Water in Gasoline

On a friends car, we used a syphon and then the electric fuel pump to get the gas dregs, we let it stand and separate and then poured the gas back in but not the water. That worked for him. Your son may be gradually removing the water via the ethanol, but too much water to do it quickly.

Did he change the contaminated fuel filter?

If he can get a hose to the low part of the tank from the outside, he may be able to siphon out the remaining water. Clean, empty 2 liter soda bottles work well to separate out the water.

Shot in the dark.......May have nothing to do with the fresh gas.

Could it be that when the tank was dropped, it shifted the pickup line in the tank? Perhaps a problem with the connections, fuel filter, or fuel pump (in that order).

"running badly when the tank gets below 1/4"

Was this the problem before he pull and drained the tank?

Water in the gas tank would not depend on the fuel level to cause a problem.

Exactly. The level of water does not change at all with the level of gas. He could try removing (and reinstalling) the cap at 1/4 tank, to check for venting problems. Water can accumulate in the filter, but again, this has nothing to do with fuel level.

One way to make sure, would be to disconnect fuel supply at engine, (when it starts running rough), turn the vehicle over and run gas into a clear container, and do a visual inspection.

It doesn't seem like the level would matter, but if the gas is cloudy or milky, it would tell a different story. Maybe it's getting sloshed around more at the lower level.

"Turn the vehicle over"?

Be sure all loose objects are secured before turning the vehicle over, or you'll have a big mess on your hands.

Seriously, be very careful when disconnecting the fuel supply line as the gas is under a lot of pressure and could spray out all over the place.

That's true. I assume that people know these things.

I got a water soaked batch of gas in my truck one time, and it took about a month of running until it ran right again.

Since most products that are additives to remove water are alcohols of one form or the other and since he has run several hundred mile on gas with 10% Ethanol. I would think that the water in the gas problem is gone.

One other thing it mite be is sediment in the tank. The sediment would be dispersed in smaller volume of gas as the fuel level decrease.

Could be. He may have to completely remove the tank and flush it out.................or if it's sediment, a pressure test on the fuel line might be helpful.

Thanks for all the comments. He initially disconnected the fuel line from the tank and pumped gas into an outside container, about 5 gallons obviously water contaminated. He did change the filter. After pumping that gas into an outside container and changing the filter, he still had problems so he siphoned all the gas he could from the tank. He then dropped the tank, drained it and filled with fresh gas. Same problem. ?????

He may want to hook up a code reader and see if it's kicking out any malfunction codes.

Most of the parts stores will do this for free.

This new stuff is so full of sensors, etc., my trouble shooting skills are lacking.

I would bet on the fuel pump / fuel pressure hypothesis.

GA

You said it all....

I'd just take a marker and print an "E" on the 1/4 mark on the dash display. Troubles over.

Just turn the radio way up, and drive 'er till she quits.

There should be a tiny breather hole somewhere near the filler cap, if not part of it. Check that this hole is not blocked, and if it is then unblock it.

This actually depends on the car, most modern cars do not have a breather. They have a charcoal filter or similar that "catches" any fumes trying to get out of the tank on hot days for example.

Conversely, when driving, fresh air is sucked through the filter as the fuel is used up, cleaning it of the petroleum products....

No hole anywhere else for cars so built.

This is designed to dramatically reduce emissions of petroleum products into the atmosphere. I believe it has been done for around almost 20 years.....in Europe at least, maybe the USA is different?

Hopefully your son did not damage the fuel pickup in any way at the time he drained the tank. Additionally, check the pickup's filter for contamination and clogging.

Drop the tank and thoroughly empty it, to the very last drop, even if you have to waste the gas in it.

Also, thoroughly flush the fuel lines completely, and replace the fuel filter. Check the vapor relief hole in or near the cap for clogging.

I have difficulty believing it is still water (unless he has a bad dealer for his fuel). The alcohol in the new fuel would rapidly absorb any remaining amounts.

I used to fly a 1946 era aeroplane, and after a week or two of sitting on the tarmac it would accumulate a couple cc's of water in the site bowl of the fuel filter. That would be drained off and a we would also drop about ten ounces from each tank to make sure we found no additional water in the lines. (The mechanic said it was condensation that was accumulating as the tanks breathed from day and night temperature changes - keeping the tanks topped of greatly reduced the problem). However, we never had any engine roughness - perhaps it was the procedure.

I've always thought that water had an affinity for Ethanol, and binds to it.

Am I incorrect on this? Just curious!

You are correct. It is used as a desiccant. (Technically I do not if it binds or just forms a solution).

Water is not added to gasoline. Condensation can occur, contaminating your fuel but auto shops sell additives that are designed to dry out your fuel. As for the gas station that you are having a problem with, I'd call the Dept of weights and measures. His pump could be tampered with or he could be adding something to his gas to stretch his profits. I've seen this before and it resulted in the owner of the station losing his franchise. Either way, I'd report it and shop elsewhere.

I'm not sure if the water came from the gas station or from the 55 gallon drum I filled at the station. We had to stock up on gas for our generators during a 6 day power outage from a storm. Regardless, water was definately in the gas. We did remove the fuel tank and drain most of the gas. As I said in an earlier post, it was impossible to get all of the gas out of the tank due to the irregular shape of the tank. Also, none of the openings in the tank were in a low point that would facilitate complete emptying of the tank. There was a few ounces of gas left in the tank. He did replace the fuel filter. My son has gone through several tanks of ethanol gas since and the engine performance is getting better.

the pump screen could be clogged or the pump is'nt getting enough voltage to pump the fuel from 1/4 tank.. change the filter of course.