Ciera V6-231 3.8L (1986)
Fuel Routing
TEST DESCRIPTION:
Numbers below refer to circled numbers on the diagnostic chart.
1.
Pressure but less than 37 psi (255 kPa) falls into two areas:
a. Regulated pressure but less than 37 psi. Amount of fuel to injectors OK but, pressure is too low. System will be lean running and may set
Code 44. Also, hard starting cold and overall poor performance.
b. Restricted flow causing pressure drop - normally, a vehicle with a fuel pressure of less than 24 psi (165 kPa) at idle will not be driveable.
However, if the pressure drop occurs only while driving, the engine will normally surge then stop as pressure begins to drop rapidly.
2.
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 (517 kPa).
3.
This test determines if the high fuel pressure is due to a restricted fuel return line or a pressure regulator problem.