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Vehicles With Diesel Engines

  1. Turn ignition switch to "RUN" position. Place switch in "FRONT" position. Disconnect selector valve connector. Check voltage between terminals 2 and 1. If okay, go to step 2. If no voltage is present, go to step 3.
  2. Using a jumper wire, connect motor terminal 2 to battery positive post. Using a second jumper wire, connect motor terminal 1 to ground. Motor should run. Reverse jumper wires. Motor should run in opposite direction. If motor does not run in one or both directions, replace motor. If motor runs in both directions, go to step 4.
  3. Check voltage across fuse No. 7 (No. 15 on 6.9L engines) in fuse block. If fuse is blown, repair shorts in selector valve circuit. Replace fuse. Repeat test starting at step 1. If fuse is okay, check voltage between terminal 2 and ground. If okay, check for open ground circuit from motor, through switch to ground. If ground circuit is not okay, repair ground circuit. If ground circuit is okay, go to step 4.
  4. Remove selector valve switch knob and trim bezel. Remove switch mounting screws and disconnect switch from harness connector. With switch in "FRONT" position, check continuity between terminals 2 and 4, and between terminals 1 and 3. Place switch in "REAR" position. Check continuity between terminals 1 and 4, and between terminals 2 and 3.
  5. If continuity is not okay, replace selector valve switch. If continuity is okay, check continuity of Orange wire (circuit 974) and Brown/White wire (circuit 674) between selector switch and selector valve. If continuity is not okay, repair open circuits. If continuity is okay, go to step 6.
  6. On 2.3L Turbo Diesel engine, turn key to "RUN" position. Place switch in "FRONT" position and turn key off. Pinch off fuel line from rear tank to selector valve. Remove fuel hose between fuel filter and injection pump. Place end of fuel line into a container.
  7. Operate primer pump on fuel filter header to obtain a minimum of one pint of fuel. Check for a solid, continuous flow of fuel. If fuel flow is not okay, go to step 10. If fuel flow is okay, remove clamping tool and go to step 12.
  8. On 6.9L engine, turn ignition switch to "RUN" position. Place switch in "FRONT" position and turn key off. Pinch off fuel line from rear tank at selector valve. Remove vacuum purge valve from fuel filter adapter. Install Adapter (3019) from Rotunda Pressure Test Kit (19-0002).
  9. Start engine and let idle. Open clamp on sample hose, allowing fuel to flow into a container. Check for a solid, continuous flow of fuel. If fuel flow is not okay, go to step 10. If fuel flow is okay, remove clamping tool and go to step 13.
  10. Disconnect supply hose to engine at selector valve. Disconnect supply hose from front tank at selector valve. Connect 2 hoses together using a piece of fuel line. On 2.3L Turbo Diesel engines, repeat steps 6 and 7. On 6.9L engines, repeat steps 8 and 9. If fuel flow is okay (either engine), replace fuel selector valve.
  11. If fuel flow is not okay (either engine), check front fuel tank sender, sedimentor, fuel filter and fuel lines for restrictions. If restrictions are found, clean, repair or replace components as necessary. If components are okay, check fuel level. On 2.3L Turbo Diesel engine, repeat steps 6 and 7. On 6.9L engine, repeat steps 8 and 9.
  12. On 2.3L Turbo Diesel engine, turn ignition switch to "RUN" position. Place selector valve in "REAR" position and turn key off. Pinch off fuel line between front tank and selector valve. Operate primer pump on fuel filter header to obtain a minimum of one pint of fuel. Check for solid, continuous flow of fuel.
  13. On 6.9L engine, turn ignition switch to "RUN" position. Place switch in "REAR" position and turn key off. Pinch off fuel line between front tank and selector valve. Remove vacuum purge valve from fuel filter adapter. Install Adapter (3019) from Rotunda Pressure Test Kit (19 0002). Start engine and let idle. Open clamp on sample hose, allowing fuel to flow into a container. Check for a solid, continuous flow of fuel.
  14. If fuel flow is not okay (either engine), go to step 15. If fuel flow is okay (either engine), fuel supply system is okay. Connect fuel line to fuel injection pump. Remove clamping tool from front tank supply line and go to step 17.
  15. Disconnect supply hose to engine at selector valve. Disconnect supply hose from rear tank at selector valve. Connect 2 hoses together using a piece of fuel line. On 2.3L Turbo Diesel engine, repeat steps 6 and 7. On 6.9L engine, repeat steps 8 and 9. On all vehicles, if fuel flow is okay, replace selector valve.
  16. If fuel flow is not okay, check rear fuel tank sender and fuel lines to selector valve for restrictions. If restrictions are found, clean, repair or replace components and repeat step 15. If components are okay, check fuel tank fuel level and repeat step 15.
  17. Disconnect fuel return hose from engine at selector valve and insert line into a container. Turn key to "RUN" position and place switch in "FRONT" or "REAR" position (problem tank). Start engine and check for a solid, continuous flow of fuel.
  18. If fuel flow is okay, turn engine off. Connect fuel return line to selector valve and go to step 19. If fuel flow is not okay, check return line for restrictions. If restrictions are found, repair or replace as necessary and repeat step 17.
  19. Disconnect fuel return line to problem tank at selector valve. Attach a 5/16" diameter hose to selector valve return port and insert end of hose into container. Start engine and check for a solid, continuous flow of fuel.
  20. If fuel flow is okay, check fuel sender and fuel line to tank (front or rear) for restrictions. If restrictions are found, repair or replace as necessary. Run engine and check for smooth running. If fuel flow is not okay, replace fuel selector valve.
Fig 1: Ford 6-Port Fuel Selector Valve Terminals are not numbered on valve.
G201187
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