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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC P42 Commercial Chassis 🢒 Engine 🢒 Engine Controls - 6.5L (L57) 🢒 Contamination Testing

Contamination Testing EFI

This procedure checks for the presence of water and gasoline in the diesel fuel that may cause the injection pump and the nozzle to incur damage.

  1. Remove the fuel filter element.
  2. Inspect the fuel filter element.
    3. • If water, gasoline or fungi/bacteria are not present, end the inspection.
    • If water, gasoline or fungi/bacteria are present, Go to Fuel System Cleaning .
  3. Cleaning the water from the Fuel System.
    4. • Disconnect the batteries.
    • Drain the fuel tank.
    • Remove the fuel tank. (Refer to Fuel Tank Replacement).
    • Remove the fuel sender unit. (Refer to Fuel Sender Assembly Replacement ).
    • Inspect the fuel tank and the fuel sender for rust, fungi or bacteria.
    • Clean the inside of the fuel tank and the fuel sender with hot water.
    • Dry the fuel tank and the fuel sender with compressed air.
    • Disconnect the ends of the following lines.
       - The lift pump suction line
       - The lift pump feed line
       - The fuel filter outlet line
       - The fuel filter drain line
       - The fuel return line
    • Inspect each of the pipes and replace any rusted pipes.
    • Clean the inside of the fuel filter housing.
    • Dry the inside of the fuel filter housing with compressed air.
    • Dry the inside of each line with low pressure air.
    • Remove the FUEL SOL fuse from the fuse panel.
    • Install a new fuel filter element.
    • Install the fuel sender and the fuel tank (add clean diesel fuel to ¼ full).
    • Reconnect the following lines.
       - The lift pump suction (both ends) lines
       - The lift pump feed (both ends) lines
       - The fuel filter drain line
       - The fuel return (at injection pump) line
    • Connect the fuel filter outlet and the fuel return line at the fuel sender to the hoses that flow to the metal containers.
    • Connect the batteries.
    • Use the Scan Tool in order to command the lift pump ON.
    • Operate the lift pump until the clean fuel flows from the fuel filter outlet into a metal container.
    • Connect the hose from the fuel filter outlet to the injection pump inlet.
    • Open each injection line at each nozzle end.
    • Crank the engine until the clean fuel flows from it.
       - Use two wrenches when loosening the injection line fittings.
       - Allow a maximum of 15 seconds cranking time, followed by 1 minute of cranking motor cooling time.
    • Use two wrenches in order to tighten each injection line fitting at its nozzle.
    • Install the FUEL SOL fuse in the fuse panel.
    • Start the engine.
    • Allow the engine to run for 1 minute while the fuel flows from the fuel return line into a metal container.
    • Stop the engine.
    • Connect the fuel return hose to the fuel sender.
    • Clean the engine of fuel spillage.
    • Fill the fuel tank and add a biocide, if needed.
  4. Cleaning Gasoline from the Fuel System.
    5. 4.1. Drain the fuel tank.
    4.2. Fill the fuel tank.
    4.3. Remove the FUEL SOL fuse from the fuse panel.
    4.4. Remove the fuel filter outlet.
    4.5. Connect the fuel filter outlet to a hose that flows to a metal container.
    4.6. Use a Scan Tool in order to command the lift pump ON until the clean fuel flows from the fuel filter outlet into a metal container.
    4.7. Connect the hose from the fuel filter outlet to the injection pump inlet.
    4.8. Install the FUEL SOL fuse in the fuse panel.
    4.9. Attempt to start and run the engine for 15 minutes (If the engine does not start, purge the injection system).
    4.10. Stop the engine.
    4.11. Clean the engine of fuel spillage.
    4.12. Clear the engine DTC(s).

Contamination Testing MFI

This procedure checks for the presence of water and gasoline in the diesel fuel that may cause the injection pump and the nozzle to incur damage.

  1. Remove the fuel filter element.
  2. Inspect the fuel filter element.
    3. • If water, gasoline or fungi/bacteria are not present, end the inspection.
    • If water, gasoline or fungi/bacteria are present, Go to Fuel System Cleaning .
  3. Cleaning the water from the Fuel System.
    4. • Disconnect the batteries.
    • Drain the fuel tank.
    • Remove the fuel tank. (Refer to Fuel Tank Replacement).
    • Remove the fuel sender unit. (Refer to Fuel Sender Assembly Replacement ).
    • Inspect the fuel tank and the fuel sender for rust, fungi or bacteria.
    • Clean the inside of the fuel tank and the fuel sender with hot water.
    • Dry the fuel tank and the fuel sender with compressed air.
    • Disconnect the following lines.
       - The lift pump suction line
       - The lift pump feed line
       - The fuel filter outlet line
       - The fuel filter drain line
       - The fuel return line
    • Inspect each of the pipes and replace any rusted pipes.
    • Clean the inside of the fuel filter housing.
    • Dry the inside of the fuel filter housing with compressed air.
    • Dry the inside of each line with low pressure air.
    • Disconnect the engine shutuff solenoid connector located on top of injection pump.
    • Install a new fuel filter element.
    • Install the fuel sender and the fuel tank (add clean diesel fuel to ¼ full).
    • Reconnect the following lines.
       - The lift pump suction (both ends) lines
       - The lift pump feed (both ends) lines
       - The fuel filter drain line
       - The fuel return (at injection pump) line
    • Connect the fuel filter outlet and the fuel return line at the fuel sender to the hoses that flow to the metal containers.
    • Connect the batteries.
    • Crank the engine until clean clean fuel flows from the fuel filter outlet into a metal container. Limit cranking to 30 seconds with 1 minutes between cranking intervals.
    • Connect the hose from the fuel filter outlet to the injection pump inlet.
    • Open each injection line at each nozzle end.
    • Crank the engine until the clean fuel flows from it.
       - Use two wrenches when loosening the injection line fittings.
       - Allow a maximum of 15 seconds cranking time, followed by 1 minute of cranking motor cooling time.
    • Use two wrenches in order to tighten each injection line fitting at its nozzle.
    • Install the engine shutuff solenoid connector.
    • Start the engine.
    • Allow the engine to run for 1 minute while the fuel flows from the fuel return line into a metal container.
    • Stop the engine.
    • Connect the fuel return hose to the fuel sender.
    • Clean the engine of fuel spillage.
    • Fill the fuel tank and add a biocide, if needed.
  4. Cleaning Gasoline from the Fuel System.
    5. 4.1. Drain the fuel tank.
    4.2. Fill the fuel tank.
    4.3. Disconnect the engine shutuff solenoid connector located on top of injection pump.
    4.4. Remove the fuel filter outlet.
    4.5. Connect the fuel filter outlet to a hose that flows to a metal container.
    4.6. Crank the engine until clean clean fuel flows from the fuel filter outlet into a metal container. Limit cranking to 30 seconds with 1 minutes between cranking intervals.
    4.7. Connect the hose from the fuel filter outlet to the injection pump inlet.
    4.8. Install the engine shutuff solenoid connector.
    4.9. Attempt to start and run the engine for 15 minutes (If the engine does not start, purge the injection system).
    4.10. Stop the engine.
    4.11. Clean the engine of fuel spillage.
    4.12. Clear the engine DTC(s) if necessary.