Obtaining Fuel System Sample
- Disconnect the appropriate fuel feed or return line quick-connect fitting. Refer to QUICK-CONNECT FITTINGS .
- Install the appropriate Fuel Line Adapters / Fitting from the (special tool #8978A, Decay Tool, Fuel). Route the opposite end of this hose and bottle into a clean clear container (Glass is preferred).
- Using a diagnostic scan tool, activate the fuel pump until a reasonable sample of fuel is obtained.NOTE:
The fuel sample should be taken from several locations in the fuel system. The samples should add up to approximately a cup obtained from before the fuel filter, after the fuel filter, fuel injection pump return, and fuel rail return.
- Allow the sample to sit for 10 minutes in a dust free environment to allow the debris to settle to the bottom. It is important to not allow any air born contaminates to get into the fuel sample. Do not shake, swirl, or agitate the fuel in any way. The contamination should settle to the bottom.
- The sample should be immediately checked for hard particle debris, cloudiness, color, and off odor.
- A fuel system that is contaminated with DEF fluid can be identified by the fuel appearing cloudy and may start to crystallize when exposed to air. Dirt, metal or other foreign objects can sometimes appear cloudy as well.
- Next, hold an LED flashlight under the container and slowly tilt the container towards you. Keep the LED flashlight at the trailing edge of the fuel as it comes down the bottom of the cup and inspect for contamination. Any dirt in the fuel will collect and be pulled by this trailing edge of fuel. It may be any color and sometimes looks as though the fuel is cloudy. This is the contamination. If you see ANYTHING AT ALL the fuel is contaminated.
- If no contamination is noticed, the sample should sit in a dust free environment for at least 2 hours then check for any separation.
- A fuel system that is contaminated with water can be identified by the water separating from the diesel fuel in the sample.
- A fuel system that is contaminated gasoline may not have noticeable separation as but can be identified by the smell of gasoline in the fuel sample.