Fuel Contamination
DIESEL FUEL CONTAMINATION TEST PROCEDURE
OVERVIEW
The contamination we are looking for on the clean side of the Fuel Filter is very small. We don't say dirt because it may be metal, water, plastic or any other contamination, other than clean diesel fuel. The smallest we can see with naked eye is about 30 Microns. Our Fuel Filters have a 10, 7 or now 5 Micron rating. The only way we can see this size of contamination is to properly collect it and view it. The fuel sample needs to be taken from the clean side of the system. In order to get a good clean side sample to inspect, perform the following procedure exactly.
1. CLEAN SIDE DIESEL FUEL SAMPLE COLLECTION AND INSPECTION
NOTE: The fuel filter MUST NOT be removed or replaced prior to taking sample in order to get accurate results.
NOTE: Warm the engine before collecting the fuel sample.
1. With the engine turned off, disconnect the HPDP return line from the front of the Fuel Filter housing and allow it to hang into a bucket. Refer to the figure above.
NOTE: The fuel flowing from the return of the High Pressure Delivery Pump (HPDP) MUST NOT be part of our sample. We are looking primarily for injector return fuel. The easiest way is to eliminate the HPDP return line and pull the injector return flow sample from the filter mount, on the front side.
2. Attach the four foot length of 5/16 clear tubing to the exposed male fitting that the HPDP return line was disconnected from.
3. Run the 5/16 clear tubing through the wheel well outside the vehicle to avoid contaminating the sample. Run the hose at a downward angle to help increase fuel flow.
NOTE: The engine RPMs may be raised using the Fuel Pressure Override Test in the scan tool to help increase return flow in the next step.
4. Start the engine, allow the fuel to flow out of the tube and into the bucket for 20-30 seconds before collecting the sample into the clean measuring cup. Fill the measuring cup to approximately half an inch or slightly less of diesel fuel.
5. Fill the second measuring cup near full with a sample of fuel.
6. Turn the engine off.
7. Allow the first 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.
8. Hold the measuring cup by the handle in one hand and shine the LED flashlight through the bottom of the container at the far side of the cup. Be careful not to shake, swirl or agitate the fuel in way. We want the contaminate to settle on the bottom.
9. Slowly tilt the cup toward you and keep the light 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 contaminate.
- If you see ANYTHING AT ALL, the fuel is contaminated.
10. If the first sample did not show any contamination, allow the second sample to sit in the measuring cup for at least 60 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.
11. After the sample has settled, SLOWLY pour the fuel out of the cup down to a level of a half inch or slightly less.
12. Check sample two for contamination as described above in test steps 8 and 9.
View the following repair options:
The fuel sample is found to be contaminated
- Go To 3
The Fuel Filter has recently been replaced and your injector return sample is clean (the filter did it's job)
- Go To 2
The Fuel sample is clean and the Fuel Filter has NOT been recently replaced
- The fuel is clean and no repair is needed. Test complete.
2. FUEL TANK SAMPLE COLLECTION AND INSPECTION
NOTE: Looking into the fuel tank with a flashlight will not allow you to see small contamination. The only way to see this size of contaminate is to properly collect it and view it using the following method.
1. Lower the fuel tank.
2. Remove the Fuel Pump Module.
3. Inspect the pick-up screen and the pump motor for metal debris stuck to the side because of the permanent magnets in the pump.
4. To inspect the fuel contents, lay the end of the clear tubing along the bottom of the tank. Put a loop in the tubing outside of the tank.
5. Have an assistant tilt the tank back and forth to agitate the fuel to stir up the small particles.
6. While the fuel is moving, draw fuel into the loop and siphon into a clean measuring cup until a half inch of fuel is collected.
NOTE: A hand vacuum pump can be used to start the fuel flowing.
7. 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.
8. Hold the measuring cup by the handle in one hand and shine the LED flashlight through the bottom of the container at the far side of the cup. Be careful not to shake, swirl or agitate the fuel in way. We want the contaminate to settle on the bottom.
9. Slowly tilt the cup toward you and keep the light at the trailing edge of the fuel as it comes down the bottom of the cup.
- 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 contaminate .
- If you see ANYTHING AT ALL, the fuel is contaminated.
View the following repair options:
The fuel sample is found to be contaminated
- Go To 3
The Fuel sample is clean
- The fuel is clean and no repair is needed. Test complete.
3. CLEANING CONTAMINATION FROM THE SYSTEM
NOTE: Do not use any chemical cleaners or solvents on any fuel system lines or metal components. Metal lines, rails and tubes have a coating that will be damaged by these cleaners.
1. Flush all lines with clean diesel fuel.
2. Flush the rail with clean diesel fuel and air. Both directions, multiple times.
3. Flush the connector tubes with clean diesel fuel and air. Ensure no corrosion is present inside the connector tubes or at mating surfaces.
4. Remove and flush out the Fuel Tank with clean diesel fuel. Wipe out the inside of the tank with a clean cloth. Use an appropriate fuel container. Dispose of the contaminated fuel using the proper procedures. Fuel Tank - Removal.
CAUTION: Dispose of petroleum based products in a manner consistent with all applicable Local, State, Federal, and Provincial regulations.
5. Inspect the Lift Pump Module screen for extreme dirt accumulation. Clean/flush the Lift Pump Module. Replace if necessary. (Most can be cleaned).
6. Install vent tubes on the rollover valves on the Fuel Tank to prevent water/dirt intrusion.
7. Reinstall the tank and 10 to 15 gallons of clean diesel fuel. Flash any controllers to the latest available software version (PCM/TIPM/CCN). Fuel Tank - Installation.
8. Pour half a bottle of CRC #05232 Diesel Fuel Therapy or equivalent diesel fuel injector cleaner into the Fuel Tank with the clean fuel.
9. Install a new Fuel Filter. Removal.
10. Test drive the vehicle somewhat aggressively to help the cleaner flush out the injectors.
11. Evaluate the vehicles idle quality, tip in acceleration, WOT performance, etc. while driving.
12. If the PCM was flashed or a Stationary Desoot was performed, drive the vehicle at least 30 miles to ensure that all values have stabilized before performing the validation of repair.
Perform the validation of repair below by monitoring the "Estimated Soot Load Based on Grams" with the scan tool while driving the vehicle at three different steady speed speed levels. Have an assistant drive the vehicle while you monitor the scan tool. If the soot level climbs rapidly during validation, view the "Soot Filter Delta Pressure" reading to see if the readings match indicating there is an issue. (The Soot Filter Delta Pressure reading voltage should increase as the soot level climbs if soot is actually being created).
Validation:
- Drive the vehicle with the engine warm at a steady speed of 45 MPH while monitoring the scan tool for a few minutes. "Estimated Soot Load Based on Grams" should maintain or may climb slowly.
- Raise the speed to a steady 55 MPH while monitoring the scan tool for a few minutes. The "Estimated Soot Load Based on Grams" should hold steady. A very slight climb or drop is okay.
- Raise the speed to a steady 65 MPH while monitoring the scan tool for a few minutes. The "Estimated Soot Load Based on Grams" should start to decrease slowly even though the vehicle is not in Desoot mode. This is because the latest software will actually scrub soot when driving at higher speeds.
- If the vehicle has a performance issue or is continuing to generate excessive soot while driving after flushing the system and adding clean diesel fuel, perform the CHECKING THE FUEL DELIVERY SYSTEM test procedure to diagnose damage to the fuel system. Checking the Fuel Delivery System