
Pumping gas with the car on might seem like an easy way to save a little time, but it could be dangerous! There’s a very serious risk of ignition from several different sources, which can lead to a catastrophic fire or explosion.
Letting the engine run while you pump gas can also affect the fuel and EVAP system. These can lead to some unnecessarily expensive repair bills.
If you really do need to pump gas with the car running, you need to be aware of these potential threats and things you can do to limit the risk of a serious problem.
Fire Risk of Refueling
Pumping gas while the car is running poses several fire hazard risks. Weather conditions, ignition sources, and the mechanical systems in the car itself might be enough to start a catastrophic fire. Before attempting to refuel with the engine running, consider the following ignition sources.
1. Static Electricity

The risk of static electricity becoming a fire hazard when refueling is much higher in cold, dry weather. When you get out of your car there can be a difference in the ambient static charge of your body and the fuel nozzle.
In some rare cases, this has been enough to cause a spark capable of ignition just as your hand brings the fuel nozzle to the fuel filler cap.
The Petroleum Equipment Institute notes that from 2000 to 2010, there were 176 reported fuel pump fires caused by static electricity alone!
Prevention Tip
You can prevent static electricity problems when refueling by simply touching the metallic chassis of the car. It’s a good habit to get into whether you’re pumping gas with the car on or off.
2. The Catalytic Converter

The heat of the catalytic converter, when the car is running,can be enough to ignite fuel favors or spilled gasoline when refueling. This is especially concerning when there’s no wind as gasoline vapors are heavier than air and once ignited the flames will rapidly follow back to the nozzle or the fuel tank.
Prevention Tip
Pumping gas with the car on is especially dangerous on still days with no wind. Even the slightest ignition source could follow the fuel vapors back to your car or the gas nozzle in your hand.
3. Engine Backfire

A backfire coming out of the tailpipe while pumping gas with the car on is one of the more catastrophic causes of gas station fires. This is compounded by the fact that backfires or after fires are usually due to a mechanical problem in the engine, allowing fuel to leak into the exhaust system.
If one tiny flash of flame manages to make contact with fuel vapor or spilled gasoline it could ignite. In a matter of mere moments, the flames can shoot back to the nozzle in your hand.
Prevention Tip
Regardless of whether you’re refueling with the engine running or not, even an occasional backfire can cause serious damage to your car’s exhaust system and possibly the engine.
Possible Damage Caused by Refueling with the Car On
Pumping gas with the car on can cause potential problems for a vehicle’s fuel and EVAP system. You might not notice it at first, but then the car starts acting strange a few miles down the road.
1. Fuel System Problems

