Test Description

The numbers below refer to the step numbers in the diagnostic procedure.

1. 2
   
   This step verifies that the fuel pump is operating.
2. 4
   
   This step verifies that the vehicle is not out of fuel. If the right fuel sender is below 0.8 volt, and the left fuel sender is above 0.8 volt, a fuel transfer condition exists.
3. 7
   
   This step tests for an internal fuel leak. If the fuel pressure drops during this test, then an internal loss of pressure is indicated.
4. 10
   
   This step inspects the fuel pressure regulator for a fuel leak from the atmospheric vent. If fuel leaks from the fuel pressure regulator while the fuel pump is commanded ON, replace the fuel pressure regulator.
5. 11
   
   This step tests for a loss of fuel pressure between the shut-off adapter on the fuel feed pipe and the fuel pump.
6. 12
   
   This step tests for a leaking fuel injector or fuel pressure regulator. If the fuel pressure remains constant during this test, the fuel injectors are not leaking fuel.
7. 15
   
   This step tests for a restricted fuel return pipe. If the fuel pressure is within the specified values, a restriction in the fuel return pipe is indicated.
8. 17
   
   This step determines if the fuel pressure regulator, or the fuel pump, is the cause of the low fuel pressure. If the pressure rises above the specified value, the fuel pump is OK.
9. 21
   
   This step verifies that a circuit condition is not the cause of a fuel pressure concern. Inspect all fuel pump electrical circuits thoroughly.