Ethanol Fuel Water Contamination

I have a barrel of E100 that I think may have water contamination… Car is running a bit rough and the ethanol content analyzer is reading all over the show… What is the best way to test this? And is there is an easy method to dry it? Molecular sieves or the likes?

Also how hygroscopic is ethanol really? If I were to leave a drum pump fitted to a drum, would the small amount of air able to enter ruin in the fuel in say 3 months?

I have also heard some people saying that the GM/Continental analyzers have quite a large reading offset? Like 10% over actual.

Thanks

Hi. When I need to dry the water out from fuel tank I use acetone - it's very hygroscopic. 100- 150 millilitres are added to the tank every morning for a couple of days. But that works with reqular petrol fuel, I never tried it on ethanol...

Hey Richard,

Is this a new setup or something you have run for a while that suddenly has issues? Have you checked through the ethanol tuning course section titled 'Measuring Ethanol Content'? There is some information regarding fuel flow issues in there which may be relevant/worth double checking: https://www.hpacademy.com/dashboard/courses/ethanol-and-flex-fuel-tuning/

For your specific question though I can't be of much help. We've had barrels E100 and E85 last for over 12 months down here in Queenstown as well as fuel left sitting in the tanks of cars for the same amount of time without issue, but it's pretty dry here and we don't leave a pump attached and instead put the lid back on when we've grabbed what we need.

Even with a pump or the lid off, it would be really hard to put a specific time frame on how long it would take for serious contamination to happen in a meaningful way for any location and weather history.

Generally if the ethanol was very contaminated the car would also be more difficult to start or not start at all, which is another data point that might help you troubleshoot this.

For testing, we haven't used anything other than the sensor in the car, but you can send a sample to a testing lab or try some DIY options like the graduated cylinder test or density measurement methods, etc.