Alcohol/Contaminants-In-Fuel Testing Procedure

DESCRIPTION
The concentration of alcohol-in-fuel can be detrimental to the fuel system. Higher than recommended alcohol-in-fuel concentrations may cause driveability problems such as hesitation, lack of power, stall, no start, etc. High concentrations may also cause corrosion of the fuel system components and subsequent fuel filter plugging as well as deterioration of the rubber and the plastic components.

Commercial automotive fuel can contain alcohol in various types and levels of concentration. Some forms of alcohol are more detrimental to the fuel system components than others. If an excessive amount of alcohol-in-fuel is suspected as the cause of a driveability problem, the following procedure can be used to detect its presence. This procedure uses water to extract the alcohol from the fuel. The specific type of alcohol contamination cannot be determined from this test.


SAMPLING PROCEDURE
The fuel sample should be drawn from the bottom of the tank so that any water present in the tank 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 and the fuel system should be cleaned.

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

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