Operation CHARM: Car repair manuals for everyone.

Component Tests and General Diagnostics


Draw fuel sample from bottom of tank so any water present will be detected. Sample should be free of visible contamination.

If sample appears cloudy or contaminated with water, this procedure should not be used and fuel system should be cleaned.

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

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