Fuel Line Pressure/Pressure Valve
- Connect pressure gauge 5011, See Fig 1 . Turn ingintion off. Hold a piece of absorbent paper underneath fuel line to prevent spillage. Connect gauge between fuel line and fuel distribution rail. Use hose 5116 and adapter 5265, See Fig 1 . Plug gauge hose with 5266, See Fig 1 . Turn gauge cock to position 1 (pointing towards hose 5116), See Fig 1 .
- Check main fuel pump and tank pump. Remove panel from right-hand of footwell. Disconnect main relay. Connect a bridge wire across terminals 30 and 87/2, See Fig 2 . Fuel pump is easiest to hear. To check tank pump, remove fuel tank lid and listen.
- If neither pump operates, disconnect bridge wire from terminals 30 and 87/2, See Fig 2 . Check for voltage at terminal 30. If there is no voltage, check fuse and wire between battery and relay. Connect a bridge wire from terminals 30 and 87/2, See Fig 2 . Both pumps should start. If pumps do not start, check wires between relay pumps. If one of the pumps operates, check wiring from fusebox to defective pump. Install a new pump if wiring is OK.
- Measure line pressure, it should be 36 psi. If the Line pressure is too high, then disconnect the wire connected between the fuel pump relay connections 30 and 87/2, See Fig 2 . Disconnect the fuel return line from pressure regulator. Blow through the line. Disconnect vacuum hose from pressure regulator. Blow through the line. If both hoses are free from blockages, regulaor is defective and should be replaced. Re-check pressure after installing new regulator. If the pressure is too low, then pinch the fuel return line w/hand and check pressure increase. It is very important to no allow the pressure to exceed 85 psi. If pressure rises quickly, pumps and fuel lines are OK. Replace the regulator and measure again. If pressure rises slowly, this indicates a blocked fuel filter, tank pump filter or fuel line. If pressure does not rise, fuel pump is defective.
- Check the pressure regulator. Connect a vacuum pump to regulator. Use vacuum pump 5843, or equivalent. See Fig 3 . Pump air out of regulator and check that line pressure drops. Line pressure should drop to same extent as drop in regulator. 36 psi minus vacuum should equal line pressure.
- Switch off fuel pumps. Disconnect wire between terminals 30 and 87/2, See Fig 2 . Connect the connector to the main relay. Reinstall the panel under the dashboard.
- Disconnect pressure gauge 5011. Hold a piece of absorbent paper underneath fuel line to prevent spillage. It is important to know that any plastic fuel line ties must be refitted.