Download 1. Connect Rotunda High Fuel Pressure Adapter 014-00931-3 or equivalent to the Schrader valve mounted in the fuel regulator block on the side of the fuel filter housing. 2. Connect a line for a 160 psi gauge to the adapter 3. Run the engine at low idle and check for leaks in the gauge. 4. Operate the engine at high idle (maximum engine speed out of gear with brake set and wheels blocked). 5. Fuel pressure should be at least 30-70 psi . 6. Repeat this test for both front and rear tanks. 7. If fuel pressure is low, replace fuel filter and repeat this test.