How Do I Re-Gas an Out of Gas Fuel Injector Vehicle?

by Richard Rowe

Running out of gas is inconvenient and embarrassing, but at least your car will be easy to start again if you have fuel injection. Unlike old carbureted vehicles, fuel injected cars almost always use an electric in-tank fuel pump that simplifies the restart procedure. The steps are a little different, but the object remains identical: prime the pump and get fuel back into the engine.

Gassing and Priming

The first and only step that many people will need to take to restart a fuel-injected engine that has run out of gas is to simply add enough gasoline to the tank to submerge the pump (usually 1 to 2 gallons). Once the pump's pickup is submerged in fuel, you need only turn the key to the on position and listen for a loud mechanical hum that suddenly goes quiet. Three to five seconds after that hum subsides, the pump is primed and is ready to begin its standard duties.

Starting

With the pump primed, you'll still have a bit of air in the system that must be purged. There are two schools of thought on purging: "floor it" and "bump it." The "bump it" school says to start the car as you normally would (without applying any throttle) and wait for the system to purge itself. However, this approach assumes that air trapped in the fuel rails will distribute evenly. A better solution is to floor the gas while you attempt to start the car, and ease off to about half throttle while the engine begins to fire. As the engine stutters to life, gently feather the throttle pedal from the half to 3/4 throttle position and back again. This approach causes the fuel injectors to go wide open, purging the system much faster than starting as you normally would. Once the engine is running, hold it at about 2,500 RPM until all stuttering ceases and the car can idle on its own.

Rocking

If you ever find yourself in the position that you cannot add more than 1/2 to 1 gallon of gas, fear not; almost all fuel pumps use a pickup that mounts at the rear of the tank. If you cannot add enough fuel to fully submerge the pump in level ground, try having an assistant sit on the edge of your trunk lid and gently bounce up and down. Their weight alone will cause the car to squat, submerging the pump pickup in sloshing fuel. The gentle bouncing is to give the fuel puddle that little bit of extra height needed to prime the pump. Your assistant can cease their hopping when the engine begins to fire. Most fuel injected cars are designed to run for a little while after that fuel puddle runs dry, so even this small amount should get you 5 to 10 miles closer to a gas station.

Starting Fluid

A note on "Starting Fluid" (Ether): this stuff is designed for engines with mechanical fuel pumps, which yours probably doesn't have. Spraying ether into a fuel injected engine is more likely to result in a massive and dangerous backfire than it is to facilitate starting.

About the Author

Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.

Photo Credits

  • photo_camera speedometer image by Joy Fera from Fotolia.com