fill tank with car running?

Question

I know gas station stickers, and what not say you are not supposed to fill your tank with the engine running (and i'm not thinking of actually doing it) but what are the odds of this actually causing a problem? couldn't a car fill up while on the move similar to how military jets do? as long as no spark found its way into the tank, or gas supply?

Answer 1

If it's a 1996 or newer car it will turn the check engine light on period because the '96 and newer OBDII pressure sensor in the tank of every car/truck sold in the U.S. will notice a change in tank pressure to atmospheric pressure as soon as you take the gas cap off with the key on/running thinking there is a leak that could cause gas fumes to leak out. When it does come on, you pay me $85 dollars so I can tell you why it came on and clear the code. I usually only charge half price of $42.50 after talking to the customer to find out if they did indeed fill it running or left the cap loose. The two typical codes are: PO442=small leak and P0455=large leak.

I have a '69 Chevy i've put gas in with it running a billion times. One time an old man started yelling at me and went inside the station complaing to the attendent saying my dual carbs were too loud and would cause an explosion. He was talking about the dual exhaust! The attendent told him to get lost.

I pretty much shut the motor off all the time now so some soccer mom doesn't attack me next.

Getting back in the car after putting the nozzle in and then getting out to shut the pump off can cause static electricity which can cause a spark as soon as you touch the pump handle. That's alot more dangerous than leaving the engine running and I do personally know somebody that caused a fire this way.

However, I am in no way saying it's ok to leave the engine running while refueling on '95 and older cars.

Answer 2

I do it all the time and have been for about, oh .. 50 years mostly in the winter when I want to keep the heater going.

I also fill my lawnmower while it's running but that is a LOT more dangerous! (If the grass was high one tank isn't quite enough and a hot engine is difficult to get re-started on a hot day.) I let it idle for a few minutes so the exhaust gas components have cooled down to reduce the chance of a spark.

The key thing is to simply not allow gasoline fumes to find any kind a spark. The worst thing thing some idiots do is smoke near gasoline fumes. But exhaust systems on most newer cars today present no spark hazard at all from an idling engine and I think the rule is generally archaic.

Answer 3

To start with, when jets are mid air refueled, you are not talking about gas, but JP-4 jet fuel. This is similar to diesel and is not as quick to explode.

With gas, on newer cars, it is as others have said, you could set an error code on the cars computer. There is also a fuel return line that is putting the fuel back into the tank if there is excess gas going to the injectors or the pressure is too high. This will also increase the amount of vapors that are released into the air. That makes it more dangerous, and there is no sense to take the chance. If your car is a standard shift, it may roll some and pull the gas filler out of the neck. If it is an automatic shift, then it may fall out of park and go into reverse and again dislodge the hose from the filler neck.

There is no sense to have the engine running and wasting the gas while you are fueling it up. It only takes just a couple of minutes to get the fuel into the tank, why chance it?

Answer 4

I rarely shut off my car when I fill the tank, been doing that for 13 years and have never had a problem.

With todays newer cars however, there is a sensor in the fuel tank that will monitor the pressure, removing the fuel cap while the engine is running can cause your "check engine" light to be illuminated.

Answer 5

Well, I do it most of the time with my 06 Mazda Miata, never had a problem...although one time I filled up my tank in Arkansas and they didnt have an auto shut off on the hose, I walked away to find a squeegee and came back to a petrol lake under my car and horrified people all around me!!! Good thing nobody was smoking...GULP!

Answer 6

Suggest to you that vapors leaving the gas tank as you fuel up can ignite from static electricity,sparks from engine,etc,etc,etc. There is also the danger of fuel spillage ,so for sure it is a safety issue. It is more dangerous in my opinion in more ways then I have mentioned here,to fuel up while the engine is running. my suggestion is to fuel up with the engine shut off.

Answer 7

I tried this ONE time with my 2000 Buick. When I started to put the gas in and mind you this was winter and cold, it blew the gas all back on me. Some cars will allow it and some won't. I know the older ones will, but I would be afraid to do it again.==

Answer 8

safety is only 1 reason to fill your car with the engine off. newer cars will set a code turning on the check engine light if the gas cap is removed with the engine running or if you don't get it back on tight

Answer 9

I leave mine running a lot of the time while I'm fueling. It really depends, if it is really hot, I leave it running for the A/C, and the same for heat when cold.

I next to never shut off my diesel trucks when fueling.

Answer 10

yes you can fuel your car with it running its called hot fueling one of the reasons is that there can be a larger build up of vapors with the car running and being fueled at the same time. i have done it many times and i have no fear of doing it or problems with doing it