Alcohol/Contaminants-In-Fuel Testing Procedure

DESCRIPTION
Certain driveability complaints such as hesitation, lack of power, stall, no start, etc. may be caused by an excessive amount of alcohol in the fuel. The complaints may be due to fuel system corrosion and subsequent fuel filter plugging, deterioration of rubber components such as the O-Rings.

Various types and concentrations of alcohols are used in commercial gasoline. Some alcohols are more detrimental to fuel system components than others. If an excessive amount of alcohol in the fuel is suspected as the cause of a driveability condition, the following procedure may be used to detect the presence of alcohol in the fuel. In this procedure water is used to extract the alcohol from the fuel. However, the specific type of alcohol (ethanol or methanol) will not be determined by this procedure.

The fuel sample should be drawn from the bottom of the tank so that any water, if already present, can be detected. The sample should be bright and clear. If the sample appears cloudy or contaminated with water as indicated by a water layer in the bottom of the sample, this procedure should not be used. The fuel system should then be cleaned.

TESTING PROCEDURE
- Using a 100 ml cylinder with 1 ml graduation marks, fill with fuel to the 90 ml mark.
- Add 10 ml of water to bring the total fluid volume to 100 ml and install a stopper.
- Shake vigorously for 10 to 15 seconds.
- Carefully loosen the stopper and release the pressure.
- Close the stopper and shake vigorously again for 10 to 15 seconds.
- Carefully loosen the stopper to release the pressure.
- Put the graduated cylinder on a level surface for approximately 5 minutes to allow time for adequate liquid separation.

If alcohol is present, the volume of the lower layer (which would now contain both alcohol and water) will be greater than 10 ml.
For example, if the volume of the lower layer is increased to 15 ml, it will indicate at least at least 5 percent alcohol in fuel. The actual amount of alcohol may be somewhat greater because this procedure does not extract all of the alcohol from the fuel.