Pumping gas with the car on sends a rush of fuel into the tank which can disturb tan varnish and fuel deposits on the bottom of the tank. There’s a low risk of these deposits being sucked into the fuel pump.
However, this is more likely to be an issue with an older car that’s been on the road for five years or more. Yet even a small amount of tank debris that enters the fuel system can clog an older fuel filter, or cause the solenoid to get stuck on one of the fuel injectors.
2. EVAP System Problems
Pumping gas with the car on can wreak havoc on the car’s Evaporative Emission System (EVAP). It’s designed to capture ambient fuel vaporsin a charcoal canister and release them precisely into the fuel/air mixture, rather than letting them be released into the atmosphere.
When the engine is off the valve allows vapors to move from the EVAP charcoal canister to the engine is closed. When the engine is running the ECU waits until the engine reaches the correct operating condition and then releases a precise amount of fuel vapor.
The sudden on-rush of fuel vapors from pumping gas with the car on allows those vapors to rush into the engine to a degree that the ECU might not be able to compensate for.
Not only can this temporarily affect engine performance, but it can turn the check engine light on. This will throw a code that you can pick up on a diagnostic scanner.
TIP
If you pump gas with the car on, and you get codes P0440, P0455, P0496, or P0441, you might be able to simply clear the codes using the scan tool. Then restart the engine and go for a short drive to let the ECU rebalance the fuel/air intake.
If you get codes P0446 or P0442, or one of the previous codes pops up again after clearing the stored codes, then refueling with the engine running likely damaged something in the EVAP system.
Regulations Against Pumping Gas with the Car On
Most states have laws prohibiting pumping gas with the car on. However, there are very few if any criminal codes.
The gas station attendant has the right to refuse sale to anyone who doesn’t comply with regulations. So, the most likely thing is they will shut the pump down and you’ll be asked to leave.
If you don’t pay for whatever gas has been dispensed and leave peacefully, they will be within their rights to call the police.
What to Do in a Gas Station Fire
If you’re refueling with the engine running, and a fire starts, try to release the handle to stop the flow of gas, but leave the nozzle in the car. While also telling everyone to vacate the car immediately.
Then turn off the automatic shut-off switch or yell for someone close to do it. Immediately call 911, and alert the gas station owner, while telling any other bystanders to get away.
Most fuel pumps have fusible links built into the hose, nozzle connection, or dispenser. The intense heat of a fire often seals the line, which disengages pressure. However, this isn’t always the case and the fire can spread. Especially if you spilled gasoline on the pavement.
Frequently Asked Questions
What are good reasons to pump gas with the car on?
You should only consider refueling with the engine running in an emergency situation. This includes things like trying to get your car to a mechanic while nursing a dying battery, alternator, or a bad starter motor, where the car likely won’t restart. Otherwise, the wise move is always to turn your car off before pumping gas.
How can I reduce the risks if I need to pump gas with the engine running?
If an emergency situation forces you to pump gas with the car on, there are some things you can do to reduce fire risks. This starts with pulling up to the outer-most fuel pump, where there is likely to be the most breeze to blow away ambient fuel vapors.
When you step out of the car make sure to touch the body of the vehicle to discharge any static electricity that might have built up. Do not smoke, and let the engine settle to it’s lowest idle.
Prepay at the pump before touching the nozzle or any other control panels. Then open the gas cap and allow a few seconds for any outrushing air to settle. In some cars, this will cause the EVAP valve to close due to the change in pressure.
Then insert the nozzle deep into the fuel filler, and pump only as much gas as you need to get home or to the mechanic. Remain with your hand on the pump and do not reenter the vehicle.
How common are gas pump fires?
The National Fire Protection Association notes that from 2014 through 2018, local fire departments responded to an estimated average of 4,150 fires in or on service or gas station properties per year. Of these 56% were vehicle fires caused by either mechanical failures malfunctions, or electrical malfunctions. Within these incidents, 7% were caused by fires at the pump or nozzle.
Conclusion
Pumping gas with the car on is something you should only do in an emergency. The risk of a catastrophic fire isn’t worth taking just to save a few seconds or to keep the AC running while you refuel.
Not to mention the very real risk of causing a problem with the fuel or EVAP system. The potential repair cost of these problems can be $200 or more!
If you absolutely must refuel with the engine running, try to park at an outside pump where the breeze can blow away fuel vapor. Then make sure to touch the car to release any static electricity before touching the gas pump. Always stay with your hand on the nozzle, and do not go back into the car for anything until you’re done pumping gas.
If a fire does start, leave the nozzle in the fuel filler port, have everyone evacuate the car, and activate the pump shutoff switch. Then notify the gas station attendant while calling 911.

Written By
Jason Farrell
Jason Farrell is a certified master technician, the editor of Mechanic’s Diary in Pittsburgh, Pennsylvania. He is ASE (Automotive Service Excellence) certified and earned a Bachelor’s Degree in Automotive Technology from Pittsburg State University. With nearly 18 prior years of experience in the automotive field, he has extensive knowledge about Domestic, European, and other foreign makes and models of cars and light trucks. Jason’s experience working as a technician and service manager at dealerships, gave him the experience and know-how of most aspects of inspection, diagnosis, and repair from engine and drivability to electrical, HVAC, brakes, steering and suspension and everything in between.