Seneca fuel range

[Foster15]

Question re fuel range. Max I have traveled between fill is 456 miles; burned 48.6 gal for 9.3 mpg. Burned 25 gal from one tank and 23 gal from other. Any clue on usable fuel per tank or ranges others have gotten between fills. Guage not reliable.

Thanks

[mikew968]

With the fill mounted somewhat on the side it is impossible to get all 70+ gallons. It has been suggest to add a short extra filler neck to get all the capacity. Also, keep in mind the pick for the fuel is not on the bottom but rather an inch or two off the bottom. I am thinking of carrying couple of 5 gal tanks and test the mileage!! lol

[Mnwelsh]

I have gone 400 miles between refueling stops many times and would not hesitate to go 500 miles. However the trips I have taken often had limited stations for refueling after I had covered 400 miles. I tow a Jeep and average 8.3 mpg. Who really knows what the usable fuel in the Seneca is? It's got two tanks that hold 74 gallons, so, I would take a wild guess you might be able to use 70 gallons of that 74 gallon capacity. 70gal x 8.3 mpg=581 miles. But when you get there are you guaranteed there is not a power outage that would mean the station could not pump fuel? (I have experienced this once in my travels). Thus I refuel every 400 miles + or -.

[Mnwelsh]

My guess is if you add a short filler neck to the tank the extra fuel you put in the neck will flood the tank and it will flow out of the breather tube that lets air into the tank as you burn the fuel down and spill onto the ground.

[Robbbyr]

I'm one of the "lucky" ones, my gauge is fairly close.

I try not to go too much below 1/2 tank, around 400 miles or so, before I am looking for fuel. Maybe it was my time in the Navy, and certainly my time as a firefighter; both imprinted the habit to watch the fuel carefully!

But another big reason I fuel earlier is the generator low-fuel cutoff. Somewhere around 1/4 tank the generator will run out so as to not drain your entire supply. I always want to retain the ability to run the generator, so I always keep a "cushion".

[WaltW]

I'm like Rob...I drive on the 1/2's, that is, when I hit 1/2 tank I start looking. This is especially important when you are off the interstates and in unknown territory.

[Mr.Oz]

Fill the passenger side first, that seems to make the gauge more accurate at least for me. That said I fill up between 450-500 miles and have never put in more than 51 gallons. I averaged 9.5 mpg towing our Jeep. Cruise set at 62 mph.

[anav8or]

I agree with the others - I try to plan fuel stops every 400 miles or so. I've gone as much as 500 miles in a pinch, but I'm not comfortable going much beyond that. It would be nice to get an actual capacity at some point.

[Themobiledude]

We had to contact freightliner headquarters. They finally tested the dash, they ended up replacing it and now it seems to be ok. Have only been on a couple short trips.

[Mnwelsh]

When you say they tested the dash do you mean they tested the fuel gage in the dash?

[Themobiledude]

On the 2014 Seneca it has an electronic dash, no separate gauges. They put a restricter on the gauge wires and had to drive the coach 150 miles to see if the gauge still moved. If it moved one direction the dash was the problem and if it moved the other direction it was another problem.

[Mnwelsh]

Ok, thanks for the reply . Now I understand the entire instrument cluster is considered one unit. Please keep us informed with how this turns out. I have talked to several Seneca owners and they all seem to have inaccurate fuel gages. We all assumed it was the sending unit in the tank but as you are finding out it my be the instrument cluster that contains the fuel gage .

[Mnwelsh]

This is the instrument cluster

[tpastorini]

I am picking up my newly purchased 2014 seneca today. I am reading this thread...... are their two fuel tanks or one?

I thought you can fuel from either side into one tank.

[anav8or]

Originally Posted by tpastorini

I am picking up my newly purchased 2014 seneca today. I am reading this thread...... are their two fuel tanks or one?

I thought you can fuel from either side into one tank.

Two separate saddle tanks - you will need to fill them both up. On our 2015, I found it worked best to fill the passenger side first and then fill the driver side.

[Robbbyr]

Originally Posted by tpastorini

I am picking up my newly purchased 2014 seneca today. I am reading this thread...... are their two fuel tanks or one?

I thought you can fuel from either side into one tank.

Like Ty stated above they are two separate tanks. The engine draws from both and returns excess fuel to both. It uses a system called "Equiflo" to keep the tanks approximately level. However the generator only draws fuel from the driver's side tank, so if you are stationary running the generator for a prolonged period you may see the driver's side tank lower, but once you drive a bit the tanks will equalize again. Also, the fuel level sender is located in the driver's side tank only.

Lastly each tank has a small vent hose that is visible on the inboard side of the tanks, it is important that those lines remain unobstructed for proper tank equalization.

The days of a bottom connecting line between the tanks to allow single-point fueling are gone, too often they would get torn off by road debris and make a big and expensive mess.

Here is a link to a simple explanation of our Equiflo system: https://rvunderground.com/jayco-sene...oes-this-work/

[tpastorini]

That must be fun at a busy station. Oh well looking forward to my new coach.

How do you switch tanks? And how do you read how much is in each one?

[Robbbyr]

Originally Posted by tpastorini

That must be fun at a busy station. Oh well looking forward to my new coach.

How do you switch tanks? And how do you read how much is in each one?

Fueling is easy, you just get in line with the semis at the truck lanes. They have pumps for both sides so it can be done quickly. Plus they (usually) have DEF on a separate nozzle so you can top it off too.

You don't switch tanks, it draws from both simultaneously. No driver intervention required. Likewise, since it self-levels the one sender in the driver's side tank displays the combined fuel level status.

But most Freightliner Seneca fuel gauges (prior to 2018.5) read artificially low. Guage might read empty but it only takes 50 gallons or less to refill. Total tank capacity is 74 gallons. If a salesperson told you Senecas have one tank they were referring to 2018.5 and newer. They have one 100-gallon tank and only one filling point.

A recommendation- Don't ever let it run out of fuel! Unlike a gasoline vehicle where you just put more in the tank and start it back up, diesels are different. They must be primed and it might even involve a tow unless you know how to correctly prime your rig.

[tpastorini]

thank you!

[tpastorini]

thanks