Fuel System Cleaning

WARNING: This procedure will NOT remove all fuel vapors. DO NOT attempt any repair on the tank or filler neck where heat or flame is required, as an explosion resulting in personal injury could occur.

NOTE: If the fuel is contaminated, or if there is foreign material in the tank, the tank can usually be cleaned. If the tank is rusted internally, it should be replaced.

PROCEDURE:

1. Disconnect the negative battery cable.
2. Disconnect the engine harness connector at the HEI distributor.
3. Place a dry chemical (Class B) fire extinguisher near the work area.
4. Relieve the fuel system pressure, refer to FUEL SYSTEM PRESSURE RELIEF.
5. Drain the fuel tank, refer to FUEL TANK DRAINING.
6. Remove the fuel tank, refer to COMPONENT REPLACEMENT AND REPAIR PROCEDURES/FUEL TANK AND FUEL LEVEL SENDING UNIT.
7. Remove the external fuel filter and inspect it for contamination. If the filter is plugged, replace it.
8. Locate the tank away from heat, flame or any other source of ignition. Remove the fuel level sending unit and inspect the condition of the fuel strainer. If the strainer is contaminated, install a new strainer at reassembly.
9. Complete the draining of the fuel tank by rocking it and allowing the fuel to run out of the fuel level sender tank opening.
10. Purge the fuel tank, refer to FUEL TANK PURGING.
11. Disconnect the fuel feed pipe at the in-line filter and use air pressure to clean the fuel line. Apply air pressure in the opposite direction fuel normally flows through the line. Disconnect the return line and apply air pressure to clean the line.
12. Use low air pressure to clean the pipes on the fuel level sender assembly.
13. Install a new strainer on the fuel level sender assembly, if required.

NOTE: Care should be taken not to fold over or twist the strainer when installing the sending unit as this will restrict fuel flow. Also, make sure that the strainer does not block full travel of the float arm.

14. Install the fuel level sending unit with a new O-ring gasket into the tank, and install the fuel tank. Connect the fuel level sender harness to the body harness. The fuel level sender harness must be routed below the sender unit fuel pipes. Connect all fuel lines except the feed line at the engine. Install the fuel filter.
15. Connect a hose at the fuel feed line at the engine, and insert the other end of the hose into an empty one gallon fuel can.
16. Connect the negative battery cable.
17. Put 23 liters (six gallons) of clean fuel in the fuel tank and apply 12 volts to terminal G of the ALDL to operate the electric fuel pump. Pump two quarts of fuel into the fuel can. This will purge the fuel pump and lines.
18. Remove the hose and reconnect the fuel line at the engine. Connect the engine harness connector to the HEI distributor.
19. Start the engine.
20. Check all connections for leaks. Tighten all hose clamps.