I've always been told that running out of gas is particularly hard on fuel injectors and pumps in modern fuel injected cars. Is this true and why?

Reason I ask, is that my daily driver (a 2004), that ran perfectly, died in the parking lot of a grocery store today. I had been really busy the last week and had driven it on empty for about 3 days, kept forgetting to stop at gas station. Today, on the way to gas station, it was running on fumes and sputtered and died. It restarted and I made to the gas station and filled it up. I drove it a mile down the road to the grocery store, and it started idling really low when I parked in the stall. I gave it gas, and it had no effect and died.

I couldn't get it to start and had to get towed home. It cranks when I turn the key, but wont start. I cranked it several times and did not smell any gasoline, which makes me think its not an ignition issue. My main suspicion is the fuel pump. Im thinking it was hard on the pump to drive it for so long on empty, and the pump died. I cannot hear it prime when I turn the key to the on position, but that could also be because the car is newer and well insulated and probably has a very quite pump. Ill get too it this weekend and probably rent an OBD tester as well.

couple of things.

the pump is cooled by fuel circulating. so yes it is hard on the pump as you run below a 1/4 of a tank.
running that long means it lacked cooling.

second, you might just be air bound at the injectors and not getting enough fuel. you might try purging the fuel rails with the schrader valve at the end and see if that helps.
either way a fuel pressure tester would be the way to go. you should be able to rent one at the parts store.

Not sure I buy into the common belief about overheatinbg a fuel pump by running low on fuel. Seems to me, if its pumping any fuel, some cooling is taking place, a pump is not likely to run long on low fuel, because when it runs out, engine stops, and there is the liability issue that would arise from an overheated pump on millions of EFI cars..

I also think the out of fuel hard restarting issue came from the old mechanical diesel injection pumps that air locked.

I've run many EFI vehicles low in fuel for years over 500K? miles, still waiting for a problem to develop, but that is of course only my experience, and I might just be lucky.

When you turn your key to the run position, typically the fuel pump runs for the first few seconds to prime the system. Usually you can do this 2 or 3 times before the computer gives up on the priming cycle, so if you're counting on this blowing the air out of the lines, this may not work. Also, many newer vehicles are now running fuel pressure regulators at the fuel tank, so the fuel system will not purge the air from the lines by cranking.

Why not, if efi injector pulses open with pressure, why does it care what comes out?

Being a fleet manager for years I can assure you the pump is done if not now soon Hit the tank with a rubber hammer and or bottom shoe firmly don' beat the snot out of it, you maybe surprised

Go to parts store and rent/borrow a fuel pressure gauge for EFI , better yet by it that way you have it on hand , that will end any speculation.

Have done the pound on the bottom of tank trick here too, to get another bit of run time on a soon to drop pump. I always keep my fuel level away from minimum in the tank because the cooling that the pump being submerged in the gas is hard to beat. (some vehicles have frame mounted tank-disregard) Have not found any injectors here that don't bleed quickly after a run out situation.

0. SAAB cars of the mid '70s would seize the fuel pump if there wasn't gas to lubricate it. My brother-in-law found out the hard way.
1. The fuel running through the pump is hardly sufficient to cool the motor. The design uses the fact that the motor is submerged in a liquid to carry away most of the heat. However, in reality I don't think that running near empty would immediately cook the pump. I've done it for long periods of time during periods of cashlessness. But I do think that running low most of the time will shorten the life of the motor.
2. The more important job of the fuel running through the pump is to lubricate the pump bearings, which are most likely plastic on steel.
3. I do not see how an electronic fuel injector would suffer damage from running out of fuel. They are pretty tough.
4. Air in the line can play havoc with fuel delivery. The factory service manual may even have a procedure to get the air out. For one thing, on older systems that used a Schrader valve, it is possible to screw the valve out to get air out of the lines quickly.
5. Old Diesel systems were far less forgiving of running out of fuel, as the fuel lubricated the close tolerances in the fuel pump and injectors.

R.

The injectors never open during the key-on prime.

We always run our cars to the 0 miles to empty stage and have never had an issue.
For the first time in six years, last week the Challenger ran out of fuel. A couple of cranks with two added gallons in the tank and she fired with no issues.
I've always wondered where all the negativity came from about modern engines running low or out of fuel.

Might have picked up enough junk from the bottom of the tank to clog the fuel filter.

Megasquirt MX3 Pro manual Ver 1.4:

"6.3.6.2 Priming pulse This curve allows you to specify an initial pulse, in milliseconds, that is fired
on the first turn of the key to clear air from the fuel lines. You can set the pulse width as a function of
coolant temperature."

A lot of cars shoot an initial pinch squirt as soon as the key is turned on. But otherwise will remain closed until they see engine rpms

The FiTech has an adjustable prime squirt(s) for cold starts,...don't remember off hand if adjustable or needed for warm start ups,...haven't received mine yet.

They are always sucking from the bottom of the tank and usually the lowest spot in the tank.

Also I run mine to well below the "E" every single time and have not had a fuel pump die on one of my rigs in 15 years even useing e-10 or e-85 in non flex fuel cars.

Seems whenever we do one for a customer it always has dirt in the tank or it was just a chevy, we replace more fuel pumps in them than all other cars combined.

One thing that no one has mentioned: When you start to run out of fuel, for whatever reason, self tuning EFI systems will see the engine start to go lean and increase the injector flow. Later, when you fix the fuel system problem the EFI system will be over rich for a period of time until it relearns.

True story:
I had a Holley HP customer who ran out of fuel on the highway. Holley systems can learn very fast and it followed as the engine leaned out and died. BUT one nice thing about the Holley software is that the base fuel table doesn't change. Learned fuel changes are stored in a "learn table" which the software overlays with the base table when running. So when the customer called saying his engine won't run because it was over rich, all he had to do was zero out the learn table. Car started and ran great.

I always figured nickle and dimeing the first quarter of the tank was as easy as the last quarter. I never understood running low on fuel.

My reason for keeping fuel in the tank comes from old carbs not liking ice in the lines in the winter.
More fuel in the tank meant less crap in the lines.
It just became a habit to keep the tank at 3/4s full.

Not true and why.

Fuel is always picked up from the bottom, through a strainer. Fuel flowing through a pump will cool it. For those that believe a pump must be submerged to live, in most pick up trucks, that means 1/2 a tank or more.

I drive all my cars and work vehicles until they are dangerously low on fuel. Like past 0 miles to empty and sitting on the pin. If I fill up and it takes 15 gallons to fill and I have a 17 gal tank, I bought too early.

Another example is, I used to car pool with a dude that would put in like $5 everytime he drove. The car was never off the pin.

I think Adam, your problem is unrelated.