Check the fuel filter restriction by measuring the pressure drop across the fuel filter using the following steps.
NOTE: The fuel inlet and outlet are labeled on the fuel filter head using text or arrows. Figures do not necessarily display the true orientation of the inlet or outlet of the fuel filter.
Fuel Pressure (Filter In)
Install an M10 male CompuchekTM fitting, Part Number 3824842, to the diagnostic port on the inlet side of the fuel
filter.
NOTE: The fuel filter head mounting capscrews may need to be loosened in order to center the test ports for
attaching to the CompuchekTM fitting.
Connect a fuel pressure gauge to the CompuchekTM fitting.
Measure the fuel pressure at low idle.
Record the fuel filter inlet pressure measured.
If the fuel pressure is below the minimum at the inlet side of the filter, perform the following checks.
โข Check for a high fuel inlet restriction. Refer to Procedure 006-020 in Section 6.
โข Check for air in fuel. Refer to Procedure 006-003 in Section 6.
โข Check for a damaged gear pump. Refer to Procedure 005-016 in Section 5.
Fuel Pressure (Filter Out)
NOTE: The fuel inlet and outlet are labeled on the fuel filter head using text or arrows. Figures do not necessarily
display the true orientation of the inlet or outlet of the fuel filter.
Install an M1 0 male CompuchekTM fitting, Part Number 3824842, to the diagnostic port on the outlet side of the
fuel filter.
Connect a fuel pressure gauge to the CompuchekTM fitting.
Measure the fuel pressure at low idle.
Record the fuel filter outlet pressure value and subtract it from the previously measured fuel filter inlet pressure.
If the pressure drop is greater than the specified value, the fuel filter must be replaced.
