With a fuel injected car, when the gas tank becomes empty and the engine stops, is there any special procedures needed to restart the car once fuel has been added again? An in-law says one needs to remove the tank and to get the fuel pump going again!! Also, is there any harm to the fuel pump when the gas is out?
When I ran out of gas in my 2000 Blazer, AAA came out and put in 2 gallons to get me to the nearest gas station. The truck started right up with no problem. It’s not good for the fuel pump to run out of gas so it’s best not to make a habit of it.
No, there’s nothing special you have to do. Just put some gas in the tank and the engine should start. I’d turn the key to “ON” and wait 5 or tens seconds to give the fuel pump time to pressurize the system, but it should start.
The fuel pump is submerged in gasoline in the tank. The gasoline serves as a coolant for the fuel pump, so running the tank extremely low on fuel can allow the pump to heat up more than it normally would. If this were happening on a regular basis it could shorten the life of the fuel pump.
I normally recommend that people not let the tank get lower than the 1/4 mark on the gauge.
Make sure there is enough gas to cover the fuel pump. That’s all. Start it up and drive. Old wives tales are hard to put to rest.
“I’d turn the key to “ON” and wait 5 or tens(sic) seconds …”
That would be a waste of 3 to 8 seconds, since the fuel pump is only energized for about 2 seconds. If the engine isn’t running by then the pump is turned off.
A more appropriate approach might be to turn the key to the “Run” position for 2 seconds, then turn it off and repeat two or three times before attempting to start the engine.
Your in-law probably thinks that the pump needs priming. And who knows, maybe there is/was a car somewhere, sometime where the in-tank fuel pump needed to be primed by pouring fuel into it. But in general fuel pumps and other pumps that sit in the fluid to be pumped are said to be self priming. I know that’s true because the internet told me so. Does that trump an in-law?
Conventional wisdom says that routinely running the fuel pump when the fuel is low is bad for the fuel pump which is cooled and lubricated by the fuel it is pumping. Could be, however given the possible consequences of a pump in a tank full of gasoline fumes deciding to burst into flames from overheating, one wonders just how true that is. I can guarantee you that by now, any possible source of actual information is buried in huge volumes of stuff that people just made up. Unless you wish to instrument a fuel tank and run some tests, there’s probably no way to tell.
As others have said, the pump self-priming and modern cars have a fuel return line that should clear any air out of the system. Some diesels have/had a sort of dead-end fuel injector rail that you had to bleed air from if you ran it out of fuel, and some older gasoline fuel injection systems may have had the same set up, but I think all the new ones don’t have that issue.
While running the tank empty is not good for your fuel pump, once or twice probably won’t hurt it. I’ve only run a submerged pump fuel injected system empty once. That was on my motorcycle, but the basics are the same. I did that 10 or 15 years ago and I’m still riding the same motorcycle with the same fuel pump.
Some/many new cars no longer have a fuel return line.