[Shiny35]

What I mean is that when the truck "thinks" there's zero miles till empty, after awhile it will cut power for about two seconds, then be normal for six or seven, then cut out, then normal, etc., until the 'miles to empty' updates to anything above zero. I have a TransferFlow tank in the bed- and it reads the factory gauge, often telling me I have a half a tank yet the truck hasn't updated and I end up with this issue while going down the road. The TransferFlow gauge is accurate- verified by how much I can pump in the factory tank. Just the truck's cluster doesn't update near quick enough on some long hauls.


Is there any way to either disable this "hey dummy you're about to run out of fuel feature" or force the damn thing to update the fuel gauge/miles to empty faster? I can manually pump more fuel in as I'm going down the road, but it's kind of a pain in the *** and not a very fast method with the small pump on the TF tank setup.

I have FORScan and a cable, if there's something I can modify that way. Probably not, I'm sure.

I have 104 gallons total capacity but it's tricky to run it more than half empty on a trip.

Even when I manually pump fuel into main tank, like 25 gallons even, the gauge will eventually read near full, but fifty miles down the road it's back down toward empty probably based on what kind of **** mileage it thinks I'm getting or something.

Thanks for any insight, sorry for the novel!

 

[bismic]

Sounds like more of an issue with your fuel level sending unit. After 25 gallons added, it should not be near empty. That would be 2 mpg, I doubt you are getting that. It shouldn't be slow to react either.

As to the request on disabling the low fuel level software, sorry I can't help there.

 

[Shiny35]

Here's the thing though. The TransferFlow setup I have has an LCD readout that shows how many gallons are in both the main and auxiliary tanks- it uses the factory in tank sending unit- and it's accurate. Like dead on accurate, always. That tells me the sending unit itself is fine.

I appreciate your reply. This is probably just something I'm gonna have to live with.

 

[backhoebill]

I have owned a few 6.0 trucks, and have run them down well past the “zero miles to E” a couple of times. Started missing, and took a couple of cycles to start again after fueling. If there is a low power mode for low fuel, my trucks were not aware of this. I would look at fuel delivery/filtration, or accuracy of actual fuel available.


Sent from my iPhone using Tapatalk

 

[bismic]

Here's the thing though. The TransferFlow setup I have has an LCD readout that shows how many gallons are in both the main and auxiliary tanks- it uses the factory in tank sending unit- and it's accurate. Like dead on accurate, always. That tells me the sending unit itself is fine.

I appreciate your reply. This is probably just something I'm gonna have to live with.

So is a splitter used to send the fuel level information from the OEM tank to both the PCM and Transferflow display?

 

[bismic]

I have owned a few 6.0 trucks, and have run them down well past the “zero miles to E” a couple of times. Started missing, and took a couple of cycles to start again after fueling. If there is a low power mode for low fuel, my trucks were not aware of this. I would look at fuel delivery/filtration, or accuracy of actual fuel available.


Sent from my iPhone using Tapatalk

Some years and some calibrations have it. I am not sure which do and which don't though. It actuates well after the low fuel light comes on (or it should). DTC P115A may or may not be thrown.

 

[Shiny35]

The TF is piggybacking the factory sending unit wires, and does not give any information to the truck's PCM, from what I understand. I can power down the TF and the truck has no idea it's even there- gauge operates just the same either way.

As for backhoebill's comment- this isn't a misfire, it's literally as if I'm pulling my foot off the accelerator. The first time this happened I thought it was that- actually running out of fuel. But it isn't, it's just the computer trying to warn me I am going to- even though I'm not. Under certain conditions, I can have a gauge read below 1/4 to near empty, miles to empty at 0, transfer flow shows 25 gallons in tank, and if I stop to fuel up manually at the pump- I can only pump in 4 gallons. There's fuel in there.

Damn Ford programming lol

 

[bismic]

Are you sure it isn't in the wiring that was done to "piggyback" the TF system? I have never added a tank to any of my trucks, so I don't know what was done to get the TF system display functional. Since there was no splitter/adapter connector apparently, I guess I should ask - did you have to cut wires then? If so, then I would think that that is the cause of your issue.

 

[Shiny35]

I did have to cut a wire from the sending unit. But I just sat here and tried a few things out while watching the gauge and numbers and I suspect I’ve got a dead spot between half and probably three quarters/full area on the sensing unit. Dang it.

That would make some sense, as the TF is designed to draw both tanks down together, rather than have main tank go empty and then refill all at once. It’ll burn a few gallons then refill a few, repeat until both tanks are empty. So the sending unit is doing a lot of work until everything gets down half way. And I really don’t ever use more than 50-60 gallons before I refill everything. This cycle happens near daily.

Now how bad is it to drop the tank? I only worry about the fuel lines. The rest of that process is easy enough. Prefer that over raising bed cause the other tank is in there and a fifth wheel hitch with in bed rails and everything else.

 

[Shiny35]

Gonna recheck those wires before anything else of course.

 

[bismic]

It may not be an installation issue of the TF wiring - but certainly worth checking. The way the fuel tank level works is on a variable resistor controlled by the position of the float arm, then interfacing with the instrument cluster. High resistance means a high fuel level. Low resistance means a low fuel level.

It may turn out to be a cluster issue.

 

[Shiny35]

Thanks for that bit of info.
Could very well be the cluster too, I am plagued with Messages of “trailer disconnected/TBC Error” though that seems to actually be the TBC. (Still operates brakes fine)

I will also add that there is actually a code present for P115A- Low Fuel Level- Forced Limited Power

 

[Hydro]

Since this an almost daily instance, leave ForScan connected and monitor the fuel level
set it so that it registers min / max and look at the results when you are stopped

maybe you can figure if it is the sending unit or a rubbed wire

the "modern" fuel is very corrosive to metal parts if any moisture is mixed in, so you may find the sending unit is almost rotted off

 

[bismic]

Not surprised at the code .

 

[Shiny35]

Well it turns out I am dum. Janky connection at the back of the TF display.

Even though the TF does not send any 'modified' data to the pcm, it does relay the fuel float signal- float to TF was a good connection, and thus the TF display was accurate- but the TF to PCM wire was not making good contact so the PCM and therefore gauge cluster weren't getting good data at all times.


711 miles today, everything worked as it should. I appreciate everyone's input and patience working with the mentally handicapped!