I have 2015 FK and the tank gauges are way off. When filling up put in around 50 gallons. Pain having to fill both sides. really not happy with the fuel system on this unit and the capacity.

[ronsimmmons41]

Just got this reply back from freightliner about fuel tanks. you only have about 64 net gallons not 74.
Hi Ron: Thank you for using our online services.** I reviewed the spec of your vehicle and determined you have 2 separate fuel tanks with the equiflow inboard fuel system.
*Let me first advise that you will never be able to get a full 74 gallons of fuel in this vehicle. The reason why is the fuel pick up tubes do not pull directly from the bottom of the tanks. They are approx. 1 inch from the bottom and each tank needs approx 9 gallons of fuel before reaching the pick up tube.* I am also thinking that you are filling both tanks independently at the same time.* Keep in mind that if you are only filling one tank it will take several hours for the tanks to equalize. Also keep in mind this vehicle only has 1 fuel sender located in the left hand tank. Meaning if fuel is only being added to the left tank only , the gauge will read accurately and will take a while to equalize fuel to the right tank , if the right tank is not also being fueled at time at fueling station.****

There are several other conditions that can cause this type of issue.
If this vehicle was brought to one of our dealers, I would ask the technician to review the following:
1. This truck left our factory as an incomplete vehicle that was going to be modified. Did the body builder Jayco move the tanks from their original factory mounted location and are their any blockages or restrictions in the fuel filling tubes?*
2.Are the fuel tanks clocked / mounted in the saddles correctly and are they sitting level?
3. Is the truck suspension sitting level?

If I know the answer to these questions , I can provide further assistance, but that would be the starting point.


I did notice a few concerns that I need to bring to your attention:

1. This vehicle is currently not showing registered to you. If you would please fill out the attached document and e-mail it back to this e-mail address:* dtna-warrantydep@daimler.com , this will help update our records. It is very important to do this right away. The reason why is, you will begin receiving notification like recalls and service bulletins that apply to your vehicle.

2. This vehicle currently has an open recall, see attached document FL672.***


If you need further assistance please feel free to use the reply back to this e-mail feature.

Kind regards: Steve McRobert

[Les7h]

Freightliner acts like they have never heard of this erroneous fuel tank reading before - I had Freightliner of Albuquerque NM look at mine and they also acted like it was the 1st time they had heard of this and ultimately they determined that it is my imagination - but if I had read their YELP reviews I would have gone somewhere else

[RVermont]

I suspect one of the reasons freight liner doesn’t either care or don’t know is that this is a medium duty regional truck body. This configuration is used in thousands of fleets for local/regional deliveries with the vast majority of these returning to the yard each night after a few hundred miles. They are then filled and ready for the next day. So these people it really is only an indicator and is not needed to be.

If the truck is set up for longer hauling they have 80 and 100 gallon tanks available.


Makes sense that you have to bank an inch or two of fuel to prevent crap getting sucked up.

Thanks again


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[Abe padgett]

Freightliner Steve said you need 9 gallons in each tank before it will pickup fuel 74 - 18 =56 gallon capacity. Gosh, I don’t know if he is correct in that statement.

[Robbbyr]

Originally Posted by Abe padgett

Freightliner Steve said you need 9 gallons in each tank before it will pickup fuel 74 - 18 =56 gallon capacity. Gosh, I don’t know if he is correct in that statement.

I put about 65 gallons in mine once. So there must be "manufacturing tolerances". I also do admit I tend to cram as much fuel in as I can provided I'm not racing the clock or have another rig waiting on my pumps.

Maybe I was luckier than I thought!

[memphis02]

I guess I am lucky, too Robby... I recall a trip coming back from Bowling Green, Ky where I put around 67 gal in mine. I was certain I was going to run out all the way down the off-ramp but sighed in relief that it was still in the 60's as I "knew" the tanks held ~70.

I guess the rule about this fuel-situation is that there are no rules...

[memphis02]

Originally Posted by Abe padgett

Freightliner Steve said you need 9 gallons in each tank before it will pickup fuel 74 - 18 =56 gallon capacity. Gosh, I don’t know if he is correct in that statement.

I don't think I believe that at all... I don't know a lot about much, but I do know about tank strapping calculations. For one inch to equal 9 gallons, The tank would have to be approximately 9,000 gallons in capacity.

I used a bit of kentucky windage to calcualte a strap for our tanks and got pretty darn close on the first try: a vessel of 3' length x 1.5' diameter would have around 39.6 gal of capacity; Filled to a height of 1" it would have just shy of .9 gallons.

Now, this calculation is for a perfectly cylindrical vessel and our tanks are not that... but it would not affect my calculations such that it's off by an entire order of magnitude!!!

[RVermont]

I agree his statement of 9 gallons each seems crazy. That is a loss of over 30% tank capacity.

The smaller tank is rectangular and measures about 32*18 so about 576 cu inches. Each gallon is 231 cu in or 2.5 gallons per inch. So to have 9 gallons we would need 3.6 inches. The fill is around 14 inches. I can see an inch in each tank or even two. That would be at total of 5-10 gallons combined.

With the dual pickup you have to maintain more hold up as I would assume if one tank goes dry you will loose prime in both.




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[Crossingover]

What is the recall mentioned by Freightliner?


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[RVermont]

It had to do with the automatic parking brake on some 2013-2015 units. I put in the code and freight-liner recall in google and the information popped up.




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