I usually keep my truck fairly topped off. Rarely, if ever, is it below 1/4, and it is usually above 1/2.

Within the past six months or so, it does seem as if the gauge is not as consistent as it used to be; reading FULL for a lot longer than it used to, and then instantly dropping to 1/4 for a while before reading around 1/2 like I might expect after that much driving.

Last week, it wouldn't start (I think I may have had around 1/4), acting as if it wasn't getting fuel (hard pedal). After I verified that my fuel valve was open (I have a manual cable that push/pulls it) I tried starting it again, and it took a minute, but it finally lit off and ran. Coincidentally, I topped off the tank at the same time, not knowing what may have caused that problem. It ran just fine all week since...

Until yesterday morning. I just returned from an 800-mile trip with a loaded trailer, so was using more fuel than usual. But I still topped off along the way from my cans, though finally adding what is usually not much more than I need to make it back home. So yesterday, the morning after returning home, the truck started enough to move the trailer 10 feet and then it sputtered and died, and would not restart, with a hard pedal telling me it was not getting fuel.

Only six months ago, I had to replace the lift pump (with a Cummins OEM part), and that, too, happened right after the long trip to Texas with that big trailer, which gave me just enough coincidence to really confuse me.

I unscrewed the fuel filter and found it only half-full of fuel. I topped it off and resecured it. It still would not start. I added five gallons of fuel to the tank. It took it a minute, but I could tell it made a difference, and then it sputtered to life. Within seconds it was purring like a kitten again.

Today, I filled the fuel tank from a metered pump at a legitimate fueling station. It took only 22 gallons to fill it. I figure I added 4-6 gallons just before I got it to start. Which means it only took 26-28 gallons to fill the tank, which is 35 gallons, right?

So I was not out of fuel, but it acted as if it was. There was even 3/16 - 1/4 showing on the gauge when I returned home from the trip, and the low-fuel light came on only a few miles before I got home, which is usually 30-50 miles remaining.

So, with all that information, do I have a possible pick-up tube failure inside the tank? Does my tank use a pick-up tube?

 

Its possible the module is broken inside. There is three plastic legs on the top half that the lower module bolts onto. My 24v had a broken module when I opened it up to install my Espar. It never affected either my readings or fuel suction. Lift the bed and pull the module and see whats what inside. Could be a module that is broken, or a cracked draw straw. The one in my trucks are plastic, so they do flex.

 

There is a screen at the bottom of the pickup (about the size of a hockey puck, bit smaller) and mine was plugged solid when I cleaned it all out last summer. With the fuel gauge level issues as well it does sound like a broken "module".

I had to lift the bed myself so I used a come-along and a tree, worked great for reaching the top of the tank.

 

Get a friend to pick up the bed and and stuff some dunnage between it and the frame rails. Then you can work easily. Just make sure to disconnect the fuel filler neck first.

 

Some of the earlier tank modules were put together with sharp self tapping screws that could poke a hole in the pickup tube.
When that happens the lift pump can only suck fuel down to the level of the hole.

 

I was having problems with my 98 24v and ended up rebuilding the fuel pickup canister.....I don't know for a fact but I suspect the canister is the same. Sounds like the screen through which the pickup is suppose to pull fuel is restricted and when you add enough fuel it starts to spill over the top of the canister's sides.
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