Restricted Fuel Flow
- Normally, a vehicle with a fuel pressure of less than 24 psi (1.7 kg/cm2 ) at idle will not be driveable. However, if the pressure drop occurs only while driving, the engine will normally surge and then stop as pressure begins to drop rapidly.
- Restricting the fuel return line allows the fuel pump to develop its maximum pressure (dead head pressure). When battery voltage is applied to the pump test terminal, pressure should be above 75 psi (5.3 kg/cm2 ). Test system to determine if the high fuel pressure is due to a restricted fuel return line or a pressure regulator problem.