Bosch Secondary Fuel Filter Pressure Test Diagram

Pressure tester gauge connected between the secondary fuel filters and the injection pump inlet: 1, fuel filter housing; 2, transfer pump; 3, tester.

Refer to Figure above and disconnect the fuel line between the outlet side of the secondary fuel filter(s) and the inlet side of the fuel injection pump. Insert a special pressure gauge or, alternatively, a fuel pressure gauge and clear plastic line between the filters and injection pump as shown in Figure above.