Originally Posted by CarpeDiem

Any issues will depend on the mileage on the vehicle (number of tank fills), where and when you get your fuel (was the station high volume/was the buried tank filled recently), and how often you run the tank down low - I assume you don’t run until the engine actually quits. The empty mark on the gauge is not zero gallons left in the tank so you may have never actually used the last few gallons. Current high pressure fuel systems are more prone to dirty fuel issues compared to vehicles from ten years ago or earlier. In addition a plugged fuel filter may very be difficult for the driver to diagnose unless he runs at WOT often.

The last few gallons are intended to be “sacrificial” to protect the fuel system. Running the tank down very low has two potential problems: sucking up dirty/wet fuel, and compromising fuel pump cooling in hot weather.

Originally Posted by GTThurston

Sacrificial is the perfect word to use...here in New Zealand we use litres and kilometres, even though I was taught to never let my tank get below 1/4 due to moisture and sediment. Sediment comes from petrol stations. Heed the advice of CarpeDiem and keep your tank about 1/4 full at all times.

Originally Posted by redpoint5

I expected people to say "you're the dumb one for wanting a thing to work correctly", which is why I wanted to solicit the experience and knowledge of a dedicated forum. My expectation is that a dealership would waste several days of my time either telling me there's no problem, or throwing the wrong parts at the car because they can't understand that 13 is less than 15 (gallons).

Fuel capacities are spec'd at what they will deliver, not some larger amount that cannot be used.

My 2nd fill-up in the car, I drove 406 miles and filled 14.4 gallons and got 28 MPG. According to specs, I had 1 gallon of fuel remaining, which explains why I didn't run out. Since then there have been several occasions where I fill with more than 14 gallons, each time going past the estimated range remaining.

On 3 occasions now, the car ran out of fuel with estimated range remaining above 20 miles. One of those occasions I was showing 1/4 tank and the low fuel light wasn't on. Car died and I pulled to side of the road. It would start, run for a few seconds, then die again. I did that half a dozen times, and on the last attempt I got enough speed going to rock sharply side to side, and that allowed me to make the next fuel station 20 miles away.

I have 2 pieces of evidence suggesting I'm not getting full use of the capacity:

1. I pumped only 13 gallons into an empty tank, which should have a capacity of 15.4 gallons.
2. My fuel economy was 27 MPG on my most recent trip, and I ran out of fuel at 352 miles. 352 miles / 27 MPG = 13 gallons of fuel used.

These 2 methods of determining how much fuel was used perfectly support each other, making it highly likely I'm not getting all the fuel I'm supposed to, not that there's a gauge malfunction.

There's some chance I'm interpreting things incorrectly, but I don't think so, and am completely open to all hypothesis. Mostly I'm interested to know how fuel is collected from the tank and delivered to the engine, and a poorly detailed schematic doesn't inform my understanding well enough (which again is why I'm on the forum and not easily solving my own problem).

It's a fleet vehicle, so I have little incentive to put my own effort into this, except that I'm curious and like to solve problems. I might pop the fuel pump out and put an inspection camera in the tank to see what's going on... but I'm at 57k miles and it should be under warranty still.

EDIT: A Youtube video shows the fuel pickup tube is attached very low on the fuel pump. Perhaps this has detached and I'm only pulling fuel directly from the pump, and not from the hose that sits lower in the tank. The fuel hose in the tank isn't listed in any parts diagrams I'm finding.

https://www.youtube.com/watch?v=tvtfm_3k1bI

Originally Posted by grim_reaper

I can confirm its is possible to upset or miss-position the fuel float when refitting the fuel pump assembly. I've probably replaced a hundred pumps myself as part of this recall.
If you don't insert the pump assembly back into the tank at the right rotation it is possible to cause interference of the float.

Originally Posted by Callisto

The issue of debris in fuel tanks was somewhat resolved by most all auto manufactures having more than one fuel filter. The biggest problem with not servicing the fuel system filters was not the fuel pumps failing as much as with fuel injector being contaminated which would either reduce or just flat stopping the fuel injectors proper operation. Aside from extreme water content it is very difficult to clog a fuel filter and most debris sinks and rest at the bottom of the tank below the lowest pick point of the fuel pump pick up. This is why fuel filters should be serviced as per the schedule set by the auto manufacturer or sooner.